Note: Descriptions are shown in the official language in which they were submitted.
CA 02223214 2001-04-30
APPARATUS FOR AXIALLY DISPLACING A DOWNHOLE
TOOL OR A TUBING STRING IN A WELL BORE
RELATED APPLICATIONS
This application is related to Canadian Latent
No. 2,216,668 entitled TELESCOPING JOINT FOR USE IN A
CONDUIT CONNECTED TO A WELLHEAD AND ZONE ISOLATING TOOL FOR
USE THEREWITH.
TECHNICAL FIELD
This invention relates to the handling of downhole
well tools and tubing strings, and in particular to an
apparatus for axially displacing a downhole well tool or
tubing string in a well bore equipped with a wellhead, the
downhole well tool be:i.ng supported by a tubing string in the
well which includes a l~elescoping j oint to permit the axial
displacement of the ~~ownhole well tool and the t=ubing
string.
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CA 02223214 1997-11-27
BACKGROUND OF THE INVENTION
Downhole operations and the handling of downhole
well tools in completed wells has always presented a certain
challenge, especially when working in wells having a natural
pressure that exceeds atmospheric pressure, necessitating
the containment of the well at all times. A further
challenge has been the maintenance of well bores which pass
through production zones that are not well suited to
continuous production. For example, a production zone which
yields both water and oil or gas or any combination thereof
may require relatively frequent repositioning of a lower end
of a production tubing in order to recover oil or gas
efficiently. Production zones which produce crude oil high
in waxy compounds or asphaltines, or laden with salts, which
tend to plug casing perforations and therefore require
frequent treatment to maintain an economic flow of
hydrocarbon are further examples of such production zones.
To date, the maintenance of such wells has proven
time-consuming and expensive. For example, in wells which
produce both oil, water and gas and/or water and gas and
have a mobile water/hydrocarbon interface, the production of
hydrocarbon gradually decreases over time until only water
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CA 02223214 2001-04-30
or gas is produced from the well. Relocation of the bottom
end of the productic:m tubing string is then required to
recommence oil produc:ti.on. The relocation of the t=ubing
string has been a complex process which involved many time-
consuming and expensive steps that are well known in the
art. It is not difficu7_t to appreciate that there is a need
for a more efficient <~nd less costly system for producing
oil or gas from such wells. Such a system is described in
applicant's Canadian Pa~ent No. 2,216,688 referenced above.
The apparatus described in that patent application
eliminates many of the shortcomings of prior art procedures
for selectively producing fluids from wells, performing
barefoot completions o_~ well bores in sensitive zones, and
other downhole operations using production tubing and tools
that require axial displacement within a limited range in a
well bore. At the time of filing that patent application,
it was considered that the apparatus described in Llnited
States Patent 4,867,243 which issued on September 19, 1989
to Garner et al. would be suitable for effecting the axial
displacement of the downhole well tools. It has now been
recognized that such prior art tools for inserting mandrels
through wellheads is not necessarily
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CA 02223214 1997-11-27
adequate or optimal for performing the axial displacement of
such downhole well tools.
There are several reasons why such prior art tools
are not optimal tools for this purpose. First, they are
designed for inserting wellhead isolation mandrels into
wellheads and withdrawing them from the wellheads after the
well is serviced. Since wellhead isolation mandrels are of
inconsequential weight, they are stroked through a wellhead
relatively easily. Moving a tubing string of 4,500' (1,500
metres), which is not uncommonly encountered in handling
downhole well tools, may require a force in excess of
50 tons. The force required is due not only to the
considerable weight to be lifted but also to the extra force
required to unseat anchors and/or packers supporting the
tubing string. Such forces may subject the wellhead to
potentially damaging stresses. Second, wellhead isolation
tools provide no mechanism for rotating a downhole tubing
string since rotation is not required for the insertion or
withdrawal of a wellhead isolation mandrel. When
manipulating a downhole tubing string, however, rotational
movement is often required in order to release or set
components such as packers, anchors, hangers and the like.
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CA 02223214 1997-11-27
Considerable rotational force may be required to accomplish
the release of such components and it is therefore desirable
to provide a mechanism for selectively rotating the downhole
string as required.
SUMMARY OF THE INVENTION
It is an object of the invention to provide an
apparatus for axially displacing a downhole tool or tubing
string in a well bore equipped with a wellhead which is
robust enough to permit a lengthy tubing string to be
displaced in the well bore.
It is a further object of the invention to provide
an apparatus for axially displacing a downhole tool or
tubing string in a well bore equipped with a wellhead which
permits a tubing string alone or a tubing string supporting
the downhole tool to be rotated, if required.
It is yet a further object of the invention to
provide an apparatus for axially displacing a downhole tool
or tubing string in a well bore equipped with a wellhead
which is stabilized to reduce stress on the wellhead.
It is yet a further object of the invention to
provide an apparatus for axially displacing a downhole tool
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CA 02223214 1997-11-27
or tubing string in a well bore equipped with a wellhead
which is safe to use.
It is also an object of the invention to provide
an apparatus for axially displacing a downhole tool or
tubing string in a well bore equipped with a wellhead which
is readily transported from one well bore to another.
These and other objects of the invention are
realized in an apparatus for axially displacing a downhole
tool or tubing string in a well bore equipped with a
wellhead, the downhole tool being supported by a tubing
string in the well which includes a telescoping joint to
permit the axial displacement of the tool, comprising:
a lift rod string;
a tool entry spool adapted to be mounted to a top of
the wellhead;
at least one annular seal for containing well pressure
mounted above the tool entry spool, the annular seal
providing a fluid seal around a periphery of the lift rod
string;
means for axially displacing the lift rod string;
means for selectively rotating the lift rod string; and
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CA 02223214 1997-11-27
a swivel joint for enabling free rotational movement in
a link rod between the means for axially displacing the lift
rod string and the means for selectively rotating the lift
rod string.
The apparatus in accordance with the invention
includes a lift rod string which is equipped with a
releasable latch tool for connecting a free end of the lift
rod string to a latch point in or near a telescoping j oint
described in applicant's copending patent application. The
lift rod string is supported on its top end by a stem which
is connected to the means for selectively rotating the lift
rod string. The means for selectively rotating the lift rod
string is preferably a motor. A hydraulic or an electric
motor or a mechanical rotational device can be used.
Attached to the stem for supporting the lift rod string is a
link rod that includes a swivel joint for enabling free
rotational movement between the stem for supporting the lift
rod string and the means for axially displacing the lift rod
string. The means for axially displacing the lift rod
string is preferably a hydraulic cylinder or a mechanical
jack, but any other hoisting mechanism may be used.
CA 02223214 1997-11-27
In preferred embodiments of the apparatus designed
for use on deep wells, the apparatus is supported and
stabilized by adjustably extendible support posts designed
to rest on a ground surface surrounding the wellhead. The
support posts help bear the weight of heavy tubing strings
and stabilize the apparatus to reduce torsional stress on
the wellhead.
The apparatus preferably includes a tool entry
spool adapted to be mounted to a top of the wellhead. The
tool entry spool provides a space for accommodating a latch
tool such as a spear, key, collet, slip or friction type
tool, attached to the bottom end of the lift rod string.
Mounted above the tool entry spool is at least one annular
seal for containment of well pressure. The annular seal may
be a stuffing box, but it is preferably one or more blowout
preventers. Desirably, a spool which includes at least one
tool window is provided above the blowout preventer. The
tool window provides access to the lift rod string with
gripping or locking devices useful for inhibiting axial or
rotational movement while lift rod joints are being inserted
or removed. Alternatively, a pair of oppositely oriented
well slip assemblies such as described in United States
g
CA 02223214 2001-04-30
Patent 3, 846, 877, wt-as.ch issued on November 12, 19'74 to
Spiri, can be used in. place of the tool access spool to
selectively inhibit axial or rotational movement of the lift
rod string.
Each joint o:E the lift rod string may include
axial bores which permit fluid to be circulated or pumped
straight through the lift rod string, if required. For
1C example, conditions are sometimes encountered in wells such
as gas wells where hy~~rating frequently occurs at or near
the well surface. ;3uch hydrates can prevent entry or
retrieval, or foul or seize latch tools such as spears,
keys, collets, slips t~~pe or friction type tools and prevent
1~ their release or proper functioning. If the lift rod ;st:ring
includes axial bores tc> permit the circulation of hot fluid,
the string can be heated to melt ice or paraffins, etc. and
free up the seized component to effect the desired release.
One way of circulating fluid through the lift rod string is
2C to use aligned bores that extend through the means for
axially displacing the lift rod string so that a fluid
connection can be mace at the top of the apparatus. If a
hydraulic cylinder is used for axially displacing the lift
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CA 02223214 1997-11-27
rod string, the hydraulic cylinder is provided with a
polished rod that extends through a top of the cylinder. A
free end of the polished rod is equipped with threaded
connectors for the attachment of fluid circulation hoses
which are in turn connected to a pump and a heated
reservoir. It may also be desirable to pump fluid straight
through a lift rod string. This can be advantageous for
clearing hydrates or paraffin buildup from a production
tubing. One way of accomplishing this is by modifying the
spear, collet, slip or friction type tool to let fluid flow
out a bottom end of the lift rod string, or to run in the
lift rod string without a tool on its bottom end so that
fluid can be pumped through one or both axial bores.
Although the apparatus in accordance with the
invention is versatile and robust, it may be easily
disassembled for transport to another well site. It can
also be transported without disassembly, permitting well
bores equipped with telescoping joints to be readily
serviced at minimal cost.
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CA 02223214 1997-11-27
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will now be explained by way of
example only, and with reference to the following drawings
wherein:
Fig. 1 is a cross-sectional view of a first
preferred embodiment of the apparatus in accordance with the
invention connected to a wellhead of a well bore;
Fig. 2 is an elevational view of the apparatus
shown in Fig. 1;
Fig. 3 is an elevational view of a second
preferred embodiment of an apparatus in accordance with the
invention;
Fig. 3a is an enlarged cross-sectional view of a
connection between a stem and a lift rod joint in accordance
with the invention, showing the arrangement of fluid
circulation bores in each;
Fig. 4 is an elevational view of another preferred
embodiment of the apparatus in accordance with the
invention;
Fig. 5 is an elevational view of yet a further
preferred embodiment of the invention suitable for use in
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CA 02223214 1997-11-27
shallow wells where production tubing string weights are
moderate; and
Fig. 6 is a cross-sectional view of the apparatus
shown in Fig. 1 connected to a telescoping joint described
in applicant's copending patent application.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
This invention relates to an apparatus for axially
displacing a downhole tool or a tubing string in a well bore
equipped with a wellhead, the downhole tool being supported
by the tubing string in a well which includes a telescoping
joint to permit axial displacement of the downhole tool or
tubing string.
Fig. 1 shows a cross-sectional view of a first
preferred embodiment of an apparatus in accordance with the
invention, generally indicated by the reference 10. The
apparatus is mounted to a top of a wellhead generally
indicated by reference 12. Typically, the wellhead 12
includes a surface spool 14 and a master valve spool 16, the
structure of each being well known in the art. Some
wellheads do not include master valves. Mounted to a top of
the master valve spool 16 or an uppermost part of the
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CA 02223214 1997-11-27
wellhead is a tool entry spool 18, which is the lowermost
component of the apparatus 10. The tool entry spool 18
accommodates a latch tool 96 (see Fig. 6) for connecting a
lift rod string 20 to a latch point 94 of a telescoping
joint 90 when the lift rod string 20 is run into the
wellbore, as well as when it is removed from the wellbore,
as will be explained in detail with reference to Fig. 6.
Mounted to a top flange 19 of the tool entry spool 18 is an
annular seal for containing well pressure, such as a blowout
preventer 22. As will be understood by those skilled in the
art, other annular seals for containing well pressure can be
adapted for use with the apparatus 10. For example, certain
stuffing box structures or multiple ram type or annular
preventers can be adapted for such use. The blowout
preventer 22 is preferred, however, because of the ease of
use and the security of the seal it provides. Preferably,
the apparatus includes two blowout preventers 22 connected
in sequence in order to increase the safety of the apparatus
and to provide extra room between the master valve spool 16
and the uppermost blowout preventer 22 to accommodate latch
tools 96 of different lengths. With two or more blowout
preventers safety is increased because the preventers can be
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CA 02223214 1997-11-27
opened and closed in sequence at each lift rod joint
connector in the lift rod string to prevent tears in sealing
surfaces which can result from forcing rough surfaces at the
connectors through a closed preventer. For this reason, it
is preferable that the adjacent preventers be spaced about
10-13 cm (4"-5") apart to accommodate a lift rod joint
connector between them.
Mounted to a top of the uppermost blowout
preventer 22 is a tool access spool 24 having at least one
tool window 26 or an integral locking mechanism (not
illustrated). The tool window 26 permits gripping or
locking devices to be inserted for engaging the lift rod
string. As will be explained below in some detail, the tool
window 26 permits the lift rod string 20 to be gripped to
permit joints to be added to, or removed from, the lift rod
string 20. It also permits the lift rod string 20 to be
locked against axial movement when joints are being added
to, or removed from, the lift rod string 20. For example,
the weight of the tubing string 94 can be supported at the
tool window 26 in low pressure wells while lift rod string
joints are being added, or removed. If wells with
exceptionally high pressure are being worked, a lock
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CA 02223214 1997-11-27
inserted through the tool window 26 prevents the lift rod
string 20 from being forced up out of the well bore while
joints are being added to, or removed from, the lift rod
string.
The tool access spool can be replaced by a pair of
oppositely oriented well slip assemblies described in United
States Patent 3,846,877 to Spiri. Preferably, two
oppositely oriented slip tools are mounted to a top of the
uppermost blowout preventer 22. They may be operated
separately, or in unison, to control axial or rotational
movement of the lift rod string 20, as required by well
and/or operating conditions.
Bolted to the top flange 25 of the tool access
spool 24 is a lower support plate 28 which is preferably
supported by a plurality of support posts 30a to reduce
compressive and torsional forces on the wellhead which may
be induced by the lifting and manipulation of heavy
production tubing strings. The number of support posts 30a
is a matter of design choice. Preferably at least three are
provided and four support posts 30a are considered more
appropriate for supporting the lower support plate 28.
Located above the lower support plate 28 is an upper support
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CA 02223214 1997-11-27
plate 32 which is supported by support posts 30b. The
support posts 30b may be integral extensions of support
posts 30a or may be separate posts which threadably engage
threaded bores in the lower support plate 28. For the sake
of rigidity and optimal support, it is preferable that the
support posts 30a and 30b be integral and that the support
posts 30a,b pass through bores in the lower support
plate 28. The support posts 30a,b may be secured to the
lower support plate 28 in any one of several ways well known
in the art, such as pins, wedges, set screws or the like.
Reciprocally moveable between the lower support
plate 28 and the upper support plate 32 is a travelling
support plate 34. The travelling support plate 34 includes
bores 37 which receive the upper support posts 30b with
adequate clearance to permit the travelling support plate 34
to move reciprocally between the upper support plate 32 and
the lower support plate 28 without undue resistance. The
support posts 30b stabilize the travelling support plate 34
and inhibit it from rotational movement when a motor 36 is
operated to rotate the lift rod string 20. Affixed to the
travelling support plate 34 is the motor 36 for selectively
rotating the lift rod string 20. The stator 38 of the
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CA 02223214 1997-11-27
motor 36 is mounted to the travelling support plate 34 and
the rotor 40 is attached to a link rod 42. The link rod 42
connects the lift rod string 20 with a piston rod 44 of a
hydraulic cylinder 46, which provides the motive of force
for axially displacing the lift rod string 20 and the tubing
string 94 to which it is attached, as will be explained
below in more detail with reference to Fig. 6. The motor 36
may be a hydraulic motor or an electric motor, for example.
A hydraulic motor such as the Bowen PS-60 Power Sub
available from Bowen Tools, Inc., a division of IRI
International Corporation, is suitable for most
applications. An electric motor with equivalent torque can
also be used.
Interconnecting the link rod 42 and the piston
rod 44 is a swivel joint 48 which permits free rotation of
the link rod 42 with respect to the piston rod 44 to permit
the lift rod string 20 to be selectively rotated without
causing damage or wear in the hydraulic cylinder 46. The
hydraulic cylinder 46 is mounted to a top surface 56 of the
upper support plate 32 by one or more mounting brackets 50
in a manner well understood in the art.
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CA 02223214 1997-11-27
Fig. 2 shows an elevational view of the
apparatus 10 shown in Fig. 1. As described above, four
supports posts 30a,b preferably support the lower support
plate 28, the upper support plate 32 and stabilize the
travelling support plate 34. In plan view, the respective
support plates 28, 32 and 34 may be square, circular,
hexagonal or any other convenient shape. The travelling
support plate 34 is shown in a position in which the piston
rod 44 is nearing an end of its stroke. As described above,
the travelling support plate 34 freely reciprocates between
the lower support plate 28 and the upper support plate 32
with the extension and retraction of the piston rod 44. The
only other component of the apparatus shown in Fig. 2 which
was not described above is a valve 52 preferably provided on
the tool entry spool 18. The valve 52 permits the release
of well pressure after the lift rod string 20 has been
withdrawn from a well and the master valve 16 has been
closed but before the BOPS 22 are opened. Each BOP 22 also
includes one or more of bleed off or equalization valves 54,
which are well known in the art. The operation of the
apparatus shown in Fig. 2 will be described below with
reference to Fig. 6.
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CA 02223214 1997-11-27
Fig. 3 shows an elevational view of another
preferred embodiment of the apparatus in accordance with the
invention. The apparatus shown in Fig. 3 is similar to that
shown in Figs. 1 and 2 with the exception that the
travelling support plate 34 is eliminated and the stator 38
of the motor 36 is mounted to a top surface 56 of the upper
support plate 32. As shown in dotted lines, the upper
support plate includes a guide roller assembly 58 through
which a splined link rod 60 extends. The splined link rod
meshes with a splined hub (not illustrated) of the rotor 40
(see Fig. 1) of the motor 36. The splined link rod 60
reciprocates through the splined hub to permit the lift rod
string 20 to be axially displaced. A swivel joint 48
connects the piston rod 44 to the splined link rod 60 as
described above with reference to Fig. 1. The mounting
brackets 50 which support the hydraulic cylinder 46 are
elongated to support the hydraulic cylinder about the length
of its stroke above the upper support plate 32.
The embodiment shown in Fig. 3 also illustrates a
further feature of the invention which may be implemented in
the embodiments shown in Figs. 1, 4 or 5 as well. In the
embodiment shown in Fig. 3, a polished rod 62 extends
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CA 02223214 1997-11-27
through a top end of the hydraulic cylinder 46. The
polished rod 62 is attached to the piston of the hydraulic
cylinder 46 and reciprocates with the piston through seals
in a top wall of the hydraulic cylinder 46 in a manner well
known in the art. A top end of the polished rod 62 includes
connectors 64 to which fluid circulation hoses may be
attached. The fluid circulation hoses permit fluids to be
circulated through axial bores in the polish rod 62, the
piston of the hydraulic cylinder 46, the cylinder rod 44,
the swivel joint 48, the splined link rod 60 and each joint
of the lift rod string 20. The fluid circulation bores are
useful in certain instances where it is advantageous to
circulate fluid through the lift rod string 20. For
example, in certain gas wells it is not unusual to have
hydrate conditions near the top of the well bore in which
ice accumulates on tools and connections. In oil wells,
paraffins accumulate on tools and connectors. Under either
of these conditions, it is possible for a latch tool 96
(Fig. 6) such as a spear, key, collet, friction or slip type
connector to freeze or become clogged with hydrates or
paraffins. If that happens, it may not be possible to
release the latch tool 96 or move the lift rod string 20
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CA 02223214 1997-11-27
unless the latch tool 96 can be heated to melt accumulated
hydrate or paraffin deposits. It is therefore advantageous
to circulate heated fluid such as heated oil through the
lift rod string 20 when this occurs.
Fig. 3a shows an enlarged cross-sectional view of
the connection between the lift rod string 20 and the
splined link rod 60. Joints in lift rod string 20 have
similar connectors. A fluid circulation bore 66 is an axial
bore which extends through each lift rod string joint 20 and
the splined link rod 60 so that the ends of the bores are
connected when the two are securely screwed together. A
recirculation bore 68 is radially offset from the fluid
circulation bore 66. Since the recirculation bore 68 in one
component may not align with the recirculation bore 68 in
the other component when two joints are connected, a
recirculation chamber 70 is machined in the bottom of each
female component of the joint so that a fluid recirculation
path is enabled even though the two recirculation bores 68
are not aligned when the components are securely connected.
The swivel joint 48 is constructed in the same manner to
permit the swivel j oint to freely turn while ensuring that
fluid circulation is not inhibited.
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CA 02223214 1997-11-27
Fig. 3a also shows a further feature of the
invention in which each joint of the lift rod string 20
includes opposed peripheral areas of reduced diameter to
provide parallel tool gripping surfaces 72 that are adapted
to be engaged by a clamping or securing device to permit
joints to be added to, or removed from, the lift rod
string 20 and to permit the lift rod string 20 to be secured
to prevent axial movement when joints are added or removed.
Clamping or securing devices used for this purpose are well
known in the art and may include wrenches or hydraulic or
mechanical clamps, all of which are commercially available.
Fig. 4 shows yet another embodiment of the
apparatus 10 in accordance with the invention. The
embodiment shown in Fig. 4 is identical to the embodiment
shown in Fig. 1 with the exception that the hydraulic
cylinder 46 is replaced with a mechanical j ack 74 that has
an axially displaceable jackpost 76, such as a ball jack
which is well known in the art. A lower end of the
jackpost 76 is affixed to the swivel joint 48 which is in
turn affixed to the link rod 42. Reciprocal movement of the
jackpost 76 is effected by rotation of a drive shaft 78.
The drive shaft 78 may be rotated by a hydraulic motor, an
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CA 02223214 1997-11-27
electric motor or the like, as appropriate. A mechanical
jack such as the ball jack 74 is capable of securely moving
significant loads and provides a safe mechanism for shifting
the position of very long tubing strings in deep wells.
Fig. 5 shows another preferred embodiment of the
invention principally intended for use on shallow wells
where production tubing strings are of a weight that is
safely supported directly by the wellhead. In this
embodiment, support posts 80 are bolted directly to a top
flange 25 of the tool access spool 24. The number of
support posts 80 is a matter of design choice but at least
three are required and preferably at least four are used.
The top end of the support posts 80 are bolted directly to a
bottom flange 82 of a hydraulic cylinder 46 and supports the
hydraulic cylinder 46 above the tool access spool 24. A
smaller version of the travelling support plate indicated by
reference 84 reciprocates with movement of the piston rod 44
as explained above with reference to Fig. 1. The stator 38
of the motor 36 is mounted to the travelling support
plate 84, as also explained with reference to Fig. 1. In
operation, the apparatus shown in Fig. 5 functions the same
as the apparatus described above with reference to Figs. 1-
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CA 02223214 1997-11-27
4. The apparatus is somewhat lighter and easier to handle,
which makes it ideal for use in areas where there are an
abundance of shallow wells that require service.
Fig. 6 is a cross-sectional view of the
apparatus 10 described above with reference to Figs. 1 and 2
mounted to a wellhead in which a production tubing 94
produces oil from a formation B that bears gas, oil and
water. As is understood by those skilled in the art, such
wells may require frequent service in order to maintain oil
production as the gas/oil/water interface moves upwardly or
downwardly with the production of hydrocarbons from the
well. In certain areas, the gas/oil/water interface may
move upwards several feet annually. In order to produce
principally a selected fluid from such formations, the
applicant has invented an apparatus generally indicated by
reference 86 for isolating fluid zones in a casing 88 of a
well bore. Periodically, the apparatus 86 must be
repositioned within the casing 88. This is accomplished
using one of the preferred embodiments of the apparatus 10
in accordance with the invention. In an initial step in the
process, the apparatus 10 is attached to the top of the
wellhead 12 as described above with reference to Figs. 1-5.
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CA 02223214 1997-11-27
If the well is a deep well, the apparatus is preferably one
of those described with reference to Figs. 1-4. If the well
is a shallow well, any one of the apparatus shown in
Figs. 1-5 may be used.
After the apparatus 10 is bolted to a top of the
wellhead 12, the adjustable support pads 31 located
respectively at the base of each support leg 30a are
adjusted so that the apparatus 10 is level and the support
legs 30a will share the load to be placed on the
apparatus 10 when the lift rod string 20 supports the tubing
string 94. Once the apparatus 10 is properly set up, the
lift rod string 20 is assembled using a plurality of joints
which are interconnected. Attached to a free end of the
first joint is a latch tool 96 for releasably connecting to
a latch point 92 of a telescoping joint 90 described in
applicant's copending patent application. The telescoping
joint 90 permits the tubing string 94 and the apparatus for
isolating fluid zones 86 to be axially displaced in the
casing 88. The latch point 92 is engaged by any one of a
number of well known latch tools 96 which may include quick-
disconnect threads, spears, keys, collets, friction or slip
type tools, releasable packers or rotary taper taps, each of
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CA 02223214 1997-11-27
which is commercially available from several manufacturers
and well known in the art. The latch tool 96 is shown in an
engaged position with the latch point 92 at the bottom of
the telescoping joint 90. After the lift rod string 20 has
been extended down through the telescoping joint 90 and a
connection with the latch point 92 has been effected, the
downhole tool 86 may be raised or lowered within the range
of the telescoping joint 90. This permits a variety of
downhole tool manipulations to accomplish tasks such as
those described in applicant's copending patent application
without setting up a derrick or bringing in a crane, killing
the well or performing many of the other steps required
using prior art methods.
To run the lift rod string 20 into the well, a
latch tool 96 is attached to a first joint of the lift rod
string 20 and the joint is connected to the stem 41 at the
end of the link rod 42. The hydraulic cylinder is extended
until the tool grip surfaces 72 are in the tool window 26 of
the tool access spool 24. The tool grip surfaces 72 are
then engaged using a locking tool inserted through the tool
window 26, the motor 36 is operated to release the stem 41
from the first joint of the lift rod string 20, the piston
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CA 02223214 1997-11-27
of the hydraulic cylinder is stroked back to the top of the
cylinder 46 and another lift rod joint is added between the
first joint and the stem 41. The hydraulic motor 36 is
operated to make the connection between the first and second
joints of the lift rod string 20 and the stem 41. The
locking tool is then released from its grip on the tool grip
surfaces 72 of the lift rod string 20, the hydraulic
cylinder 46 is stroked downwards until the tool grip
surfaces 72 of the second joint appear in the tool
window 26, and the process is repeated until the latch
tool 96 engages the latch point 92 of the telescoping
joint 90. After engagement of the latch tool 96 with the
latch point 92, the lift rod string 20 is tensioned to
remove weight from compression anchors, hangers or
packers 98 which support the tubing string 94 in the
casing 88, and the motor 36 is operated to rotate the tubing
string 94 by rotation of the lift rod string 20 to release
the anchors, hangers or packers 98. A production packer 100
is released in the same way. Once the anchors, hangers or
packers 98 and the production packer 100 are released, the
tubing string may be raised or lowered in the casing 88 by
adding or removing joints of the lift rod string 20 as
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described above. When the downhole tool 86 has been
repositioned to a new location in the well bore, the
motor 36 is operated to reset the anchors, hangers or
packers 98 and the production packer 100.
After the anchors, hangers or packers 98 and the
production packer 100 are reset, the latch tool 96 may be
released from the latch point 92 using methods well known in
the art . For example, if the latch tool 96 is a releasing
spear, release is accomplished using a "bump down" to break
the attachment. The releasing spear is then rotated two or
three times to the right. The rotation moves a releasing
spear mandrel up through a grapple of the releasing spear,
forcing the grapple against a release ring and putting the
spear in the released position. A straight upward pull will
then generally free the spear, however, it is recommended
that the spear be rotated slowly to the right when coming
out. The motor 36 is operated to accomplish the rotation.
The lift rod string 20 is then disassembled in reverse order
of the process described above for adding joints to the lift
rod string 20. After the latch tool 96 is withdrawn above
the wellhead 12, the master valve in master valve spool 16
(see Figs. 1-4) is closed and well pressure is bled off
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CA 02223214 1997-11-27
through the release valve 52 in the tool entry spool 18.
The BOPS 22 are fully opened after the well pressure is bled
off through the release valve 52, the latch tool 96 is
stroked up through the BOPS and the last joint of the lift
rod string 20 is removed. The apparatus 10 may then be
disconnected from the top of the wellhead 12 and the well
may be put back into production.
Although only one process for the relocation of a
downhole tool has been described, it will be understood by
those skilled in the art that the apparatus in accordance
with the invention can be used for any of the processes
described in applicant's copending application as well as
processes that have yet to be discovered. For example, it
can also be used to accomplish such tasks as setting plugs,
packers or subsurface safety control valves in a production
tubing string using the lift rod string 20 for running those
components into the tubing string. As will be understood by
those skilled in the art, there is no practical limit to the
length of a lift rod string 20, so even deep well operations
can be accomplished, if required. The light weight and
versatility of the apparatus make it deal for many
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operations now accomplished using much heavier rigs which
are more expensive to construct and maintain.
Changes and modifications to the embodiments
described above will no doubt become apparent to those
skilled in the art. The scope of this invention is
therefore intended to be limited solely by the scope of the
appended claims.
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