Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
CA 02270268 2006-09-06
78543-149
1
ORIENTING TOOL AND METHOD
FIELD OF THE INVENTION
The present invention is generally directed to an
assembly for drilling and completing deviated boreholes.
More particularly, the invention relates to orienting tools
for positioning in well bore casing.
BACKGROUND OF THE INVENTION
Deviated boreholes are drilled using whipstock
assemblies. A whipstock is a device which can be secured in
the casing of a well and which has a tapered, sloping upper
surface that acts to guide well bore tools along the tapered
surface and in a selected direction away from the straight
course of the well bore.
To facilitate the use of a whipstock, a section of
casing is used which has premilled window openings through
which deviated well bores can be drilled. The whipstock can
be positioned relative to the window using a landing system
which comprises a plurality of stacked spacers mounted on a
fixed mounting device at the bottom of the casing and
defining at the top thereof a whipstock retaining
receptacle, or by use of a latch between the whipstock and
the casing. A stacked landing system can cause difficulty
in aligning the whipstock with the window opening as the
distance between the mounting device and the window
increases. The whipstock may also turn during the drilling
or setting processes resulting in the deviated well bore
being directed incorrectly and/or the well bore tools being
stuck in the wellbore. Sometimes a latch system is used to
overcome some of these disadvantages. However, the latch
CA 02270268 2006-09-06
78543-149
la
can sometimes disengage between the whipstock and the
casing, allowing the whipstock to turn or move down in the
casing.
After the deviated wellbore is drilled, it can be
left uncompleted or completed in any suitable way. To seal
the deviated wellbore hydraulically from the main casing, a
liner can be installed and cement can be pumped behind the
liner. This is expensive and
CA 02270268 1999-04-27
2
often creates obstructions in the main casing which complicates removal and
run of the
tools.
When the tools are used in horizontal primary bores, new problems arise.
Running and
retrieval tools which are useful for vertical tool manipulation are not always
useful in
horizontal applications.
SUMMARY OF THE INVENTION
An assembly for drilling and/or completing a deviated wellbore has been
invented. In
one aspect the assembly includes a toolguide which can be positioned relative
to a
window opening in a casing section and releasably locked in position. The
toolguide
or portions thereof can have applied thereto a coating which prevents damage
to the
metal components of the toolguide and facilitates removal of the toolguide
from the
wellbore after use.
A tool guide for creating deviated borehole branches from a wellbore includes
a
whipstock including a sloping face portion and a lower orienting section,
including at
least one latch biased radially outwardly from the orienting section and
positioned in a
known orientation relative to the sloping face portion and a latch locking
means to
releasably lock the latch in an extended position, the latch locking means
being
actuated to lock the latch by torsion of the mandrel within the lower
orienting section.
Each latch of the orienting section is selected to fit within and lock into
its own latch
receiving slot formed in the casing. When the latch of the orienting section
is locked
into the latch receiving slot the toolguide will be maintained in position in
the casing.
Preferably, the casing includes at least one premilled window opening
positioned in
known relation relative to the latch receiving slot. Preferably, a removable
liner can be
positioned in the casing to close the window opening temporarily and to cover
the latch
receiving slot.
The orienting section can be releasably connected to the whipstock. Such
connection
CA 02270268 1999-04-27
3
is preferably by connectors such as, for example, shear pins to the whipstock
so that
these parts can be installed together into the casing. Preferably, the
connectors are
selected such that the sections can be separated by an application of force
sufficient
to overcome the strength of the connectors. This permits the whipstock and the
lower
section to be separated and removed separately should one part become stuck in
the
casing.
The sections are movable relative to one another and means are provided to
translate
such movement to actuate such means as a seal.
Preferably, the lower orienting section includes a mandrel engaged slidably
and
rotatably within an outer housing. The mandrel is releasably connected to the
whipstock and moveable with the whipstock. Preferably, the latch locking means
is an
extension of the mandrel. The extension can be formed to fit behind the latch
to lock
it in the outwardly biased position.
Another toolguide for creating borehole branches from a wellbore, the
toolguide having
a longitudinal axis and comprising a whipstock including a sloping face
portion, a lower
orienting section, the whipstock and the lower orienting section being
connected and
moveable relative to each other along the longitudinal axis of the tooiguide,
and an
annular sealing means mounted below the whipstock, the annular sealing means
being
actuatable to expand and retract upon movement of the whipstock and the lower
orienting section relative to one another.
The whipstock is attached to a central mandrel of the lower orienting section.
The
central mandrel is engaged slidably and rotatably within an outer housing of
the lower
orienting section. The outer housing carries the annular sealing means which
is
actuatable to expand or retract by movement of the mandrel within the outer
housing.
Preferably, the outer housing includes a first section and a second section
and
disposed therebetween the annular sealing means. The first section is moveable
toward the second section to compress the annular sealing means therebetween
and
cause it to expand outwardly. In this embodiment, preferably the mandrel has a
CA 02270268 2006-09-06
78543-149
4
shoulder positioned thereon to abut against the first
section and limit the movement of the mandrel into the outer
housing. Abutment of the shoulder against the first section
causes the first section of the housing to be driven in
towards the second section and the annular sealing means to
be compressed and expanded outwardly.
Previous orienting tools were difficult to use
because it was necessary to run the tool to a known depth
and then search around for the position of the slot for
accepting the latch on the tool. Because the latches of
some orienting tools have to be biased outwardly on the trip
down into the well, it has been difficult to use the
orienting tools in wells, for example, having more than one
lateral window and therefore more than one orienting slot
for accepting the latch of the tool. To the problem of
having the latch lock into the incorrect slot, where
multiple slots are present, it has been necessary to shape
the slots in the casing such that they will only accept one
form of latch. This solution presents logistical problems,
however, and limits the number of slots which can reasonably
be positioned in the casing.
Thus, in accordance with one broad aspect of the
present invention, there is provided an orienting tool for
positioning in a well bore casing having a profile
positioned therealong, the tool comprising: a body; at least
one member mounted on the tool body and biased outwardly, at
a selected pressure, therefrom, the selected pressure being
great enough to permit determination of when the at least
one member has moved past the profile but not being so great
as to prevent the at least one member from moving past the
profile using an applied force.
CA 02270268 2006-09-06
78543-149
4a
In accordance with another broad aspect of the
present invention, there is provided a method for
positioning an orienting tool within a section of casing
comprising: providing a well bore casing having a profile
positioned therealong, providing an orienting tool including
a body; at least one member mounted on the tool body and
biased outwardly, at a selected pressure, therefrom, the
selected pressure being great enough to permit determination
of when the at least one member has moved past the profile
but not being so great as to prevent the at least one member
from moving past the profile using an applied force; moving
the orienting tool along the well bore casing using an
applied force until it is determined that the at least one
member has moved past the profile.
The at least one member can be a spring loaded dog
or an arm such as, for example, a part of a collet, a collar
locator or any other means. In preferred embodiment, the at
least one member is part of a ring of dogs mounted about a
circumference of the tool body and biased outwardly
therefrom. The at least one member is outwardly biased at a
selected pressure which will require the application of
20,000 to 30,000 pounds force to the tool in order to move
the at least one member past the profile. At this pressure,
when the member passes a profile, there will be an
indicative overpull or decrease in drill string weight.
CA 02270268 1999-04-27
The at least one member can be biased outwardly by any desired means such as,
for
example, springs. In a preferred embodiment, the biasing means is selected to
exert
increased pressure as the depth of the tool is increased. This biasing means
is
preferred as it provides that less force is required to move the tool through
the casing
5 at shallower depths but requires greater force to be moved through the
casing when it
is at greater depths and, therefore, when there is greater available drill
string weight to
act on the tool. One such biasing means is sensitive to hydrostatic pressure
and
applies a pressure to the at least one member which increases with an increase
in
hydrostatic pressure of the fluids about the tool. It may be necessary to set
an upper
limit for the selected pressure applied to the at least one member.
The profile and the at least one member are preferably correspondingly
positioned so
that the at least one member will be affected by the profile regardless of the
rotational
orientation of the tool within the casing. To avoid forming a protrusion which
extends
inwardly from the casing inner surface and reduces the ID of the casing,
preferably the
profile is a groove sized to accept the at least one member therein. In a
preferred
embodiment, the groove is a radial groove extending about the ID of the
casing.
There can be more than one profile along a length of casing. Where more than
one
profile is present along the casing, the at least one member will be affected
by each
profile in a similar manner. Preferably, the profiles are non-selective. The
specific
profile which is affecting the member can be determined using tool depth
information,
the measurement of which is well known in the art.
Where it is desired, in addition to positioning the tool at a selected
orientation along the
casing, to position the tool at a selected rotational orientation within the
well, the tool
can further comprise a latch for fitting into a slot positioned at a selected
rotational
position about the center axis of the casing. The tool is selected to provide
for rotation
of at least the portion of the tool carrying the latch to permit the latch to
be located in
its slot. In one embodiment, the tool body includes a first part carrying the
at least one
member, a second part carrying the latch and a joint positioned therebetween
for
permitting the second part to rotate relative to the first part and preferably
also to move
CA 02270268 1999-04-27
6
out of axial alignment with the first part.
The orienting sections according to the present invention can be used to
orient
whipstocks as well as other tools such as, for example, retrieval tools,
sleeve shifting
tools and lateral completion tools.
A whipstock for use in creating wellbore branches from a well bore can have a
main
body formed of a first material of reduced diameter to facilitate washover or
engagement by die collars or overshots. The main body has extending out
therefrom
centralizers such as stand off rings or extensions the main body. Sometimes a
coating
material is disposed at least over a portion of the main body, the coating
material being
softer than the first material and being resistant to oil and gas.
In a whipstock having a main body of reduced diameter relative to centralizers
formed
thereon, it has been found that the width of the sloping face portion is
greatly reduced.
This reduces the surface area which is available to guide the drill bit or
mill off the
whipstock face and the mill or drill bit tends to roll off the sloping face
portion in the
direction of rotation of the drill.
To prevent roll off and to centralize and stabilize the upper tapered end of
the
whipstock, while continuing to facilitate washover procedures, a whipstock is
provided
including a main body having an outer surface, a sloping face portion formed
on the
main body and having a slope angle and an extension formed on the main body
about
the sloping face such that the diameter of the extension is greater than the
diameter of
the main body.
Preferably, the extension about the sloping face portion forms an effective
diameter
which is substantially equal to the drift diameter of the casing into which it
is to be used.
The extension preferably conforms to the slope angle of the sloping face
portion and,
where the sloping face portion has a curvature, follows and continues the
curvature of
the sloping face portion.
CA 02270268 1999-04-27
7
The whipstock can include centralizers extending out from the main body.
Preferably,
the effective diameter of the whipstock at the centralizers is substantially
equal to the
effective diameter of the whipstock at the extensions.
In one embodiment, the main body has applied thereto a coating, for example of
polymeric material. The coating material can be applied against the extension
and the
centralizers, if any.
Running and retrieving tools are required for moving the tools through the
well bore.
Previous running tools for whipstocks used shear bolts for attachment between
the
running tool and the whipstock. These shear bolts are prone to shearing
prematurely
if the whipstock is bumped at surface while entering the will or sue to
running the
assembly through a tight area in the casing. The shear bolt may also shear
prematurely
if the assembly is rotated.
A new tool has been invented which is positively latchable to the whipstock in
a manner
that allows forces to be applied upwardly or downwardly as well as
rotationally without
risk of prematurely releasing the whipstock. At the desired time of release,
hydraulic
pressure is applied to the tool to unlatch it from the whipstock.
In accordance with a broad aspect of the invention, therefore, there is
provided a
running/retrieval tool for moving a well tool through a well bore casing, the
running/retrieval tool comprising: a body; a latch for releasably engaging the
well tool
and being driven to move between a retracted position recessed in the body and
an
extended position in which a portion of the latch extends from the body; and a
guide
selected to act against the well tool to guide the latch into engagement with
the well
tool.
The latch can be driven between the retracted position and the extended
position by
any desired means. Preferably, the drive means for the latch can be controlled
from
surface and can be, for example, a hydraulic system.
CA 02270268 1999-04-27
8
The guide is formed on the tool and can be selected to engage with the well
tool in such
a way as to transmit rotational energy to the well tool. A key can be provided
on the
tool to assist in the location of the tool relative to a well tool to be
retrieved. In a
preferred embodiment, an outwardly biased key is provided which is engage able
into
an orienting slot formed on the casing section adjacent the mounting position
of the well
tool to be used with the running retrieval tool.
In another embodiment, the running/retrieval tool according to the present
invention
includes a outwardly extendable and retractable key useful for applying force
against
the casing in which the tool is positioned to urge it toward one side of the
casing. The
key can be extendable by a hydraulic system.
A casing section for a deviated wellbore junction comprises a cylindrical
casing tube
having a central axis and a window opening formed therein. A sleeve having an
opening therein is mounted relative to the casing tube to move between a first
position
in which the opening of the sleeve is aligned with the window opening of the
casing tube
and a second position in which the opening of the sleeve is not aligned with
the window
opening of the casing tube.
Another casing section for a deviated wellbore junction includes a casing tube
having
a central axis and a window opening formed therein. A sleeve having a first
opening
and a second opening therein is mounted relative to the casing tube to move
between
a first position in which the first opening of the sleeve is aligned with the
window
opening of the casing tube and a second position in which the second opening
of the
sleeve is aligned with the window opening of the casing tube.
Preferably, sealing means are disposed between the casing tube and the sleeve.
These sealing means are preferably selected to effect a hydraulic seal between
the
parts. In one embodiment, the sealing means are formed of deformable materials
such
as rubber or plastic and is disposed around the opening of the sleeve and
along the top
and bottom thereof.
CA 02270268 1999-04-27
9
In a preferred embodiment, the sleeve has formed therethrough two openings.
The first
opening is sized to allow access to the window opening of the casing section
by
deviated borehole tools and the second opening is smaller than the first
opening.
In one embodiment, the sleeve is disposed within the casing tube in a
counterbore
formed therein such that the inner diameter of the sleeve is greater than or
substantially
equal to the inner diameter of the casing away from the position of the
sleeve.
Preferably, the window of the casing is formed to accept a flange of a
junction fitting
such as, for example, a tieback hanger of a branched wellbore. In a preferred
embodiment, the sleeve is selected to seal against the flange of the fitting.
Some prior methods of tieing back or hanging a liner to a window opening of a
casing
section requires that the ID of the main casing is reduced or completely
closed off. This
is undesirable since it restricts the ability to move tools through the casing
past the
junction of the liner with the casing. In an effort to avoid restricting the
ID of the casing,
some other prior methods increase the OD of the main casing by attaching
tieback
hanger engaging means on the outside of the casing. This is also undesireable
as it
can complicate the run in of casing, especially in unstable boreholes.
Thus a system for tieing back a liner has been invented wherein the ID of the
casing is
not restricted and the OD of the casing is not increased. In accordance with a
broad
aspect of the present invention, there is provided a system for tieing back a
liner from
a well bore casing, the system comprising: a well bore casing including a
window
opening formed therethrough, the window opening defined by edges extending
between
the outer surface of the casing and the inner surface of the casing, the edges
including
beveled portions formed such that an acute angle is formed at the intersection
of the
edges and the outer surface of the casing; and a tieback hanger having a
outboard end
onto which a liner attachable and an anchored end for attachment to the casing
when
the outboard end has been inserted through the window opening of the casing,
the
anchored end having thereon a flared tab for engaging against the beveled
portions of
the window opening edges.
CA 02270268 1999-04-27
In one embodiment, the beveled portions of the window opening are positioned
on
opposite sides of the window opening such that a dovetail mortise is formed
therebetween and the flared tab is dovetailed to wedge into the dovetail
mortise formed
between the beveled portions. There can be more than one tab formed on the
tieback
5 hanger, as desired.
The edges of the window opening and the anchored end of the tieback hanger can
be
formed to snappingly engage with each other to prevent the tieback hanger from
both
passing outwardly through the window opening and moving back into the ID of
the
casing, once the parts are engaged together.
10 Preferably, the flared tab is sized such that when it is engaged against
the beveled
portions, the tab substantially does not extend inwardly past the inner
surface of the
casing.
BRIEF DESCRIPTION OF THE DRAWINGS
A further, detailed, description of the invention, briefly described above,
will follow by
reference to the following drawings of specific embodiments of the invention.
These
drawings depict only typical embodiments of the invention and are therefore
not to be
considered limiting of its scope. In the drawings:
Figure 1 is a schematic representation of an embodiment of an assembly
according to
the present invention, the assembly being positioned in a wellbore;
Figure 2 is a view showing the orientation of Figures 2a and 2b.
Figures 2a and 2b are a longitudinal section along a casing section for a
deviated
wellbore junction useful in the present invention;
Figure 3A is a view showing the orientation of Figures 3A-a and 3A-b;
CA 02270268 1999-04-27
11
Figures 3A-a and 3A-b are a front elevation view, partly cutaway, of a
whipstock of a
toolguide according to the present invention;
Figure 3B is a view showing the orientation of Figures 3B-a and 3B-b;
Figures 3B-a and 3B-b are a section along line 3B-3B of Figure 3A;
Figure 4A is a view showing the orientation of Figures 4A-a and 4A-b;
Figures 4A-a and 4A-b are a front elevation view, partly cutaway, of a
whipstock of
another tooiguide;
Figure 4B is a view showing the orientation of Figures 4B-a and 4B-b;
Figures 4B-a and 4B-b are a section along line 4B-4B of Figure 4A;
Figures 4C and 4D are sectional views along line 4C-4C and 4D-4D,
respectively, of
Figure 4B;
Figure 4E is a bottom end view of Figure 4A;
Figure 4F is a top end view of Figure 4A;
Figure 5A is a front elevation view of a lower section of a toolguide
according to the
present invention, partly in section and in un-compressed configuration;
Figure 5B is a front elevation view of the toolguide of Figure 5A in
compressed
configuration;
Figure 5C is a section along line 5C-5C of Figure 5A;
Figure 6A is a view showing the orientation of Figures 6Aa and 6Ab;
CA 02270268 1999-04-27
12
Figures 6Aa and 6Ab are longitudinal sections along another lower section of a
toolguide in a set configuration;
Figure 6B is a view showing the orientation of Figures 6Ba and 6Bb;
Figures 6Ba and 6Bb are longitudinal sections along another lower section of a
tooiguide;
Figure 7 is a view showing the orientation of Figures 7A to 7C;
Figures 7A to 7C are longitudinal sections along a casing section for a
deviated
wellbore junction;
Figure 8 is a view showing the orientation of Figures 13a and 13b;
Figures 8a and 8b are longitudinal sectional views along a running/retrieving
tool;
Figure 9 is a longitudinal section along another casing section for a deviated
wellbore
junction according to the present invention;
Figure 10 is a rear plan view of a sleeve according to the present invention
in flattened
configuration;
Figure 11A is a sectional view through a deviated wellbore junction using a
casing
section according to the present invention;
Figure 11 B is a front elevation view of a tieback hanger;
Figure 11 C is a front elevation view of a tieback hanger;
Figure 12 is a front elevation view of another sleeve according to the present
invention
in flattened configuration;
CA 02270268 1999-04-27
13
Figure 13 is a view showing the orientation of Figures 13a and 13b;
Figures 13a and 13b are elevation views of a casing section including a window
opening;
Figure 14 is a longitudinal sectional view along a liner positioning tool;
Figure 15 is schematic representation of a system for imparting rotational
force on a drill
pipe;
Figure 16A is a longitudinal sectional view along a sleeve shifting tool
according to the
present invention;
Figure 16B is front elevation view of a portion of the sleeve shifting tool of
Figure 16A
showing the sleeve engaging slips;
Figure 17 is an elevation view of a casing section including a window opening
according
to the present invention;
Figure 17A is a sectional view along line A-A of Figure 17;
Figure 17B is a sectional view along line B-B of Figure 17;
Figure 17C is an enlarged view of an edge of the window opening, as noted in
Figure
17A;
Figure 18 is a front elevation view of a tieback hanger in accordance with
another
aspect of the present invention;
Figure 18A is a sectional view along line A-A of Figure 18 showing the lower
setting tab;
Figure 18B is a sectional view along line B-B of Figure 18 showing the mid
setting
CA 02270268 1999-04-27
14
flanges;
Figure 18C is a sectional view along line C-C of Figure 18 showing the upper
setting
tab;
Figure 19A is a sectional view through a casing section according to Figure 17
having
a tieback hanger according to Figure 18 therein with the upper setting tab in
unengaged
position; and
Figure 19B is a sectional view as in Figure 19A with the upper setting tab in
engaged
position in the window of the casing section.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
For the purposes of clarity, in the Figures only reference numerals of the
main
components are indicated and like reference numerals relate to like
components.
Referring to Figure 1, there is a shown a tubular wellbore casing 2 for
installation in a
primary wellbore 4 drilled through a formation. Primary wellbore 4 can be a
main
wellbore directly opening to surface or a lateral wellbore drilled from a main
wellbore.
Primary wellbore can range between a vertical and a horizontal orientation.
Casing 2
includes upper and lower sections of production casing 6 and secured
therebetween
a casing section 8 for use in deviated wellbore junctions. The deviated
wellbores
branch from wellbore 4.
Casing sections 6 and 8 are connected by standard connectors 9 or any other
suitable
means. A float collar 10 is provided at the lower end of casing 2 which allows
fluids to
flow out of the casing but prevents flow of fluid and debris back into
wellbore casing 2.
Any similar one way valve can be used in the place of float collar 10. By a
completion
procedure, cement 11 is disposed in the casing annulus.
Casing section 8 includes a window in the form of an elongated opening 12
extending
CA 02270268 1999-04-27
in the longitudinal direction of casing 8. In use, opening 12 is oriented
toward the
desired direction of a deviated wellbore to be drilled, shown in phantom at
14. The
window is sized and shaped with reference to the desired diameter and azimuth
of the
deviated wellbore to be drilled and the diameter of the casing, as is known in
the art.
5 Casing section 8 further has formed therein a latch receiving slot 16a at a
selected
orientation relative to window opening 12. The latch receiving slot can be
oriented at
any point around the interior circumference of the casing section, so long as
its position
is known with respect to the window opening. Preferably, latch receiving slot
16a is
aligned with the longitudinal axis of window 12, as shown, or is directly
opposite window
10 opening 12.
A toolguide 18 is installed in casing 2 with its latch 20 extending into slot
16a. Toolguide
18 includes a lower orienting section 22, also called a monopositioning tool,
from which
latch 20 is biased radially outwardly, and a whipstock 24 having a sloping
face portion
26. Sections 22 and 24 are connected so that they are not free to rotate
relative to
15 each other, whereby face portion 26 is maintained in a fixed and known
orientation
relative to latch 20. In a preferred embodiment, as shown, latch 20 is aligned
at the
bottom of sloping face portion 26, so that the surface of the sloping face
portion will be
aligned opposite window opening 12, when latch 20 is in slot 16a.
An annular expandable seal 28 is disposed on toolguide 18 below sloping face
portion
26. The seal 28 when expanded, acts to prevent debris and fluids from passing
down
the wellbore. Seal 28 is, therefore, selected to have an outer diameter, when
expanded, which is greater than the inner diameter of the casing in which it
is to be
used.
Toolguide 18 is placed in casing 2 by use of a running tool 30 which
releasably locks
onto whipstock 24 and is shown in this drawing still attached to the
whipstock. Running
tool 30 is connected to a drill pipe 32.
To remove the toolguide from the wellbore, a retrieving tool can be used.
Figures 8,
CA 02270268 1999-04-27
16
show a tool that is useful for both running and retrieving operations.
To prepare for the drilling of a deviated borehole, such as that shown at 14,
the
wellbore casing 2 is installed and completed. Figures 2 shows apparatus useful
for
permitting completion of the well while preserving features used in the
invention.
Casing section 8 is milled to include a window opening 12 and a latch
receiving slot
16a. Preferably, a slot 17 (Figures 2) for alignment of retrieval tools is
also milled out
in casing section 8. Preferably, window opening 12 and latch receiving slot
16a are
aligned along the casing.
A liner 34 is positioned in casing 8 and seals 36a and 36b are provided
between liner
34 and casing 8. A float collar 38 and an orienting subassembly 39 are
attached above
liner 34. Float collar 38 and orienting subassembly 39 can be positioned, as
shown, or
can be positioned further up the casing provided orienting subassembly is in a
known
configuration relative to window opining 12. Preferably, a removable filler 41
which is
selected to withstand high downhole hydrostatic pressures, such as high
density
polyurethane or cement, is inserted between casing 8 and liner 34 between
seals 36b
to fill window opening 12 and the casing section 8 is wrapped in a rigid
material 40,
such as fibre glass or composite tape, to cover at least opening 12.
Preferably, slots 16a and 17 are filled with liquid or easily removable
filling materials
such as grease and/or foam to prevent materials from entering into the slots
and the
remainder of spaces 43, defined between casing 8, liner 34 and seals 36a, 36b,
are
filled with cement. To further prevent entry of materials into slots 16a, 17,
caps 44 are
welded onto the outer surface of casing 8 over the slots.
Casing 8, including the parts as noted hereinbefore, is connected to casing
sections 6
to form casing string 2 and float collar 10 is attached. Casing string 2 is
lowered into
wellbore 4. The casing string is rotated until window opening 12 is oriented
in the
direction in which it is desired that the deviated wellbore 14 should extend.
Suitable
methods are well known in the oil and gas industry for orienting downhole
tools. As an
example, a surface reading gyro, a mule shoe or other suitable means can be
used.
CA 02270268 1999-04-27
17
The cased wellbore is completed by forcing cement through the casing string
and into
the annulus between the casing and the wellbore. During completion, the cement
is
forced through float collar 38 and liner 34 but is prevented from moving
behind liner 34
by seals 36a and the cement and fillers in spaces 43. As the cement fills the
casing
annulus, it is prevented from entering slot 16a by cap 44 and is prevented
from entering
window opening 12 by the filler 41 and rigid materials 40. The cement is
allowed time
to set.
After completion, a drill (not shown) of a diameter selected to be
approximately equal
to the inner diameter of the casing is run into the well to remove cement from
the casing
bore. The drill wRl also drill out liner 34, seals 36a, 36b, float collar 38
and cement in
spaces 43. Thus, liner 34 is formed of a material such as, for example,
aluminum, fibre
glass, or carbon fibre-containing composite, which can be removed by drilling
or by any
other method without having to retrieve to surface. Where aluminum is used in
the
wellbore, preferably any aluminum surfaces which are exposed and will be
contacted
by the cement used in the completion operation, are coated with a suitable
material,
such as rubber cement, to improve the bond of the cement to the aluminum.
The casing is then ready for production or for drilling deviated wellbores.
Where
deviated wellbores are to be drilled a toolguide 18 will be run in and
oriented in the
casing as shown in Figure 1.
In Figures 3A and 3B and Figures 4A to 4F, two embodiments of a whipstock are
shown. Referring to Figures 3A and 3B, a whipstock 24 tapers toward its upper
end to
form a sloping, ramped face portion 26 which is formed to direct any tool
pushed along
it laterally outwardly at a selected angle. The face portion is machined to
have a
selected slope x or range of slopes with respect to long axis 52 of the
section
depending on the build radius desired for the deviated wellbore. As an
example, when
x is 4 , the build radius will be approximately 15 /30 meters drilled.
Preferably, sloping
face portion 26 is formed to be concave along its width.
An entry guide 49 is welded at the top of face portion 26. Entry guide 49
assists in
CA 02270268 1999-04-27
18
centralization and tool retrieval and need only be used, as desired. A bore 50
extends
a selected distance through the whipstock parallel to its central axis 52.
Bore 50 is
formed to engage a fishing spear device and provides one means of retrieving
the
tooiguide from the wellbore. Extending back from face portion are slots 53
formed to
accept and retain a retrieval tool having corresponding sized and spaced hooks
thereon. Also formed on face portion 26 are apertures 54 formed to accept
shear pins
(not shown) for attachment to running tool 30 (Figure 1).
Centralizers 56 are spaced about the whipstock. While only one centralizer is
illustrated
in the drawing, there are preferably at least three centralizers on the upper
portion to
center the whipstock in the hole. The centralizers can take other forms, as
desired.
A socket 58 extends from the bottom of whipstock 24 parallel with central axis
52.
Socket 58 is shaped to accept a male portion 68 on the lower orienting section
22, as
will be discussed hereinafter with reference to Figures 5A and 5B. Preferably,
socket
58 is faceted at 60 and male portion 68 is similarly faceted so that the parts
lock
together and male portion 68 cannot rotate within socket 58. Shear pins 61 are
inserted
through apertures 62 to secure male portion 68 in socket 58 and thereby, the
whipstock
to the lower section.
The whipstock is formed of hardened steel and has applied thereto a polymeric
coating
64 (shown only in Figures 3B). Polymeric coating 64 is, preferably, formed of
cured
polyurethane but can be formed of other polymers such as epoxy. Coating 64
acts to
prevent damage of the metal components of the whipstock and can be reapplied
if it is
removed during use. Coating 64 further facilitates wash over operations,
should they
become necessary, to remove the toolguide or whipstock from the casing. The
coating
is thick enough so that it will accommodate normal damage from, for example,
abrasion
and will prevent damage to the metal surfaces of the whipstock and is
preferably also
thick enough so that substantially only the coating will be removed by any
washover
operation. In a preferred embodiment, the coating is about'/2 inch thick and
is applied
using a mold, so that the shape of the tool after coating is controllable. If
damage
occurs to the coating, it can be replaced.
CA 02270268 1999-04-27
19
The maximum outer diameter of the whipstock to the outer surface of the
coating is
selected to be smaller than the inner diameter of the casing in which it is to
be used.
In particular, the maximum effective outer diameter of the whipstock is
selected to be
as large as possible without exceeding the drift diameter (i.e. the maximum
diameter
permitted according to regulations for any tool for use in a casing of a
particular id) for
the casing.
Because coating 64 is easily abraded and, to a limited degree, deformable, the
coating
can interfere with tool centralization. Thus, to permit correct centralization
of the
whipstock within the casing, preferably centralizers 56 extend out from the
metal portion
of the whipstock a distance at least equal with the thickness of coating 64.
In this way,
centralizers 56 are either flush with the surface of the coating or extend out
therefrom.
Referring to Figures 4A to 4F, another whipstock 24' is shown. Whipstock 24'
includes
a sloping face portion 26'. Generally, whipstocks are useful for producing
deviated
wellbores having only a selected one of a long, medium or short radius
deviated
wellbore. However, the profile of sloping face portion 26' of whipstock 24' is
formed to
allow flexibility to produce both medium and short radius laterals.
Whipstock 24' is selected to be useful with a running/retrieval tool as is
described in
more detail in Figures 8. In particular, whipstock 24' has formed at its upper
end a
dove-tail slot 51 and a second slot 55. These slots will be described in more
detail with
respect to Figures 8.
Centralizers 56' are formed integral with the metal portion of the whipstock.
While six
centralizers are shown, it is to be understood that only three centralizers
are required
for proper functioning.
Whipstock 24' includes a socket 58' which is generally similar to socket 58
described
with reference to Figures 3B. Socket 58' includes a faceted portion 68.
Apertures 62
CA 02270268 1999-04-27
extend through centralizers 56' and open into socket 58' for accepting shear
pins (61'
in Figures 6A) for securing the whipstock to the lower section.
A coating 64' of polymeric material is applied over selected portions of
whipstock 24'.
As noted with respect to Figures 3B, preferably coating 64' is applied to be
flush with
5 the outer, contact surface of centralizers 56'. The effective diameter of
the whipstock
to the outer surface of the coating is substantially the same as the effective
diameter
of the whipstock at the centralizers, which is selected to be equal to or just
less than the
drift diameter of the casing in which whipstock is to be used.
In using whipstocks that are of a reduced diameter and have applied thereover
or
10 attached thereto coatings or brass stand-off rings or that have been
modified in other
ways to facilitate washover or engagement by die collars or overshots, it has
been
found that the surface area of the sloping face portion is greatly reduced.
This reduces
the surface area which is available to guide the drill bit or mill off the
whipstock face and
the mill or drill bit tends to roll off the sloping face portion in the
direction of rotation.
15 To prevent roll off and to centralize and stabilize the upper tapered end
of the
whipstock, while continuing to facilitate washover procedures, the surface
area of face
portion 26' is increased by an extension 65 which extends around face portion.
Extension 65 acts to extend the width of face portion 26' such that the
effective
diameter of the whipstock at the extension 65 is equal to or just less than
the drift
20 diameter for the whipstock which is substantially equal to the effective
diameter at the
centralizers. A cavity is formed on the outer surface of the whipstock between
the
centralizers and the extension into which coating 64' is applied. The radial
length of the
whipstock relative to the long axis 52' is selected to be substantially equal
along the
length of the whipstock. As an example, in the preferred embodiment, the
radial length
r1 at the extension, the radial length to the outer surface of a coated area
r2 and the
radial length to the outer contact surface of a centralizer 56' r3 are each
substantially
equal. The extension is preferably 1/2" to 1" thick.
In Figures 5A and 5B, one embodiment of a lower orienting section 22 is shown.
Figures 6A show another embodiment of a lower orienting section 22'. Orienting
CA 02270268 1999-04-27
21
sections 22 or 22' can be utilized to position and orient any assembly in any
desired
depth profile included in the casing string. This may include whipstocks, for
example
as shown in Figures 3A or Figures 4A, packers, completion diverters or tubing
splitters
or any other completion tools required to be oriented in a particular location
in the
casing, such as for example, adjacent a lateral window.
Section 22 is shown uncompressed in Figure 5A. In Figure 5B, section 22 is
shown in
a compressed, set condition as would be the condition of the section when used
in a
toolguide which is locked in position in a wellbore ready for use. Lower
orienting section
22 includes a male portion 68 shaped to fit into the sockets 58 or 58' on the
whipstocks.
Bores 70 (only one is shown) accept ends of shear pins 61.
Male portion 68 is connected to a central mandrel 72. Central mandrel 72 is
mounted
in a bore 73 in a housing 74. Mandrel 72 is both moveable through and
rotatable within
bore 73 as limited by movement of pin 76 on housing 74 in jay slot 78 formed
in
mandrel 72. Mandrel 72 can be releasably locked in position in housing by
locking
collet 77 frictionally engaging into knurled area 77a.
Housing 74 includes a top portion 80 and a lower portion 82. Each portion has
a flange
84 which together retain an annular packing seal 28. Top portion 80 is
moveable
towards lower portion 82 as shown in Figure 5B to compress packing seal 28 and
cause
it to expand outwardly.
Referring also to Figure 5C, housing 74 at its lower end accommodates latch
assembly
83. Latch assembly 83 includes latch 20, a latch retaining plate 84 and
springs 86.
Springs 86 act between latch 20 and latch retaining plate 84 to bias latch 20
radially
outwardly from housing 74. Latch 20 is retained in a channel 88 through
housing 74
which opens into bore 73. Latch 20 is prevented from being forced by the
action of
springs 86 out of the channel, by abutting flanges 90 which act against
shoulders 92 on
the latch. Latch 20 can be pushed into channel 88 by application of force on
the latch
toward plate 84.
CA 02270268 1999-04-27
22
Latch 20 is formed to fit into latch retaining slot 16a on casing 8 and has a
ramped
surface 94 on its upper edge, to ease removal from the slot, and an acute
angle portion
96 which acts as a catch to resist against the latch moving out of the slot by
any
downward force.
Mandrel 72 is bifurcated at is lower end to form two arms 98a, 98b. Arms 98a,
98b are
formed to be extendable through bore 73 on either side of latch 20. Arms 98a,
98b are
generally wedge-shaped to permit rotation of mandrel 72 in bore 73. As mandrel
rotates, arms 98a, 98b are driven from a position in which they do not
restrict movement
of the latch in the channel to a position in which arm 98a abuts against
shoulder 99 of
latch 20 and prevents it from moving back into channel 88. In this way arm 98a
can be
moved to act as a lock against retraction of latch 20 into channel 88. Arm 98b
serves
to stabilize the end of the mandrel, but, can be omitted from the mandrel, as
desired.
In use, a tooiguide is constructed by attaching a whipstock (ie. Figure 3A or
Figure 4A)
to lower section 22 by insertion of shear pins 61 through apertures 62 and 70.
The
toolguide is run into the well until the latch 20 is about 1 meter below the
slot 16a in
casing section 8. The toolguide is hoisted and rotated slowly, until latch 20
is located
in slot 16a. When the latch is located in the slot, the torque load will
suddenly increase.
As the string torques up, jay pin 76 will release, allowing mandrel 72 to
rotate in a
direction indicated by arrow a. When the force on the tooiguide is released,
the
mandrel will be free to move down in housing 74 (Figure 5B). During rotation
of the
mandrel, arms 98a, 98b will be rotated so that arm 98a abuts against shoulder
99 of
latch 20 and locks latch in the outwardly biased position. Mandrel arms can
take other
forms provided they are formed to lock behind the latch in response to
rotation of the
mandrel and/or movement of the mandrel through the housing.
A downward movement of the string allows the toolguide to travel down until
portion 96
of the latch lands against the bottom of slot 16a. Latch 20 and housing 74
will support
the weight of the tool and upper portion of the housing will be driven down by
the weight
of the whipstock to compress seal 28 allowing it to set. The set force is
locked in by
collet 77. The whipstock 24 is now aligned with window opening 12 and the
directional
CA 02270268 1999-04-27
23
drilling operations can begin.
After the directional drilling operations are completed, a retrieving tool is
run in to
retrieve the toolguide. Preferably, in the simplest retrieval procedure, a
straight upward
force, for example of about 20,000 pound force on the toolguide will unlock
locking
collet 77 and permit mandrel 72 to be pulled up. This pulls arm 98a out of
abutting
engagement with the latch and releases seal 28. The toolguide can then be
removed
from the well.
If the toolguide gets stuck in the well, a force is applied which is
sufficient to shear pins
61 so that the whipstock can be removed separately from the lower section.
Referring to Figures 6A, another lower section 22' is shown. Lower section 22'
is
illustrated connected to a whipstock 24'. Lower section 22' includes a male
portion 68'
shaped to fit into socket 58' of whipstock 24'. Bores 70' accept ends of shear
pins 61'.
Male portion 68' is an extension of a mandrel 172 which is positioned in a
bore 173 in
housing 174. Mandrel 172 is slidably moveable through bore 173 along long axis
178
of the lower section, but can be releasably locked against longitudinal
sliding movement
by frictional engagement of locking collet 177 against knurled portion 177a of
the
mandrel. Mandrel 172 and bore 173 are correspondingly faceted along
corresponding
portions of their length to substantially prevent rotational movement of
mandrel 172
within bore 173.
An annular packing seal 28 is retained on housing 174 and a tube 179 is
positioned to
ride over an upper surface of housing 174. Tube 179 is releasably secured
through
shear pins 179a to whipstock 24' to move therewith. Pressure of tube 179
against
annular packing seal 28, for example when the weight of the whipstock is
released onto
the lower section, compresses the seal and causes it to expand outwardly.
Lower section 22' carries a latch assembly including a latch 20', a latch
retaining plate
184 and latch biasing springs 186. Springs 186 act between latch 20' and plate
184 to
CA 02270268 1999-04-27
24
bias latch 20' to extend radially outwardly from housing 174. Latch 20' is
formed to fit
into a latch retaining slot, such as slot 16a in Figure 1.
Latch 20' is retained in a channel 188 which opens into bore 173. Latch 20' is
prevented from being forced by the action of springs 186 out of channel 188 by
abutting
flanges 190 which act against shoulders 191 on the latch. Latch 20' has formed
into
its surface an upper cavity 192 and a lower cavity 193.
Mandrel 172 has an extension 198 on its lower end which is capable of fitting
into cavity
192 when mandrel is moved toward the latch. When extension 198 of mandrel 172
fits
into the cavity, latch 20' is prevented from moving back into channel 188 and,
thereby
is locked in an outwardly extending position. To strengthen the locking of
latch 20' in
the outward position, the latch preferably has formed thereon a cavity on each
side
thereof for accepting a pair of spaced extensions on the mandrel.
A rod 199 extends below latch 20 in a bore 200. Rod 199 is slidably moveable
in bore
200 and the rod and the bore are correspondingly faceted along at least a
portion of
their lengths so that rod 199 is substantially prevented from rotating within
the bore.
Rod 199 has an end 199' which is capable of fitting into lower cavity 193 on
latch 20'.
End 199' is tapered to facilitate entry into lower cavity 193 even when the
rod end and
the cavity are not directly aligned, but cavity is formed such that when latch
20' is biased
outwardly into a slot in the casing, end 199' will not align with and fit into
the cavity.
When end 199' is inserted into cavity 193, the latch is maintained in a
recessed position
in the channel and is prevented from being biased to extend fully outwardly.
Thus, rod
199 acts as a lock for maintaining latch 20' in a recessed position within
channel 188.
Apertures 201 are formed through housing 174 for alignment with holes 202 on
rod 199.
Shear pins (not shown) can be inserted through apertures 201 into holes 202 to
releasably lock rod 199 against slidable movement in bore 200. Other
releasably
lockable means can be used in place of shear pins such as spring biased pins
or a
locking collet. A releasable locking means which can be repeated locked and
unlocked
is preferred where the tool is to be repeatedly used downhole without being
brought
back to surface.
CA 02270268 1999-04-27
Rod 199 extends out of housing 174 and opposite rod end 199" is retained in a
bore
204 formed in a lower housing 206. A portion of end 199" is enlarged so that
rod is
retained in the bore. However, bore 204 is selected to have a greater inner
diameter,
lDb, than the width, w, of end 199" so that rod 199 can move laterally within
bore 204.
5 This forms a wobble shaft arrangement and provides that housing section 206
can
move out of axial alignment with axis 178 of housing 174.
Housing 206 houses an orienting assembly including a plurality of orienting
dogs 208.
Preferably, there are four orienting dogs spaced apart 90 degrees aligned
around a
circumference of the housing. Dogs 208 are retained in housing in any suitable
way
10 such as by abutting flanges, not shown. Dogs 208 are biased outwardly by
springs 210,
such as Belleville washers, which are actuated to apply various, selectable
degrees of
force to the dogs. Springs 210 are actuated to vary their biasing force by a
hydrostatic
piston assembly 212. In particular, piston 212 includes a piston 214 having a
face 214'
in communication with a chamber 216 opening though aperture 218 to the
exterior of
15 the tool. Opposite face 214" of the piston is open to a chamber 219
containing a fluid
selected to be at a pressure generally corresponding to ground surface
atmospheric
pressure. Piston 214 is drivingly connected to rod 220 and rod cup 222. Upper
end
222' of rod cup 222 is drivingly connected to springs 210.
As the pressure in chamber 216 increases relative to the pressure in chamber
219,
20 piston 214 will be driven to drive rod 220 and rod cup 222 to compress
springs 210. It
will be readily understood that movement of the rod cup varies the pressure
applied to
the springs and thereby the pressure at which dogs 208 are biased outwardly
from
housing 204. Rod cup 222 is preferably limited in travel so as to apply a
limited degree
of force on springs 210. In particular, in a preferred embodiment, the rod cup
travel is
25 required only to preload springs past 400 meters depth. Extra force action
on the piston
beyond this depth is not transmitted to the springs. Preferably, at maximum
compression springs 210 are selected to bias dogs 208 outwardly at a pressure
which
will require 20,000 to 30,000 pounds force and preferably 25,000 pounds force
to move
the dogs out of the profile. The springs can be replaced with other biasing
means such
as a hydraulic means which is acted upon by the hydrostatic piston. In
addition, the
CA 02270268 1999-04-27
26
assembly can be selected to act on the dogs from both the bottom side and the
top side
or just from one side, as shown.
Where greater load is required to be applied to the dogs, additional
hydrostatic pistons
can be added in series.
Where an orienting section is required that does not restrict fluid flow past
the tool, a
bore can be formed through the tool. Referring to Figures 6B, an orienting
tool is shown
including a central bore 207. The tool includes a set of dogs 208' biased
outwardly by
springs 210'. Springs 210' are acted upon by a torus-shaped piston 215 which
has an
end 215' open to the hydrostatic pressure in the well and another end open to
chamber
219'. The pressure of the fluid in chamber 219' is maintained at atmospheric
pressure.
A latch 20' is spaced from dogs 208'. Latch 20' is biased outwardly by springs
186.
The lower sections of Figures 6A and 6B are useful with a casing section 224
as shown
in Figures 7A to 7C. To fully understand the operation of the lower sections
to orient
and lock a toolguide into position, we must first review the structure of the
casing
section. The operation of the lower sections will be described only with
reference to the
orienting section shown in Figures 6A, although the operation of the orienting
section
of Figures 6B would be similar.
Because of the length of casing section 224, it has been separated into three
views.
As shown in Figure 7, Figure 7A shows the lower portion of the casing section,
Figure
7B shows the middle portion of the casing section and Figure 7C shows the
upper
portion of the casing section. For ease of production and handling, the casing
section
can be produced in separate sections, as shown, for connection together.
Alternately,
the casing section can be formed as one piece. Casing section 224 is used with
other
sections, such as those indicated as sections 6 in Figure 1 to form a casing
string.
Casing sections 6 can be connected below the section by threaded engagement to
pin
end 224' in Figure 7A and casing sections can be connected above casing
section 224
by threaded connection to box end 224" in Figure 7C.
CA 02270268 1999-04-27
27
Casing section 224 includes a window opening 112 which is sized and shaped to
permit
any various assemblies to pass therethrough, such as directional drilling and
completion
tools. Casing section 224 retains therein a sleeve 123 as will be described
hereinafter.
A radial profile 230 is formed at a selected distance below window 112. Radial
profile
230 is selected to have a length Lp greater than the axial length Ld of dogs
208 (Figure
6b) so that dogs 208 can be accommodated in profile 230. Casing section 224
also
includes a latch receiving slot 16a formed a selected distance below and a
selected
radial orientation from window 112. Preferably, latch receiving slot 16a is
positioned
directly below the window for ease of manufacture. Latch receiving slot 16a is
selected
to be of a size to accommodate the face of latch 20'.
In use a toolguide including lower section 22' and whipstock 24' is run into a
casing
string including section 224. The lower section is selected such that both the
diameter
across dogs 208, when they are fully extended, and the diameter of the tool
across
seals 28, will be greater than the diameter of the casing. Since dogs 208 are
biased
outwardly, they will engage against the surface of the casing.
A running tool is connected to whipstock and the weight of the tool guide is
supported
on running tool. At surface, the tool is in the relaxed, unset position (not
shown). In
particular, the shear pins are inserted through apertures 201 into holes 202
which locks
housing 174 down in close position to housing 206 and maintains end 199' in
cavity 193
to retain latch 20' in a recessed position. To maintain this configuration
during handling,
the shear pins at this connection are selected support the weight of the
housing 206
and its components. No weight of the whipstock is applied at locking collet
177 and
therefore substantially no engagement is made between the locking collet and
portion
177a. Finally, the pressure in chamber 216 is generally equal to the pressure
in
chamber 219. Thus, piston is equalized and substantially no pressure is
applied at
springs 210 of dogs 208. Dogs 208 are therefore biased outwardly a minimum
selected
pressure, for example, 0 to 500 psi and are capable of being driven inwardly
to move
into and along the casing string.
CA 02270268 1999-04-27
28
As the tool is being run into the casing string, the hydrostatic pressure of
the fluids in
the well about the tool will increase as the depth of the tool increases. As
the pressure
of the well fluids increase, the pressure in chamber 216 increases relative to
the fixed
fluid pressure in chamber 219. This pressure differential causes piston 214 to
be driven
into chamber 219. Movement of piston 214 is translated to rod 220 which,
though rod
cup 222, compresses springs 210. Compression of springs 210 drives dogs 208
outwardly at increased pressures until maximum pressure is reached. When
maximum
pressure is reached the weight of the running string is sufficient to drive
the tool through
the casing string. However, the pressure biasing the dogs outwardly is
selected such
that it will affect the load required to move the tool though the casing. In
one
embodiment, the maximum biasing pressure on dogs 208 is selected such that an
upward or downward force of about 20,000 to 30,000 pounds force is required to
cause
the dogs to collapse to permit the assembly to pass out of a profile.
Preferably, the
leading, lower edges 208' of the dogs are sloped to facilitate movement of the
dogs
over raised or recessed portions of the casing string.
It will be appreciated that, because of the alignment of the dogs about a
circumference
of the lower section and the pressure acting on the dogs, it will be
determinable, by
overpull or by a decrease in string weight, when the dogs have passed from the
standard casing diameter over or into a profile such as profile 230 in the
casing.
Preferably, the trailing, upper edge 208" of each dog is selected to be square
or only
slightly sloped to engage more firmly against raised shoulders in the casing.
Thus, to
ensure that the dogs are located in profile 230, the toolguide can be pulled
up while
monitoring the force on the running string to confirm that the dogs have
engaged in and
against the upper shoulder of the profile.
There can be further radial profiles similar to profile 230 along the casing.
The radial
profiles are non-selective. Any tool having a set of dogs thereon will pass
through each
profile and as the dogs pass downwardly through a profile there will be
indicative
overpull or string weight decrease, depending the direction in which the tool
is being
moved within the casing. Thus, tool orientation along the length of the casing
string can
be determined by monitoring the force applied to the running string to
determine when
CA 02270268 1999-04-27
29
the dogs are located in profile 230 and referencing that information to depth
information
to determine at precisely which profile the tool is located.
The non-selective profiles can be utilized above or below window openings at
any
known depth in the well. This is useful in positioning a number of various
tools relative
to a window.
During use of the toolguide in a horizontal section of well, the housing 206
can move
laterally, at the connection of rod 199 in bore 204, out of alignment with the
remainder
of the tool. This prevents the dogs from being compressed by the entire weight
of the
string.
During confirmation of dog orientation, sufficient pressure will be applied to
the string
in a upward (toward whipstock) direction, that shear pins in apertures 201
will shear
(i.e. at 5,000 psi) and housing 174 will be pulled along rod 199 away from
housing 206.
This will cause end 199 to be pulled out of cavity 193. The pressure of
springs 186
behind latch 20' drives latch 20' outwardly. If latch 20' is biased outwardly
to its full
extent such that shoulders 191 abut against stops 190, then cavity 193 will
then be out
of alignment with rod end 199', engagement cannot be made again between latch
20'
and rod 199, even where force is again applied toward the lower section.
Alternately,
if the outward movement, of latch 20' is restricted, as by abutment against a
wall of the
casing, weight on the tool will drive end 199' back into cavity 193 such that
latch 20' will
be retracted.
The distance between latch 20' and dogs 208 is selected to be generally equal
to the
distance between profile 230 and latch receiving slot 16a so that when dogs
208 are
located in profile 230, latch 20' will be at the same position along the
casing as the slot
16a. Thus, by rotation of the tool, latch 20' can drop into slot 16a. In this
configuration
sloping face 26' of whipstock 24' will be oriented to direct tools moved along
it, laterally
outwardly toward window 112.
When the running tool is removed from the whipstock, the weight of the
whipstock will
CA 02270268 1999-04-27
be pushed down or set down on the lower section causing tube 179 to force seal
28 to
expand outwardly and to cause extensions 198 of mandrel to move into cavity
192 to
lock latch 20' in outwardly extended position. Also when the weight of the
whipstock is
set down on the lower section, locking collet 177 will be driven by its spring
to engage
5 against the knurled portion 177a of mandrel.
While the embodiment of dogs 208 biased outwardly in response to hydrostatic
pressure is preferred, it is to be understood that other assemblies for
locating profiles
such as collar locators, sleeve shifting tools or collets can be used.
The tools disclosed herein must be run into and retrieved from the well.
Running and
10 retrieval tools are known. However, previous running and retrieval tools
are sometimes
difficult to manipulate and operate. These previous tools are particularly
difficult to
operate in horizontal runs of casing.
Previous running tools for whipstocks used shear bolts for attachment between
the
running tool and the whipstock. These shear bolts are prone to shearing
prematurely
15 if the whipstock is bumped at surface while entering the will or sue to
running the
assembly through a tight area in the casing. The shear bolt may also shear
prematurely
if the assembly is rotated.
A new tool 270 which can be used for both run in and retrieval of whipstocks
is shown
in Figures 8. Tool 270 is intended for use with a whipstock as shown in
Figures 4A and
20 4B and a casing section as shown in Figures 7A to 7C. To facilitate
understanding of
the tool 270 reference should be made to those Figures.
Tool 270 is positively latched to the whipstock in a manner that allows forces
to be
applied upwardly or downwardly as well as rotationally without risk of
prematurely
releasing the whipstock. At the desired time of release, hydraulic pressure is
applied
25 to the tool to unlatch it from the whipstock.
Tool 270 includes a front end 270' and a threaded end 270" for connection to a
drill
CA 02270268 1999-04-27
31
pipe, such as that shown as 32 in Figure 1. A bore 272 extends a portion of
the length
of the tool and opens at end 270". A piston 274 is disposed to move slidably
along a
length of bore between shoulders 276, 277 and a spring 280 is disposed between
piston 274 and an end wall 284 of bore 272 to bias the piston outwardly
against
shoulder 276. A rod 286 is connected to piston 274 and is driven thereby. Rod
286 is
extends through a channel 287 extending from bore 272 and has a tapered end
286'.
Preferably, rod 286 is bifurcated to form two arms, each with a tapered end.
Tool 270 houses a latch assembly including a latch 288, a latch retaining
plate 290 and
a plurality of springs 292 acting between the latch 288 and the plate 290 to
bias the
latch radially outwardly from the tool. Of course, the plate can be replaced
with an end
wall formed integral with the body of the tool. However, a plate is preferred
for ease of
manufacture. Latch 288 is retained in a channel 294 through tool 270 which
opens into
channel 279. Latch 288 can be recessed into channel 294 by application of
force
sufficient to overcome the tension in springs 292 on the latch toward plate
290. Latch
288 is prevented from being forced by the action of springs 292 out of the
channel, by
abutting against end 286' of rod 286 which extends into channel. In
particular, latch 288
has a ramped surface 296 over which tapered end 286' can ride.
Movement of rod 286 through channel 287, by movement of piston, causes latch
288
to be moved radially inward and outward in tool, by movement of tapered end
286' over
ramped surface 296. Thus, by controlling the pressure acting on piston face
274', latch
288 can be selectively moved.
Latch 288 is formed to fit into a slot, such as slot 55 on whipstock 24' of
Figure 4A.
Latch has a ramped surface 300 on its front edge, to ease the movement of the
latch
over protrusions. A reverse angle portion 302 is provided on the rear edge of
the latch
which acts as a catch to resist against the latch moving out of the slot by
any force
applied toward end 270".
Tool 270 further includes an orienting key 304 retained in cavity 305. Key 304
is biased
radially outwardly from the tool by means of springs 306 acting between the
key and an
CA 02270268 1999-04-27
32
end wall 305a of cavity 305. Key 304 is prevented from being forced out of
cavity 305
by shoulders 308. Key 304 is selected to fit into an orienting slot on a
casing section,
such as slot 309 in casing section 224.
Tool 270 has formed thereon a dove-tailed rail 310. Rail 310 is selected to
fit into a
dove-tail slot on a whipstock, such as that indicated as slot 51 in Figure 4A.
Rail 310
is oriented relative to latch 288 with consideration as to the orientation of
slots 51 and
55 on the whipstock with which the tool is to be used. Rail 310 is spaced from
latch 288
a selected distance which corresponds to the distance between slot 55 and 51
on the
whipstock. Preferably, rail 310 is formed to be in longitudinal alignment with
latch 288.
Rail 310 is oriented on the tool relative to key 304, with consideration as to
the
orientation which slot 309 has relative to a slot 51, when a whipstock is
mounted in the
casing section. In the illustrated embodiment, slot 309 is longitudinally
aligned with
window. Thus, when a whipstock is mounted in the casing section, the sloping
face of
the whipstock will be positioned opposite the window and slot 309 and in the
illustrated
embodiment rail 310 is spaced 180 degrees from key 304.
Another key 312 is preferably provided on the tool and spaced 180 degrees from
rail
310. Key 312 rides in a port 314 opening between the outer surface of the tool
and
bore 272. Key 312 can be moved along a portion of the port 314 as limited by
shoulders 316a, 316b.
Tool 270 preferably includes. a first fluid delivery port 318 extending
between bore 272
and an end 310' of rail 310. A second fluid delivery port 320 extends between
bore 272
and a position adjacent latch 288.
In use in a running operation, tool 270 is attached to whipstock 24' at
surface. This is
done by advancing the tool toward the whipstock so that rail 310 is inserted
into slot 51.
This requires that latch 288 be forced into channel 294 by any suitable means.
When
rail 310 is fully inserted in slot 51, latch 288 will engage in slot 55. A
drill pipe is
attached at end 270". Latch 288 is maintained in slot by action of springs
292.
CA 02270268 1999-04-27
33
Tool 270, with whipstock 24' attached, is then run into the well on the drill
pipe. When
whipstock is properly mounted in the casing, whipstock 24' is released tool
270 by
applying pressure against the piston to drive rod 286 through channel 287 to,
thereby,
drive latch 288 into a recessed position in the tool. Pressure can be applied
to the
piston, for example, by forcing a drilling fluid, such as mud, through the
drill pipe into
bore 272. Application of drilling fluid increases the pressure in the bore and
drives
piston 274 against spring 280, which in turn drives rod 286 to advance against
latch
288.
When latch 288 is removed from slot 55, rail 310 can be removed from slot 51.
Tool
270 is then free to be returned to surface.
To use tool 270 in a retrieval operation, the tool is run in on a drill pipe
until it runs into
the whipstock. The tool is then pulled out a short distance and is rotated
until key 304
drops into slot 309. Because the orientation of slot 309 with respect to a
whipstock
mounted in the casing section is selected to correspond to the location of key
304 with
respect to rail 310, the rail will be aligned with slot 51 of the whipstock
when key 304
is engaged in its slot 309.
Pressure is then applied to piston, such as by pressuring up the drill string,
to retract
latch 288 so that the tool can thus be advanced to insert rail 310 in slot 51.
Applying
fluids to bore 272 also serves to cause fluid to be passed through and out
ports 318 and
320 at high pressures to clean out slots 51 and 55 which may be filled with
debris.
Pressure in bore 272 also acts against key 312 to cause it to be driven
radially
outwardly from the tool. This causes the rail to be driven toward the casing
wall. Key
312 is particularly useful when the tool is used in horizontal runs of casing.
In horizontal
wells, the whipstock is sometimes mounted against the upper side of the
casing, as
determined by gravity. When the tool is used to latch onto the whipstock, the
weight
of the tool and drill pipe will cause key 304 to be driven into cavity 305.
Thus, rail is out
of position for insertion into slot and will simply ride under the sloping
face of the
whipstock. Key 312 can then be used to raise the tool toward the upper side of
the well
casing so that rail 310 can align with slot 51.
.~_
CA 02270268 1999-04-27
34
When rail 310 is inserted fully into slot 51, the drill pipe can be
depressurized to permit
the latch to be biased outwardly into slot 55. Tool 270, with whipstock 24',
attached can
then be retrieved back to surface.
When rail 310 and latch 288 are engaged in their respective slots on the
whipstock, all
forces, either longitudinal or torsional, which are applied to the tool are
directly
transmitted to the whipstock. Tool 270 permits both run in and retrieval and
is useful
in horizontal well sections.
Referring to Figure 9, another casing section 108 is shown. Casing section 108
is
useful in the drilling and completion of deviated well bores. It is used
attached to other
casing sections such as those indicated as sections 6 in Figure 1 to form a
casing
string.
Casing section 108 includes a window opening 112 and a sleeve 123. Casing
section
108 has a known internal diameter, indicated at lDc. Casing section 108 is
formed or
assembled in such a way as to allow the placement of a sleeve 123 internally.
In
particular, a cylindrical groove 119 is formed in the inner surface of the
casing. Groove
119 has a larger inner diameter than the casing such that, when the sleeve is
disposed
therein, the sleeve and the casing on either side of the sleeve have the same
ID. A key
121 is secured, as by welding, in the groove adjacent its bottom edge.
Sleeve 123 is disposed in groove 119. An embodiment of the sleeve for use in
the
embodiment of Figure 9 is shown in flattened configuration in Figure 10. To
ready the
sleeve shown in Figure 10 for use, sides 123a, 123b of the sleeve are brought
together
and preferably attached, as by welding.
Sleeve 123 has a key slot 125 at its lower edge to engage key 121. Key slot
125 has
two locking slots 125a and 125a' and a ramped portion 125b therebetween to
facilitate
movement of key 121 between slots 125a, 125a'. Sleeve 123 is rotatable and
longitudinally moveable in groove 119 and key slot 125 is formed to limit the
movement
of sleeve 123 over key 121 between a first position at locking slot 125a and a
second
CA 02270268 1999-04-27
position at locking slot 125a'. Sleeve 123 is selected to have an inner
diameter IDs
which is greater than or equal to the inner diameter lDc of casing 108.
Sleeve 123 has a first opening 127 which is larger than window opening 112 but
is
positioned on the sleeve such that it can be aligned over window opening 112.
Sleeve
5 123 preferably also has a second opening 129 which is substantially equal to
or smaller
than window opening 112. Second opening 129 is shown spaced about 180 degrees
from opening 127 in Figures 7A to 7C, while in Figure 9 opening 129 is rotated
only
about 80 degrees from first opening 127. Second opening 129 is also positioned
on
sleeve 123 such that it can be aligned over window opening 112. Key slot 125
is
10 shaped relative to key 121 to permit movement of the sleeve to align one of
the first and
second openings 127, 129 over window opening 112 and locking slots 125a, 125a'
are
positioned to lock the sleeve by its weight at these aligned positions.
Seals 131 are provided at the upper and lower limits of the sleeve between the
sleeve
and groove 119. In the embodiment of Figure 10, seals 133, 135 are also
provided
15 about openings 127 and 129, respectively. Seals 131, 133, 135 are each
formed of
materials which are hydraulically sealing such as o-rings positioned in
retaining grooves
or lines of vulcanized polymers such as urethane. Preferably, the seating
areas for the
seals are treated, for example by machining to provide a smooth surface, to
enhance
the sealing properties of the seals. The seals act against the passage of
fluids between
20 the sleeve and the structure to which they are seated, for example the
casing or the
flange of a tieback hanger. In an alternate embodiment, the seals are secured
to the
casing and the sleeve rides over them.
In the embodiment of Figure 10, an aperture 137 is provided on the sleeve
which is
25 sized to accept, and engage releasably latches on a shifting tool (not
shown). The
latches of the shifting tool hook into apertures 137 on sleeve 123 and shift
tool is raised
to pull the sleeve upwardly to release key 121 from locking slot 125a or 125a'
into
which the key is locked. The shifting tool then rotates sleeve 123 within
groove 119.
The sleeve can be shifted by other means such as a sleeve shifting tool, as
will be
CA 02270268 1999-04-27
36
described in more detail hereinafter, having pads with teeth formed thereon
for being
forced against the sleeve material so that the sleeve can be rotated in the
groove.
Window opening 112 has a profiled edge 113. Edge 113 is formed to accommodate
and retain a flange 115 (Figure 11A) formed on a deviated wellbore liner or
tieback
hanger 117.
In use, casing section 108 having sleeve 123 disposed therein is prepared for
placement downhole by aligning opening 127 over window 112. To prevent
inadvertent
rotation of sleeve 123 in its groove, shear pins 138 are inserted to act
between the
sleeve and the casing section. A liner is then inserted through the internal
diameter and
opening 112 is filled and wrapped, as discussed with respect to Figure 2. A
casing
string is formed by attaching casing section 108 to other casing sections
selected from
those which have window openings or those which are standard casing sections.
The
casing string is then inserted into the wellbore and is aligned, as desired.
The wellbore
is then completed.
After completion, the hardened cement and the liner are removed from the
casing
string. This exposes sleeve 123 within casing section 108. A toolguide, for
example,
according to Figure 1 or any other toolguide, is positioned in the well such
that the face
of its whipstock is opposite opening 112 and a deviated wellbore is drilled.
Once the deviated wellbore is drilled, at least a junction fitting such as a
tieback hanger
117 is run into the well and positioned such that its flange 115 is engaged on
edge 113.
Sleeve 123 is then lifted and rotated by engaging the setting tool in
apertures 137 such
that opening 129 is aligned over opening 112 and thereby the central opening
of the
tieback hanger. This causes seals 135 to seal against flange 115 and prevents
fluids
from outside the deviated casing from entering into casing section 108 at the
junction.
Using the sleeve of the present invention, the deviated wellbore does not need
to be
completed using cement to seal against passage of fluids outside the casing.
However,
where desired, the deviated wellbore can be completed using cement to increase
the
pressure rating of the seal.
CA 02270268 1999-04-27
37
The sleeves according to the present invention can be rotated using any
suitable tool.
A tool which engages in apertures 137 can be used or alternately a sleeve
shifting tool
450 can be used as shown in Figures 16A and 16B which does not require the
alignment of dogs into apertures but rather frictionally engages the sleeve.
In particular,
tool 450 is sized to be insertable into the inner bore of the casing and
sleeve and
includes an elongate body 452. A plurality of sleeve engaging slips 454a, 454b
are
mounted in the body to be moveable radially inwardly and outwardly between a
retracted position (i.e. 454a') and an extended position (i.e. 454b'). In the
extended
position, the slips 454a, 454b are selected to frictionally engage against the
sleeve with
sufficient force to permit lifting and rotating of the sleeve.
Preferably, the sleeve engaging slips are selectively positioned along the
tool so that
they will engage the sleeve adjacent the upper and lower edges thereof and at
a
plurality of positions about the inner radius. The sleeve engaging slips can
be formed
in any suitable way to engage against the sleeve. In one embodiment, the
sleeve
engaging faces 455 of the slips are roughened or knurled or have teeth formed
thereon
in a suitable way to permit the slips to bite into the material of the sleeve.
In the
illustrated embodiment, slips are provided in two orientations. Slips 454a are
selected
to enhance frictional engagement to provide for longitudinal movement (ie.
lifting) of the
sleeve and slips 454b are selected to enhance frictional engagement to provide
for
rotational movement of the sleeve. In particular, slips 454a include elongate
teeth 456a
formed orthogonal to the long axis 452x of the body 452 and slips 454b include
elongate teeth 456b formed substantially parallel to long axis 452x.
Preferably the teeth
456a, 456b are formed with leading edges formed to define acute angle so that
they
exhibit enhanced frictional engagement in one direction.
Sleeve engaging slips 454a, 454b can be moved radially inwardly and outwardly
between the retracted position and the extended position in any suitable way.
In the
illustrated embodiment, the slips 454a, 454b are moveable by changes in fluid
pressure
as controlled from surface. In particular, body 452 is formed as a tube having
an inner
bore 458 closed at one end 452a by a plug 458b. Body 452 is connected at
opposite
end 452b to a tubing string 459 extending upwardly toward surface such that
bore 458
CA 02270268 1999-04-27
38
can be pressured up by feeding a fluid from surface through tubing string 459.
Slips 454a, 454b are mounted in ports 460 to be radially slidable therein
relative to the
long axis of the tool. The outer diameter of the slips conform closely to the
inner
diameter of the ports so that resistance is provided to fluids passing
therebetween.
0-rings 463 are provided about the slips to form a seal between ports 460 and
slips
454a, 454b. Ports 460 open into bore 458 to be in communication therewith and
open
to the outer surface 452' of body 452. Ports 460 have a reduced diameter at
portion
460' to prevent slips 454a, 454b from dropping into bore 458 and straps 464
are
mounted, as by use of fasteners or weldments, across ports adjacent outer
surface 452'
to hold the slips in the ports. Slips 454a, 454b each include a slot 466
extending across
the engaging face thereof to accept strap 464. Slot 466 permits the engaging
face of
the pad to extend out beyond strap. As will be appreciated, strap 464 also
prevents the
rotation of the slips within the ports, thereby preventing the teeth from
rotating out of
their selected orientation. Springs 467 are provided between the straps and
the slot
466 to bias the slips inwardly. Preferably, straps 464 are not intended to
hold the slips
in the ports against fluid pressure behind the slips. Instead, the tool is
intended only to
be pressurized while within a member such as the casing which prevents the
slips from
extending to bear against the straps.
Although Figure 16B appears to show that a plurality of slips are positioned
in close
proximity about the tool, preferably there are two to four slips 454a
positioned at each
of the top and the bottom of the tool. In each position, these slips are
equally spaced
apart around the circumference. The same arrangement is selected for the slips
454b.
As noted above, the slips 454a, 454b are moveable by changes in fluid pressure
in
bore. In use, when the pressure of the fluid in bore 458 is increased relative
to the
pressure about the tool, slips 454a, 454b are driven outwardly through ports
460
against the tension in springs 467 and into extended position until the slips
engage
against the sleeve. If a sufficiently high pressure is provided to the bore,
the slips will
bite into the sleeve with a frictional engagement sufficient to move the
sleeve by
movement of the tool, as by movement from surface. If the pressure is
maintained, the
CA 02270268 1999-04-27
39
slips will remain in the extended position. If the pressure is lowered, to a
pressure
relatively equal to or less than the ambient pressure around the tool, the
slips will be
retractable and will not maintain a frictional engagement with sleeve which is
sufficient
to move the sleeve by movement of the tool.
To assist in the pressurization of the bore, a check valve 468 is provided
adjacent end
452b, either in the bore of the tubing string 459, as shown, or in bore 458 of
body 452
above the upper set of slips. Check valve 468 permits the flow of fluid behind
slips
454a, 454b, but substantially prevents fluid from passing upwardly out of bore
458.
Thus, pressure can be maintained behind the slips to maintain them in an
extended
position without maintaining the pressure in the entire tubing string to
surface. When
check valve 468 is used, a means for releasing the pressure from within the
bore is
required in order to permit the tool to be disengaged from the sleeve, once
the sleeve
has been shifted. As an example, valve 468 can be mechanically or electrically
openable or a vent can be provided. In the illustrated embodiment, plug 458b
is
burstable by application of pressure greater than a selected value. Therefore,
when it
is desirable to release the tool from engagement with the sleeve, further
fluid pressure
is forced into bore 458 through check valve 468 until plug 458b bursts
allowing
equalization between the bore pressure and the pressure about the tool.
To permit proper positioning of the tool at the location of the sleeve in the
well bore, a
wobble shaft arrangement 470 and an orienting assembly 471, as discussed
hereinabove with respect to Figure 6, can be used.
The sleeve according to the present invention can be modified to permit other
uses.
For example, a sleeve can be used which has one or two openings. One of the
openings of the sleeve can be aligned with a casing window opening, while the
sleeve
can be repositioned such that a solid portion of the sleeve blocks the window
opening.
Referring to Figure 12, sleeve 223 is shown in flattened configuration and
when readied
for insertion into a groove of a casing section sides 223a, 223b are brought
together.
A key slot 225 is formed at the lower edge of sleeve 223 for riding over a key
formed
in the groove of the casing section in which the sleeve is to be used. Key
slot 225 has
CA 02270268 1999-04-27
three locking slots 225a, 225a'and 225a" to permit sleeve 223 to be moved
between
three positions. The first position of which is where the key is locked, by
the weight of
the sleeve, into slot 225a and opening 127 is aligned with the window opening
of the
casing section. The second position is that in which the key is locked into
slot 225a,
5 and opening 129 is disposed over the casing window opening. The third
position is the
one in which the key is locked into slot 225a" and a solid portion of the
sleeve indicated
in phantom at 234, is disposed to block off the window opening of the casing
section.
The sleeve can be moved between any of these positions by a shifting tool. The
groove
into which the sleeve is mounted is formed to accommodate such movement.
10 Seals 233, 235 are provided around openings 127, 129 and seals 231 are
provided
around the upper and lower regions of sleeve 223 to hydraulically seal between
the
sleeve and the casing into which the sleeve is mounted. The seals are on the
other
side of the sleeve and are shown in phantom in this view.
Referring to Figure 11 B, generally the tieback flanges are formed as tabs
115' and are
15 disposed on the tieback 117 to extend out from the sides thereof. There can
be two
tabs 115', as shown, or four tabs 255 shown in phantom. Because of the
arrangement
of the tabs and the way in which they extend out from the sides of the tie
back, it has
been difficult or impossible to use a liner having an outer diameter just less
than the
inner diameter of the casing through which it is to be run. In particular, in
such an
20 arrangement, the casing window is so large across its width that the flange
tabs have
nothing to latch against.
Referring to Figure 11 C, a tieback hanger 117' has been invented which is
useful for
use in tying back a liner having an outer diameter close to that of the casing
inner
25 diameter. Tieback hanger 117' has flanges 252 positioned at the top and
bottom of its
open face 254.
Tieback hanger 117' is intended to be used with a casing section, such as that
shown
in Figures 7A to 7C and in Figures 13. The casing section includes a wall 256a
extending out into window 112 adjacent the top thereof and another wall 256b
CA 02270268 1999-04-27
41
extending out at the bottom of the window. Walls 256a, 256b provide surfaces
against
which flanges 252 can latch. Walls 256a, 256b are recessed relative to the
inner
surface of casing section 224, so that when flanges 252 latch against the
walls, sleeve
123 can be rotated over the open face 254 of the tieback hanger to
hydraulically seal
off the liner. In this embodiment, preferably, the open face 254 of the
tieback hanger
has bonded thereto, as by vulcanization, a polymeric material 258 such as, for
example,
urethane to seal against the sleeve.
Walls 256a,256b can be partial or complete. Preferably the walls are disposed
at the
top and bottom of the window and form a V-shaped opening. The walls can be
formed
integral with the casing section 224 or can be attached, as by welding, to the
outside
of the casing section.
To facilitate use of the tools and the casing sections described herein and
others not
herein described, preferably a high side tool is used. To facilitate use of
the high side
tool, preferably sensors such as, for example, magnetic sensors, are mounted
in the
tools and/or the casing section components (ie. the sleeve), for reading by
the high side
tool. The sensors are preferably mounted so that it can be determined both (a)
where
the high side, according to gravity, is and (b) the degree to which any well
component
has been rotated.
Another problem which occurs in downhole assembly manipulation is the
orientation of
the tieback hanger in proper position for insertion through the window.
Previous tools
actuate the tieback hanger and liner too slowly and therefore increase the
chances of
the liner being stuck against a negative pressure formation.
Referring to Figure 14, a tool 330 has been invented which useful for downhole
placement and positioning of tieback hangers. Tool 330 includes a housing 332
with a
bore 334 extending therethrough. Slidably positioned in bore 334 is a rod 336.
Rod
336 and bore 334 are similarly faceted at least along a portion of their
lengths so that
rod 336 is substantially prevented from rotating in the bore. Rod 336 has a
box end
336' for connection to a drill pipe (not shown). Box end 336' acts to limit
the sliding
CA 02270268 1999-04-27
42
movement of rod 336 through bore 334 by abutment against housing 332.
At its opposite end 336", the rod has formed thereon threads 338 for
connection to a
flex shaft which extends into a whipstock and bends along the face thereof for
connection to a hydraulic liner running and setting tool, as are known (not
shown). A
shoulder 340 is formed to abut against the end of the flex shaft, when the
flex shaft is
engaged on the rod.
Housing supports a collet 341, a key 342 and a poppet 343. Collet 341 includes
a
plurality of (ie. four) circumferentially aligned dogs 344. Dogs 344 are
biased radially
outwardly by springs 345 and are selected to locate in a profile formed in a
casing
section (not shown) for use with the tool. Preferably, the profile is a radial
groove to
avoid having to properly orient the dogs to drop into the profile and to
thereby ease
location of dogs 344 therein. Operation of dogs 344 is similar to the
operation of dogs
208 of Figures 6A.
Key 342 is biased radially outwardly from housing by springs 346 but is
secured in the
housing by walls 348. Rearwardly extending arms 347 extend from key 342 into
bore.
Cavities 348 are formed in rod 336 to accept arms 347, when they are aligned.
When
key 342 is recessed into cavities, rod 336 is prevented from sliding movement
through
bore 334. The diameter of the tool at key 342, when the key is fully extended
is
selected to be greater than the diameter of the casing in which the tool is to
be used.
This provides that when the tool is located in the casing, the key will be
forced against
the tension in springs 346 into the housing. Key 342 has chamfered ends 342'
to
facilitate riding over protrusions. The sides of key 342 (which cannot be
seen) have
substantially no chamfer to be square or to form a reverse angle so that they
will tend
to catch on protrusions in the casing. The key is formed to fit into an
orienting slot on
the casing section in which it is to be used. When whipstock is connected
through the
flex shaft to tool 330, the whipstock face is positioned in a selected
orientation relative
to key 342. The selected orientation will depend on the orientation of the
slot for key
342 relative to the window opening in the casing.
.~ -
CA 02270268 1999-04-27
43
Poppet 343 is positioned in a hole 349 opening into bore 334 and is biased
into the
bore by a spring 350. A cavity 351 is formed on shaft 336 for accepting head
343' of
the poppet, when the head and the cavity are aligned. When poppet 343 is
positioned
in cavity 351, shaft 336 is prevented from sliding movement within bore 334. A
seal 352
disposed about poppet 343 forms a chamber 354. The pressure in chamber 354 is
selected to be a level near surface pressure. A port 356 extends from the
exterior of
the tool either along shaft 336, as shown, or along housing to open adjacent
head 343'.
Tool is used to rapidly position a tieback hanger for proper placement in the
window to
affect latching of the tieback flange against the window. In use, at surface
tool is
connected at end 336" to a flex shaft which has attached thereto a tieback
hanger and
a hydraulic liner running tool. Housing 332 is moved along rod 336 until
poppet 343
snaps into cavity 351. A drill pipe (not shown) is attached at end 336' and
the tool with
attachments is inserted into the well.
In the casing, dogs 344 ride along the inner surface of the casing and key 342
is driven
inwardly so that arms 347 engage in cavities 348. As the tool run further into
the well,
the hydrostatic pressure in the well will be communicated to head 343' of the
poppet
through port 356. As the hydrostatic pressure increases, poppet will be driven
back into
chamber 354 and out of engagement with rod 336. This will release the full
weight of
the rod and attachments onto key 342. Rod will remain in fixed position
relative to
housing, however, because of arms 347.
The tool is run to a depth such that dogs 344 drop into their profile in the
casing. When
the dogs are located in their profile, the key will be positioned at the
appropriate level
to engage in its slot and the tool need only be rotated to locate key 342 in
its slot.
When key 342 locates in its slot, springs 346 drive arms 347 out of cavities
348 and rod
336 will immediately slide through bore 334 in response to the weight of the
attached
tieback hanger and other attachments. Because of the fixed orientation of key
342
relative to the tieback hanger face and the fixed orientation of the key's
slot relative to
the casing window, the tieback hanger will be advanced through the casing and
the
window in proper position for latching the flanges onto the window edge. The
liner can
CA 02270268 1999-04-27
44
then be manipulated using the hydraulic liner running tool.
It will be appreciated therefore that this tool is particularly useful in
placement of a
tieback hanger. The liner remains stationary only long enough for the tool to
be rotated
to located key 342 in its slot. This is a great reduction in liner stationary
time over
previous tools and prevents liner lock up against negative pressure
formations.
The tools for formation and completion of deviated wells, as described
hereinbefore and
other not specifically described herein, require manipulation by rotation of
the tool. In
deep well operation and particularly in horizontal well applications, it is
virtually
impossible to rotate the tool by manipulation from surface.
Referring to Figure 15, according to one aspect of the present invention, a
motor 400
for imparting rotational drive such as, for example, a mud motor is connected
at an end
of a drill pipe 32' adjacent the tool 402 or well component to be rotated. The
motor is
connected to the drill pipe such that when the motor is driven, rotational
force will be
communicated to the drill pipe to cause it to rotate within the casing.
Preferably, the motor is driven by pumping drilling fluid therethrough. The
motor is
preferably a high torque, low speed motor which is selected to stall when the
load
thereon exceeds a selected level. In particular, when, for example, a tool is
to be
rotated until a latch drops into a slot, the motor will have a selected power
to drive the
drill pipe to rotate but when the latch is positioned in the slot and the load
increases, the
motor will stall to cease rotation of the drill string.
In an embodiment, where hydraulic pressure is required below the motor, such
as for
example, where the tool 402 is like tool 270 of Figure 13, a bypass valve 404
is
positioned above motor 400 to permit flow through a bypass port 406 passing
without
effect through motor and extending towards tool 402.
Figure 11 C shows a tieback hanger which is useful for tying back a liner
having an outer
diameter close to that of the casing inner diameter. Figures 17 to 19B show
another
CA 02270268 1999-04-27
tieback hanger 500 and casing 502 arrangement which is similarly useful to
secure a
liner having an outer diameter close to the inner diameter of the casing to
which it is to
be attached. In addition, the interaction of the tieback hanger with the
casing does not
result in a reduction in the ID of the casing at the junction of the liner
with the casing.
5 It is undesirable to increase the casing OD at the window. Thus, the present
invention
provides a tieback junction in which the casing OD is not increased over the
remainder
of the casing.
Tieback hanger 500 is intended to be used with a casing 502, such as that
shown in
Figures 17 to 17B. Casing 502 includes a window opening 504 formed
therethrough.
10 The casing wall edges 505 defining the window opening include profiled
areas 506, 508
formed into the thickness of the casing wall material. Profiled areas 506, 508
are
beveled towards the outer surface 502' of the casing such that an acute angle
is formed
at the intersection of wall edges 505 and outer surface 502'. The profiled
areas can be
formed to extend at selected positions around the window opening or about the
entirety
15 thereof. In the illustrated embodiment, profiled areas 506 are formed
adjacent the
bottom of window opening 504 and profiled areas 508 are formed adjacent the
upper
end of the window opening.
Profiled areas 506 are positioned on opposite sides of the window to form a
tapering
dovetail mortise therebetween, as best seen in Figures 17 and 17A. Profiled
areas 508
20 are also positioned opposite to form a dovetail mortise therebetween.
Tieback hanger 500 includes a sleeve 510 including an outboard end 512 for
connection to a lateral liner (not shown) and an anchored end 514 for
connection to
casing 502. End 514 has a lower setting tab 516 and an upper setting tab 518.
Setting
tabs 516, 518 have edges 516', 518' formed to flare outwardly to effectively
form
25 dovetail extensions. In particular, setting tab 516 forms a tapering
dovetail
configuration, as best seen in Figures 18 and 18A, which can be wedged into
the
dovetail mortise formed between profiled areas 506. Upper setting tab 518 is
also
flared to form a dovetail, as best seen in Figure 19A, and can be wedged into
the
mortise formed between profiled areas 508. The engagement of edges 516' of the
CA 02270268 1999-04-27
46
lower setting tab against profiles 506 and the engagement of edges 518' of the
upper
setting tab against profiles 508 prevent the tie back from being pushed
entirely out of
the window during setting.
The thickness of setting tabs 516, 518 is preferably selected such that end
514 of the
sleeve substantially abuts against the outer surface of the casing, while the
setting tabs
substantially do not extend inwardly beyond the inner surface of the casing.
This
selected thickness provides that a minimum amount of material is added to the
OD of
the liner tieback so that the tabs do not hinder insertion of the tie back
hanger through
the casing.
When setting tabs 516, 518 are engaged against corresponding profiled areas
506,
508, tieback hanger will extend through the window opening and hang off from
the
casing.
In some wells, the laterals extend from the main well bore in such a way that
the liner
tieback can drop back into the casing and obstruct the passage of tools
through the
main well bore and into the lateral. In one embodiment as shown, the tieback
hanger
can be prevented from dropping into the casing by forming the edges of the
window
opening to engage the end of the tieback hanger against both passing through
the
window opening both outwardly and inwardly back into the casing bore. The
edges of
the window opening are formed so that the edges of the tieback hanger can snap
into
the opening and be engaged therein. In particular, as best shown in Figure
17C, the
window edges on which profiled areas 508 are formed include a recess 520
formed in
the thickness of the casing wall. Recess 520 is formed between profiled area
508 and
inner edge 522 of the window opening. Setting tab 518 is formed to wedge
against
profiled area 508 and engage into recess 520. Setting tab 518 includes an
extension
524 which can be snapped past edge 522 and be accommodated in recess 520. The
recesses and extensions can be any suitable shape, provided that each
extension can
fit into its corresponding recess. Preferably, trailing edges 525 of
extensions 524 are
chamfered to facilitate unsnapping of the tieback liner from the recess, if
desired.
Recesses and extensions can be elongate extending along any selected lengths
of the
CA 02270268 1999-04-27
47
edges of the window and the tieback hanger. However, the positioning of the
recesses
and extensions on their respective parts must be selected so that they can be
aligned
and mated into each other. It is to be understood that the recess can be
alternately
formed on the edge of the tie back hanger, while the extension is formed on
the window
opening.
In one embodiment, the distance dl across the setting tab 518 is slightly
greater than
the distance d2 across the window between the profiled areas 508. This
increases the
engagement of the tieback hanger in the window opening and strengthens the
casing
about the window by transmission of forces laterally outwardly though the
walls of the
casing.
Preferably, all profiled areas 506, 508 and recesses are formed in the wall
thickness of
the casing without changing the ID or the OD of the casing at the window.
In addition to the recess/extension engagement or as an alternative thereto,
flanges
530 can be provided on the tieback hanger to abut against the edges of the
window
opening when setting tab 516 is wedged between profiled areas 506. Flanges 530
acts
to abut against the casing to prevent the tieback hanger from tipping back
into the
casing bore. It is useful to provide both the profiled area 530 and the
recesses 520 to
act as back up systems against each other.
Preferably all parts of the tieback hanger either sit within the window
opening or extend
outwardly of the window opening without extending into the bore of the casing,
so that
a sleeve, such as sleeve 123 of Figure 7A to 7C, can be rotated over the
window
opening 504.
It will be apparent that many other changes may be made to the illustrative
embodiments, while falling within the scope of the invention and it is
intended that all
such changes be covered by the claims appended hereto.
