Note: Descriptions are shown in the official language in which they were submitted.
CA 02284488 1999-10-06
Whipstock Apparatus and Methods of Use
Technical Field
The present invention relates to oil and gas drilling equipment and more
specifically
relates to an apparatus and method for drilling deviated holes from an
existing wellbore.
s Background Art
At times it is desirable to sidetrack (deviate) existing wellbores for various
reasons
in producing a more econ~umical wellbore. It is well known in the oil and gas
industry that
whipstocks are used in drilling to direct or deviate a drill bit or cutter at
an angle from a
wellbore. The wellbore c,an be cased (lined with pipe) or uncased (open hole;
not lined with
to pipe). It has been customary to follow plug and abandonment (P&A)
procedures when using
a whipstock. These P&~~ procedures vary as to cased or uncased wellbores. Most
P&A
procedures follow OCS guidelines as the operator does not want communication
between the
"old" wellbore and the "new" bore. OCS guidelines would not be followed where
the
operator is drilling additional "drain" bores in an existing well. For the
cased wellbore, the
rs operator will set a cement plug in the wellbore, about 30 meters [100']
thick at a minimum,
followed by a bridge plug; or EZ-drill plug. The bridge plug is a wire line
device which is
set 0.9 meters [3'] to 1.5 meters [5'] above the casing collar (or joint) near
the required point
that deviation of the went>ore is needed. The position of the bridge plug and
the whipstock
is critical because the deviated hole must NOT penetrate the casing at or near
a casing collar
zo (or joint). The whipstock is traditionally set about one meter [3'] above
the bridge plug.
Great care is exercised tn coordinate wire line and pipe measurements to
assure that the
whipstock is clear of the easing collar (or joint). In an uncased hole, only a
cement plug of
the proper length is used. The length of the plug is determined by the depth
of the uncased
hole to the point at which the deviation is required. The downhole tool is
traditionally set
as above the cement plug.
The complete downhole assembly generally consists of the whipstock assembly
attached to some form of packer assembly. There are presently two conventional
whipstock
types available, the "Pachstock" and the "Bottom Trip". The Packstock is a
whipstock and
a packer assembly that is combined to form a single downhole unit. The bottom
trip device
3o is a single whipstock wit~c a plunger, sticking out of the bottom of the
downhole tool, which
when set down on the bottom of t:he hole, will release a spring loaded slip or
wedge within
the whipstock which in turn holds the tool in place. The whipstock is the
actual oil-tool that
CA 02284488 1999-10-06
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causes the drill bit or cutter to deviate from the wellbore. The packer is
another oil-tool that
holds the whipstock in place once the whipstock has been set in the wellbore
at the desired
orientation. This packer is given the name anchor packer and it is this packer
that rests
above the bridge plug in a cased hole and above the cement plug in an uncased
hole. In the
s case of the bottom trip whipstock, it is the bridge plug that forces the
plunger to release the
spring loaded slips or wedges, thus holding the tool in place. It should be
apparent that there
are two fundamental types of packer in use; the first operates in a cased hole
and the second
operates in an uncased hole. The bottom trip device operates only in a cased
hole; it is an
old device; and, it is fraught with problems because it has only a single slip
or wedge which
to can work loose.
The whipstock is a triangularly shaped tool about 3 meters [10'] to 3.7 meters
[12']
long. It is slightly less then the diameter of the wellbore at its bottom and
slopes so that its
diameter approaches infinitely at its top. The back of the tool usually rests
against the low
side of the wellbore, where the low side of the wellbore is defined as that
side of the hole
Is most affected by gravity. The tool face is cup-shaped and guides the hole
drilling equipment
off to the side of the hole in the direction set by the orientation of the
tool face. The bottom
of the tool is attached to t:he packer.
Traditionally the whipstock must be chosen for each wellbore so that its
bottom
diameter matches the wel:lbore and the packer, if used. Its top end must match
the inside
ao diameter of the wellbore so that the. drilling equipment sees a smooth
transition off to the side
of the hole; and the back of the tool should match the internal diameter of
the wellbore. In
addition the cupped face of the tool has been chosen to match the bore size in
order to
properly guide the drilling; equipment. This means that the oil or gas field
operator must
keep a stock of different whipstocks to match the various standard wellbores
used in the
as industry. Wellbore standards are traditionally given in the British or US
system of units.
Approximate conversions t:o metric units are used throughout this disclosure
with the industry
standard found in square brackets.
This invention standardizes the whipstock tool to three varieties to fit hole
sizes from
9.53 centimeters [3 3/ "] uI> to 31.75 centimeters [ 121/z "] . The invention
proposes one style
30 of whipstock for use with both mechanically set packers and hydraulically
set packers. And
finally, the invention proposes an apparatus and method for retrieval of the
valuable and
expensive downhole assembly after the deviated hole is completed. This
retrievable
whipstock would be invaluable in multiple drain holes in a single wellbore and
would be used
CA 02284488 1999-10-06
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in both cased and open hole (uncased) conditions.
The whipstock has passed through two generations of tool since its
introduction in the
early nineteen-thirties. The initial apparatus and method of use involved a
multi-step
procedure. Standard P&A procedures were followed prior to the use of the tool;
i.e., the
s wellbore was properly plugged below the desired deviation point. An anchor
packer was
then set in the hole in order to support and maintain the orientation of the
whipstock. The
packer had a key slot in its bottom which would mate with a "stinger" on the
whipstock.
Wireline tools would be run into the hole to determine the orientation of the
key slot and the
stinger on the whipstock would be adjusted to match the packer key slot so
that when the
to whipstock was run into the: hole, the whipstock would orientate itself in
the correct direction.
This procedure required multiple runs into and out of the wellbore and was
fraught with risk.
After the whipstock was "set", a starting mill tool would be run into the
wellbore to remove
attachment points on the face of the whipstock, cut into the side of a cased
hole, and
generally prepare the well.bore for a deviated hole. The starting mill tool is
used for about
Is the first one-half meter [20"] of hole. These same procedures are followed
in the next
generation tool and will be explained later.
The next generation (second), which is the presently used technique, mated the
whipstock to the anchor packer. 'The combination of the whipstock and the
anchor packer
is attached to the drill stem using a shear pin which in turn is attached to a
raised face
ao attachment point, known ass the shear pin block, mounted on the face of the
whipstock. The
downhole assembly is lowered into the wellbore until it touches bottom.
(Bottom would be
defined as the bridge plug in a cased hole and the cement plug in an uncased
hole.) The
assembly is then raised slightly and the orientation of the whipstock is
checked using wireline
tools. The drill stem is rotated one way or another and the orientation is
checked again.
as This procedure is continued until the face of the whipstock is properly
orientated. The
anchor packer is then "set" in the wellbore.
There are two ty~?es of packer, mechanical set and hydraulic set. The most
commonly used packer is the hydraulically set packer. U.S. Patent 5,193,620
(Braddick)
discloses a whipstock setting apparatus and method for a mechanical packer.
Mechanical
3o packers are "set" by applying weight to the packer which, in turn, causes
the packer slips
to extend against the wellbore, thus locking (or setting) the packer in place.
This is similar
to the bottom set whipstoc;k device in that there is a plunger extending from
the bottom of
the packer; however, spring loaded slips are not used as in the bottom set
whipstock. One
CA 02284488 1999-10-06
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other difference, the bottom set whipstock will not have any packing or
resilient material that
expands against the hole to seal the lower hole section.
U.S. Patent 4,397,355 (McLamore) discloses a whipstock setting method and
apparatus for a hydraulic ~~acker. Hydraulic packers are "set" by applying
hydraulic pressure
s to the packer which, in turn, causes the packer slips to extend against the
wellbore, thus
locking (or setting) the packer in place. The hydraulic pressure is obtained
through a device
called a "running tool". 'The running tool converts the drill stem mud
pressure to hydraulic
pressure; the hydraulic oil being run from the running tool to the hydraulic
packer through
tubing to the whipstock and then through a series of channels within the
whipstock and onto
zo the packer. The packer is set by pressuring up the drill stem which then
passes that pressure
onto the packer.
Once the packer is "set", the whipstock must be broken free from the drill
stem
before any milling or regular drilling operations may proceed. This is a
simple operation -
the drill stem is raised. The packer, if properly anchored in the wellbore,
will not move
zs and the shear pin will shear. All that remains is to remove the shear pin
block which is
mounted on the face of the whipstock and to cut into the side of the wellbore.
The removal of the shear pin block is undertaken by "milling". In both the
first
generation and initial second generation tool a starter mill bit is placed on
the drill stem and
lowered into the wellbore. The starter mill is rotated and in turn removes the
raised face.
ao This same milling tool makes the initial cut into the side of the casing in
a cased hole. The
initial milling operation makes about a 50.8 cm [20"] deep hole. That is to
say the operator
only runs the starter mill for about one-half meter [20"] total depth before
coming out of the
wellbore and changing his starter mill bit assembly. Once this first mill run
is complete, the
starter mill is replaced with a second and larger mill, known as a window
mill. Another
as mill, known as a water-melon mill, is mounted above the window mill. The
window mill
and water-melon mills operate together to enlarge the deviated opening in the
wellbore so
that regular drilling operarions ma:y pass without restriction. Generally the
window/water-
melon bit combination is used for 2 meters [7'] to 3 meters [10'] into the
deviated hole.
McLamore improved the second generation apparatus and method by placing the
so initial mill assembly on the end of the drill stem immediately above the
whipstock. Thus,
once the whipstock was frf;ed from the drill stem, initial milling could
proceed immediately.
This was certainly an improvement because one trip into and out of the
wellbore was
eliminated; however, the iinitial milling operation can only last about one-
half meter [20"]
CA 02284488 1999-10-06
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before the mill must be removed. This is because the setting tool, that is the
piece of metal
between the mill and the whipstoc;k which holds the whipstock to the drill
stem, will bump
against the casing of a ca~~ed hole and cause the mill to cut into the
whipstock rather than the
casing. This has caused problems in the past because the whipstock face can be
damaged
s or the whipstock can be c;ut into requiring that another complete assembly
be placed in the
hole.
Braddick uses the same initial milling technique as McLamore. Braddick has
other
disadvantages. In a mechanical set packer, the application of sufficient
weight to set the
packer is an absolute necessity. Braddick uses the shear pin between the
setting tool and the
ro whipstock to transfer wei;;ht to the mechanical packer. This means that the
shear pin must
be carefully chosen so that it will transfer drill stem weight to the packer
for setting and yet
be sufficiently weak to shear when the drill stem is pulled upwards. It is
possible for the
packer to move upward a:nd rotate when the stem is pulled out of the hole in
order to shear
the retaining pin because the pin rnay be stronger than the packer retaining
force.
rs A major impediment for the second generation whipstock is the shear pin
block on
the face on the whipstocl~: which must be milled away so that the face becomes
a smooth
cupped face. The shear pin block ranges in size from 2.54 to 3. 81 centimeters
thick [ 1 " -
11/z"], 5.08 to 7.62 centimeters wide [2'/2" - 3"], and 7.62 to 10.16
centimeters long [3" -
4"]. It takes a considerable amount of time to mill this block away after
setting the
ao whipstock. Reports from the field indicate that this block can cause
numerous problems and
often results in several trips with fresh starter mills in order to remove the
shear pin block
and make the initial one-half meter plus or minus [20" ~] starting cut in the
casing (or
formation) .
Second generation. whipstocks have further detriments. One of these further
as detriments is found in the location of the shear pin itself and the fact
that this shear pin can
shear if the downhole assembly is rotated. That is, not only will the pulling
force shear the
pin when shearing of the pin is required, the torsional force which can be
induced when the
whipstock is being rotated in the hole can inadvertently shear the pin. This
inadvertent
shearing is a disaster! 'lf he possibility of inadvertent shearing due to
rotational forces
so becomes very large in a high angle wellbore. Wellbore angle is defined as
angle from
vertical, thus a high angle hole approaches a horizontal bore.
A further detriment for the second generation whipstock occurs in nearly
vertical or
low angle hole. The back of the whipstock must rest against the wellbore and
the whipstock
CA 02284488 1999-10-06
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is designed to pivot about a hinge pin near the bottom of the tool just above
the anchor
packer. In a medium to high angle hole the whipstock easily falls against the
wellbore, but
in a nearly vertical hole there is little gravity component to pull the tool
against the wall.
This can cause some problems during the initial (or starting) mill operation -
that is the
s whipstock chatters against the wellbore. There remains an unfulfilled
requirement to be able
to force the tool against the wellbore in a low angle hole.
The final detriment for second generation whipstocks is that retrieval of the
tool after
use is practically impossible. Retrieval of the tool will be invaluable in
modern production
operations where multiple; drains ~~re desired in a wellbore.
to There are a number of other prior art patents as listed in the following
table that
relate generally to whipst~ocks.
U.S. Patent.Inventor Title Issued
No.
Is
2,362,529 Barren et Side Tracking Apparatus 11/14/44
al.
2,558,227 Yancey et Sidewall Core Taking Apparatus.06/26/51
ail.
2,821,362 Hatcher E;~tensible Whipstock 01/28/58
3,115,935 Hooton Well Device 12/31/63
20 4,765,404Bailey et Whipstock Packer Assembly 08/23/88
al.
5,035,292 Bailey et Whipstock Starter Mill with Pressure Drop
al. Tattletail 07/30/91
5,109,924 Jurgens One Trip Window Cutting Tool and Apparatus
et a.l. 05/05/92
5,113,938 Clayton Whipstock 05/19/92
5,154,231 Bailey et Whipstock Assembly with a Hydraulically
al. Set Anchor 10/13/92
2s
Barren et al. disclose "Side Tracking Apparatus" or a whipstock with roller
bearings
in its face. The roller hearings are meant to force the mill against the
casing. The
whipstock is particularly designed to be used with casing that has hardened
such that
conventional milling techniques would not work - i.e. the mill would probably
mill into the
3o whipstock rather than the casing. This whipstock could be called the first
of the second
generation whipstocks as it has its own set of slips built into the whipstock;
the slips being
set by forcing the whipsto~~k against the bottom of the bore hole. The
whipstock is held to
its mill by a shear pin. The roller bearings run the entire face of the
whipstock. The
whipstock design is somev~rhat different than those used today in that the
whipstock does not
ss have an angled slope to kick the mill into the casing (or side track the
hole) but rather has
a straight offset section that runs the entire length of the desired window.
The whipstock
CA 02284488 1999-10-06
_7_
then has a very sharp slope at the bottom of the whipstock which would act to
shove the mill
to the side. Additionally this disclosure has no method for orientation of the
whipstock.
Yancey et al. disclose a "Sidewall Core Taking Apparatus" which uses a
whipstock
to force a core taker into the side of a wellbore. The device uses a very
sharp angle on the
s whipstock face which requires that the core taker use a set of universal
joints in order to be
able to make the bend towards the side wall. The universal joints must be
guided and the
device provides a set of roller bearings in the face of the whipstock. These
bearings will
also act to improve the mechanical efficiency of the device. It should be
noted that the
milling surface of the core taker does not act on these bearings.
io Hatcher discloses ;gin "Extensible Whipstock" which is retrievable. The
device is not
designed to be orientated in the hole and is set by placing weight on the
whipstock; there is
no releasable device. Once the deviated hole is drilled, the whipstock will be
withdrawn
from the hole with the removal of the drill string. There is no anchor packer
associated with
the device and the device can only be used at the bottom of a hole in a rocky
formation into
is which the whipstock can grip with a sharp point. The sharp point is meant
to prevent
rotation of the whipstock during the drilling operation.
Hooton discloses a "Well Device" which is an improvement to the whipstock by
providing a well plug at the bottom of a standard whipstock which can be set
in place "by
hydraulic, pneumatic, explosive or mechanical means. " The disclosure shows an
anchor
zo packer attached to the whipstock which in turn is attached to the drill
stem by a shear pin.
The mechanical setting means is by loaded spring action and not by setting
drill string weight
onto the anchor packer. Also disclosed is a single spring which functions to
force the
whipstock against the wellbore. 'l~he disclosure claims that the single spring
is releasably
held in place, but does not show nor claim the apparatus to accomplish this
function. This
Zs disclosure states that the slhear pin is sheared by applying downward force
to the shear pin;
this method could be used to set a mechanical packer; but, because the shear
pin is broken
by the downward force, there is no method left to check and see if the packer
is properly
secured in the wellbore. (Normally the operator pulls upward, if there is
large movement
in the drill stem, then it is known that the packer did not set. If on the
other hand there is
30 only slight movement - the; natural spring of the string - followed by
jump, then it is known
that the packer is properly set. )
Bailey et al. ('404) disclose a "Whipstock Packer Assembly" which is designed
to be
used with a single trip whipstock assembly and starter mill. This patent is an
improvement
CA 02284488 1999-10-06
_ g _
to the McLamore device.
Bailey et al. ('292) disclose a "Whipstock Starter Mill with Pressure Drop
Tattletail"
which is designed to be used with the single trip whipstock assembly. This
device causes
a pressure drop in the drill string when the starter milling operation has
past a predetermined
s point on the face of the vvhipstock.
Jurgens et al. disclose a "One Trip Window Cutting Tool and Apparatus" which
utilizes a whipstock assembly, a window mill and one or more water melon
mills. The
disclosure also states that the whipstock slope should be between 2 and 3
degrees, but there
is no claim as to a given angle nor a statement as to why such an angle is
disclosed. The
to device uses a "shear pin block" which is milled off by the water melon
mill. Other parts of
the disclosure are similar. if not the same, as all other second generation
whipstocks.
Clayton discloses ;~ "Whipstock" which will allow bore hole deviation from the
low
side of the hole. The whipstock uses two springs to force the whipstock
against the top side
of the hole. The device is designed to operate in conjunction with a hydraulic
packer and
rs the setting tool runs through the; face of the whipstock. The running tool
keeps the
whipstock springs in their compressed position; the springs are released when
the setting tool
is removed. The setting tool also provides hydraulic pressure to the packer
from the running
tool. The setting tool is secured by threads and release of the setting tool
from the whipstock
is accomplished by "a fev~~ right hand rotations to unscrew the setting tool
conduit from the
ao threads."
Bailey et al. ('231) disclose a "Whipstock Assembly with a Hydraulically Set
Anchor"
which uses the traditional whipstock in conjunction with an novel hydraulic
packer. The
hydraulic packer utilizes a better technique to set itself in the wellbore and
will remain so
set upon loss of hydraulic pressure. The patent proposes two methods of
setting the
as assembly, the first being a method for setting the assembly without a
starter mill, thus
requiring a minimum two pass operation. The second calls for setting the
assembly with a
starter mill in place which results in a minimum one pass operation. In
general this patent
is an improvement to previous devices disclosed by Bailey et al.
Thus the prior art has left a number of disadvantages:
30 - it is difficult to use a mechanically set packer, which is cheaper than
the
hydraulic packer.
- the retaining shear pin can inadvertently shear when the whipstock is being
positioned vvithin thc: wellbore.
CA 02284488 1999-10-06
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the raised face of the mounting attachment to the whipstock face (shear
block) must be milled off before any deviation operations can commence.
- the whipstock assembly must be specifically designed to fit the given
dimension; of the wellbore; thus, many sizes must be warehoused.
s - it is easy to mill into the face of the tool during the initial (or start)
milling
operation.
- there is no method of using an MWD (Measurement While Drilling) Tool
to determine whipst:ock orientation; only wireline techniques can presently be
used.
ro In summary, existing whipstocks used with sidetracking (or deviation)
operations are
inflexible as to various wellbore sizes and the different conditions
encountered downhole.
This inflexibility leads to :increased manufacturing costs and added risk of
failure because the
whipstock is extended beyond its design criteria. This invention resolves a
number of
inflexible constraints.
rs
Disclosure of Invention
The whipstock of this invention can be permanent or retrievable and consists
essentially of a setting tool which holds the whipstock assembly to the drill
stem, a deflector
head which attaches to the top of the whipstock body and is sized to the
diameter of the bore,
ao a whipstock body which is available in three size, and an optional bottom
end spacer. There
is no shear pin block on the face of the whipstock that must be milled off;
initial starting
guidance for the window mill is provided by the deflector head. The deflector
head, which
varies between 30.5 cm [l.') and 61 cm [2'] long depending on bore hole size,
is furnished
in hardened steel with optional PC'.D (polycrystaline diamond) inserts. These
inserts serve
as to stop the initial milling operation from cutting into the whipstock and,
as stated, further
force the mill against the ~wellbore. The whipstock body has a retrieval
system centered at
the mid point of the body which will interlock with a special fish hook to
allow for retrieval
of the whipstock, deflector head and anchor packer. The whipstock incorporates
a set of
springs in the hinge which are held in a compressed state until the unit is
set at which time
3o the springs can be released to help hold the back of the whipstock against
the wellbore. The
whipstock body and settin~; tool are; adapted to operate with either a
mechanically set anchor
packer or a hydraulically <,~et anchor packer with the choice being made in
the field.
In addition to provi~3ing for an improved and workable tool, an object of the
invention
CA 02284488 1999-10-06
- 10-
is to minimize required oil tool inventory which is accomplished by using
three body sizes,
20.32 cm [8"], 13.97 cm [51/z"], and 8.89 cm [31/2"], for the whipstock. Thus
three
whipstock bodies can be used for bore holes from 9.53 cm through 31.75 cm [3
3/ " through
121/a "]. The deflector he;~d, which is attached to the top of the whipstock
body and occupies
s at least the topmost three-tenths meter [1'] of the whipstock assembly,
allows for different
bore sizes within the range of the three whipstock bodies. An optional spacer
may be
required at the bottom of the whipstock, below the hinge, to take up the gap
between the
whipstock body and the wellbore.
When the whipstock is used with a mechanically set packer, it is easy to use
MWD
ro (Measurement While Drilling) tools for whipstock tool face orientation. Mud
circulation is
maintained through the port in the running tool that is normally used for
hydraulic oil when
the downhole tool is used with a hydraulically set packer. Of course standard
wire line
orientation techniques are still useable for tool face orientation. MWD is
possible with a
hydraulic packer, but an additional tool incorporating a pinned by pass valve
would be
Is required because the exit port on the running tool would be attached to the
hydraulic system.
The whipstock incorporates a special slot (setting/retrieval slot) in the face
of the tool
which starts just below the deflector head and runs to approximately the mid
point of the
tool. The slot is of varial;~le depth because the tool face has an angle and
the slot is to form
a perpendicular entry into the tool face. The setting tool fits into this slot
and bottoms at the
ao bottom of the slot. The setting tool is held in place by a shear pin
located near the bottom
of the slot, which enters from thc: tool back and is screwed into the setting
tool. Thus,
vertical force can readily be asserted on the tool and anchor. If the force is
in the downward
direction, that force is transferred directly to the tool and anchor. If the
force is upward,
the shear pin must bear th~.e force or fracture. On the other hand, if the
force is torsional,
zs then that torsional force is transferred to walls of the setting slot.
The setting slot also acts as a guide for the retrieval tool. A retrieval slot
is located
slightly above the bottom of the setting slot. The retrieval slot runs from
the front of the
setting slot to the back of the tool and is designed to fit about a hook
located on a specially
designed retrieval tool. 'hhe retrieval tool has an opening in the hook face
which allows
3o drilling fluid to pass through it. Thus MWD tools can be used in
conjunction with the
retrieval tool to help in establishing hook orientation. The hook also has a
spring
loaded/pinned valve which is designed to close when the hook properly engages
the retrieval
slot. Closure of this valve will cause a pressure pulse at the surface which
tells the operator
CA 02284488 1999-10-06
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that the retrieval tool has properly engaged the whipstock. The hook is
further designed so
that it tends to straighten out the whipstock when a pulling force is applied.
A properly
designed whipstock is meant to fall against the "backside" of a wellbore and
if the tool is not
pulled straight, then the top of the tool will catch against each joint in the
casing. The
s retrieval tool helps reduce this problem.
Finally, there is au integral spring loaded shear pin within the retrieval
tool which is
designed to prevent inad~~ertent release of the retrieved whipstock while
reciprocating the
whipstock in order to help it past an obstruction in the wellbore. The spring
loaded shear
pin springs into a matching cavity within the setting/alignment slot within
the tool face of the
to whipstock as the retrieval tool fish-hook properly engages the retrieval
slot. The spring
loaded shear pin prevents independent downward motion between the whipstock
and the
retrieval tool; thus, locking the fish-hook in place. Note that the spring
loaded pin can be
sheared, thus allowing for "controlled releasability".
The further advantage to this design is the "controlled releasability" of the
Retrieving
rs Tool. The spring loaded shear pin will shear and allow the retrieval tool
to disengage from
the whipstock whenever sufficient downward weight is applied to the drill
string. Complete
retrieval is then performed by slacking off the retrieval tool which will back
away from the
retrieval slot because the hook is tapered from its base to its face and then
rotating the drill
string by a quarter turn, thus, turning the hook of the retrieval tool away
from the slot. As
zo the hook initially pulls away from the whipstock, the wash ports) will open
and at the same
the mud circulation pumps can be re-started. The excess mud pressure appearing
at the wash
ports) will be a tremendous aid in releasing the hook from the whipstock.
The method of u~~e is relatively simple. First, one of the three body sizes of
whipstock is chosen to most closely match the wellbore. Second, a deflector
head is chosen
as that matches the wellbore and is secured to the appropriate whipstock.
Third, the proper
sized anchor packer is chosen that most closely matches the wellbore and, if
required, the
optional bottom spacer is bolted to the whipstock body. Finally the running
tools must be
chosen. If the anchor packer is hydraulic, then both a setting tool and an
improved piston
sub are required; however, only the setting tool is required for a mechanical
anchor packer.
so The setting tool is sized to the appropriate whipstock body and the same
tool serves for both
mechanical or hydraulic p<rckers. 'The complete downhole tool is assembled in
the standard
manner on the drill floor/notary table with proper attachment made between the
whipstock
and the setting tool via a shear pin. The downhole tool is then lowered into
the wellbore.
CA 02284488 1999-10-06
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In the case of the mechanically set packer/whipstock downhole tool assembly,
the tool
is lowered into the wellbore until it hits bottom. The drill string is then
raised, as per
standard procedures, and mud circulation started. The circulation allows
orientation signals
from the MWD tool to pass to the surface. The drill string is then manipulated
until the
s proper orientation is obtained. The packer is then set by placing the
required weight on the
downhole assembly. Oric;ntation could be checked immediately after setting by
MWD. The
drill stem is pulled free from the whipstock and the string is returned to the
surface. Note
that standard wireline orientation techniques can still be utilized.
The running tool is replacE;d and a window mill and watermelon mills) run into
the
io hole; there is NO need for a starting mill as there is no shear pin block
to remove from the
face of the whipstock. Standard milling techniques follow and the initial side
track
established. The milling; tools are then removed and regular drilling
operations begun.
Thus, the whipstock invention still results in a two-pass operation as does
the present second
generation device unless the operator wants to enlarge the window beyond that
obtainable
rs with the second pass.
In the case of the hydraulic set packer, the complete downhole tool is
assembled and
attached to its setting tool. The setaing tool is in turn attached to a piston
sub which converts
mud pressure to hydraulic; pressure in order to set the hydraulic packer.
Hydraulic tubing
is run through the channc;ls provided in the whipstock and connected between
the setting
ao tool/running tool assembly and the hydraulic packer. All other installation
details are the
same as presently used in the industry. Note that standard wireline techniques
must be used
for tool face orientation vrith the hydraulic packer. It is possible to use
MWD techniques
to orientate to tool face; however, experience has shown that there are high
failure rates with
pinned by-pass valves (a downhole tool which permits the use of MWD with
hydraulic
as running tools).
Retrieval of the whipstock is relatively straightforward for operators who are
experienced with "fishing techniques. " The retrieval tool is attached to the
bottom of a
downhole string which includes an MWD tool and any required fishing jars. The
drill string
is run into the hole and circulation is maintained. In the area of the
whipstock, the retrieval
3o tool is orientated to closely align with the setting slot which acts as the
tool guide for the
retrieval tool. The mud port in the retrieval hook guides the circulation in
such a manner
that the setting slot and retrieval slot can be flushed clear of any debris
(cuttings, sand, etc.)
that could interfere with the retrieval operation. The drill string is then
lowered until it
CA 02284488 1999-10-06
-13-
"bottoms"; the drill string; is then raised which causes the hook to pull into
the retrieval slot.
As soon as proper engagement is made with the retrieval slot, the mud port
valves) close,
which sends) a pressure pulse to the surface announcing engagement of the
retrieval slot.
At almost the same time, the spring loaded shear pin will latch the retrieval
tool into the
s whipstock. Mud circulation should cease and the drill string raised to set
the retrieval tool
into the retrieval slot. Note that the spring loaded shear pin which locks
into the face of the
setting slot can be used a.s a landing point in order to "reset" any fishing
jars that may be
included in the downhole retrieval assembly. The weight required to shear this
locking pin
is much higher than the weight needed to re-set the fishing jars; thus,
"controlled
ro releasability" is maintained.
As the drill string is raised.. the pulling force should increase. An increase
in pulling
force is a second indication of engagement. With the retrieval tool properly
engaged and as
the tool is pulled upward, the hook will move further back into the retrieval
slot and pull the
whipstock tool face into alignment with the whipstock base and anchor.
Additionally, the
rs extra length of the hook will extend beyond the whipstock back assuring
that the tool top will
not rub against the wellbore. This means that the chances of the tool top (or
head) catching
against each and every ca;~ing joint are substantially reduced. The optional
fishing jars can
be reset as needed in order to assist in the retrieval of the whipstock.
The anchor packer used with a retrievable whipstock, be it mechanically set or
ao hydraulically set, is chosen so that: it incorporates shear screws in the
upper set of slips (or
wedges). As the whipstock/packe.r is raised, the pulling force will increase
and shear the
upper slip shear screws. 'This releases the upper slips on the anchor packer
and the packer
can now move upward. As the packer moves upwards, the packing will collapse as
the
packer extends against the bottom set of slips, which should release. It
should be noted that
as the lower set of slips on a packer are designed to grip in the downward
direction; thus, if
the lower slips do not release, the packer can still be pulled out of the
wellbore. The entire
whipstock/packer assembly is now free to be withdrawn from the wellbore and a
standard
trip operation now follows.
It should be noted a. setting slot and, if necessary, a retrieval slot can be
manufactured
so or placed in the tool face of existing whipstocks. In fact existing
warehouse stock could be
modified in the field to incorporate a setting slot and a retrieval slot. This
would allow the
techniques described above; to be used with second generation whipstocks. This
concept will
be discussed at a later time.
CA 02284488 1999-10-06
- 14-
Brief Description of Drawings
Figure 1 is an elevational view of the WHIP-ANCHOR used with a mechanical
packer
whose OD is approximately the same as the WHIP-ANCHOR.
Figures lAA through lEE are cross-sectional views of the WHIP-ANCHOR taken at
s the lines indicated in the main figure
Figures lA through lE are cross-sectional views of the WHIP-ANCHOR taken at
the
lines indicated in the main figure showing the prior art.
Figure 2 is an elevational vie;w of the WHIP-ANCHOR used with a hydraulic
packer
whose OD is larger than the WHIP-ANCHOR. This figure serves to illustrate
to a variant of the WHIP-ANCHOR system which uses the optional spacer.
Figures 2AA through 2FF are cross-sectional views of the WHIP-ANCHOR taken at
the
lines indicated in the main figure
Figures 2A through ;?F are cross-sectional views of the WHIP-ANCHOR taken at
the
lines indicated in the main figure showing the prior art.
Is Figure 3 is a frontal elevational view of the WHIP-ANCHOR system looking
directly
at the tool face and used with a mechanical packer whose OD is larger than the
WHIP-ANCHOR. The illustration shows the prior art profile.
Figures 4A through ~GD show a series of views the deflector head used on the
WHIP-
ANCHOR system.
zo Figures SA through .'iC show a series of views of the WHIP-ANCHOR hinge,
hinge
pin, hinge springs, and spring retainer shear pin.
Figures 6A through 6~C show the details of the optional spacer block.
Figure 7 is a side elevationa.l view of the WHIP-ANCHOR system attached to its
respective variant of the Mechanical Setting Tool.
as Figure 8 is a side elevational view of the WHIP-ANCHOR system attached to
its
respective variant of the Hydraulic Setting Tool.
Figure 9 gives details of attachment of the Setting Tool to the WHIP-ANCHOR.
Figure 9A is a cross-sectional view of the Setting Tool within the WHIP-ANCHOR
setting slot taken at AA in Figure 9.
3o Figures l0A and 10>3~ show construction details for the preferred
embodiment of the
setting tool using a setting bar and tubular welded to a top sub.
Figures lOC and l0I) show construction details for an alternate embodiment of
the
setting tool using a setting bar welded to a top sub with space for attachment
of
CA 02284488 1999-10-06
- 1$ -
a hydraulic hose.
Figure 11A is a front view crf the lower portion of the setting slot giving
the location
of the retrieval slot.
Figure 11B is a side: sectional view of the lower portion of the setting slot
shown in
s Figure 11A.
Figure 11C is a side: sectional view of the setting and retrieval slot shown
with the
retrieval tool latched in place.
Figure 12A is a side sectional view of the First Embodiment of the lower
section of the
retrieval tool.
to Figure 12AA is a cross section of the First Embodiment of the retrieval
tool taken at
AA/AA in Figure 12A.
Figure 12B is a side sectional view of the Second Embodiment of the lower
section of
the retrieval tool.
Figure 12BB is a cross section of the Second Embodiment of the retrieval tool
taken at
rs BB/BB in Figure 12B.
Figure 12C is a cross sectional view of the Piston Sleeve Valve to be used
with the
Retrieval Tool of Figure 12A or Figure 12B and illustrates the preferred
positive
retrieval tool engagement indicator.
Figure 12CC is a section vif:w of the Piston and Surrounding Spring of the
Piston
ao Sleeve Valve taken at CC in Figure 12C.
Figure 12D is a frontal view of the hook face of the retrieval tool taken at
C/C in
Figure 12A or Figure 12B.
Figure 13A illustrate; a first alternate to a positive retrieval tool
engagement indicator
which is shown on a tool using the First Embodiment of the lower section of
the
zs retrieval tool.
Figure 13B illustrates a second alternate to a positive retrieval tool
engagement indicator
which is shown on a tool using the Second Embodiment of the lower section of
the retrieval tool.
Figure 14A shows the: preferred embodiment of the retrieval tool latching
mechanism
3o with the retrieval latch pin in the body of the whipstock and the receiving
slot
in the body of the retrieval tool.
Figure 14B shows an alternate embodiment of the retrieval tool latching
mechanism with
the retrieval latch pin in the body of the retrieval tool and the receiving
slot in
CA 02284488 1999-10-06
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the body of the whipstock (the reverse of Figure 12A).
Figure 15A shows the retrieval tool near the top of the WHIP-ANCHOR about to
be
orientated to scrub the setting slot.
Figure 15B shows the retrieval tool with its hook face facing the setting slot
at the
s beginning of the scrub of the setting slot.
Figure 15C shows the retrieval tool near the bottom of the setting slot
immediately prior
to bottoming out on the base of the slot and prior to pulling up to engage the
retrieval slot.
Figure 15D shows the retrieval tool fully engaged in the retrieval slot,
retrieval latching
ro mechanism aligned and latched, and with the hook extending through the back
of the WHIP--ANCHOR thus drawing the back of the WHIP-ANCHOR away
from the wellbore.
Figures 16 through 1!~ show details for the setting tool showing how one tool
is used for
both mechanical and hydraulic operations. Figures 16 and 17 show the First (or
rs Preferred) Err~bodiment of the setting tool, whereas Figures 18 and 19 show
the
Second (or Alternate) Embodiment of the setting tool, both respectively used
for
setting Mechanical and Hydraulic Packers.
Figure 20 shows details for the making up of the running arrangement for the
WHIP-
ANCHOR with a mechanical packer which includes the setting tool, MWD, etc.
ao Figure 21 shows details for the making up of the running arrangement for
the WHIP-
ANCHOR with a hydraulic packer which includes the setting tool, the standard
wireline orientation sub, etc.
Figure 22 shows details for the making up of an alternative running
arrangement for the
WHIP-ANCHOR with a hydraulic packer which includes the setting tool, MWD,
as a pinned by-pass sub, etc.
Figures 23 and 24 show the drill stem, setting tool, and downhole assembly in
place in
a wellbore before shearing the shear pin for a Mechanical and Hydraulic Packer
respectively.
Figures 23A and 24A show the respective prior art.
3o Figures 25 and 26 show the drill stem, setting tool, and downhole assembly
in place in
a wellbore after shearing the shear pin at the end of the first pass for a
Mechanical and Hydraulic Packer respectively.
Figures 25A and 26A show th.e respective prior art.
CA 02284488 1999-10-06
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Figure 27 shows thf: complete milling assembly at the beginning of the second
pass
operation in a cased wellbore for either a Mechanical and Hydraulic Packer
respectively.
Figures 27A and 2713 show the prior art.
s Figure 28 shows the complete milling assembly at the end of the second pass
operation
illustrating the open window in a cased wellbore for either a Mechanical and
Hydraulic Packer respectively.
Figure 29 shows a cross section of a "Sub with Piston" Bottom Hole Assembly
(BHA)
running tool which is used in the preferred method for setting a WHIP
ro ANCHOR with a hydraulic packer.
Figure 30A is an enlarged view of the Piston of Figure 29.
Figure 30B is a bottom view of the Piston of Figure 29.
Figure 31 illustrates a proposed Bottom Hole Assembly (BHA) assembly for use
with
the retrieval t~~ol.
Is Figure 31A illustrates the alternate make up if an orientation sub is used
in the place of
and MWD tool.
Figure 32 illustrates an alternate embodiment for the setting tool and setting
slot which
considers problems raised if the strength of material becomes a factor.
ao
Modes for Carrying Out the Invention
The present invention will be described in detail in what is termed as a two
pass
operation in which the whipstock (the item of the invention) and an anchor
packer (be it a
hydraulically or mechanically set packer) are releasably secured to a setting
tool and any
as other required tools, all of which are in turn, connected to a drill
string. The entire
downhole whipstock and anchor-packer assembly will be referred to as a Whip
Anchor in
this discussion.
A two pass operation begins when the drill string, with the Whip-Anchor
attached via
a setting tool, is lowered tn the desired level in a wellbore and then
manipulated and so that
3o the whipstock faces in the desired direction. The drill string is then
further manipulated to
set the anchor packer which in turn holds the whipstock in the desired
orientation in the
wellbore. Once the packer is properly set the drill string is freed from the
Whip-Anchor by
pulling upward on the drill string. The drill string is withdrawn from the
hole; thus,
CA 02284488 1999-10-06
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completing the first pass.
In a cased hole, a window and watermelon mill assembly is then placed on the
drill
string and the drill string lowered into the wellbore for the second pass
operation. (Note that
the window and watermelon mill assembly generally consists of a single window
mill and
s one or more watermelon mills.) The drill string is then used to cut a window
in the casing
for drilling the wellbore in a deviated direction. Once the window is complete
the drill
string is withdrawn from the hole thus completing the second pass. If the
wellbore is open
hole or uncased, the second pass may be omitted and regular deviated hole
drilling may be
commenced. All of thesc; procedures are well known in the art and the main
discussion of
ro this invention will center about its use in cased holes. It should be
understood that this
discussion does not serve to limit the use of the invention in cased holes;
but only serves to
aid in the description of the device: and method where needed comments will be
made about
the apparatus and its use in open hole.
In discussing multiple pass operations for setting the prior art whipstock or
the instant
Is invention, it must be realiized that, although preparation of the bore hole
is critical, proper
preparation of the bore hole is NOT considered to be a part of the setting
operation for a
whipstock. The wellbore: must be clean and free from any and all obstructions
and hole
conditions must be known. (That is: size of casing, if cased; type of cement;
where cement
is; formation type; etc.) 'the term. "hole conditions" is a term well used in
the art and also
zo refers to the ability to circulate drilling fluids in the wellbore.
Part of the preparation for setting a whipstock involves making a trip into
the
wellbore with a full gauge taper mill plus two full gauge watermelon mills (a
so called
"locked up bottom hole assembly") to below the point of planned sidetrack. A
"trip" is a
term of art which describes entering a bore hole with a drill string and
exiting the bore hole,
as although the term can be used for a "one-way trip". Once the bottom hole
assembly is below
the planned point, drilling fluid is circulated until the hole is clean. A
"clean hole" is readily
determined by those skillf;d in the art of wellbore drilling by observing
circulation rates,
pump horse power requirements, mud plasticity (rheology), net weight on bit,
as the bottom
hole assembly is lowered and raised in the hole, etc. If the hole conditions
do not allow free
so movement (reciprocation) of the drill string and bottom hole assembly, then
the planned
setting of the whipstock should be <~bandoned. Those skilled in the art of
setting whipstocks
know that running a whipstock/packer assembly into a wellbore with unknown
conditions is
foolish and dangerous.
CA 02284488 1999-10-06
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Wellbores are notorious for collapsing, for having highly twisted conduits,
and other
myriad problems. Thus, when the actual whipstock is run into the wellbore, it
is often
necessary to rotate the whipstock/anchor assembly and reciprocate that
assembly. The same
may be said when a whipstock is retrieved from a wellbore; thus, the retrieval
tool must be
s capable of retaining the whipstock/packer assembly during reciprocation of
the drill string.
The current technique of mounting the whipstock to the drill string via a
shear pin and
shear block does not prevent torsional shear on the pin, nor does the method
allow for large
downward exertion of force on the whipstock; thus, the shear pin can shear
when it should
not! This invention resolves these problems; however, it does not resolve the
upward
ro exertion of force because the shear pin must shear at a given force which
may be less than
the force needed to free a stuck whipstock. The mere fact that increased
downward force
is available could save a wellbore if the whipstock becomes stuck. This is
because the stuck
whipstock can be forced t:o the point of deviation, orientated and used: or
the stuck whip-
stock could be forced below the point of deviation and abandoned.
rs In sidetracking wellbores, the deviation to the new well path must be
established from
the old wellbore. This c:an be accomplished by setting the present art
whipstock/packer
assembly and proceeding through a series of milling operations. The amount of
deviation
of the new well path from the old wellbore path is limited by the strength of
materials from
which the mill bodies are made, when using rotary drilling techniques to
sidetrack the old
zo wellbore. These mill bodies can only withstand a certain amount of bending
(or flexing)
stress before they fracture. Experience has shown that:
8.57 cm [33/s"] OI) mill bodies which are used on hole sizes from 9.53 cm [3
3/ "]
OD to 13.34 cm [5',/ "] OD will safely withstand a maximum of 2.5 degrees
of deflection per 30 meters [100'] whist milling;
as 12.07 cm [43/ "] O:D mill bodies which are used on holes sizes from 13.74
cm [51/ "]
OD to 20 cm [7~/s"] OD will safely withstand a maximum of 3 degrees of
deflection per 30 meters [100'] whist milling;
16.51 cm [61/z "] OD mill bodies which are used on holes sizes from 20 cm
[7~/s"] OD
to 24.13 cm [91/2 "] OD will safely withstand a maximum of 6 degrees of
so deflection per 30 meters [100'] whist milling; and,
20.32 cm [8"] OD mill bodies which are used on holes sizes from 24.13 cm
[91/z, "]
OD to 31.7 > cm [121/2 "] OD will safely withstand a maximum of 12 degrees
of deflection per 30 meters [100'] whist milling.
CA 02284488 1999-10-06
-20-
Thus, current whipstock manufacaures adjust the Tool Face slope to meet these
criteria;
however, each sized whipstock has its own particular slope and body size. When
a
whipstock is set in a wellbore, it is centered within that wellbore. The hinge
in a whipstock
allows the centered whipstock to drop or fall against the wellbore so that the
top has no gap
s and the mill "sees" a continuous surface that is properly deflected at the
correct slope.
The inventor has noted that the "effective tool face slope" will increase
whenever the
tool drops against the back of the wellbore. Advantage of this fact can be
taken by
proposing three (or more) Whip-,Anchor types. For example, in an 20.96 cm [81/
"] ID
bore, with a Whip-Anchor having a 20.32 cm [8"] OD body and having a tool face
slope of
l0 3.18 degrees, the effecti~~e tool face slope will increase to about 3.28
degrees. This is
because the back of the tool falls against the wellbore thus increasing the
deflection angle.
The resulting "effective tool face angle" is well within the constraints
listed above. In a
similar manner, in a 31.75' cm [12'.h"] ID bore using a Whip-Anchor having a
20.32 cm [8"]
OD the effective tool face angle will increase to about 4.07 degrees. But
again, this effective
is angle is well within the above listed constraints.
Similar examples c:an be stated for other sizes of wellbore and the inventor
proposes
that three types (or sizes) of Whip-Anchor will safely and effectively operate
in common
wellbores sized from 9.53 cm [33/ "] to 31.75 cm [121h"]. This concept could
readily be
extended to larger (or smaller) bore sizes and the choice of three types of
Whip-Anchor
zo should not be taken as a limitation on the invention. These three types
will cover the most
commonly encountered we;llbores in the industry and will serve to reduce
inventory stock of
whipstocks. With all these; points in mind the instant invention, which is a
series of singular
small inventions and impr~wements forming a workable downhole tool, will be
described.
Attention is first directed to Figure l, Figure 2, and Figure 3 of the
drawings which
as illustrate the instant invention as it would appear prior to being placed
inside a wellbore.
Figures 1 and 2 show a side elevational view and a series of cross-sectional
views of the
main part of the instant invention, namely the improved whipstock mounted to a
mechanical
packer (Figure 1) and to a hydraulic packer (Figure 2). There is little
difference between
the two Whip-Anchors in Figures 1 and 2 as regards the whipstock. Very little
discussion
30 of the packer will be undertaken since it does not form a part of this
invention; however, the
type of packer used does affect the "plumbing" of the instant invention and
the make-up of
the tools used to manipulate the Whip-Anchor. Figure 3, on the other hand,
shows a front
elevational view of the tool attached to a mechanical packer which is the
simplest
CA 02284488 1999-10-06
-21-
embodiment of the instant invention.
The invention, as previously stated is a series of inventions which make up a
complete
system (apparatus) and a series of methods for setting and retrieving Whip-
Anchors. The
system is made up of:
s
A deflector head,
A whipstoc;k body with a spring hinge section,
An optional spacer,
A crass-over sub, and
io A mechanical packer, and
A mechanical setting tool, or
A hydraulic packer, and
A hydraulic setting tool, and
an improved piston sub, or
is A retrieving tool, plus
Other necessary (existing) drill string tools.
Starting with Figure 1 and Figure 3, which illustrate the instant invention in
its
simplest embodiment, the: top of the tool body, 4, is shown with its deflector
head, 7, in
ao place. The deflector head is further illustrated in Figures 4A-D and will
be discussed in
detail later. The deflector head, 7, is mounted to its whipstock body, 4. Both
the deflector
head and the whipstock body must be chosen to fit the particular wellbore
size, 30. Figures
lAA through lEE (as well as 2AA through 2FF) show cross-sectional views of the
whipstock
body; the equivalent prior art cross-sectional views are shown on the left-
hand side of the
zs illustration. The difference between the prior art and the instant
invention are clearly
illustrated. In the prior art the cupped or curved face, 11, of the whipstock
ran completely
from one side of the wellbore to the other side; the inventor has discovered
that this complete
cupped face is not necessary and that a shortened version as shown in the
cross-sectional
views will suffice. On the other hand the deflector head, 7, must run from
side to side of
so the wellbore in order to deflect the window mill to the side of the
wellbore. Once the
window mill has started i1a cut into the wellbore side, it need only be guided
by the partial
cupped face of the instant invention. The fulcrum effect of the drill string
will also aid in
directing the window mill to the side of the wellbore.
CA 02284488 1999-10-06
-22-
This discovery further means that a single whipstock body can serve in a
number of
different sized wellbores which is completely different from the prior art in
which a
whipstock body could only be usE;d in a given bore size for which the body was
designed.
Thus, the inventor contemplates three types (or sizes) of whipstock bodies as
given in the
s table below, which will operate in wellbores from 9.53 cm [33/ "] to 31.75
cm [121h"]. It
should be noted that the given sizes of wellbore are in common use and these
sizes are not
intended to act as a limiti~tion on the invention, as the concept could easily
be extended to
smaller or larger bores by the simple expedient of changing the size of the
body. In a
similar manner additional body sizes could be inserted in the table so that
the optional spacer,
io to be discussed, would become unnecessary. The actual whipstock body would
be
manufactured using current materials and techniques. A mild steel will be
used; however,
the tool face should have a hardened surface formed from Tungsten Carbide to
resist wear.
The finishing technique goes by such trade names as "Clusterite" or "Zitcoloy"
. These are
proprietary and well established wf:lding techniques for placing a hard finish
on a surface that
rs will resist wear.
WHIP-ANCHOR TYPE (oR
slzE) AND PARAMETERS
Type Bode Size Fits Bore Fits CasingTool Face
Size Size
Whipstock cm CentimetersCentimetersAngle Curvature
20
I 8.F~9 9.53-13.9711.43-16.832.09 13.97
II 13.!7 4..61-20.3217.78-21.912.62 20.32
III 20.:32 20.96-31.7524.45-33.973.18 31.75
C othf;r as needed
2s
METRIC
TABLE
1
As a specific example of whipstock configuration consider that the operator is
cutting
a 21.59 cm [81h "] window and drilling a new well path from 70.09 kg/m [47
pounds per
3o foot] 24.45 cm [95/s"] cas ing. The deflector head must match the ID of the
24.45 cm [95/s"]
casing and its tool face must match the 21.59 cm [81/z "] window mill. This
deflector would
be mounted on a Type III whipstock whose back face will have a curvature of
21.59 cm
[81h "] and whose tool face: will have a curvature of 31.75 cm [121h "] with a
tool slope angle
of 3.18°. These dimensions are given for example only and are not to be
considered a
3s limitation on this invention.
The deflector head, shown in Figures 4A - 4D, must be sized to fit the bore of
the
wellbore. The object of the deflector head is to "shove" the initial window
mill into the side
of the bore. It has been noted that the initial milling operation places
severe wear on the top
CA 02284488 1999-10-06
-23-
section of a whipstock. 'Thus, the deflector head is made of hardened steel
with optional
PCD (polycrystaline diamond - industrial diamond) inserts in the face of the
head, 51. The
deflector head length, 58, ranges yin length from about 0.3 meters [1'] to
about 0.61 meters
[2']; the actual length being determined by the bore size. For example in a
8.89 cm [31/2 "]
s bore size, the head should be about 0.3 meters [1'] long; whereas in a 31.75
cm [121/2"] bore
size the head should be about 0.61. meters [2'] long. The back of the
deflector head, 57, is
shaped to match the bore. That is, the back of the head will lie "flat"
against the curved
surface of the bore. The heading edge, 50, of the head is about 1.6
millimeters [1/16"] thick
and matches the bore at its backside.
ro Starting from the leading edge and running down to the joint, 52, between
the
deflector head and the whipstock body, the tool face slopes outward from its
back, forming
a cupped surface with a tool face slope ranging from about two degrees
(2°) to about 4
degrees (4°). The actual tool face slope will depend on the bore size,
the deflector head
length, and the whipstock body tool face angle. For example, the deflector
head would have
rs a tool face angle chosen t~o match the 2.09° angle found in the Type
I whipstock, the 2.62°
angle found in the Type I f whipstock, and the 3.18 ° angle found in
the Type III whipstock.
As a specific example of deflector head configuration, if the operator is
cutting a
21.59 cm [81/2 "] window .and drilling a new well path from 70.09 kg/m [47
pounds per foot]
ao 24.45 cm [95/s"] casing, then the deflector head back would have curvature
to match the ID
of the 24.45 cm [95/s"] caging, namely 22.05 cm [8.681 "], the deflector head
tool face would
have 21.59 cm [81/2 "] curvature with a 3.18 ° tool face slope angle
and the length would be
just over 40.64 cm [16"]. Again, it must be noted that these angles and
dimensions should
not be taken as a restriction on thc: invention as they only serve to give the
best known tool
zs face parameters as set by the bore: conditions. If larger or smaller bores
are in use, these
parameters would have to be changed.
The deflector head will be manufactured from 4340 steel or from a material
that has
a similar hardness. Optional PCD inserts, 51, are placed in the standard
pattern to minimize
wear and actually can be. considered as acting as a bearing surface for the
window mill.
3o Techniques for the insertion of PCD inserts and heat treating of metal to
maintain a given
hardness are well known in the art and will not be discussed.
The deflector is alaached to the whipstock body by pins, 53, press-fitted into
holes,
54, in the whipstock body. As the deflector head will suffer considerable
vibration when the
CA 02284488 1999-10-06
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window mill is on it, a number of pins will be needed and most likely the two
sections will
be welded to each other along the back junction gap, 60 and 69. The weld must
be ground
to match the back curvature of the deflector head. Figure 4B clearly
illustrates the deflector
head attached to the whipstock body when the head and the body are of equal
curvature, i.e.
s 8. 89 cm [31h "] body to 8. 89 cm [31/z "] deflector head, 13. 97 cm [5'/a
"] body to 13. 97 cm
[51/a "] deflector head, or 20.32 crn [8"] body to 20.32 cm [8"] deflector
head. Figure 4C
and Figure 3 illustrate the larger deflector OD when attached to the smaller
whipstock body
OD; i.e., a 31.75 cm [12'/z"] deflector head attached to the Type III or 20.32
cm [8"] body.
A table of recommended dimensions for the three deflector heads that the Whip-
to Anchor system will require is given below. The radius of curvature for the
backside of the
various deflector head is not given because the required radius will be set by
the bore ID in
which the head is being used. A person skilled in the art of drilling
wellbores can easily
supply the required radius remembering that the backside radius of curvature
must be chosen
so that the backside of the. deflector head rests firmly against the bore.
This, of course, will
Is require a proper radius of curvature equal to that of the ID of the bore
and a curved cone
shape across the top side; of the deflector head. All of these calculations
are currently
practiced and well known. The table is given for illustration only and is not
intended to
serve as a limitation on tile instant invention. As previously noted, the
sizes (or types) of
whipstock can be modified to fit larger or smaller bores than those presently
discussed.
ao DEFLECTOR HEAD PARAMETERS
WHIP-ANCHOR Slope Length Thickness at
Type and Size cm Degree cm Connection cm
2s I - 8.89 OD 2.09 34.93 1.27
II - 13.97 OD 2.62 41.91 1.91
III - 20.32 OD 3.18 45.72 2.54
METRIC TABLE 2
The Setting Tool !ilot, 13, can be found starting at or about 5 centimeters [a
couple
of inches] below the deflector head to whipstock body joint, 26. The relative
position of the
setting slot can best be seen in Figure 3. The setting tool slot is about 2.54
cm [1 "] wide
in the type I tool, about 3.81 cm [1'/z"] wide in the type II tool, and about
5.08 cm [2"]
3s wide in the type III tool. The width is actually determined by strength of
material
considerations based on the force required to set a mechanical packer and by
the retrieval
tool slot (these considerations will be discussed). The setting slot has a
variable depth
determined by the tool face angle., The back of the setting tool slot is
perpendicular to the
CA 02284488 1999-10-06
-25-
base of the whipstock and parallel to the back of the whipstock; thus, its
variable depth as
the slot continues towards the base of the whipstock. The slot terminates
above the mid
point of the whipstock. The actual termination point, 25, is determined by the
type of
whipstock (Type I, II or III) and is set by the properties of strength of
materials. The depth
s of the slot at the bottom will range from about 1.27 cm [lh"] in the Type I
tool to about 2.54
cm [ 1 "] in the Type III tool.
A recommended sca of parameters is given in the table below for the setting
slots used
in the three types of Whip-Anchor system. These parameters are given to
illustrate the
instant invention and should not be considered as limitations on the present
invention. If
ro additional types of Whip-t~nchor are proposed, the same constraints that
apply to the example
table below will yield the required parameters for smaller or larger Whip-
Anchor types.
SETT:~1G TOOL PARAMETERS
WHIP-ANCHOR Slope Setting Slot Thickness to Deflection of
1s Type and Size Length, Width, Depth Back of Tool Milling Tool
I - 8.89 OD 2.09 56.52 x 2.62 x 2.06 1.27 3.33
II - 13.97 OD 2.62 49.53 x 2.94 x 2.29 1.91 4.19
III - 20.32 OD 3.18 45.72 x 5.16 x 2.54 2.54 5.08
METRIC TABLE 3
In the table above, the column entitled "Deflection of the Milling Tool"
denotes the
distance the Whip-Anchor Tool Face has moved the Window Mill into the casing
(or bore
zs side wall in an uncased h~~le). And the column entitled "Thickness to Back
of Tool" is the
distance measured at the bottom or base, 25, of the setting slot from the
setting slot face to
the tool back (this is shown as length 66 in a number of Figures).
It should be noted that all setting slots should end at the setting slot base,
25, at about
91.44 cm [36"] from thc: top of the Whip-Anchor. The setting slot length is
restricted
3o because the milling tool must be able to fulcrum (lever) off of a smooth
cupped face in order
to properly guide the milling operation on its deviated trajectory.
[Additional discussion on
trajectory appears later in this discussion.]
The setting slot also provides access to the retrieval slot, 12, which runs
from the face
of the setting slot at an upward angle and exits at the back of the whipstock
body. The
3s retrieval slot is the same width as the setting slot and its bottom starts
from about 3.81 cm
[ 11/Z "] to 6.35 cm [2'/z "] above the bottom of the setting slot extending
upward for about
25.4 centimeters [10"]. ~~hese dimensions depend on the Type of Whip-Anchor
and will be
discussed along with the retrieval slot and its function in a later portion of
this discussion.
CA 02284488 1999-10-06
-26-
Slightly above the retrie~~al tool slot, 12, is the location of the retrieval
tool shear pin
aperture or mechanism, 27; the choice being made by the particular embodiment
being
described. This location operates in conjunction with the Retrieval Tool
latching system and
its purpose will be explained later.
s An upper hydraulic passageway, 19, is found at the saddle point of the
cupped tool
face slightly below the bottom of the settling slot. This passageway runs from
the saddle
point of the cupped tool face to a 'cut-a-way', 9, located in the back of the
whipstock. The
hydraulic passageway is threaded at both ends to accept a hydraulic street-ell
fitting. The
'cut-a-way', 9, extends from the hydraulic passageway to the base of the
whipstock below
to the hinge, 6. These components operate in conjunction with a hydraulic
anchor packer and
serve to conduct hydraulic fluid from a running tool located on the drill
string to the
hydraulic anchor packer ~Nhen onc: is used with the Whip-Anchor system. This
subsystem
will be explained later.
The upper section of the whipstock, 4, is hinged to the whipstock base, 5, via
a hinge
is assembly, 6. The hinge assembly is shown in detail in Figures SA through SC
and is similar
to a prior art hinge except that springs, 95, have been added in spring
openings, 83 through
86 and the hinge center is. offset from the Whip-Anchor center line by about
1.91 cm [3/ "]
towards the tool face. These springs serve to ensure that the whipstock will
fall away from
the point of deviation against the back of the wellbore. These springs are
similar to those
zo found in "valve-lifters" used in engines. The springs are retained in their
compressed
position while the whipstock is being manipulated by a spring retainer shear
pin, 88. This
pin is approximately 6.35 mm [ 1/4 "] in diameter and runs through its
respective spring
retainer shear pin openin~; in the upper section, 96, and base section, 97, of
the whipstock.
The upper section opening, 96, .and base section opening, 97, will only align
when the
as springs are compressed and when the whipstock is perpendicular to its base.
The spring
retainer shear pin, 88, is held in place by two snap rings, 93, in a snap ring
groove, 94, at
either end of the pin within the base opening, 97. The technique for shearing
this pin, when
the whipstock is set, will be explained later.
The upper and base sections of the whipstock are hinged together using a hinge
pin,
so 87, which passes through the hinge pin opening, 81, in the base, and
through the
corresponding hinge pin opening, 80 in the upper section of the whipstock. It
should be
noted that the center of the hinge pin is offset towards the front of the
whipstock by about
1.91 cm [3/ "]; unlike the present art. This offset assures that the spring
retainer shear pin,
CA 02284488 1999-10-06
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88, will shear, whenever weight is applied in the downward direction on the
Whip-Anchor,
when it is set. Careful observation of Figure SB will show that a large
downward force will
tend to push the upper secaion of the whipstock backwards or away from the
tool face. This
is the direction that the ~whipstock must fall (or move towards) in order for
proper hole
s deviation to occur. The downward force will pivot about the off-set hinge,
87, thus shearing
the spring retaining pin, 8.8. This releases the hinge springs which will hold
the back of the
whipstock against the wellbore. The back of the hinge base, 89, is sloped to
assure that the
upper hinge section 82, is not prohibited from its backward motion while
shearing the spring
retainer shear pin, 88. In a similar manner the top of the back of the hinge
base, 90, is also
Io sloped to avoid any chance of intc;rference.
The spring force feature will find great utility in near vertical holes
(within ~5 ° of
vertical) and in holes where the operator wishes to deviate from the low side
of the wellbore.
Deviation from the low s ide is seldom performed because of the high failure
rate that most
operators have experienced.
is The base section o~f the whipstock continues the 'cut-a-way', 9, which is
designed to
hold a high pressure hydraulic line for use with a hydraulic packer. The 'cut-
a-way', 9,
terminates in a another hydraulic fluid passageway, 23. This passageway runs
from the cut-
away, 9, in the base section, through the center of the base, and terminates
in the bottom
flange of the base where it can communicate with a hydraulic packer, 14H,
through a cross-
zo over sub, 15. The base hydraulic passageway, 23, has threads for a street-
ell connection
where it enters the 'cut-a-way', 9. The actual hydraulic plumbing will be
explained later.
In the prior art of setting Whipstocks, it was generally accepted that the OD
or
profile, 29, of the Whips,tocks should have an approximate clearance of, or
slightly more
than, 1.27 cm ['h "] within the wellbore. It is possible in special
situations, where the
as wellbore is in very "good condition", to reduce this clearance to 6.35 mm
[1/a"]. This
invention has three sizes of whipstock bodies to fit bore sizes from 9.53 cm
[33/ "] to 31.75
cm [121h"] ID. Thus, for example, in a wellbore using 89.48 kg/m [60 pounds
per foot]
casing having an ID of 3'1.75 cm [12'/z"], the correct Whip-Anchor would be
the Type III,
which has a body OD of 20.32 cm [8"]. After the Whip-Anchor was anchored
(centered)
so in the 31.75 em [ 121/z "] ID wellbore, there would be a 5.72 cm [21/a "]
clearance or gap
between the 320.38 cm [~~"] OD Whip-Anchor body and the 31.75 cm [121/z"] ID
wellbore.
Depending on the degree of inclination in the wellbore to be sidetracked and
the direction
of the intended sidetrack. an Optional Spacer, 8, may be required to reduce
this clearance
CA 02284488 1999-10-06
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(gap) to a minimum of 1.27 cm [1/z "] in the direction of the intended
sidetrack. This
example is given for illustration only and optional spacer requirements for
given wellbores
can easily be calculated using known art.
The drill string has a fulcrum effect created by the milling/drilling tool and
the
s watermelon mills) whenever it is deflected (or deviated) to the "high side"
of a wellbore
having some degree of inclination from vertical. Thus, as the window milling
operation
proceeds, the drill string ;acts as a lever to force the window mill into the
casing (or wall of
an uncased hole) under the guidance of the Deflector Head and subsequent
travel along the
Tool Face of the Whip-Anchor body. Once the initial cut into the side of the
wellbore has
to been made and once the :mills have moved along the Tool Face of the Whip-
Anchor, they
have formed a "line of trajectory" equal to (or more than) the degree of slope
placed on the
Tool Face of the Whip-Anchor. When the window mill reaches the bottom of the
Tool Face,
it will have milled nearly all the casing wall (or side of an uncased hole).
The watermelon
mills) will still be on the Tool Face of the Whip-Anchor, giving guidance and
"fulcruming"
rs the window mill away from the old wellbore. In the instant invention, it
may be
necessary to use an optional spacer at the base of the Whip-Anchor Tool Face
whenever the
gap between the wellbore and the Whip-Anchor body exceeds 2.54 cm [1 "] and
the Whip-
Anchor System is being used in a wellbore with less than 10 degrees of
inclination. The
higher the degree of inclination from vertical in a wellbore, the more
pronounced the
ao "fulcrum effect" and the spacer is not necessary. It might be noted, that
as the top of the
Whip-Anchor rests again~;t the 31.75 cm [121/2"] wellbore, the "trajectory
path" created by
the 20.32 cm [8"] OD Whip-Anchor Tool Face increases from 3.18 degrees to 4.07
degrees.
This increase in deviation from the old wellbore further enhances the movement
of the new
path away from the old wellbore. Figures 6A and 6B give greater details on the
optional
as spacer and its attachment to the Whip-Anchor body to extend the Tool Face
and lessen the
gap. (In general, all illustrations of the Whip-Anchor system which use a
hydraulic packer
are shown with this optional spacer; see for example Figure 2.) In designing
this Whip-
Anchor system, the bottom or base, 25, of the setting slot should be located
above the
fulcrum point for the watermelon mills. If this is not done, then special
watermelon mills
3o must be used which do n~~t bit into the setting slot when in use.
The optional spacer, 8, is attached to the lower portion of the upper section
of the
Whip-Anchor by two (or more if required) studs, 74. The tool face side of the
spacer, 72,
is a continuation of the Whip-Anchor Tool Face, 11. As a consequence, the tool
face of the
CA 02284488 1999-10-06
-29-
optional spacer will have the same: slope and cupping as the type (size) Whip-
Anchor body
to which it is attached. The two studs, 74 pass through apertures in the
optional spacer, 75,
and into threaded openings, 68 which are in the Whip-Anchor body. The back of
the spacer
has the same curvature as the body OD of the type of Whip-Anchor to which it
is being
s attached. The width of the optional spacer, 79, will be the same as the
width of the upper
section of the Whip-Anchor and the length of the spacer, 78, will be set by
the Whip-Anchor
type (size). The optional spacer depth, 77, and the spacer base length, 76,
will be set by
parameters to be determined by tl-ae Whip-Anchor type (size) and bore hole
diameter.
OPTIONAL SPACER PARAMETERS
to
Whipstock Casing Size Bore Size SpacerCurve Tool
Face
Type Size cm cm Depth Back Cup and Slope
I 8.89 11.43-16.83 9.53-11.430 NA NA at NA
1s I 8.89 11.43-16.83 12.07-13.971.27 8.89 13.97
at 2.09
II 13.97 17.78-21.91 14.61-17.78 0 NA NA at NA
II 13.97 17.78-21.91 18.42-20.32 1.59 13.97 20.32 at 2.62
20 III 20.32 24.45-33.97 20.96-25.40 0 NA NA at NA
III 20.32 24.45-33.97 25.40-27.94 2.54 20.32 31.75 at 3.18
III 20.32 24.45-33.97 29.21-31.75 4.45 20.32 31.75 at 3.18
METRIC TABLE 4
2s
The table above gives approximate dimensions for commonly used wellbores and
conditions. The table is n.ot intended to serve as a limitation on this
disclosure but is offered
only as illustration and guidance for those skilled in the art. Remember that
a spacer is not
generally necessary and the optional spacer will find its greatest use
whenever the wellbore
3o is within 10 degrees of vertical and when the gap between the centered
(set) whipstock body
and the wellbore exceeds about 2.54 centimeters [1 "].
The base of the whipstock, 5, is attached to a cross-over sub, 15, which in
turn is
attached to a mechanical packer, 14M. The packer that is shown in Figure 1 is
a very old
style called a "set-down " packer. This packer is shown for illustration and
ease of
ss explanation only and is not considered to be a limitation on the invention.
This invention
is designed to be used with any style of mechanical (or hydraulic) anchor
packer.
The instant invention can readily be adapted for use with a hydraulic packer
as shown
in Figure 2. The exact same whipstock is used except for additional plumbing
features. A
hydraulic street-ell, 20, is screwed into the matching threads within the
upper hydraulic
ao passageway, 19, in the face of the whipstock. In a similar manner another
hydraulic street-
CA 02284488 1999-10-06
-30-
ell, 21, is screwed into the backside entry of the same upper hydraulic
passageway, 19.
Finally a further hydraulic street-ell, 22, is screwed into the base hydraulic
passageway. A
high pressure hydraulic hose, 24, is attached between the two street-ells
located in the 'cut-a-
way', 9, in the backside ~of the whipstock. Standard hydraulic packer
procedures are now
s followed. A cross-over sub, 15, is screwed onto the whipstock followed by a
hydraulic
packer, 14H. A hydraulic; connection is made between the face street-ell, 20,
and the setting
tool. This part of the invention and procedure will be explained later.
Thus, one model of Whip--Anchor System using three sizes of whipstock body can
serve as a whipstock/packer assembly in wellbores from 8. 89 cm [31/z "] to
31.75 cm [ 121/z "]
io and the same one model can be used with mechanical or hydraulic packers. As
will be
explained in a latter part of the discussion, this Whip-Anchor is retrievable.
Attention should now be directed to the Setting Tool illustrated in Figures 7
through
10. It should be remennbered that the same setting tool will operate a
mechanical or
hydraulic packer used in conjunction with the instant invention. The general
setting tool will
rs be described first and then the necessary changes that make it a mechanical
or hydraulic
Whip-Anchor setting tool will be described. There are three different sizes of
setting tool
because there are three different sizes (or types) of Whip-Anchor. The setting
slot, 12, is
determined by strength of material and requires set by the size of the tool
and the pull that
will be required to retrieve the tool. Thus, the slot width varies from about
2.54 cm [ 1 "]
ao for the Type I tool, to about 3.81 cm [11/a"] for the Type II tool, and to
about 5.08 cm [2"]
for the Type III tool. It should be noted that other sizes of Whip-Anchor
could be used and
the setting slot width will still be determined by similar strength of
material consideration;
thus, this example width ~~hould not be construed as a limitation on the
instant invention. In
a similar manner the length of the tool, 109, as measured from the sub, 100,
to the bottom
zs face of the setting tool, 108, will vary with the Whip-Anchor type.
The setting tool, 2, consists of three subassemblies, which are best
illustrated in
Figure 7 or 8, these bein;;:
the setting tool rectangular bar, 101;
the setting tool fluid line or tubular, 102; and
3o the setting tool sub, 100, often called the top sub.
The rectangular bar fits v~~ithin the setting tool slot, 13, located in the
face of the whipstock
as previously discussed. In the preferred embodiment of the setting tool the
fluid line or
tubular, 102, is threaded into the t:op sub as shown in Figure 10A. The
threads can be back
CA 02284488 1999-10-06
-31-
welded if desired. The fluid line or tubular is capable of safely carrying
circulation mud or
hydraulic fluid under pre:>sure. T'he bar is welded to the setting tool fluid
line or tubular,
102, and in turn to the top sub, 100, which is capable of connection to the
drill string. It
is possible to weld the tubular directly into a recess in the top sub without
using threaded
s fittings; however, threaded fittings would make construction of the setting
tool easier.
Figure 9A illustrates a cross-sectional view of the setting tool, 2, within
the setting slot, 13.
The pertinent details of the setting tool will be discussed. Turn now to
Figure 9,
which shows a close up view of the tool in the setting slot and at the base of
the setting slot
and to Figures l0A through IOD, which show construction of the tool. The
bottom face of
ro the setting tool, 108, has a slight angle, 106, which means that the
setting tool bottom rests
on the setting slot bottorr~ of the whipstock at the point farthest away from
the tool face.
There will be a slight ga~~ betwee:n the setting tool bottom face, 108, and
the setting slot
bottom, 25, nearest the whipstoc;k tool face, 11. This gap is on the order of
several
hundredths of a millimeter [several thousandths of an inch] and its purpose
will be described
is later. The setting fluid line or tubular, 102, terminates at a point
slightly below the
termination of the bar. The actual distance is not critical because it is used
to allow for ease
of attachment of a hydraulic fitting. The inside of the open end, 107, of the
fluid line is
threaded to accept a hydraulic fitting. The setting tool is attached to the
Whip-Anchor by
a shear pin, 39. This shear pin is the same as used in the art for currently
setting
ao whipstocks; however, it is scored to assure perfect fracture.
The shear pin, 39, is made of mild steel and is threaded to fit the threaded
aperture,
105, in the setting tool. 'Che shear pin passes through a corresponding
aperture, 62, in the
whipstock. This opening is larger than the shear pin and allows for slight
movement of the
shear pin within that openiing. This is to give the shear pin some relaxation
from any applied
as downward or torsional forces exerted by the Setting Tool in reaction to
forces applied to the
drill string. This allows the downward force to be applied directly to the
bottom of the
setting slot and the torsional forces. to be directly applied to the side
walls of the setting slot.
Additionally, this loose fit of the shear pin, 39, in the whipstock aperture,
62, ensures that
if sufficient downward force is applied on the setting tool, then the bottom
face of the setting
so tool will fully set down o~n the bottom of the setting slot. This action
will impart a shear
force to the spring retaining shear pin, 88, because of the combination of the
offset hinge,
6, and the bottom tool face angle, 106, on the setting tool.
It should be noted that if the spring retainer pin, 88, is sheared while the
Whip-
CA 02284488 1999-10-06
-32-
Anchor is being run into the wellbore, the hinge section of the instant
invention reverts back
to the prior art employed by current whipstock/packer systems using an
unpinned hinge.
This condition, which could be brought about by having to force the whipstock
through a
particularly tortuous path and having to exert a great amount of downward
force on the
s setting tool, does not cause any problems in using the instant device. This
is because the
base of the anchor packer has a larger OD than the slips (wedges or scaling)
elements section
of the packer and further more is "bullet shaped." (See Figure 3) The instant
invention will
operate better than the prior art in a tortuous path for two reasons:
a) a great amount of downward force (of weight) can be applied without any
fear of
to shearing the shear pin because the force is applied directly to the Whip-
Anchor via the setting tool sitting in the bottom of the setting slot, and
b) because the Whip-Anchor can be rotated without fear of shearing the shear
pin due
because thc: torsional force (rotation) is applied directly to the walls of
the
setting slot.
is Additionally the shear pin has a groove, 38, cut axially around the pin at
such a
location so that when the pin is installed the groove is located slightly
inside the setting slot
face. This groove assures that the shear pin will shear at the groove. This
means that, once
the pin has sheared, there will be no material extending from the whipstock
shear pin
aperture, 62, into the setting slot. The back of the whipstock has a recess,
63, which accepts
zo the Allen Cap Head of the shear pin and assures that no material extends
beyond the back
side of the whipstock. The recess, 63, has an axial groove, 64, which can
accept a keeper
ring, 37, which will keep the Allen Cap Head within the body of the Whip-
Anchor after it
is sheared. Any type of rcaainer mechanism, such as welding could be employed.
The table
given below is for purposes of illustration of the best mode. It should not be
construed as
as a limitation. All dimensions will be set by strength of material
considerations; thus, if the
material changes, or if a 'weakness shows up, a metallurgical engineer would
know how to
adjust the values given below.
SHEAR STUD PLACEMENT AND SETTING SLOT BASE PARAMETERS
30 Whip-Stock Stud Slot Slot Slot Up from Stud
base
Size Size Width Depth Length of Slot
Depth
I 1.2'72.62 2.06 56.52 2.54 0.95
II 1.5!a3.89 2.27 49.53 3.18 1.27
3s III 1.91 5.16 2.45 45.72 3.81 1.91
METRIC TABLE 5
CA 02284488 1999-10-06
-33-
When the setting tool, 2, is used with a mechanical packer, the setting tool
fluid line,
102, is left open as shown in Figure 7. Mud can be circulated through this
fluid line and
if an MWD tool is attached to the setting tool sub, proper Whip-Anchor tool
face orientation
may be accomplished. l f the operator requires, the fluid line, 102, can be
attached to
s circulate through a mechanical anchor-packer with a check valve to be able
to wash to
bottom in open (uncased) hole conditions. (This arrangement is not shown and
would not
impair the operation of the Whip-.Anchor. The arrangement would use all of the
described
hydraulic anchor packing plumbing and the mud would circulate in the same path
down
through the cross-over sub and out of the bottom of the mechanical packer.)
to Figure 8 shows thE: arrangement of the setting tool when it is used to set
a hydraulic
packer. If the setting tool is used with a hydraulic packer, then a hydraulic
hose, 1135,
would be attached to tubing at t:he threaded open end, 107, and run to the
equivalent
hydraulic fitting, 20, on the cupped face of the Whip-Anchor. The procedures
(or methods)
for using this setting tool with either the hydraulic or mechanical packer
will be discussed
is later. It should be noted that the Whip-Anchor is illustrated in Figure 8
as being connected
to a larger packer via the cross-over sub, 15. The optional spacer, 8, is also
shown;
however, the hydraulic fittings and hose within the whipstock have been
omitted for clarity.
Additional illustrations may be found in Figures 16 through 19.
An alternate embodiment of the setting tool is shown in Figure lOC and IOD. In
this
ao embodiment, the steel fluid line or tubular, 102, has been replaced with a
high pressure
hydraulic hose, 113L, which runs directly from the threaded tubular recess,
112, on the top
sub, 100, to the street-ell fitting, 20, on the Whip-Anchor tool face. This
hose would be
held in place by stainless steel clamps, 114, and screws (not shown) screwed
into the setting
bar as needed. In fact, arc previously mentioned, the same hydraulic fluid
lines can be used
as in conjunction with a mechanical packer to wash the bottom of the hole with
drilling mud
in open hole (uncased) conditions, otherwise, when using a mechanical packer,
either variant
of the hydraulic hose, 11:3, would. be omitted.
A table giving ap~aroximate dimensions for the three tools is given below.
These
dimensions should not be construed as a limitation on the invention, nor
should the fact that
so only three sizes are givc,n be similarly construed, for the reasons given
earlier in this
discussion of the invention. The table is for illustration only and allows a
person skilled in
art of whipstocks to choose the proper tools) for the proper application.
ADDlITIONAL SETTING TOOL PARAMETERS
CA 02284488 1999-10-06
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Whipstock Type Bar Tool Fluid Line Top Sub OD Shear Stud
or Size Length, 'Width, Depth Size - Rating & Connection** Size
I - 8.89 OD 101.60 x 2.54 x 2.54 0.625 - 272 AT 33/a" w/ 23/s"IFB 121
II - 13.97 OD 101.60 x 3.81 x .9.18 1.19 - 272 AT 43/a " w/ 3'h "IFB 1~
III - 20.32 OD 101.60 x 5.08 x .9.81 2.54 - 272 AT 6'h" w/ 4'/a"IFB 1.91
METRIC TABLE 6 ** No metric equivalent
The retrieval tool for the Whip-Anchor is designed to engage a retrieval slot
located
in the upper portion of the whipstock within the setting slot. Figures 11A-B
and 12A-D
show the particulars needed to understand the device. The preferred embodiment
for the
retrieval tool is shown in Figure 12A, with a cross-section in Figure 12AA.
The preferred
Is embodiment uses a hydraulic hose to pass fluid to the wash port, located in
the face of the
hook in the retrieval tool. The alternate embodiment is shown in Figure 12B,
with a cross-
section shown in Figure 12BB. The alternate uses a welded tubular in place of
the hydraulic
hose, which will increase the strength of the tool and will be the most useful
for Type III
Whip-Anchors. Any retrieval tool must not exceed the diameter of the Whip-
Anchor body
ao (bore), and the tool must be able to withstand three times the force
required to release the
anchor-packer at the base of the Whip-Anchor.
The preferred emhodiment will find greatest use with Type I and Type II Whip-
Anchors because the ID of the bore hole limits the size of the Retrieval Tool.
Turning then
to Figure 12A, the Retrieval Tool simply consists of a tool joint, 180, a bar,
178, and a
zs specially shaped hook, 1T7. Although the hook could be welded to the bar,
it is much better
to manufacture the hook ;end bar as a unit because of the tremendous forces or
weight that
the Retrieval Tool will have to endure in releasing the anchor packer (not
shown). The tool
joint, 180, can have a threaded fitting or a weld fitting for attachment to
other Bottom Hole
Assembly (BHA) tools, such as t:he piston sleeve valve assembly or sub, 140,
shown in
3o Figure 12C and which will be discussed shortly. The tool joint is attached
to the Retrieval
Tool bar, 178, and to the: hook, 1.77, either during manufacture of the
Retrieval Tool as a
complete unit or by welcLing the bar to the tool joint. [The preference is for
a complete
integral unit due to, again, the tremendous forces that will present.] There
is a recess, 179,
whose depth, 168, is set by the type of Whip-Anchor being used. The recess
permits the
ss Retrieval Tool to centralize itself in the setting slot, 13, of the Whip-
Anchor, thus, the depth,
168, will vary with tool type. The retrieval tool latching mechanism, 28, is
located on the
face of the bar (at location 27) that will engage the retrieval slot. This
mechanism and its
CA 02284488 1999-10-06
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embodiments will be discussed later.
The hook, 177, has a wash port, 175, located in its face. The wash port, 175,
connects directly to a wa~~h passageway, 176, which is cut through the center
of the hook,
through the bar, and terminates in a threaded outlet at the back (opposite the
tool face) of
s the bar. A hydraulic street-ell, 185, is fitted in this back opening of the
wash passage and
a hydraulic hose, 183, runs from the street-ell to a threaded port, 182, in
the tool joint. The
threaded port, 182, connects to the; inside of the tool joint via a fluid
passageway, 181. The
hydraulic hose, 183, is strapped to the back of the bar, 178, by stainless
steel clamps, 184,
which are in turn, attached to the bar, 178, by stainless steel screws (not
shown). An
ro additional piece of metal, 190, is welded to the back of the bar, by weld,
205, to protect the
street-ell, 185. It would be possible to form the protector plate, 190, as a
part of the
complete Retrieval Tool, while manufacturing the bar/hook/tool joint.
The wash port, 175, is designed to swab the wellbore and the setting/retrieval
slots,
12 and 13, as the retrieval's tool is making its trip into the wellbore. It is
realized that during
is regular drilling operations, involving a deviated hole, cuttings (formation
chips) will settle
in all crevices within the 'Whip-Anchor. Thus the setting slot, 13, which acts
as a guide for
the Retrieval Tool hook.. as well as the actual retrieval slot, could become
filled with
cuttings. High pressure mud flog will wash those cuttings free of these
critical slots.
The Retrieval Tool hook is carefully shaped to accomplish several ends. Viewed
zo from the bottom, as in Fiigure 12AA, the front of the hook is slightly
narrower, 165, than
the body of the hook, which has the same width, 166, as the Retrieval Tool
bar, 178.
Furthermore, when viewed end on as in Figure 12D, it can be seen that the
width of the top
of the hook, 164, is slightly narrower than the width of the front of the
bottom of the hook,
165, which widens to the width oil the bar, 166. The Retrieval Tool hook is
set at an angle
as of 35 degrees to the Retrieval Tool bar and all leading edges are rounded
for ease of
engagement into the retr ieval slot, 12. All dimensions of the Retrieval Tool
hook, bar,
setting slot and retrieval slot are set by strength of material considerations
and a representa-
tive set is given in table 7 below. There must be sufficient strength for the
hook to on pull
the Whip-Anchor and break the lower anchor packer loose, plus be able to pull
the Whip-
so Anchor assembly from thE; hole without material failure. Thus, these
dimensions change with
the size of the Whip-Anchor. The tables of dimensions give best mode
dimensions for
accomplishing this purpose; however, with the use of different steels, the
dimensions could
change and are readily calculated by metallurgical engineers. A suggested set
of parameters
CA 02284488 1999-10-06
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is given in the table below; these parameters are suggestions only and can
easily vary with
the material of construction.
RETRIEVAL TOOL DIMENSIONS
Whip-Anchor Tool Tool Hook Hook Hook Wash Material Top** Latch Hook
Size Length Wid~h Depth Width Length Port ID Strength Connection OD Angle
I 1.37 m 8.8!3 2.54 2.54 x 1.27 10.16 0.635 100K 2'/a " IFB
0.635 35°
1o II 1.42 m 13.89 3.81 3.81 x 2.54 12.70 0.953 120K 2'la" IFB
0.953 35°
III 1.47 m 19.05 5.08 5.08 x 3.81 15.24 1.270 160K 4'/a" IFB
1.270 35°
METRIC TABLE 7 ** No Metric Equivalent
Figure 11C shows the Retrieval Tool hook fully engaged within the retrieval
slot, 12.
The distance, 172, between the base of the setting slot, 25, and the bottom
opening of the
retrieval tool is set by strength of material considerations. This length also
contains the shear
zo pin aperture, 62, which its NOT shown in the figure. The 35 degree angle
for both the
retrieval slot and the Retrieval Tool hook is designed to allow the hook to
slide backwards
and away from the retrieval slot whenever the operator "slacks off" on the
weight. This
means that the hook can be disengaged if the Whip-Anchor becomes stuck in the
bore.
It is important that the hook remains engaged until the operator truly wishes
zs disengagement. For example, if there is a set of fishing jars in the BHA,
and the operator
wishes to use them, they must be reset each time after use. Fishing jars are
reset by slacking
off and allow the drill string weight "cock" the jars. Thus, disengagement of
the hook must
be controlled so that fishing jars can be reset. This can readily be
accomplished by the
Retrieval Tool latching rnechanisrn, 28, whose approximate location is shown
at 27. The
30 latching mechanism consists of a spring loaded shear pin and corresponding
opening for the
pin to pop into whenever the retrieval tool is fully engaged in the retrieval
slot. There are
two embodiments for the device.
The preferred embodiment: for the Retrieval Tool latching mechanism is shown
in
Figure 14A, in which the latch pin, 206, and spring, 207, are retained by a
keeper, 208, in
3s an aperture, 209, within tlhe setting slot face of the Whip-Anchor. This
position is preferred
as best mode because of strength of material considerations. The latch pin,
206, strikes
within a corresponding opening, 210, in the Retrieval Tool face. The opening,
210, is larger
than the diameter of the pin to ensure engagement. The diameter of the pin
(and the
corresponding opening) is set by the reset weight requirement of the fishing
jars. This
CA 02284488 1999-10-06
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latching pin will shear if sufficient weight is applied to the pin; however,
the pin is designed
to bear the weight of re;~et for the fishing jars; thus, disengagement is
controlled. The
operator can reciprocate the Whip-Anchor; he can reset his fishing jars and he
can rotate it
without fear of inadvertent disengagement of the Retrieval Tool hook; but,
when the tool is
s completely stuck, the operator can disengage by slacking off hard on the
tool, shearing the
latch pin, and falling out ~~f the retrieval slot. The operator would rotate
the Retrieval Tool
by at a quarter turn and :rip out of hole. The alternate embodiment of the
retrieval latch
mechanism, shown in Figure 14B, is the reverse of the first; however, this is
not best mode
because the opening for tlhe mech;~nism, 211, would weaken the Retrieval Tool
bar.
ro An alternate embodiment of the basic Retrieval Tool is shown in Figure 12B.
This
embodiment, as previously explained, will work best with the larger Whip-
Anchor Types due
to the ID of smaller wellbores. 'The Retrieval Tool consists of the same tool
joint, 180,
Retrieval Tool bar, 178, and hook, 177, as with the preferred embodiment and
all the
features are similar. The difference is in the use of a tubular, 187, which is
welded to the
rs bar, 178, to conduct fluid to the hook wash port, 175 rather then a
hydraulic hose. The tool
joint has a fluid passage, 181, which terminates in a weld fitting, 186, in
which the tubular,
187, is welded. (It would be possible to use a threaded fitting and back weld
the threads if
desired.) The tubular is :hen welded to the back of the Retrieval Tool bar,
178, along the
joint, 188, between the t:wo parts. The hook fluid passage, 176, from the wash
port is
ao extended into the tubular and the tubular is sealed by a cap or plug, 189.
All other details
are the same as with the preferred embodiment - hook dimensions, bar
dimensions, etc.,
which are set by strength requirements.
Figures 15A through 15D show the Retrieval Tool hook approaching the Whip
Anchor, rotation or alignment with the setting slot and engagement. As
explained later in
as this discussion, the Retrieval Tool with the proper BHA running tools would
be tripped into
the hole and the Retrieva l Tool face alignment would be checked when the tool
is near the
Whip-Anchor, the drill string rotated (as in Figure 15B) to align the tool
with the setting slot,
and further lowered. The setting slot would provide guidance to the Retrieval
Tool hook
face. The hook would bottom out on the bottom of the setting slot bottom or
base, 25. This
3o condition can be observed by a decrease in travelling block load or drill
string weight. The
string would be pulled upward an<I the Retrieval Tool hook should engage the
retrieval slot.
Engagement should be noted by an increase in drill string weight. However,
often when
pulling a drill sting upw;~rd over short distances, the string will jam in the
wellbore and
CA 02284488 1999-10-06
-38-
frictional effects would give higher weight indications; thus, it is possible
that a false
indication of hook engagement could be observed at the surface. There is a
secondary
method to indicate proper hook engagement which sends a mud pressure pulse to
the surface.
The inventor proposes several different embodiments for sending a mud pressure
s pulse to the surface. The preferred apparatus for determining hook latch in
the retrieval slot
may be found in a "piston sleeve valve" which is designed to shut off mud flow
when a
'hook load' is applied to the piston sleeve valve. Simply stated a sub
containing the piston
sleeve valve is attached to the tool joint, 180, and is placed in the BHA
immediately above
the Retrieval Tool such that whenever weight is 'picked up' by the Retrieval
Tool hook, the
to piston sleeve valve closes and sends a pressure pulse to the surface.
Figure 12C illustrates a sleeve valve, 140, but does not show the Retrieval
Tool
subassembly which would contain the only retrieval tool bar and hook as shown
in Figure
12A or Figure 12B. The piston valve starts with a tool joint, 141, in which an
upper fluid
passageway, 142, has been machined to intersect a cross-passageway, 139. The
cross-
rs passageway terminates on the side of the tool joint in a threaded opening
in which a
hydraulic street-ell, 143L1, is placed. A hydraulic line (or hose), 144,
extends from the
upper street-ell to a lower street-ell, 143L. The lower street-ell conducts
fluid into the piston
chamber, 156, which is machined in the lower section, 160. The lower section
of the piston
sleeve valve is screwed to the tool joint by buttress threads, 145. The fact
that the piston
ao sleeve valve can be opened allows service of the internal parts.
The piston valve, :146, resides within the lower section, 160, and its
associated piston
chamber, 156. The piston valve, 146, has a piston valve head, 154, which is
larger then the
piston valve and is capable of supporting the hook load transferred by the
Retrieval Tool
hook whenever the Whip--Anchor is latched and pulled. A spring, 148, is
generally placed
zs between the piston head ;and the bottom of the piston chamber which helps
to support the
piston valve up against the tool joint, 141. The piston valve, 146, has a set
of piston rings,
147, which will seal the ~~iston valve at area, 159, immediately below the
piston chamber,
156. There is a central fluid passageway, 157, in communication with a cross
fluid passage,
158, within the piston valve. Fluid flow may occur between the lower street-
ell and the
3o piston passageways via the upper piston chamber and around the piston
spring, 148.
Normal fluid flow, 150, would enter the top of the tool at the tool joint
passage, 142,
and follows the path shown by the heavy arrows through the hydraulic hose and
the
associated street-ells, into the piston chamber, through the piston
passageways and out of the
CA 02284488 1999-10-06
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bottom of the tool. The force of the fluid acts against the piston head and
holds the head
(along with some help from the spring) up against the tool joint. When a hook
load is
transferred to the tool, the piston extension, 149, will transfer the load to
the piston, 146,
and onto the piston head, 154, thus compressing the piston spring and
overcoming the force
s exerted by the fluid. This. will draw the piston across passage below the
entry point of fluid
at the lower street-ell, 14:3L, thus., shutting off fluid flow to the lower
portion of the piston
and onto the Retrieval Tool. The closure of the access port will, of course,
send a pressure
pulse to the surface which is an indication of Retrieval Tool hook engagement
on the Whip-
Anchor.
to Although the piston sleeve valve has been described in conjunction with the
retrieval
tool, the device can be used in any fishing operation in which drilling fluid
is circulated. For
example, in wireline fishing operations, it is very difficult to know when the
fishing tool has
engaged the broken wireline. Normally, the driller lowers the wireline fishing
tool into the
wellbore, while rotating the drill string. The string is run a point where the
broken line is
rs expected; an attempt to p ick up the line is made; and, the drill string is
tripped back to the
surface. If nothing is captured, the operation is repeated, except the drill
string is run to a
lower point in the wellbore.
A major problem 'will occur if the drill string entangles the broken wire line
for any
distance above the fishing; tool. This entanglement will cause the drill
string to stick in the
ao wellbore and it can become impossible to trip the drill string out of the
wellbore. A wireline
device is extremely light, so that normal drill string weight indicators will
not measure any
increase in weight whenever a broken wireline is captured by the fishing tool.
The piston
sleeve valve can be set to indicate capture of the wireline by sending a
pressure pulse up the
drill string in the circulating mud. Now it should be noted that the piston
sleeve valve will
Zs actually cut off circulation; howc;ver, a similar drill string arrangement
may be used as
shown in Figure 20 when: the piston sub, 100, is replaced by the Piston Sleeve
valve. The
pinned-by-pass valve, 12 ~~, will allow for continued mud circulation. It is
possible to design
the openings within the piston sleeve valve so that circulation is only
partially cut off; thus,
producing a pressure pulse at the surface while maintaining circulation.
3o It is possible to increase the circulation pressure at the surface and
attempt to force
the piston head back up into the tool joint. Thus, complete latching of the
Whip-Anchor,
wellbore deviation assembly, broken wireline, or other device can be tested
for by increasing
the mud pressure and seeing if t:he flow increases. If an increase in pressure
does not
CA 02284488 1999-10-06
-40-
significantly increase the mud flow, then hook engagement has occurred.
There are two alternate devices which are capable of producing a pressure
pulse at
the surface and these are shown in Figures 13A and 13B. Figure 13A shows the
preferred
embodiment for a Retriev,~l Tool incorporating a hydraulic pressure hose, 183,
to bring fluid
s to the wash port, 175. This technique will work equally well with the
alternative method of
applying fluid to the wash port which uses the welded tubular (not shown in
Figure 12B).
The mud pressure pulse is produced by stopping the wash port fluid at the wash
port, 175,
through the use of a valve, 203, located in the hook, 177. The hook valve,
203, is operated
by a loaded stem actuator, 204, which protrudes from the top of the hook. When
the hook
ro properly engages, the retrieval slat at the top of the slot will squeeze on
the actuator, 204,
thus closing the hook val~~e and sending a mud pressure pulse to the surface.
An alternate
embodiment is shown in Figure 1:3B which uses an internal flapper valve, 201,
actuated by
a control rod, 202.
The second alternate embodiment uses a full body tubular Retrieval Tool with a
hook.
rs The Retrieval Tool is madle in several parts. A standard tool joint, 191,
is welded to tubular
section, 192, which terminates in a threaded connection, 194. A second tubular
section, 187,
is welded to a Retrieval 'pool hook, 177, has a rounded bottom end, 198, and
matches the
first tubular, 192, at the threaded connection, 194. The second tubulax
section, or Retrieval
Tool tubular, 187, contains a flapper valve sleeve, 195, which restrains and
holds the flapper
ao valve, 201. The sleeve provides a slightly offset passage for the fluid,
196, and stops the
fluid from getting behind the flapper valve and closing it inadvertently. The
sleeve passage,
196, continues through a smaller passage, 197, and joins the wash port
passage, 176, which
terminates in the wash port, 175. All other details, hook dimensions, lengths,
etc. are
similar to the preferred embodiment. When the Retrieval Tool hook engages the
retrieval
zs slot, the hook is naturally pulled towards the setting slot, which presses
against the flapper
valve actuator, 202, thus., closing the flapper valve, 201, producing a
pressure pulse at the
surface.
A final alternate embodiment for the setting tool is illustrated in Figure 32.
In this
embodiment, the base of the setting tool is extended into the body of the Whip-
Anchor. This
3o enlarged base would permit greater downward force to be exerted on the Whip-
Anchor. This
alternate would compromise the integrity of the Whip-Anchor if it is to be
retrieved, for it
would be weakened.
The use of the Whip-Anchor does not differ greatly from the prior art;
however, this
CA 02284488 1999-10-06
-41 -
tool simplifies the procedure, actually reduces a step, provides methods
whereby only one
type of tool need be kept in warehouse stock, provides a whipstock that can be
set in tortuous
wellbore conditions, promides a retrievable whipstock, and provides a tool
which permits
bottom hole washing in open hole. conditions with a mechanical packer, just to
name a few
s of the myriad difference~~ in the apparatus and method of using the present
invention. In
keeping with the spirit of the previous discussion, the simplest operation
will be described
initially and the differences between the use of the mechanical anchor packer
and the
hydraulic packer will be: discussed. The various embodiments and how they
affect the
operator will also be considered.
ro Reference will be made to Figures 15 through 29. Normal drill floor
procedures for
assembling the Whip-Anchor and choosing the proper combination of downhole
running tools
is almost the same as with the prior art and it makes little difference, as
far as this general
discussion is concerned, the Type (size) of Whip-Anchor for a given size bore
or whether
the wellbore is open or eased. Those skilled in the art of setting whipstocks
will be able to
is supply minor missing details and see the minor differences that would occur
between cased
and uncased holes. The real differences between the instant invention and the
prior art will
be discussed.
Assume that the operator has made the decision to deviate a wellbore, that the
operator has properly surveyed the wellbore, that the collar locator run has
been made, that
zo the operator knows the hole conditions and, that the operator has made the
proper trip with
a locked up bottom hole assembly, thus, preparing the hole for setting a
whipstock. Assume
further, that the hole is cased and that the operator has decided to use a
mechanical packer,
which is the simplest meahod to describe. This discussion will also assume
that the operator
will take advantage of the instant invention in that it allows the use of MWD
(Measurement
as While Drilling) and that the operator has chosen to use an MWD tool to
orientate the face
of the Whip-Anchor.
The Whip-Anchor would normally be brought to the drill floor in an assembled
condition. That is, the I~hip Anchor service representative would assemble the
tool. Proper
choice would be made for the deflector head which would be mounted per the
previous
so discussion. Proper choice would be made for the anchor packer size and that
would be
mounted to the base of the whipstock using the proper cross-over sub. If the
optional spacer
is required, then that would be mounted. In other words the tool would look
some what like
Figure 1, or Figure 2 a:nd/or Figure 3. The assembled Whip-Anchor would be set
at the rig
CA 02284488 1999-10-06
-42-
staging area while all preliminary procedures (standard) would be undertaken.
The running assembly, that is the tools which will be attached between the
setting tool
and the drill string, should be assembled before placing the Whip-Anchor on
the rig floor.
Normally a single section (or joint) of Heavy Weight Drill Pipe, 122, is
picked up with the
s drill pipe elevators and u~~ed as a "handling sub" because of the ease in
attaching the tools
below it. Any cross-over sub, orientating sub, by-pass valve, piston sub and
setting tool,
that are required, would be attached to the single joint of heavy weight drill
pipe and made
up to their proper torque with the rig tongs at this time. Figure 20 shows an
assembly for
the assumed conditions given above. These tools are the setting tool, 100, a
cross-over sub,
l0 131, if necessary, and MWD tool., 127, or an optional orientation sub [not
shown], a single
joint of heavy weight drilll pipe, 122, and required collars, 121, for
attachment onto the drill
string, 120. These assembled tools would be stored in the elevators out of the
rotary table
working area (above or to one side) because the travelling block with drill
pipe elevators is
not needed in handling the Whip-Anchor assembly.
Is The Whip-Anchor assembly would be picked up with an "air hoist" or the "cat
line"
and landed in the rotary table. It is then secured with appropriate slips and
clamps. The
aforesaid assembled tools would be brought into position, via traveling block
and elevators,
and the setting tool, 100, would be attached to the Whip-Anchor, using the
shear stud, 39.
The shear pin keeper ring;, 37, should be placed in its proper position on the
Whip-Anchor
ao to make certain that the sheared head does not interfere with the operation
of the Whip-
Anchor. After orientation of the Whip-Anchor tool face to a "mark" on the tool
joint of the
heavy weight drill pipe, because the MWD tool is to be used for orientation,
the "blind
rams" on the Blow Out Preventer (BOP) system would be opened, if closed, and
the total
assembled tools would be; landed in the rotary table with the tool joint of
the heavy weight
as drill pipe at "working height". Because an MWD tool is to be used, it would
be picked up
with the drill pipe elevators and traveling block, and aligned with the "mark"
on the tool
joint of the heavy weight drill pipe.
It might be noted here, that some operators like to run an orientating sub
(not shown)
above the MWD in case of MWD failure or simply because they want to check the
30 orientation with two different survey instruments; hence, the choice of a
wire line device.
Also in the prior art, the joint of heavy weight pipe was required to give the
needed "fulcrum
effect" for the Starter r~Iill, which was attached to the whipstock, to make
the 50.08
centimeter plus or minus [20" ~] starting cut. In the instant invention,
although no longer
CA 02284488 1999-10-06
-43-
needed in the Whip-Anchor setting run, the joint of heavy weight drill pipe
would still be
very helpful in picking up and laying down the tools that are used directly
above the Whip-
Anchor.
It is important to note that with the simplest embodiment it does not matter
which
s embodiment of setting tool is in use. In the preferred embodiment, the
opening, 107, in the
tubular, 102, is left open. In the alternate embodiment, the threaded opening,
112, is left
open.
Now suppose that the operator wished to use this invention to its full
potential and
wash the hole bottom through the: mechanical packer. Before the Whip-Anchor
would be
zo lowered into the hole, a high pressure hydraulic hose must be connected
between the setting
tool and the hydraulic fitting on the Whip-Anchor tool face. It is assumed
that the Whip-
Anchor service representative has installed the internal plumbing in the Whip-
Anchor:
namely the extra street-ells, 20, 21, and 22 plus the 'cut-a-way' hydraulic
line. The internal
plumbing is identical to the plumbing required for a Hydraulic packer. The
difference in
is setting tool embodiments is not much for in the preferred embodiment, a
short hydraulic
hose, 1135, should be att;~ched between the tubular opening, 107 (via the
required hydraulic
fitting, 110) to the tool face street-ell, 20, before the Whip-Anchor is
lowered into the hole.
In the case of the alternatE; embodiment, a long hydraulic hose, 113L, is
attached to threaded
recess, 112, and onto the Whip-Anchor tool face street-ell, 20. [Note there is
really no
zo difference between this procedure and the procedure required with a
hydraulic packer - the
only difference is in the l;ype of fluid passing through the plumbing.]
A suggested bottom hole tool assembly for a hydraulic packer is shown in
Figure 21
where the operator choosf;s to use only a wire line survey for orientation of
his Whip-Anchor
face. These tools are, the setting tool, 100, a piston sub, 130, a short sub
129, an
as orientation sub, 126, any required cross-over, 124, followed by the single
joint "handling
sub", 122. An alternate assembly is shown in Figure 22 where the operator
chooses to use
an MWD tool for Whip-~~nchor orientation [if an orientation sub were required
it would be
placed above the MWD tnol]. The order of the tools is somewhat critical for
the pinned by-
pass sub, 128, must be ylaced below the MWD, 127, and above the short sub,
129. The
3o assembly techniques for these tools is similar to that described above and
it is known that the
short sub, 129, is initially made up "chain tight" until after hydraulic fluid
is placed in the
piston sub.
An illustration of a piston sub, 130, which would fit a Type II Whip-Anchor,
is
CA 02284488 1999-10-06
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shown in Figure 29. This concept is in relatively common use, but it will be
described here
because this particular tool serves two functions and will greatly enhance the
Whip-Anchor
setting process; hence, the use of this tool forms a part of the preferred
method of setting
the tool. These two functions are:
s 1) the sub provides isolation between the drill mud fluid and the required
clean hydraulic fluid needed to set a hydraulic packer, and
2) the sub provides a simple way for mud to drain from the drill string as it
is withdrawn from the bore hole after setting the Whip-Anchor, thus avoiding
the spray of mud on the rig floor when each stand is broken.
ro The Whip-Anchor will most likely be used in old bore holes and, usually, an
oil based
drilling mud, which is considered toxic by the regulating authorities, is
used. Thus, when
pulling out of the hole, it is imperative that the amount of fluid spray
coming from a
"breaking" tool joint be rc;duced. This piston sub will accomplish that
purpose and is much
better than most similar tools currently supplied by major suppliers of
whipstocks.
rs Figures 29 and 30A-B, are illustrations of an improved piston sub to be
used with a
Type II Whip-Anchor. 'l~he dimensions of a similar sub for a Type I or Type
III Whip-
Anchor will change, but only in GD/ID of the sub. The internals will only vary
slightly to
fit the different sub OD/IID. Thus, anybody skilled in the art will be able to
reproduce this
tool for different sizes of Whip-Anchor. The improved piston sub consists of a
lower sub,
zo 130, about 18.3 m [6'] long whose dimension is actually set by the volume
of hydraulic fluid
needed to operate the chosen hydraulic packer; wherein, the ID at the bottom
of the lower
sub is enlarged to form an enlarged piston landing, 136. A piston, 131, having
an o-ring and
groove, 132, is placed wil:hin the sub. This piston normally seals tightly
against the internal
wall of the lower sub. Tlhe piston has a riser, 134, which passes through the
piston and is
as terminated in a removable: cap, 135. When the piston is within the normal
bore of the sub,
it seals tightly against the wall; however, when the piston is in the landing,
136, the o-ring
seal is broken. The piston serves as an interface between drilling mud and
clean hydraulic
fluid. There are two 0.95 cm [3/a"] circulation channels, 133, that enhance
the mud flow past
the piston after it reaches the landing.
3o It should be noted that a similar tool is commercially available, but the
commercial
tool uses a particularly complex piston cage and valve arrangement at the
bottom of the
lower sub in order to break the seal between the two fluids. This particular
caging
arrangement is unreliable because: it is so complex. The inventor removed the
cage and
CA 02284488 1999-10-06
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"bored-back" the area where the cage had been positioned. "Bore-back" is a
term which
means increasing the ID of a part to a certain depth. In this case the
inventor enlarged the
ID of the lower sub so that it was reasonably larger than the piston and
reasonably longer
than the piston. These dimensions are not critical -- they must be chosen so
that the piston,
s when it lands in this region, no longer seals against the inner wall of the
lower sub. Any
person skilled in the art oil downhcrle tools will recognize the exact
dimensional requirements
as they are set by the relative size; of the tools themselves. The bore-back
will range from
several millimeters [fracti.ons of an inch] to a couple of meters [several
feet] depending on
tool and piston length; whereas, the bore-back diameter will range from
several millimeters
io [fractions of an inch] to ;~ number of centimeters [several inches] larger
than the diameter
of the piston.
The complete piston sub assembly, consisting of the upper (short) and lower
subs plus
the piston riser generally is attached to the setting tool and hydraulic
connections made. The
short sub, which is only chain tight, is opened and the piston riser, 134,
pulled up to the top
rs of the piston sub. The ri;~er cap, 135, is opened and the proper hydraulic
fluid required by
the hydraulic packer is poured through the riser opening, 137, until the
entire volume below
the piston, 131, is filled with hydraulic fluid. This volume includes the
packer, the hydraulic
hose, and fittings in the Whip-Anchor, setting tool, etc. The cap can be
replaced along with
the upper stub which is then brought to the proper torque, or the riser cap
can be left off.
ao If the riser cap is left off, the riser should be filled with heavy
lubricant. The heavy
lubricant will act as a removable plug or seal between the hydraulic fluid and
the drilling
fluid, similar to the function performed by the riser cap.
The hydraulic packer is set, in the standard manner, by pressuring the
drilling fluid.
Hydraulic setting pressure is transferred through the piston in the piston
sub. Once the
zs packer is set, the hydraulic line is broken between the setting tool and
the packer leaving the
entrained hydraulic fluid Free to leave the piston sub. The piston freely
moves downward.
When the piston reaches the enlarged landing, the seal between the piston and
the wall of the
lower sub is no longer functional and the drilling fluid will proceed past the
O-ring and out
of the bottom of the piston sub, through the broken hydraulic line and into
the wellbore. If
3o the piston does not have channels, then the piston will seat on the bottom
of the sub (actually
on set of threads belonging to the lower tool) and inhibit fluid flow. If the
riser cap is left
out of the assembly and the riser filled with heavy lubricant, the drilling
fluid will push the
lubricant out of the riser ;end the riser can provide a backup (or even
primary) passage for
CA 02284488 1999-10-06
-46-
the drilling fluid.
Once the Whip-Anchor is in place, the hydraulic packer is set by increasing
the
drilling mud pressure; this mud column pressure is transferred to the
hydraulic fluid through
the piston sub and the slips will move. As the hydraulic slips move, the fluid
in the piston
s sub will decrease and the piston, 131, will move towards the landing. (A
slight decrease in
mud pressure is always observed when this happens and this decrease tells the
surface
observers that the hydraulic packer is beginning to set.) After the hydraulic
packer is set,
the drill string is released from the Whip-Anchor by pulling upward on the
drill string, which
shears the shear pin and breaks the hydraulic connection to the Whip-Anchor
face. As the
to drill string is pulled upward, mud column pressure will force the remaining
hydraulic fluid
from the piston sub and the piston will land. This then allows drilling mud to
readily flow
around the piston and out of the open/broken hydraulic hose, and the drill
pipe will drain as
it is pulled out of the hole.
The actual setting procedure for the new style Whip-Anchor will now be
discussed.
Is The techniques for running the Whip-Anchor into the wellbore, be it used
with a mechanical
or hydraulic packer, are the same as used in the current art. The Whip-Anchor
service
representative need not worry as ouch about inadvertent pin shear in pushing,
because the
setting tool rests firmly in the bottom of the setting slot. Likewise, the
Whip-Anchor service
representative need not w~~rry about torsional pin shear because the setting
tool is contained
ao by the side walls of the setting slog. These two features will greatly
enhance the probability
of a successful set. The Whip-Anchor service representative must still be
concerned with
inadvertent pin shear while reciprocating the Whip-Anchor in order to force
the tool through
a particularly tortuous path, for the pin will shear as designed, with
sufficient upward pull.
Assuming that the Whip-t~.nchor service representative has successfully
positioned the Whip-
2s Anchor, that he has surveyed the tool face orientation, and that he is in
general satisfied with
the operation, all that rerr~ains is the setting of the packer-anchor.
The mechanical packer-anchor is set by slacking off on the drill string and
allowing
the proper weight to rest on the seating tool. This weight will be transferred
to the Whip-
Anchor where several things will :.happen;
so 1) the torsional twist about the offset hinge will shear the spring
retaining pin, and
2) the tran;~ferred weight will cause the mechanical packer collet to
release, the weight will compress the packing elements and then set the
CA 02284488 1999-10-06
-47-
slips.
This operation is shown in Figure 23, which illustrates the preferred
embodiment setting tool
using the open tubular, 107, immediately prior to setting the mechanical
anchor-packer.
There are no hose connections between the open tubular, 107, and the hydraulic
passageway,
s 19, on the face of the whipstock. [Note, if the operator were using this
system in open hole
and desired to bottom wash, there would be a line between the tubular and the
whipstock
passageway, as previously explained.] If the packer is being used in an open
(uncased) hole,
the operation is similar, except that mud anchors are used in the mechanical
packer instead
of casing slips.
to The hydraulic packer is se.t by well known standard procedures. This
operation is
shown in Figure 24, which illustrates the preferred embodiment setting tool
using the tubular,
102, with a short hose, 1135, connected between the tubular threaded opening,
107, and a
street-ell, 20, fitted in the; hydraulic passageway, 19, on the face of the
whipstock. Simply
stated, the mud pressure is increased. If an MWD tool is in the bottom hole
assembly, the
Is associated pinned by-pass valve will release, thus, shutting off mud
circulation and allowing
mud pressure to increase. The increase in mud pressure is applied to the
piston sub,
transferred to the hydraulic fluid and onto to the hydraulic packer. The Whip-
Anchor service
representative looks for the "pressure bobble", as previously explained, which
indicates that
the hydraulic packer has begun to set. The mud pressure is then increased to
whatever
zo pressure is necessary to sca the hydraulic anchor-packer.
Once the anchor-packer is set, be it mechanical or hydraulic, the next step is
to pull
out of hole. In order to do this the Whip-Anchor must be released from the
setting tool and,
hence, the drill string. A number of well known steps are taken which do not
differ from
the current art. Essentially, these steps are designed to make certain that
the anchor-packer
as has properly gripped the casing or that the mud slips have firmly embedded
the bore hole
(formation). The Whip-Anchor service representative generally pulls and slacks
off several
times on the drill string maintaining the strain each time for about a minute.
If the
mechanical packer moves, the setting procedure should be repeated. If the
hydraulic packer
moves, then the Whip-Anchor service representative should follow the normal
resetting
so procedure already practiced with this type of packer. After assuring
himself that the anchor-
packer has properly set, the Whip-.Anchor service representative pulls back on
the drill string
slowly, increasing the force until the shear pin fractures. The situation for
both types of
packer is shown in Figurca 25 and 26. Note that in Figure 26, the short
hydraulic hose,
CA 02284488 1999-10-06
-48-
1135, breaks clear of the whipstock face taking the fractured street-ell, 20,
with it.
Fracturing of the street-ell, 20, at the face of the whipstock at the point of
the threads is
assured by careful scoring of the street-ell, 20, before or after it is placed
in the whipstock
during assembly.
s Although the preferred embodiment of the setting tool is shown in these
illustrations,
the alternative embodiment which uses a long hydraulic hose, 113L, in place of
the shorter
hose, 1135, operates in the same manner. Upon breaking away from the
whipstock, the
longer hose will take the fractured street-ell, 20, with it. The entire string
is removed from
the hole and the second pass tools are prepared for the actual window mill
cut.
ro SHEAR PULL VALUES
Whip-Anchor Size Bore size Shear Stud Size Approximate Shear Force*
Thousands of Kilograms
1s I 8.89 OD 9.53-13.97 1.27 x 2.54 length 4.55, 6.82, 9.09
II 13.97 OD 14.61-20.32 1.59 x 3.18 length 9.09, 11.36, 13.64
III 20.32 OD 20.96-31.75 1.91 x 3.81 length 13.64, 15.91, 18.18, 20.45
* varies with Whip-anchor size
2o METRIC TABLE 8
The approximate 'values of shear force is given in the table above. It should
be
remembered that these values are only approximate and the values seen at the
surface will
vary, depending on the wellbore conditions, hole length, etc. The actual shear
value of the
zs shear stud will be determ fined by t:he shear groove that is cut in the
stud. The shear value
is carefully chosen using techniques well known in the industry and is set by
the size and
weight of the Whip-Anchor (the whipstock and its anchor-packer), whether the
Whip-Anchor
was to later be retrieved, and the hole conditions. For example, a Type I tool
with a
retrievable hydraulic set ;anchor packer, used for drilling 11.43 cm [41h "]
multiple drain
3o holes, would normally use a 4,550 kg [10,000 pounds] shear stud if hole
conditions were
good because the tool would be slated for retrieval. On the other hand, a Type
I tool used
with a permanent hydraulic or mechanical packer would use a 9.09 kg [20,000
pounds] shear
stud because the tool would not bc: retrieved.
The second pass, the actual cutting of the window in the casing or the start
of the
3s deviated hole in an uncased hole, is radically different to the prior art.
This invention differs
from the prior art in that there is no starting mill operation. In the prior
art and referring
to Figure 27A and Figure 27B, a shear pin block, 40, was always welded onto
the surface
of the whipstock tool face, 11, within about three-tenths of a meter [1'] of
the top, to which
CA 02284488 1999-10-06
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the shear pin was bolted. The shear pin held the starter mill taper, 41, to
the block. The
starter mill in turn was attached to the drill string with necessary optional
tools required for
setting the whipstock. Simply put, a similar procedure as described above was
used to set
the whipstock. The only drawback being that the usual prior art systems were
designed to
s be used with hydraulic packers because sufficient weight, to set a
mechanical anchor packer,
cannot be imparted to the face of a whipstock through a shear pin.
For example, the; minimum set down weights for good set on a mechanical
compression packer is as follows:
Type I si:ae range 18,000 kg [40,000 pounds]
io Type II si:ae range 27,000 kg [60,000 pounds]
Type III si:ae range 36,000 kg [80,000 pounds]
Thus, it can be seen that: the prior art, which utilizes a shear pin without a
setting slot,
cannot "set" compression mechanical packers because the shear pin requirements
are roughly
one-half of the set down requirements.. There is one form of mechanical packer
that uses
rs a single slip segment which results in a lower set down requirement;
however, the procedure
for setting this particular packer requires that weight be applied to the
packer until the shear
pin shears. This means that the "set" of the packer cannot be tested by
pulling upward.
In the prior art the; initial starter mill accomplished two objectives:
1) the millLing off of the shear pin block, 40, thus preparing the
ao whipstock tool face, and
2) starting .an initial up-slope cut, 99, into the casing (or formation in
an uncased hole).
The starter mill, 42, would push against the top of the whipstock and be
deflected into the
side of the casing. An additional fulcrum effect was obtained from the
starting mill taper,
as 41, pushing against the shear block, 40. (Please see prior art insets in
Figures 23 through
27.) After the starter mill had traveled about 30 centimeters [12"] into the
hole, thus cutting
a starter window of some: 30 centimeters [12"] in the casing (or formation in
an uncased
hole), the starter mill would begin to mill the shear block. The maximum
distance that the
starter mill could travel was about 50 centimeters [20"] before the starting
mill taper would
3o hang up on the casing and keep the starting mill from moving along the
required deviation
path, 45. Quite often the starter mill would cut into the whipstock tool face;
thus, damaging
the necessary fulcrum point, 49, needed by the watermelon mill. This device
replaces the
start milling operation wish a simple window mill, 48; the window mill being
deflected by
CA 02284488 1999-10-06
-50-
the deflector head, 7.
The second pass downhole tool assembly consists of, a properly sized window
mill,
48, and a properly sized 'Natermelon mill, 47, (a second watermelon mill, 46,
can be added
by the operator if a larger window opening was needed in the casing), as shown
in Figures
s 27 and 28. These window mill tools are usually attached to a single joint of
heavy weight
drill pipe to help ensure t:he proper fulcrum effect; followed by the correct
number of drill
collars, which provide thc; necessary milling weight. The prudent operator
will add a set of
drilling jars which is followed by sufficient drill collars to provide weight
for the jars. The
additional tools, drill collars, subs and jars are not shown but are well
known tools in the
ro practice.
Figure 27 shows the start of the window milling operation. The window mill,
48,
is deflected against the casing (or formation), by the deflector head, 7. The
deflector head
will carry the full weight of the milling operation until the mill is able to
cut into the casing
(or formation) at which time more: and more mill weight will shift to the
wellbore side. It
rs is known that the starting mill will. make an initial cut into the casing,
99, and then begin to
pull itself into the casing riding up onto the initial cut. Approximately the
first third of a
meter [one foot] of milling is the critical length, although this distance
will increase with the
size of the hole. Please see the deflector head parameter table, table 2. The
actual milling
parameters are the same as the prior art uses after the initial mill, thus,
these techniques and
ao parameters are well knov~rn by those skilled in the art and need not be
discussed in great
detail. The prior art is shown in Figures 27A and 27B. As the window is cut in
the
casing, the window mill, 48, moves downward and the watermelon mill, 47,
begins to
enlarge the casing (or formation) cut. The watermelon mill fulcrums off the
whipstock tool
face, (shown approximately as point 49) to help keep the window mill on its
deviation path.
as Additional fulcrum effects are provided by the single joint of drill pipe
(and second
watermelon mill, 46, if used) t.o guide the lower tools. The Whip-Anchor
service
representative would normally use this set of tools to mill the window and
sufficient
formation to obtain a total depth of between 2.1 meters [7'] and 3.05 meters
[10'] (a normal
distance presently used in the art). These tools would then be removed and a
normal drilling
30 operation would commence on the; next trip.
The Whip-Anchor is a retrievable tool which is a highly desired characteristic
for use
in multiple drain holes or in multiple slim hole exploration. The retrieval of
the tool is made
convenient through a carefully designed fishing system based on field
experience. The major
CA 02284488 1999-10-06
-51-
problem in retrieving tools (or any object) from a wellbore is being able to
get a grip on the
object so that it can be withdrawn. The Whip-Anchor is retrievable because it
has a
specially designed slot a.nd retrieval tool (fishing tool) system which allows
for easier
gripping of the tool. The operator should properly prepare the hole for
retrieval of the tool
s which should be conducted by a qualified Whip-Anchor service representative.
Proper
wellbore preparation would include a trip with a locked up bottom hole
assembly and a good
effort to sweep all drill cuttings, which would have come from the newly
deviated wellbore,
from the main wellbore.
The choice of dovvnhole running tools for a retrieval operation is based on
myriad
Io conditions and qualified Whip-Anchor Service Representatives will have no
problem in
selecting the correct comhination of tools to be used with the Whip-Anchor
retrieval tool.
A suggested centralized Bottom Hole Assembly (BHA) arrangement is shown in
Figure 31,
starting with the retrieval tool, 3. The retrieval tool should be followed by
an unpinned by-
pass valve, 141, because the retrieval tool wash passage, 176, cannot pass
sufficient fluid
rs flow to properly ensure drainage of drilling fluid from the drill string
when pulling out of
hole. Proper drainage of the drill string is essential to assure that mud is
not released on the
drill floor. (As stated earlier, this device will find its greatest use in old
bores or in multiple
drain bores which use an oil based mud: considered toxic by the regulatory
authorities.)
A full Gauge stabilizer, 1.18, would then follow. At this point, the Whip-
Anchor service
ao representative can install an MWD, 121, or an orientation sub, 126, with a
single drill collar,
119. Either assembly can be used for orientation of the retrieval hook in the
hole, although
an MWD tool would be preferred. The orientation tools) are then followed by a
second full
gauge stabilizer, 118. A set of jars, 140, is recommended plus the necessary
drill collars,
121, for the jars. For a~ Type I Whip-Anchor, the Whip-Anchor service
representative
as should use 9,000 kg [20,000 pounds] weight of drill collars; for the Type
II tool, 18,000 kg
[40,000 pounds] is recolr~mended:, and for the Type III tool, 27,000 kg
[60,000 pounds].
This complete centralized BHA would be attached to the drill string, 120, and
run into the
wellbore using standard tf:chniques.
The retrieval tool .and BHA would be run into the wellbore to just above the
top of
3o the Whip-Anchor (see Fil;ure 15A). At this time the Retrieval Tool Hook
Face would be
orientated to face the setting and retrieval slots (See Figure 15B). After
orientation, the mud
pumps would be used, via the wash port, 175, to flush any debris out of the
setting slot, 13,
and the retrieval slot, 12, nn the Whip-Anchor as the Retrieval tool proceeds
downhole. The
CA 02284488 1999-10-06
-52-
retrieval hook passageway is designed to "scrub" the wall of the wellbore and
the
setting/retrieval slot for a more positive latch, and the centralized BHA
described above will
ensure that this action indeed happens. If the retrieval tool will not "scrub"
due to extreme
wellbore configurations, adjustments can be made to the tool in order that it
will properly
s "scrub. " These adjusts could include adding a bent sub assembly (not shown)
between the
retrieval tool, 3, and the by-pass valve, 117. If worst comes to worst, the
actual retrieval
tool could be bent.
Attempts would then be made, by reciprocating the drill string, to latch the
retrieval
tool hook, 117, into the retrieval slot, 12. (If an MWD tool is not used, the
technique would
ro still be similar, the Whip-Anchor ;service representative just would not
know which way the
hook and wash port were facing, and trial and error means would have to be
used to wash
the slots and hook the retrieval slot. That is reciprocate the drill string,
rotate 15 degrees,
reciprocate the pipe, and repeat.) Positive latching of the hook in the slot
will be indicated
at the surface by a sharp increase in mud pressure because the mud flow
through the wash
is port has been stopped by the preferred use of the piston sleeve valve, 140,
as described
previously. If, however, the alternate positive latch indictor embodiments are
used, mud
flow will be stopped by closure o~f the hook valve, 203, which is controlled
by the hook
valve actuator, 204, being; pushed inwards when the hook fully engages the
retrieval slot; or
by closure of the flapper ~ralve, 201, which is controlled by the flapper
valve actuator, 202,
ao being pushed inwards as the retrieval tool face presses against the setting
slot. A further
indication of positive latching will be a "loss of weight" if the Whip-Anchor
service
representative slacks off slightly, due to the BHA weight being carried by the
latched hook
on the retrieval tool. The: Whip-Anchor service representative must remember
not to slack
off greatly or the latch mechanism, 28, shear pin will shear; this will be
covered later in the
as discussion. After the retrieval tool properly engages the retrieval slot,
interaction of the
sloped slot and hook will draw the back of the Whip-Anchor away from its close
contact with
the wellbore as shown in Figure 15D as it rotates about the hinge assembly.
(The hinge
springs will compress due to torsional forces about the offset hinge as the
anchor is dragged
out of the hole.) This ensures that. the top of the Whip-Anchor will not catch
against casing
3o joints as it is tripped out of the hole. Additionally, the extra length of
the hook that
protrudes from the back of the Whip-Anchor, will aid in reducing the
possibility of snagging
a casing joint.
Once the hook has engaged, the latch pin mechanism, 28, will ensure that the
hook
CA 02284488 1999-10-06
- 53 -
does not come out of the retrieval slot if the Whip-Anchor service
representative has to
reciprocate the drill strin;; in order to free the Whip-Anchor. Once hook
engagement has
occurred, the Whip-Anchor service representative will slowly increase the pull
on the drill
stem to the point of known slip shear screw release force. The actual pull
force will be
s greater than the slip shear screw release force because of wellbore
friction. Once the shear
screws have sheared the ~~lips on t:he anchor will release, the packing will
collapse, and the
anchor will free itself from the wellbore. All that the Whip-Anchor service
representative
must do is trip out of the wellbore.
If the Whip-Anchor happens to stick in the hole during the trip, the Whip-
Anchor
to service representative can use the fishing jars to attempt to work the Whip-
Anchor free. The
hydraulic fishing jars must be reset, which is done by applying weight on the
jars. The
retrieval tool latch pin me~:.hanism, 28, (either embodiment as shown in
Figures 14A or 14B)
is designed to provide sufficient strength (i.e. it will not shear) for reset
of the fishing jars.
The techniques for "fishing" stuck tools from a wellbore are well known and
will not be
is discussed in this disclosure. On the other hand, if the Whip-Anchor becomes
irretrievably
stuck, the Whip-Anchor service representative may apply sufficient down
weight, which not
only resets the jars, but will shear the latch pin. This allows the retrieval
tool hook, 117,
to slide downward and ou.t of the retrieval slot. The drill string should then
be rotated and
reciprocated in order to turn the retrieval hook away from the retrieval slot.
Following this,
zo the drill string can be tripped out of the hole and the stuck Whip-Anchor
either abandoned
or retrieved using other v~~ell known time consuming and expensive fishing
techniques.
Finally, it must be realized the present art whipstocks using hydraulic (or
mechanical)
anchor packers can be converted to incorporate some of the salient features of
the instant
invention and such conversion is considered to be within the scope of this
invention. The
as conversion may be made by cutting a setting tool slot in the current state
of the art whipstock
and using the techniques described above to set the converted whipstock
attached to either
a mechanical or hydrauli~~ packer. If the user desires, a retrieval slot can
be cut in the
whipstock and the retrievable features of the above disclosure can be used. It
is recom-
mended that the top section of existing art whipstocks be cut and the
deflector plate of the
3o instant invention be used to ensure proper starting of the window cut.
Alternatively, the top
section of the whipstock ~:ool face can be hardened to the equivalent of the
deflector head.
It should be noted that converted whipstocks can only be used in the size of
wellbore for
which they were originally designed and will have a "full bore" cross-section.
CA 02284488 1999-10-06
-54-
There has been dis~,closed heretofore in the above discussion the best
embodiment and
best mode of the present invention presently contemplated. It is to be
understood that the
examples given and the dimensions may be changed, that dimensions are based on
strength
properties of the material chosen to manufacture the Whip-Anchor, and that
modifications
s can be made thereto without departing from the spirit of the present
invention. The tables
used in the disclosure are conversions from well know and established values
used in the oil
industry and are based on the British System of Units. Thus, the decimal point
notation used
in the tables does not mc;an tolerance, but rather indicates the closest
metric value to the
established oil field standard unit of measure. The original ANSI tables are
given in the
ro section following the Number Index.
Invention Drawing Number Index
Terminology = Two conventional whipstocks are available.
rs PACK-STOCKT"' and BOTTOM TRIP
The Packstock is a whipstock and packer assembly combination that forms a
single
integral unit downlhole. Note that Pack-StockT"' is a trade name other trade
names are
used in the industry. In this patent the term Whip-Anchor (or variants) will
be used
to describe the combination of a whipstock and its anchor packer.
zo The bottom trip h;as a plunger that sticks out of the bottom of the
whipstock which
when set down on the botaom of the hole will release a spring loaded
wedge/slip
which in turn sets the tool.
001 The Whipstock Invention generally - not including anchor-packer
as 002 The Whipstock Setting Tool generally
003 The Retrieval Tool generally
004 Top section of whipstock generally
005 Bottom section of whipstoc:k generally
006 Hinge section of vvhipstoch generally
30 007 Deflector head section of whipstock generally
008 The optional spacf;r
009 Whipstock cut-a-v~~ay for hydraulic pressure line
010 The complete downhole tool generally - whipstock, head, spacer, and packer
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011 The cupped face of the whipstock (tool face side)
012 Retrieval slot section of whipstock generally
013 Setting slot section of whipstock generally
014H Hydraulic anchor packer generally
s 014N1 Mechanical anchor packer generally
015 Cross-over sub (between packer and whipstock)
016 Running tool (converts mu.d pressure to hydraulic pressure)
017 MWD tool
018 Other string tools generally
ro 019 Upper Hydraulic passageway - within whipstock
020 Hydraulic street-el.l connection within whipstock face
021 Hydraulic street-ell connecaion within whipstock back
022 Hydraulic street-ell connection within whipstock base
023 Hydraulic line within hydraulic cut-a-way
Is 024 Base Hydraulic passageway - within base
025 Setting slot base (nr bottom)
026 Whipstock/deflectnr head joint in general
027 Location of Retrieval Tool Shear Pin Aperture or Mechanism
028 Retrieval Tool Latch Pin Mechanism in General
ao 029 Conventional Whipstock Profile
030 Borehole generall~~ - can be cased or uncased
031 Casing
032 Cement between casing and formation
033 Upper Slips/Wedges
as 034 Lower Slips
035 Packing
036 Bridge Plug
037 Keeper Ring
038 Shear Pin Groove
so 039 Shear Pin
040 Prior Art - Shear Pin Block
041 Prior Art - Starting Mill Taper
042 Prior Art - Starting Mill
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043 Prior Art - Shear Pin
044 Actual Deviated E~ore Hole
045 Planned Deviated Bore Hole
046 Second watermelon mill
s 047 First watermelon mill
048 Window Mill
049 Fulcrum Point (approximate) on tool
face
050 Leading edge of deflector plate
O51 PCD Inserts
l0052 Joint between Deflector Head and
Whipstock Body
053 Retainer Pins
054 Retainer Pin Hole
055 Deflector Head Sloped Side
056 Deflector Tool Face (continuation
of 11)
rs057 Curved back of Deflector Head
058 Deflector Head efFective le;ngth
059 Deflector Head Ridge
060 Deflector/whipstoc;k joint backside
weld gap
061 Weld Bead
zo062 Shear Pin Aperture
063 Shear Pin Recess
064 Keeper Ring Groove
065 Depth of Bottom/Base of Setting slot
066 Depth of Retrieval slot
zs067 End of Tool Face
068 Threaded stud aperture - on whipstock
body
069 Whipstock /joint l;~ackside weld
gap
070 Whipstock Ridge
071 Whipstock Tool Face (continuation
of 11)
so072 Spacer extended tool face (continuation
of 11)
073 Spacer back
074 Spacer Stud
075 Spacer Stud opening
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076 Spacer base length
077 Spacer depth
078 Spacer length
079 Spacer width
s 080 Hinge pin opening; - upper section
081 Hinge pin opening; - base section
082 Hinge section - upper sectiion
083 Right Spring opening - upper section
084 Left Spring opening - uppf:r section
l0 085 Right spring opening - base
086 Left spring opening - base
087 Hinge Pin
088 Spring retainer shear pin
089 Sloped back of hinge base
rs 090 Top sloped back of hinge base
091 Hinge Pin snap ring
092 Hinge Pin Snap Ring Grove
093 Spring retainer snap ring
094 spring retainer snap ring grove
ao 095 Hinge spring
096 Spring retainer shc;ar pin opening - upper section
097 Spring retainer shear pin opening - base section
098 Hinge section - base section
099 Casing Initial Cut Point
zs 100 Setting Tool Sub
101 Setting Tool Rectangular Bar
102 Setting Tool Fluid Line or Tubular
103 Weld between Bar and Fluid Line/Tubular
104 Weld between bar/line and sub
30 105 Shear Pin Threaded Aperture in setting tool bar
106 Setting Tool bottom face angle
107 Open end of fluid line - threaded female
108 Bottom Face of SE;tting Tool
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109 Setting Tool Length (measured from sub)
110 Hydraulic Hose Male Fitting
111 Setting Tube Receas or Offset
112 Setting Tool Thre;~ded Tubular Recess
s 113sHydraulic Hose - Short (Preferred)
1131.Hydraulic Hose - Long (Alternate)
114 Stainless Steel Hydraulic Hose Strap
115
116 Fishing Jars
l0117 By-pass Valve (unpinned)
118 Stabilizer
119 Single Drill Collar
120 Drill String
121 Drill Collars
is122 One Joint High Grade Drill Pipe
123 Combination of 120, 121 and 122 - upper
string assembly
124 Cross-over sub
125 Cross-over sub
126 Orientation sub
ao127 MWD tool
128 Pinned by-pass valve tool (or sub)
129 Short sub (for filling piston sub)
130 Lower Sub
131 Piston
as132 Piston O-ring and Groove
133 Circulation Channels)
134 Piston Riser
135 Riser Cap
136 Enlarged Piston Landing
so137 Riser Opening
138
139 Cross Passageway
140 Optional Piston Valve (or Sleeve Valve)
in General
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141 Tool Joint
142 Tool joint fluid passage
143 Hydraulic Street-ell
144 Hydraulic High Pressure Hose
s 145 Buttress Threaded Connection for Access to Piston Valve
146 Piston valve
147 Piston valve rings
148 Piston valve spring
149 Piston valve extension, attaches to retrieval tool
l0 150 Heavy Arrows showing fluid flow
151 Piston valve Spline
152 Piston valve Spline
153 piston valve Spline
154 Piston valve head
is 155 Lower piston valve sleeve
156 Upper piston valve sleeve
157 Piston valve centr~~l fluid passage
158 Piston valve cross fluid passage
159 Piston valve seal 1>oint
zo 160 The Retrieval Tool Generally (w/o top works)
161 Lengths of Tool
162 "
163 "
164 "
Zs "
165
166 "
167 "
168 Lengths of
Tool
169 "
30 "
170
171 "
172 "
173 "
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174 "
175 Wash Port
176 Wash Passageway
177 Hook
s 178 Retrieval Bar
179 Retrieval Tool Recess or Offset
180 Retrieval Tool Tola Sub
181 Fluid Passageway
182 Threaded opening
l0183 Retrieval Tool Hydraulic Hose
184 Stainless Steel Hydraulic Hose
Retainer Clamp
185 Hydraulic Street-ell
186 Threaded or Smooth Tubular Opening
187 Retrieval Tool Tubular
rs188 Weld
189 Tubular Plug
190 Protector Plate
191 Tool Joint
192 Tubular
ao193 Passageway
194 Threaded Connection
195 Flapper Valve Sleeve
196 Flapper Valve Passageway and Holder
197 Internal Fluid Pas;>age
zs198 Curved lower bottom
199 Sloped face of hook
200 Hook Weld to Tubular
201 Flapper Valve
202 Flapper valve Actuator
30203 Hook Valve
204 Hook Valve Actuator
205 Protector Plate Wc:ld Bead
206 Retrieval Tool Latch Pin
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207 Retrieval Tool La~:ch Spring
208 Retrieval Tool Latch Pin Retainer
209 Retrieval Tool Latch Aperture - pin and spring side in WHIP-ANCHOR
210 Retrieval Tool Latch Pin Opening - opening side in Retrieval Tool
s 211 Retrieval Tool Latch Aperture - pin and spring side in Retrieval Tool
212 Retrieval Tool Lay;ch Pin Opening - opening side in WHIP-ANCHOR
213
ro The following ANSI TA13LES are provided in the oil industry standard units
of measure,
which are based on the British System of Units. Dimensions are given in inches
unless
otherwise noted in the tables. Certain stress values are given in pound-force.
WHIP-ArJCHOR TYPE (oR slzE) AND PARAMETERS
Is
Type Bode Size Fits Bore Size Fits Casing Size Tool Face
Whipstock Inches Inches Angle Curvature
I :31/z 3'/a - 5'/z 4'/z - 66/a 2.09° 5'/z
2o II :>1/a 5',~ - 8 7 - 86/s 2.62° 8
II I .3 8 %< - 12'/z 96/e - 133/s 3 .18 ° 12'/z
C other as needed
ANSI TABLE 1
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DEFLECTOR HEAD PARAMETERS
WHfP-ANCHOR Slope Length Thickness
at
Type and Sizt~ Connection
I - 3'/2" OD 2.09 13'/ " '/2"
II - 5'/2" OIL 2.62 16'/2" 3/a"
III - 8" OD 3.18 18" 1"
ANSI TABLE
2
SETT:~1G
TOOL
PARAMETERS
is
WHIP-ANCHOR Slope Setting Slot Thickness to Deflection
of
Type and Size Length, Width, Back of Tool Milling
Depth Tool
I - 3'/2" OD 2.09 22'/a" x 1'/32"'/2" 1.31"
x 0.81"
2o II - 5'/2" OD 2.62 19'/2" x ls/32"3/a" 1.65"
x 0.90"
III - 8" OD 3.18 18" x 2'/32" 1" 2.00"
x 1"
ANSI TABLE 3
OPTIONAL SPACER PARAMETERS
Whipstock Casing Bore SpacerCurve Tool Face
Type Size Size Size DepthBack Cup and Slope
I 3'/2 4'/2 3'la 0 NA NA at NA
- 66/a - 4'lz
I 3'/2 4'/2 4 ~ - '/a 3'/2 5'/2 at 2.09
- 66/a 5'/2
II 5'/2 7 - 86/e5 % - 0 NA NA at NA
7
3s II 5'h 7 - 86/s7'la 6/e 5'/2 8 at 2.62
- 8
III 8 96/a 8'/0 0 NA NA at NA
~- 133/a- 10
III 8 96/a 10 -11 1 8 12'/2 at 3.18
~- 133/s
III 8 96/a 11'h 13/a8 12'/2 at 3.18
~- 133/s- 12'/2
ANSI
TABLE
4
SHEAR STUD PLACEMENT
AND SETTING SLOT
BASE PARAMETERS
as
Whip-Stock Stud Slot Slot Slot Up from base Stud
Size Size Width Depth Lengthof Slot Depth
I '/2" 1~/32~~0.81" 22~~" In 3/8~r
II 6/e" 1"/3z" 0.90" 19'/z" 1'/a" '/2"
III 3/a 2'/32" 1.00" 18" 1'/2 '/a
ANSI TABLE 5
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ADDITIONAL SETTING TOOL PARAMETERS
Whipstock Type Bar Tool Fluid Line Top Sub OD Shear Stud
or Size Length, Width, Depth Size - Rating & Connection Size
I - 3'/z" OD 40" x 1" x 1" 6/a" - 4000 PSI 33/a" w/ 23/a"IFB '/z"
II - 5'/z" OD 40" x 1'/z" x 1'/a" '/a " - 4000 PSI 4'/a " w/ 3'/z"IFB 6/a"
III - 8" OD 40" x 2" x 1'/z" 1" - 4000 PSI 6'/z" w/ 4'/z"IFB '/a"
1o ANSI TABLE 6
RETRIEVAL TOOL DIMENSIONS
Whip-Anchor Tool Tool. Hook Hook Hook Wash Material Top Latch Hook
Size Length Width Depth Width Length Port ID Strength Connection OD Angle
I 54" 3'/z" 1" 1" x'/z" 4" '/a" 100K 23/a" IFB
'/a" 35°
II 56" 5'/z" 1'/z" 1'/z" x 1" 5" 3/a" 120K 2'/z" IFB
3/a" 35 °
III 58" 7'/z" 2" 2" x 1'/z" 6" '/z" 160K 4'/z" IFB '/z" 35°
ANSI TABLE 7
SEIEAR PULL VALUES
Whip-Anchor Size Bore Approximate Shear
size Force*
Shear
Stud
Size
I 3'/z" OD 3'/ - 5'/z" '/z" x 1" 10, 15 & 20,000 pounds
" length
II 5'/z" OD 5'/ - 8" 6/a" x 1'/ 20, 25 & 30,000 pounds
" " length
III 8" OD 8'/4"- 12'/z" 3/ " x 30, 35, 40 & 45,000
1'/z" length pounds
* varies with Whip-anchor
size
ANSI TABLE 8
The above tables have bean provided to aid the reader, who is skilled in the
art of oil field
ao equipment, by providing the original tool tables in ANSI standard units.
