U.S. patent application number 10/202694 was filed with the patent office on 2004-01-29 for retrievable packer having a positively operated support ring.
Invention is credited to Dearing, David G..
Application Number | 20040016550 10/202694 |
Document ID | / |
Family ID | 30769878 |
Filed Date | 2004-01-29 |
United States Patent
Application |
20040016550 |
Kind Code |
A1 |
Dearing, David G. |
January 29, 2004 |
RETRIEVABLE PACKER HAVING A POSITIVELY OPERATED SUPPORT RING
Abstract
A retrievable packer (50) for establishing a sealing and
gripping engagement between a tubing string and a well casing (34)
disposed in a wellbore is disclosed. The retrievable packer (50)
comprises a collet member (64) that is slidably disposed about a
packer mandrel (52). The collet member (64) has a first operating
position wherein the collet member (64) applies an axial force on a
support ring (76) to positively position the support ring (76) at
least partially between a first slip wedge (90) and the packer
mandrel (52) to set a seal assembly (96, 98, 100). In addition, the
collet member (64) has a second operating position wherein the
collet member (64) applies an axial force on a slip assembly (80)
to set the slip assembly (80).
Inventors: |
Dearing, David G.;
(Carrollton, TX) |
Correspondence
Address: |
Lawrence R. Youst
Danamraj & Youst, P.C
Suite 1200, LB-15
12900 Preston Road
Dallas
TX
75230-1328
US
|
Family ID: |
30769878 |
Appl. No.: |
10/202694 |
Filed: |
July 25, 2002 |
Current U.S.
Class: |
166/387 ;
166/138 |
Current CPC
Class: |
E21B 33/129
20130101 |
Class at
Publication: |
166/387 ;
166/138 |
International
Class: |
E21B 033/129 |
Claims
What is claimed is:
1. A retrievable packer for establishing a sealing and gripping
engagement with a well casing disposed in a wellbore, the
retrievable packer comprising: a packer mandrel; a seal assembly
disposed about the packer mandrel, the seal assembly having a
running position wherein the seal assembly is not in sealing
engagement with the well casing and a sealing position wherein the
seal assembly is in sealing engagement with the well casing; a
first slip wedge slidably disposed about the packer mandrel and
operably associated with the slip assembly; a support ring slidably
disposed about the packer mandrel and operably positionable at
least partially between the first slip wedge and the packer mandrel
to prevent radially inward travel of the first slip wedge and to
apply an axial force on the first slip wedge to operate the seal
assembly from the running position to the sealing position; a slip
assembly slidably disposed about the support ring and operably
associated with the first slip wedge, the slip assembly having a
running position wherein the slip assembly is not in gripping
engagement with the well casing and a gripping position wherein the
slip assembly is radially outwardly extended by contact with the
first slip wedge into gripping engagement with the well casing; and
a collet member slidably disposed about the packer mandrel and
having a first operating position wherein the collet member applies
an axial force on the support ring to positively position the
support ring at least partially between the first slip wedge and
the packer mandrel and a second operating position wherein the
collet member applies an axial force on the slip assembly to
operate the slip assembly from the running position to the gripping
position.
2. The retrievable packer as recited in claim 1 wherein the seal
assembly further comprises a mandrel element slidably disposed
about the packer mandrel, a second slip wedge slidably disposed
about the mandrel element and at least one seal element disposed
about the mandrel element such that a compressive force between the
mandrel element and the second slip wedge radially expands the seal
element.
3. The retrievable packer as recited in claim 1 wherein the first
slip wedge further comprises a plurality of wedge sections.
4. The retrievable packer as recited in claim 1 wherein the support
ring further comprises a radially expanded end portion that is
operably positionable between the first slip wedge and the packer
mandrel.
5. The retrievable packer as recited in claim 1 wherein the slip
assembly further comprises a slip carrier and a plurality of slips
that are radially outwardly extendable by contact with the first
slip wedge into gripping engagement with the well casing.
6. The retrievable packer as recited in claim 1 wherein the collet
member further comprises a plurality of collet fingers that are
radially retracted when the collet member is in the first operating
position and radially expanded when the collet member is in the
second operating position.
7. The retrievable packer as recited in claim 1 wherein the coliet
member further comprises a spring cover.
8. The retrievable packer as recited in claim 1 wherein the seal
assembly can be repetitively operated between the running position
and the sealing position without removing the packer from the well
casing.
9. The retrievable packer as recited in claim 8 wherein the seal
assembly will maintain the sealing engagement with the well casing
each time the seal assembly is operated to the sealing
position.
10. The retrievable packer as recited in claim 1 wherein the slip
assembly can be repetitively operated between the running position
and the gripping position without removing the packer from the well
casing
11. A retrievable packer for establishing a sealing and gripping
engagement with a well casing disposed in a wellbore, the
retrievable packer comprising: a packer mandrel; a seal assembly
disposed about the packer mandrel, the seal assembly having running
and sealing positions; a first slip wedge slidably disposed about
the packer mandrel and operably associated with the slip assembly;
a support ring slidably disposed about the packer mandrel and
operably positionable at least partially between the first slip
wedge and the packer mandrel to apply an axial force on the first
slip wedge to operate the seal assembly from the running position
to the sealing position; a slip assembly slidably disposed about
the support ring and operably associated with the first slip wedge,
the slip assembly having running and gripping positions; and a
collet member slidably disposed about the packer mandrel and having
a first operating position wherein the collet member applies an
axial force on the support ring to positively position the support
ring at least partially between the first slip wedge and the packer
mandrel and a second operating position wherein the collet member
applies an axial force on the slip assembly to operate the slip
assembly from the running position to the gripping position.
12. The retrievable packer as recited in claim 11 wherein the seal
assembly further comprises a mandrel element slidably disposed
about the packer mandrel, a second slip wedge slidably disposed
about the mandrel element and at least one seal element disposed
about the mandrel element such that a compressive force between the
mandrel element and the second slip wedge radially expands the seal
element.
13. The retrievable packer as recited in claim 11 wherein the first
slip wedge further comprises a plurality of wedge sections.
14. The retrievable packer as recited in claim 11 wherein the
support ring further comprises a radially expanded end portion that
is operably positionable between the first slip wedge and the
packer mandrel.
15. The retrievable packer as recited in claim 11 wherein the slip
assembly further comprises a slip carrier and a plurality of slips
that are radially outwardly extendable by contact with the first
slip wedge into gripping engagement with the well casing.
16. The retrievable packer as recited in claim 11 wherein the
collet member further comprises a plurality of collet fingers that
are radially retracted when the collet member is in the first
operating position and radially expanded when the collet member is
in the second operating position.
17. The retrievable packer as recited in claim 11 wherein the
collet member further comprises a spring cover.
18. The retrievable packer as recited in claim 11 wherein the seal
assembly can be repetitively operated between the running position
and the sealing position without removing the packer from the well
casing.
19. The retrievable packer as recited in claim 18 wherein the seal
assembly will maintain the sealing engagement with the well casing
each time the seal assembly is operated to the sealing
position.
20. The retrievable packer as recited in claim 11 wherein the slip
assembly can be repetitively operated between the running position
and the gripping position without removing the packer from the well
casing.
21. A retrievable packer comprising a collet member slidably
disposed about a packer mandrel and having a first operating
position wherein the collet member applies an axial force on a
support ring that is slidably disposed about the packer mandrel to
positively position the support ring at least partially between the
packer mandrel and a first slip wedge that is slidably disposed
about the packer mandrel to set a seal assembly that is slidably
disposed about the packer mandrel and a second operating position
wherein the collet member applies an axial force on a slip assembly
that is slidably disposed about the support ring to set the slip
assembly.
22. The retrievable packer as recited in claim 21 wherein the seal
assembly has a running position wherein the seal assembly is not in
sealing engagement with a well casing and a sealing position
wherein the seal assembly is in sealing engagement with the well
casing.
23. The retrievable packer as recited in claim 21 wherein the seal
assembly further comprises a mandrel element slidably disposed
about the packer mandrel, a second slip wedge slidably disposed
about the mandrel element and at least one seal element disposed
about the mandrel element such that a compressive force between the
mandrel element and the second slip wedge radially expands the seal
element.
24. The retrievable packer as recited in claim 21 wherein the first
slip wedge is operably associated with the slip element.
25. The retrievable packer as recited in claim 21 wherein the first
slip wedge further comprises a plurality of wedge sections.
26. The retrievable packer as recited in claim 21 wherein the
support ring further comprises a radially expanded end portion that
is operably positionable between the first slip wedge and the
packer mandrel.
27. The retrievable packer as recited in claim 21 wherein the slip
assembly has a running position wherein the slip assembly is not in
gripping engagement with a well casing and a gripping position
wherein the slip assembly is radially outwardly extended by contact
with the first slip wedge into gripping engagement with the well
casing.
28. The retrievable packer as recited in claim 21 wherein the slip
assembly further comprises a slip carrier and a plurality of slips
that are radially outwardly extendable by contact with the first
slip wedge into gripping engagement with a well casing.
29. The retrievable packer as recited in claim 21 wherein the
collet member further comprises a plurality of collet fingers that
are radially retracted when the collet member is in the first
operating position and radially expanded when the collet member is
in the second operating position.
30. The retrievable packer as recited in claim 21 wherein the
coliet member further comprises a spring cover.
31. The retrievable packer as recited in claim 21 wherein the seal
assembly can be repetitively set without removing the packer from a
well casing.
32. The retrievable packer as recited in claim 31 wherein the seal
assembly will maintain a sealing engagement with a well casing each
time the seal assembly is set.
33. The retrievable packer as recited in claim 21 wherein the slip
assembly can be repetitively set without removing the packer from a
well casing.
34. A method of repeatedly setting a retrievable packer to
establish a sealing and gripping engagement with a well casing, the
method comprising: lowering the packer into the well casing to a
selected location; setting the packer by axially shifting a packer
mandrel such that a collet member that is slidably disposed about
the packer mandrel first applies an axial force on a support ring
to positively position the support ring at least partially between
a first slip wedge and the packer mandrel to set a seal assembly
and second applies an axial force on a slip assembly to set the
slip assembly, thereby establishing a sealing and gripping
engagement with the well casing; unsetting the packer by retracting
the seal assembly and the slip assembly; and resetting the packer
at least one additional time in the well casing thereby
reestablishing the sealing and gripping engagement with the well
casing.
35. The method as recited in claim 34 wherein setting the seal
assembly further comprises applying a compressive force between a
mandrel element and a second slip wedge on a seal element to
radially expand the seal element.
36. The method as recited in claim 34 further comprising the step
of repositioning the collet member from applying the axial force on
the support ring to applying the axial force on the slip assembly
by radially expanding a plurality of collet fingers.
37. The method as recited in claim 34 further comprising the step
of maintaining the sealing engagement with the well casing each
time the seal assembly is set.
38. A method of setting a retrievable packer to establish a sealing
and gripping engagement with a well casing, the method comprising:
lowering the packer into the well casing to a selected location;
axially shifting a packer mandrel within the packer; positively
positioning a support ring at least partially between a first slip
wedge and the packer mandrel by applying an axial force on the
support ring with a collet member; operating a seal assembly from a
running position wherein the seal assembly is not in sealing
engagement with the well casing to a sealing position wherein the
seal assembly is in sealing engagement with the well casing;
repositioning the collet member to apply the axial force on a slip
assembly; and operating the slip assembly from a running position
wherein the slip assembly is not in gripping engagement with the
well casing to a gripping position wherein the slip assembly is
radially outwardly extended by contact with the first slip wedge
into gripping engagement with the well casing.
39. The method as recited in claim 38 wherein the step of operating
a seal assembly further comprises applying a compressive force
between a mandrel element and a second slip wedge on a seal element
to radially expand the seal element.
40. The method as recited in claim 38 wherein the step of
repositioning the collet member further comprises radially
expanding a plurality of collet fingers.
41. The method as recited in claim 38 further comprising the step
of repetitively operating the seal assembly between the running
position and the sealing position without removing the packer from
the well casing.
42. The method as recited in claim 41 further comprising the step
of maintaining the sealing engagement with the well casing each
time the seal assembly is operated to the sealing position.
43. The method as recited in claim 38 further comprising the step
of repetitively operating the slip assembly between the running
position and the gripping position without removing the packer from
the well casing.
Description
TECHNICAL FIELD OF THE INVENTION
[0001] This invention relates, in general, to tools and equipment
for completing a subterranean well that traverses a hydrocarbon
bearing formation and, in particular, to a retrievable well packer
for releasably sealing the annulus between a tubing string and the
well casing using a collet member to positively operate a support
ring.
BACKGROUND OF THE INVENTION
[0002] In the course of treating and preparing a subterranean well
for production, a well packer is run into the well on a conveyance
such as a work string, a production tubing, a wireline or the like.
The purpose of the packer is to support production tubing and other
completion equipment, such as a sand control screen adjacent to a
producing formation, and to seal the annulus between the outside of
the production tubing and the inside of the well casing to block
movement of fluids through the annulus past the packer
location.
[0003] Typically, the packer is provided with an upper and a lower
set of anchor slips having opposed camming surfaces which cooperate
with complementary opposed wedging surfaces, whereby the anchor
slips are outwardly radially extendable into gripping engagement
against the well casing bore in response to relative axial movement
of the wedging surfaces. The packer also carries annular seal
elements which are expandable radially into sealing engagement
against the bore of the well casing in response to axial
compression forces. The longitudinal movement of the packer
components which set the anchor slips and the sealing elements may
be produced, for example, hydraulically or mechanically.
[0004] After the packer has been set within the well casing, it
should maintain its sealing and griping engagement upon removal of
the hydraulic or mechanical setting force. Additionally, it is
essential that the packer remain locked in its set configuration
while withstanding hydraulic pressures applied externally or
internally from the formation and/or manipulation of the tubing
string and service tools without unsetting the packer or
interrupting the seal. This is made more difficult in deep wells in
which the packer and its components are subjected to high downhole
temperatures and high downhole pressures.
[0005] Moreover, the packer should be able to withstand variation
of externally applied hydraulic pressures at levels such as 10,000
psi in both directions, and still be retrievable after such
exposure for long periods of time such as 10 to 15 years or more.
After such long periods of extended service under extreme pressure
and temperature conditions, it is desirable that the packer be
retrievable from the well by appropriate manipulation of the tubing
string, such as a quarter turn of rotation, to cause the packer to
be released and unsealed from the well casing, with the anchor
slips and seal elements being retracted sufficiently to avoid
becoming stuck within wellbore restrictions.
[0006] It has been found, however, that in certain packer
deployments, the deviation of the wellbore may cause the packer to
rest on the inside of the well casing. In these deployments, it is
difficult to properly set the upper anchor slips due to a lack of
cooperation of the opposed camming surfaces of the upper anchor
slips with the complementary opposed wedging surfaces as the force
of gravity cannot fully act on the support ring. Therefore, a need
has arisen for a retrievable packer that is capable of being
properly deployed in a well wherein the packer rests on the inside
of the well casing. A need has also arisen for such a retrievable
packer that is capable of withstanding the extreme downhole
pressures and temperatures without unsetting the packer or
interrupting the seal. Further, a need has arisen for such a
retrievable packer that is capable of being set, unset and reset in
the well casing and remaining in the well for long periods of
extended service then be retrieved from the well.
SUMMARY OF THE INVENTION
[0007] The present invention disclosed herein comprises a
retrievable packer that is capable of being properly deployed in a
well wherein the packer rests on the inside of the well casing. The
retrievable packer of the present invention is also capable of
withstanding the extreme downhole pressures and temperatures
without unsetting the packer or interrupting the seal. In addition,
the retrievable packer of the present invention is capable of being
set, unset and reset in the well casing and remaining in the well
for long periods of extended service and later being retrieved from
the well.
[0008] The retrievable packer of the present invention comprises a
packer mandrel that is adapted for connection to a tubing string. A
seal assembly is disposed about the packer mandrel. The seal
assembly has a running position, wherein the seal assembly is not
in sealing engagement with the well casing, and a sealing position,
wherein the seal assembly is in sealing engagement with the well
casing. A first slip wedge is slidably disposed about the packer
mandrel. The first slip wedge is operably associated with the slip
assembly and may include plurality of wedge sections.
[0009] The retrievable packer of the present invention also
includes a support ring that is slidably disposed about the packer
mandrel. The support ring is operably positionable at least
partially between the first slip wedge and the packer mandrel to
prevent radially inward travel of the first slip wedge and to apply
an axial force on the first slip wedge to operate the seal assembly
from the running position to the sealing position. A slip assembly
is slidably disposed about the support ring. The slip assembly is
operably associated with the first slip wedge and has a running
position, wherein the slip assembly is not in gripping engagement
with the well casing, and a gripping position, wherein the slip
assembly is radially outwardly extended by contact with the first
slip wedge into gripping engagement with the well casing.
[0010] In addition, the retrievable packer of the present invention
includes a collet member that is slidably disposed about the packer
mandrel. The collet member has a first operating position, wherein
the collet member applies an axial force on the support ring to
positively position the support ring at least partially between the
first slip wedge and the packer mandrel, and a second operating
position, wherein the collet member applies an axial force on the
slip assembly to operate the slip assembly from the running
position to the gripping position.
[0011] The seal assembly of the retrievable packer of the present
invention may include a mandrel element slidably disposed about the
packer mandrel, a second slip wedge slidably disposed about the
mandrel element and at least one seal element disposed about the
mandrel element such that a compressive force between the mandrel
element and the second slip wedge radially expands the seal
element. Likewise, the slip assembly of the retrievable packer of
the present invention may include a slip carrier and a plurality of
slips that are radially outwardly extendable, by contact with the
first slip wedge, into gripping engagement with the well
casing.
[0012] The collet member may include a plurality of collet fingers
that are radially retracted when the collet member is in the first
operating position and radially expanded when the collet member is
in the second operating position. In addition, the collet member
may comprise a spring cover.
[0013] It should be noted that the retrievable packer of the
present invention may be set, unset and reset any number of times.
Specifically, the seal assembly of the retrievable packer of the
present invention can be repetitively operated between its running
position and its sealing position without removing the packer from
the well casing. Likewise, the slip assembly of the retrievable
packer of the present invention can be repetitively operated
between its running position and its gripping position without
removing the packer from the well casing.
[0014] In another aspect, the present invention comprises a method
of setting a retrievable packer to establish a sealing and gripping
engagement with a well casing. This method includes lowering the
packer into the well casing to a selected location, axially
shifting a packer mandrel within the packer, positively positioning
a support ring at least partially between a first slip-wedge and
the packer mandrel by applying an axial force on the support ring
with a collet member, operating a seal assembly from a running
position wherein the seal assembly is not in sealing engagement
with the well casing to a sealing position wherein the seal
assembly is in sealing engagement with the well casing,
repositioning the collet member to apply the axial force on a slip
assembly and operating the slip assembly from a running position
wherein the slip assembly is not in gripping engagement with the
well casing to a gripping position wherein the slip assembly is
radially outwardly extended by contact with the first slip wedge
into gripping engagement with the well casing.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] For a more complete understanding of the features and
advantages of the present invention, reference is now made to the
detailed description of the invention along with the accompanying
figures in which corresponding numerals in the different figures
refer to corresponding parts and in which:
[0016] FIG. 1 is a schematic illustration of an offshore oil and
gas platform operating a pair of retrievable packers of the present
invention;
[0017] FIGS. 2A-2C are successive axial views in quarter section of
a retrievable packer of the present invention; and
[0018] FIGS. 3A-3C are quarter sectional views of a retrievable
packer of the present invention in its various positions.
DETAILED DESCRIPTION OF THE INVENTION
[0019] While the making and using of various embodiments of the
present invention are discussed in detail below, it should be
appreciated that the present invention provides many applicable
inventive concepts which can be embodied in a wide variety of
specific contexts. The specific embodiments discussed herein are
merely illustrative of specific ways to make and use the invention,
and do not delimit the scope of the present invention.
[0020] Referring initially to FIG. 1, a pair of retrievable packers
operating from an offshore oil and gas platform are schematically
illustrated and generally designated 10. A semi-submersible
platform 12 is centered over a submerged oil and gas formation 14
located below sea floor 16. A subsea conduit 18 extends from deck
20 of platform 12 to wellhead installation 22 including blowout
preventers 24. Platform 12 has a hoisting apparatus 26 and a
derrick 28 for raising and lowering pipe strings such as work
string 30.
[0021] A wellbore 32 extends through the various earth strata
including formation 14. A casing 34 is cemented within wellbore 32
by cement 36. Work string 30 includes various tools including sand
control screens 38, 40, 42 positioned in an interval of wellbore 32
adjacent to formation 14 between retrievable packers 44, 46 of the
present invention.
[0022] Importantly, even though FIG. 1 depicts a vertical well, it
should be noted by one skilled in the art that the retrievable
packers of the present invention are equally well-suited for use in
deviated wells, inclined wells or horizontal wells. Also, even
though FIG. 1 depicts an offshore operation, it should be noted by
one skilled in the art that the retrievable packers of the present
invention are equally well-suited for use in onshore
operations.
[0023] Referring now to FIG. 2, including FIGS. 2A-2C, therein is
depicted a retrievable packer of the present invention that is
generally designated 50. Packer 50 includes a substantially
tubular, longitudinally extending mandrel 52 having a substantially
cylindrical bore 54 defining a longitudinal production flow
passageway. Mandrel 52 is coupled to a substantially tubular,
longitudinally extending section of tubing 56 by a coupling 58.
Coupling 58 includes a radially outwardly extending shoulder 60.
Positioned around mandrel 52 is a spiral wound compression spring
62 that is operated against shoulder 60 of coupling 58.
[0024] Slidably positioned around mandrel 52 is a collet member 64.
In the illustrated embodiment, collet member 64 includes eight
collet fingers 66. As should be apparent to those skilled in the
art, collet member 64 may have a variety of configurations
including configurations having other numbers of collet fingers 66,
such configurations being considered within the scope of the
present invention. In the illustrated embodiment, collet member 64
also includes a spring cover 68 that extends upwardly to cover a
portion of spring 62. It should be understood by those skilled in
the art that collet member 64 could alternatively have a spring
cover that entirely covers spring 62 or could have no spring cover
associated therewith. Collet member 64 has an upper shoulder 70
that is in contact with the lower end of spring 62 such that spring
62 downwardly biases collet member 64.
[0025] While packer 50 is being described using directional terms
such as above, below, upper, lower, upward, downward and the like,
it should be apparent to those skilled in the art that the use of
such terms is in relation to the illustrative embodiments as they
are depicted in the figures, the upward direction being toward the
top of the corresponding figure and the downward direction being
toward the bottom of the corresponding figure.
[0026] Positioned around mandrel 52 in a groove 72 is a snap ring
74 that initially prevents collet member 64 from moving downwardly
relative to mandrel 52. A support ring 76 is slidably disposed
around mandrel 52 below collet fingers 66 of collet member 64.
Support ring 76 has radially expanded end portion 78. Slidably
positioned around support ring 76 is a slip assembly 80. Slip
assembly 80 includes a slip carrier 82 and, in the illustrated
embodiment, four radially extendable slips 84. As should be
apparent to those skilled in the art, slip assembly 80 may have a
variety of configurations including configurations having other
numbers of slips 84, such configurations being considered within
the scope of the present invention. Slips 84 each have a gripping
outer surface for engaging and gripping the interior of the well
casing in which packer 50 is disposed. Positioned around mandrel 52
in groove 86 is a snap ring 88 that initially prevents support ring
76 and slip assembly 80 from moving downwardly relative to mandrel
52.
[0027] Slidably positioned around mandrel 52 at a preselected
distance below support ring 76 and slip assembly 80 is a slip wedge
90. In the illustrated embodiment, slip wedge 90 includes six wedge
sections 92. As should be apparent to those skilled in the art,
slip wedge 90 may have a variety of configurations including
configurations having other numbers of wedge sections 92, such
configurations being considered within the scope of the present
invention. Wedge sections 92 each have a camming outer surface that
will engage the inner surface of slips 84, as explained in greater
detail below. The interior surface of wedge sections 92 has a
mating profile that matches the mating profile on the outer surface
of support ring 76 such that support ring 76 can be received in the
recess between wedges sections 92 and mandrel 52, as explained in
greater detail below.
[0028] Securably attached to slip wedge 90 and slidably positioned
around mandrel 52 is a mandrel element 94. In the illustrated
embodiment, three compressible seal elements 96, 98, 100 are
positioned around mandrel element 94. Slidably and sealing
positioned around mandrel element 94 below seal element 100 is a
slip wedge 102 that has a camming outer surface. Collectively,
mandrel element 94, seal elements 96, 98, 100 and slip wedge 102
may be considered a seal assembly. As explained in greater detail
below, when a compressive force is generated between mandrel
element 94 and slip wedge 102, seal elements 96, 98, 100 are
radially expanded into contact with the well casing. Coupled to the
lower end of mandrel element 94 and slidably positioned around
mandrel 52 is a mandrel element extension 104.
[0029] Slidably positioned around mandrel element extension 104 at
a preselected distance below slip wedge 102 is a slip assembly 106.
Slip assembly 106 includes a slip carrier 108 and, in the
illustrated embodiment, four radially extendable slips 110. As
should be apparent to those skilled in the art, slip assembly 106
may have a variety of configurations including configurations
having other numbers of slips 110, such configurations being
considered within the scope of the present invention. Slips 110
have gripping outer surfaces for engaging and gripping the interior
of the well casing in which packer 50 is disposed. Slips 110 each
have an inner surface that engages the camming surface of slip
wedge 102 as explained in greater detail below.
[0030] Positioned around mandrel 52 below slip assembly 106 is a
drag block assembly 112. Drag block assembly 112 includes a drag
block mandrel 114, a retainer 116 and four spring mounted drag
blocks 118. As should be apparent to those skilled in the art, drag
block assembly 112 may have a variety of configurations including
configurations having other numbers of drag blocks 118, such
configurations being considered within the scope of the present
invention. Partially disposed within retainer 116 and slidably
disposed around mandrel 52 is sleeve 120. Sleeve 120 has a housing
122 positioned around its lower end with a spring 124 positioned
therebetween.
[0031] The operation of packer 50 is now described. Once packer 50
is attached within a work string, including for example tubing
section 56, packer 50 is run downhole and located in the desired
position with the well casing. A gripping and sealing relationship
is established between the packer 50 and the well casing by
mechanically shifting packer 50. Specifically, mandrel 52 of packer
50 is moved downwardly relative to slip assembly 106. Initially,
slip wedge 102 travels with mandrel 52 until the camming surface of
slip wedge 102 engage the inner surface of slips 110, which causes
slips 110 to move radially outwardly into gripping engagement with
well casing 34.
[0032] Referring in addition now to FIGS. 3A-3C, once slips 110 are
set, mandrel 52 continues its downward travel which is now relative
to not only slip assembly 106 but also to slip wedge 90, mandrel
element 94, seal elements 96, 98, 100 and slip wedge 102. At this
time, collet member 64, support ring 76 and slip assembly 80
continue to travel with mandrel 52 until the radially expanded end
portion 78 of support ring 76 engages the inner surface of wedges
sections 92 of slip wedge 90. Specifically, as the bias force of
spring 62 is acting downwardly on collet member 64, collet fingers
66 positively operate against support ring 76 such that the
radially expanded end portion 78 of support ring 76 slides between
slip wedge 90 and mandrel 52, as best seen in FIG. 3B.
[0033] Continued downward travel of mandrel 52 now compresses seal
elements 96, 98, 100 between mandrel element 94 and slip wedge 102
into a sealing engagement with well casing 34 due to the
transmission of the spring force via collet member 64, support ring
76 and slip wedge 90. When the spring force reaches a sufficient
level, for example, 50 to 75 percent of the maximum spring force,
collet fingers 66 radially outwardly expand over the upper end of
support ring 76 and come in contact with slip carrier 82. As best
seen in FIG. 3C, once coilet fingers 66 contact slip carrier 82,
the spring force now downwardly operates on slip carrier 82 causing
the inner surfaces of slips 84 to engage the camming surfaces of
wedge sections 92 of slip wedge 90, which causes slips 84 to move
radially outwardly into gripping engagement with well casing 34. In
addition, the upper end of support ring 76 is contacted by snap
ring 74. This configuration of packer 50 represents the set
position in which packer 50 has a sealing and gripping relationship
with well casing 34.
[0034] Importantly, it can be seen that due to the dual function of
collet member 64 wherein the spring force of spring 62 is applied
first to support ring 76 then to slip carrier 82, support ring 76
is properly positioned between slip wedge 90 and mandrel 52 before
slips 84 engage slip wedge 90. This result is achieved regardless
of the directional orientation of packer 50 as it does not rely on
gravitational forces to position support ring 76 within slip wedge
90 but rather utilizes positive operation to assure proper
positioning.
[0035] Once packer 50 is set within the well casing, packer 50 will
provide its sealing and gripping functionality until it is desired
to remove packer 50 from the well or reposition packer 50 within
the well. The retrieval operation is initiated by rotating mandrel
52 a quarter turn which allows mandrel 52 to be moved upwardly.
Specifically, this upward travel retracts collet member 64 which
releases slips 84 from their gripping relationship with well casing
34. Next, snap ring 74 contacts collet member 64 and snap ring 88
contacts support ring 76 causing collet fingers 66 to return to
their radially contracted configuration and causing support ring 76
to retract from between slip wedge 90 and mandrel 52.
[0036] This allows seal elements 96, 98, 100 to release from their
sealing engagement with well casing 34. Further upward travel of
mandrel 52 allows slip wedge 102 to retract from slips 100, which
releases slips 110 from their gripping relationship with the well
casing. Additional upward travel of mandrel 52 returns mandrel 52
to it initial configuration such that mandrel 52 may be retrieved
to the surface or redeployed within the well following the setting
procedure described above.
[0037] While this invention has been described with reference to
illustrative embodiments, this description is not intended to be
construed in a limiting sense. Various modifications and
combinations of the illustrative embodiments as well as other
embodiments of the invention, will be apparent to persons skilled
in the art upon reference to the description. It is, therefore,
intended that the appended claims encompass any such modifications
or embodiments.
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