U.S. patent application number 14/417388 was filed with the patent office on 2015-07-09 for sealing apparatus and method.
The applicant listed for this patent is RUBBERATKINS LIMITED. Invention is credited to Nicholas Atkins, Vijayamirtharaj Avanashiappan, David Hare.
Application Number | 20150191989 14/417388 |
Document ID | / |
Family ID | 46881982 |
Filed Date | 2015-07-09 |
United States Patent
Application |
20150191989 |
Kind Code |
A1 |
Atkins; Nicholas ; et
al. |
July 9, 2015 |
SEALING APPARATUS AND METHOD
Abstract
A sealing apparatus (10) for use in establishing a seal in an
annulus (12) between a mandrel (14) and a bore wall (16) has an
annular seal element (18) which extends to sealingly engage the
bore wall (16) and a back-up assembly (30) for supporting the seal
element (18) and preventing or resisting extrusion of the seal
element (18). The back-up assembly (30) includes a collar (54)
interposed between a support member (40) of the back-up assembly
(30) and the end (32) of the seal element (18) and which defines a
sea-engaging surface (60), the collar (54) in use preventing or
mitigating damage to the support member (40) from the seal element
(18).
Inventors: |
Atkins; Nicholas;
(Kincardineshire, GB) ; Hare; David; (Aberdeen,
GB) ; Avanashiappan; Vijayamirtharaj; (Aberdeen,
GB) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
RUBBERATKINS LIMITED |
ABERDEEN |
|
GB |
|
|
Family ID: |
46881982 |
Appl. No.: |
14/417388 |
Filed: |
July 26, 2013 |
PCT Filed: |
July 26, 2013 |
PCT NO: |
PCT/GB2013/052011 |
371 Date: |
January 26, 2015 |
Current U.S.
Class: |
166/387 ;
166/192 |
Current CPC
Class: |
E21B 33/1216 20130101;
E21B 33/127 20130101; E21B 33/128 20130101; E21B 23/06 20130101;
E21B 33/1208 20130101 |
International
Class: |
E21B 33/12 20060101
E21B033/12; E21B 23/06 20060101 E21B023/06 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 26, 2012 |
GB |
1213270.0 |
Claims
1. A sealing apparatus for use in establishing a seal in an annulus
between a mandrel and a bore wall, the apparatus comprising: a seal
element for providing sealing engagement with a bore wall; and a
back-up assembly comprising: a ring member; a support member
arranged to extend over at least an end of the seal element; and a
collar having a seal-engaging surface arranged to engage the end of
the seal element, the collar interposed between the end of the seal
element and the support member.
2. The apparatus of claim 1, wherein at least one of: the apparatus
is configurable to define a first, retracted, configuration and a
second, expanded, configuration; the collar is configured to assist
in supporting the end of the seal element; the collar is configured
to support the end of the seal element when the apparatus is moved
from the first configuration to the second configuration.
3. (canceled)
4. (canceled)
5. The apparatus of any preceding claim, wherein the collar is
annular.
6. The apparatus of claim 1, wherein at least one of: the collar is
mounted on, or secured to, the mandrel; the collar is mounted on,
or secured to, the mandrel by at least one of a bonded connection,
thread connection, interference connection or snap-fit
connection.
7. (canceled)
8. The apparatus of claim 1, wherein at least one of: the collar is
mounted on, or secured to, the ring member; wherein the collar is
mounted on, or secured to, the ring member by at least one of a
bonded connection, thread connection, interference connection or
snap-fit connection.
9. (canceled)
10. The apparatus of claim 1, wherein at least one of: the collar
is mounted on, or secured to, the seal element; the collar is
mounted on, or secured to, the seal element by at least one of a
bonded connection, thread connection, interference connection or
snap-fit connection.
11. (canceled)
12. The apparatus of claim 1, wherein at least one of: the collar
comprises a first portion defining a first outer diameter and a
second portion defining a second outer diameter; the second outer
diameter portion is of greater diameter than the first outer
diameter portion; the collar defines a continuous outer surface
between the first and second portions; the collar comprises a
curved outer surface between the first and second portions; the
collar defines a stepped profile between the first and second
portions.
13. (canceled)
14. (canceled)
15. (canceled)
16. (canceled)
17. The apparatus of claim 12, wherein one of: the collar further
comprises a third portion defining a third outer diameter; the
collar further comprises a third portion defining a third outer
diameter and the third portion is of the same outer diameter as the
first or second portions; the collar further comprises a third
portion defining a third outer diameter and the third portion is of
a different diameter to the first and/or second portions.
18. (canceled)
19. (canceled)
20. The apparatus of claim 1, wherein at least one of: the collar
is constructed from at least one of: a plastic material; a metallic
material or alloy; a composite material; and a ceramic material;
the collar is constructed from PTFE.
21. (canceled)
22. The apparatus of claim 1, wherein at least one of: the collar
is configured or arranged to seal against the mandrel; the collar
is configured to provide a seal between the collar and the support
member; the collar is configured to provide a seal between the
collar and the ring member.
23. The apparatus of claim 1, wherein the collar comprises a recess
for receiving a seal element.
24. The apparatus of claim 1, wherein at least one of: the collar
is configured to engage the support member; the collar is
configured to retain the support member.
25. (canceled)
26. (canceled)
27. (canceled)
28. The apparatus of claim 1, wherein at least one of: the
seal-engaging surface is provided on an end surface of the collar;
the seal-engaging surface is offset from an end face of the ring
member; the seal-engaging surface is provided on an axially
directed surface of the collar; the collar comprises a first
portion defining a first outer diameter and a second portion
defining a second outer diameter and the seal-engaging surface is
provided on the second portion; the collar comprises a first
portion defining a first outer diameter and a second portion
defining a second outer diameter and the seal-engaging surface is
provided on an axially directed surface of the second portion.
29. (canceled)
30. (canceled)
31. (canceled)
32. (canceled)
33. The apparatus of claim 1, wherein at least one of: the support
member is mounted on, or secured to, the collar; the support member
is mounted on, or secured to, the collar by at least one of a
bonded connection, thread connection, interference connection or
snap-fit connection.
34. (canceled)
35. The apparatus of claim 1, wherein at least one of: the support
member is mounted on, or secured to, the ring member; the support
member is mounted on, or secured to, the ring member by at least
one of a bonded connection, thread connection, interference
connection or snap-fit connection; at least part of the support
member is interposed between the collar and the ring member; in the
first configuration the maximum diameter defined by the support
member is less than or equal to the maximum diameter defined by the
ring member.
36. (canceled)
37. The apparatus of any preceding claim, wherein at least one of:
the support member is mounted on, or secured to, the seal element;
the support member is mounted on, or secured to, the seal element
at least one of a bonded connection, thread connection,
interference connection or snap-fit connection.
38. (canceled)
39. (canceled)
40. (canceled)
41. The apparatus of claim 1, wherein the support member comprises
a first back-up element.
42. (canceled)
43. The apparatus of claim 41, wherein at least one of: the support
member comprises a plurality of first back up elements; the first
back-up element comprises a slotted portion; the first back-up
element defines discrete petals; the first back-up element is
annular; the first back-up element comprises a non-slotted portion;
the first back-up element at least partially comprises a deformable
and/or ductile material; the first back-up element is configured to
engage the bore wall; the first back-up element comprises or
defines a bore engaging surface; the first back-up element deforms
under the action of the sealing element; the first back-up element
comprises spring steel; a lower portion of the first back-up
element is received within the ring member.
44. The apparatus of claim 42, wherein at least one of: the support
member comprises the first back-up element and a second back-up
element; the apparatus is configured so that the second back-up
element is provided between the sealing element and the first
back-up element; the second back-up element is configured or
arranged to cover and/or deform into the gaps between the petals of
the first back-up element; the second back-up element is annular;
the second back-up element is of thinner construction than the
first back-up element; the second back-up element comprises a
ductile material; the ductile material comprises stainless steel;
the second back-up element comprises a slotted portion; the second
back-up element comprises a sealing element engaging surface; the
second back-up element deforms under the action of the sealing
element, the deformation being elastic or plastic; the second
back-up element is connected to the ring member.
45. (canceled)
46. (canceled)
47. (canceled)
48. (canceled)
49. (canceled)
50. (canceled)
51. (canceled)
52. (canceled)
53. (canceled)
54. (canceled)
55. (canceled)
56. (canceled)
57. (canceled)
58. (canceled)
59. (canceled)
60. (canceled)
61. (canceled)
62. (canceled)
63. (canceled)
64. (canceled)
65. (canceled)
66. The apparatus of claim 1, wherein at least one of: the ring
member defines a profiled surface; the ring member defines a
profiled outer surface.
67. (canceled)
68. The apparatus of claim 1, wherein one of: the apparatus
comprises a single back-up assembly; the apparatus comprises two
back-up assemblies.
69. (canceled)
70. The apparatus of claim 1, wherein the seal element comprises at
least one of: an elastomeric seal element; a compression seal
element; a packing element; a cup; an expandable element; a
swellable element; and an inflatable element.
71. The apparatus of claim 1, wherein at least one of: the seal
element is configured to expand in the presence of an activation
medium; the seal element is configured to expand in the presence of
oil; the seal element is configured to expand in the presence of
water.
72. (canceled)
73. (canceled)
74. The apparatus of claim 1, wherein the seal element comprises a
unitary component.
75. The apparatus of claim 1, wherein at least one of: the seal
element comprises a plurality of components; the seal element
comprises a first seal member and a second member; the seal element
comprises a first seal member and a second member and the first and
second seal members are of different construction; the seal element
comprises a first seal member and a second member and the second
seal member comprises a material of greater hardness than the first
seal member; the seal element comprises a first seal member and a
second member and the second seal member is provided between the
first seal member and the support member.
76. (canceled)
77. (canceled)
78. (canceled)
79. (canceled)
80. The apparatus of claim 1, wherein the seal element comprises a
recess configured to permit relative movement with the support
member.
81. The apparatus of claim 1, wherein at least one: the apparatus
is configured or arranged for location on the mandrel; the
apparatus is mounted on the mandrel; the apparatus comprises end
rings for use in securing the apparatus to the mandrel.
82. (canceled)
83. (canceled)
84. A method comprising: locating a sealing apparatus according to
any preceding claim in a bore; activating the apparatus from a
first configuration to a second expanded configuration to engage
the bore wall.
85. The method of claim 84, further comprising at least one of:
de-activating the apparatus; and retrieving the apparatus from the
bore.
86. (canceled)
87. A back-up assembly for use with a sealing apparatus used to
establish a seal in an annulus between a mandrel and a bore wall,
the back-up assembly comprising: a ring member; a support member
arranged to extend over at least an end of a seal element of the
sealing apparatus; and a collar having a seal-engaging surface
arranged to engage the end of the seal element, the collar
interposable between the end of the seal element and the support
member.
88. An assembly comprising a plurality of the apparatus according
to claim 1.
89. (canceled)
90. (canceled)
91. (canceled)
92. (canceled)
Description
FIELD OF THE INVENTION
[0001] This invention relates to a sealing apparatus and method for
use in establishing a seal in an annulus between a mandrel and a
bore wall, and to a back-up assembly for use in such apparatus and
methods. More particularly, but not exclusively, embodiments of the
invention may take the form of a downhole packer for use in sealing
a wellbore annulus or bore-lining tubular bore annulus.
BACKGROUND TO THE INVENTION
[0002] Sealing apparatus and methods are used in many industries
where it is desired to isolate, seal off or otherwise control
movement of fluid in a given environment. In the oil and gas
industry for example, sealing devices known as packers are commonly
used to seal the annulus between a tubing string, such as a
production conduit or the like, and a surrounding casing or other
tubular.
[0003] In some instances, one or more packer may be used to prevent
undesired movement of fluid up or down the annulus in order to seal
off the wellbore. In other instances, a number of packers may be
used to create an isolated annular region which, amongst other
things, permits isolation of a problematic formation or permits
controlled production from, or access into, a selected region of
the formation.
[0004] Known packers may comprise an elastomeric annular sealing
element mounted on a mandrel and which is capable of being extended
radially outwardly to engage, for example, the wall of a bore in
which the packer is located, thus providing a seal in the annulus
defined between the mandrel and the bore wall. The seal element may
be axially compressed, for example by a setting tool, to effect
radial expansion.
[0005] While such packers are effective and may be used reliably in
a number of applications, the high temperature and pressure
differences experienced in a downhole environment place
particularly high demands on the seal elements of the packer to
maintain the seal with the bore wall, the successful maintenance of
the seal often being of critical importance to the safe, reliable
and economic operation of the wellbore. In some instances, the
pressure difference acting across the seal elements may be
sufficient to cause extrusion of the seal element, thereby reducing
seal performance or making activation more difficult or in more
extreme cases risking failure of the seal.
SUMMARY OF THE INVENTION
[0006] According to a first aspect of the present invention, there
is provided a sealing apparatus for use in establishing a seal in
an annulus between a mandrel and a bore wall, the apparatus
comprising:
[0007] a seal element for providing sealing engagement with a bore
wall; and
[0008] a back-up assembly comprising: [0009] a ring member; [0010]
a support member arranged to extend over at least an end of the
seal element; and [0011] a collar having a seal-engaging surface
arranged to engage the end of the seal element, the collar
interposed between the end of the seal element and the support
member.
[0012] Embodiments of the present invention may, for example,
provide support for the seal element in maintaining sealing
engagement with the bore wall; prevent or resist extrusion of the
seal element; and/or prevent damage to the support member which may
otherwise result in reduced performance, control or failure of the
seal.
[0013] The apparatus may be configurable to define a first,
retracted, configuration and a second, expanded, configuration. In
use, the apparatus may be run into the bore in the first
configuration and activated or otherwise moved from the first
configuration to the second configuration to urge the seal element
into sealing engagement with the bore wall.
[0014] The collar may be configured to assist in supporting the end
of the seal element, and in particular to support the end of the
seal element when the apparatus is moved from the first
configuration to the second configuration during activation and
operation of the apparatus. Beneficially, the collar may prevent
the seal element from coming into hard contact with the support
member and so prevent damage to the support member from the seal
element. For example, in applications where the seal element is
subject to significant temperature and pressure differentials,
embodiments of the present invention resist the transfer of axial
forces resulting from the temperature or pressure differentials
being transmitted through the seal element to the support member
which may otherwise damage or inhibit the ability of the support
member to perform its required function of supporting the seal
element. In applications where the seal element is required to
expand to a large extent, embodiments of the present invention may
resist the transfer of the axial forces generated by any axial
expansion of the seal element from being transmitted to the support
member. Alternatively, or additionally, the collar may assist in
preventing or mitigating extrusion of the seal element along the
inside of the support member and/or past the ring member, which may
otherwise result in reduced performance, control or failure of the
seal.
[0015] The collar may be of any suitable form and construction.
[0016] The collar may be annular and may extend around, or at least
partially around, the mandrel.
[0017] The collar may be mounted on, or secured to, the mandrel.
The collar may be mounted or secured to the mandrel by any suitable
means. For example, the collar may be mounted or secured to the
mandrel by at least one of a bonded connection, thread connection,
interference connection or snap-fit connection.
[0018] The collar may be mounted on or secured to the ring member.
The collar may be mounted or secured to the ring member by any
suitable means. For example, the collar may be mounted or secured
to the ring member by at least one of a bonded connection, thread
connection, interference connection or snap-fit connection.
[0019] The collar may be mounted on or secured to the seal element.
The collar may be mounted or secured to the seal element by any
suitable means. For example, the collar may be mounted or secured
to the seal element by at least one of a bonded connection, thread
connection, interference connection or snap-fit connection.
[0020] The collar may comprise a first portion defining a first
outer diameter and a second portion defining a second outer
diameter. The second outer diameter may be greater than the first
outer diameter. The collar may define a continuous outer surface
between the first and second portions. For example, the collar may
comprise a curved outer surface between the first and second
portions. Alternatively, the collar may define a stepped profile
between the first and second portions. The collar may thus define a
distinct radially extending second portion.
[0021] The collar may further comprise a third portion defining a
third outer diameter, which may be of the same or different outer
diameter to the first or second portions.
[0022] The collar may be constructed from any suitable material. In
particular embodiments, the collar may be constructed from at least
one of: a plastic material; a metallic material or alloy; a
composite material; and a ceramic material. In particular
embodiments, the collar may be constructed from PTFE.
[0023] The collar may be configured or arranged to seal against the
mandrel. In particular embodiments, the collar may comprise a
recess for receiving a seal element, such as an o-ring, although
any other suitable seal element may be used as appropriate.
[0024] The collar may be configured to engage the support member.
In particular embodiments, the collar may be configured to retain
the support member.
[0025] The collar may be configured to provide a seal between the
collar and the support member and/or between the collar and the
ring member.
[0026] The seal-engaging surface may be provided on an end surface
of the collar.
[0027] The seal-engaging surface may be offset from an end face of
the ring member.
[0028] The seal-engaging surface may be provided on an axially
directed surface of the collar.
[0029] The seal-engaging surface may be provided on the second
portion.
[0030] The seal-engaging surface may be provided an axially
directed surface of the second portion.
[0031] The support member may be configured to provide support for
the seal element and assist the seal element in maintaining sealing
engagement with the bore wall. The support member may be configured
to prevent or resist extrusion of the seal element into the annulus
between the apparatus and the surrounding bore wall.
[0032] The support member may be of any suitable form and
construction.
[0033] The support member may be mounted on or secured to the
collar. The support member may be mounted or secured to the collar
by any suitable means. For example, the support member may be
mounted or secured to the collar by at least one of a bonded
connection, thread connection, interference connection or snap-fit
connection.
[0034] The support member may be mounted on or secured to the ring
member. The support member may be mounted or secured to the ring
member by any suitable means. For example, the support member may
be mounted or secured to the ring member by at least one of a
bonded connection, thread connection, interference connection or
snap-fit connection.
[0035] The support member may be mounted on or secured to the seal
element. The support member may be mounted or secured to the seal
element by any suitable means. For example, the support member may
be mounted or secured to the seal element at least one of a bonded
connection, thread connection, interference connection or snap-fit
connection.
[0036] At least part of the support member may be interposed
between the collar and the ring member.
[0037] In the first configuration, the maximum diameter defined by
the support member may be less than or equal to the maximum
diameter defined by the ring member.
[0038] The support member may comprise a single component. For
example, the support member may comprise a first back-up element.
In particular embodiments, however, the support member may comprise
a plurality of components and the support member may comprise the
first back-up element and a second back-up element. In some
embodiments, the support member may comprise a plurality of each of
the first and second back-up elements.
[0039] The apparatus may be configured so that the second back-up
element is provided between the sealing element and the first
back-up element.
[0040] In use, the first back-up element and the second back-up
element may be configured to be moved under the action of the
sealing element from the first, run-in, configuration to the
second, set, configuration.
[0041] The first back-up element may comprise a slotted portion. In
particular embodiments, the first back-up element may define
discrete petals, which may be formed between the slots.
Beneficially, the provision of slots and petals permits the back-up
element to expand to radially greater distances than a non-slotted
element and permits the material to expand without elongation.
Furthermore, a back-up element comprising slots and petals may
expand more easily than a continuous element, resulting in lower
stress levels in the sealing element.
[0042] The second back-up element may be configured or arranged to
cover and/or deform into the gaps between the petals of the first
back-up element, in particular on expansion of the first back-up
element. In use, the second back-up element can remove any
clearances between the first and second back-up elements and any
curvature mismatches between the first back-up element and the bore
wall. Removal of these clearances and mismatches is important,
since the properties of some sealing elements, for example rubber
elements, are poor at high temperatures, i.e. around 200.degree. C.
At this temperature, rubber is capable of extrusion through any
clearances in the back-up elements or between the apparatus and the
bore wall.
[0043] The first and second back-up elements second back-up element
may be of any suitable form and construction.
[0044] The first back-up element may be annular. The second back-up
element may be annular. In particular embodiments, both of the
first and second back-up elements are annular.
[0045] In particular embodiments, the second back-up element may be
of thinner construction may facilitate the expansion of the back-up
system as the sealing element moves from the first, run-in,
configuration to the second, set, configuration. This may be of
particular benefit in applications and environments where the
apparatus is required to seal across a relatively large annular
gap. A thinner construction back-up element may also be more
compliant and may result in a reduced level of stress being built
up in the sealing element during deployment, which stress may
otherwise have a detrimental effect on the mechanical properties of
the seal element.
[0046] The first back-up element may comprise a non-slotted
portion.
[0047] The first back-up element may at least partially comprise a
deformable and/or ductile material.
[0048] In use, the first back-up element, in the run-in
configuration, may be adapted to engage the bore wall. This permits
the first back-up element, in use, to be pinned to the wellbore
surface by friction once the sealing apparatus is set. This method
of constraint removes any shear loading applied to the first
back-up element, which in turn allows for a thinner section to be
used. A thinner section reduces the stress imparted into the
sealing element as the sealing element moves into the set
configuration, and once fully deployed.
[0049] The provision of relatively thin construction first and/or
second back-up elements reduces the radial extent of the support
member and of the apparatus during deployment/run-in into the bore,
thereby reducing the risk that the apparatus will be damaged during
deployment.
[0050] The first back-up element may comprise or define a bore
engaging surface. In particular embodiments, more than 50% of the
bore engaging surface is, in use, engaged with the bore surface in
the set configuration. Such an arrangement ensures that the axial
load applied to the sealing element, in use, is not sufficient to
overcome the radial load maintaining the sealing apparatus in
contact with the bore wall. More than 50% of the slotted portion
surface may be engaged with the bore surface in the set
configuration. The bore engaging surface may be of relatively high
frictional co-efficient. For example, the bore-engaging surface may
comprise at least one of a material, profile or coating of high
friction co-efficient.
[0051] The second back-up element may comprise a ductile material.
Providing a ductile element, which can form and adapt in shape, may
assist in minimising or at least reducing the stress imparted to
the seal element during setting of the apparatus and, when used
with a slotted first back-up element, may assist in directing the
second back-up element into the between adjacent first back-up
element petals. In particular embodiments, the ductile material may
comprise stainless steel, although other suitable material may be
used where appropriate.
[0052] The first back-up element may comprise an upper edge. The
upper edge may be chamfered. In particular embodiments, the upper
edge may be chamfered towards the bore wall. Beneficially, the
provision of a chamfered edge may easily deform into close
engagement with the bore wall, thereby reducing the possibility of
clearances between the first back-up element and the bore wall
opening up.
[0053] In embodiments where the first back-up element defines
discrete petals, each petal may comprise side edges which lie in a
direction parallel to the longitudinal axis of the sealing
apparatus. The side edges may be chamfered. In particular
embodiments, the side edges may be chamfered towards the bore
wall.
[0054] The second back-up element may comprise an upper edge. The
second back-up element upper edge may be chamfered. In particular
embodiments, the second back-up element upper edge may extend above
the first back-up element upper edge. In alternative embodiments,
the first back-up element upper edge may extend above the at least
one second back-up element upper edge. Beneficially, since the side
edges may be less exposed than the upper edge, it may be possible
to make the edge of the side edge chamfers sharper as they are not
as exposed as the upper edge. A sharp edge may form a tighter fit
with the second back-up element, thereby minimising the possibility
of clearances between the first back-up element and the bore wall
opening up.
[0055] The second back-up element may comprise a slotted portion.
The provision of a slotted second back-up element may also provide
for additional expansion. The second back-up element may comprise
fewer slots than the first back-up element.
[0056] The second back-up element may comprise a sealing element
engaging surface.
[0057] The sealing element engaging surface may comprise a low
friction coating. A low friction coating reduces the stresses
imparted into the element material during deployment and under
pressure.
[0058] At least one of the first and second back-up elements may
deform under the action of the sealing element. In some
embodiments, the back-up elements may plastically deform. Plastic
deformation may reduce the stresses imparted to the sealing element
by the back-up elements once the sealing apparatus is set. In other
embodiments, the back-up elements may elastically deform. Elastic
deformation may allow the back-up elements to at least partially
recover to the run-in configuration when it is desired to retrieve
the sealing apparatus.
[0059] In some embodiments, a first back-up element upper portion
may be bent inwards towards a sealing apparatus longitudinal axis.
Having the upper portion of the first back-up element facing
radially inwards, biases the first back-up element to a run in
configuration such that the first back-up element at least
partially recovers to the run-in configuration when it is desired
to retrieve the sealing apparatus. Such an arrangement may be most
effective in an apparatus in which the first back-up element upper
edge extends above the at least one second back-up element upper
edges.
[0060] In some embodiments, the first back-up element may comprises
spring steel. Spring steel can be used to assist in returning the
sealing apparatus to the run-in configuration when it is desired to
recover the sealing apparatus from the bore.
[0061] At least one of the back-up elements may be of substantially
constant cross-sections. The use of a constant cross-section
material, particularly for the first back-up element, may assist in
reducing stress concentrations in the first back-up element and may
enable a relatively thin section to be used. A thin section will
bend more easily and will reduce the stress imparted into the
sealing element.
[0062] A lower portion of the first back-up element may be received
within the ring member.
[0063] The ring member may be attached to the non-slotted portion
of the first back-up element.
[0064] An interface between the slotted and non-slotted portions of
the first back-up element may be received within the ring
member.
[0065] The ring member may be connected to an external surface of
the first back-up element lower portion.
[0066] The second back-up element may be connected to the ring
member.
[0067] The ring member may be of any suitable form and
construction.
[0068] In use, the ring member may beneficially withstand hoop
stress imparted to the back-up elements by the differential
pressure held by the sealing element.
[0069] In particular embodiments, the ring member may define a
profiled surface.
[0070] The ring member may comprise a profiled outer surface. In
use, as the sealing apparatus moves from the first configuration to
the second configuration, the first back-up element may bend around
at least a portion of the profiled surface. At least a portion of
the first back-up element, in the first configuration, may be
displaced from the ring member profiled surface. In particular
embodiments, the ring member profiled surface may taper axially
away from the first back-up element in the first configuration.
[0071] The apparatus may comprise a single back-up assembly. In
some embodiments, the apparatus may comprise two back-up
assemblies. For example, the apparatus may comprise a back-up
assembly at both of the respective ends of the seal element.
[0072] The seal element may be of any suitable form or
construction.
[0073] The seal element may comprise an elastomeric seal
element.
[0074] The seal element may comprise a compression seal
element.
[0075] The sealing element may comprise a packing element, a cup,
an expandable element, a swellable element, an inflatable element
or any suitable style of element.
[0076] The seal element may be configured to expand in the presence
of an activation medium. For example, the seal element may be
configured to expand in the presence of oil. Alternatively, the
seal element may be configured to expand in the presence of
water.
[0077] The seal element may comprise a unitary component.
[0078] In some embodiments, the seal element may comprise a
plurality of components.
[0079] In particular embodiments, the seal element may comprise a
first seal member and a second member. The first and second seal
members may be of different construction. For example, the second
seal member may comprise a material of greater hardness than the
first seal member. Beneficially, the provision of a second seal
member having greater hardness provides an anti-extrusion
effect.
[0080] The second seal member may be provided between the first
seal member and the support member.
[0081] The seal element, and in particular embodiments the second
seal member of the seal element, may comprise a recess to permit
relative movement with the support member.
[0082] The seal element may be configured for activation by any
suitable means. The seal element may be configured to support a two
or multi-stage activation.
[0083] The apparatus may be configured to provide an initial
engagement with the bore wall. Following the initial activation,
the apparatus may be configured to permit pressurised fluid between
the seal element and the mandrel which acts to urge or inflate the
end of the seal element and the support member.
[0084] The apparatus may be configured or arranged for location on
the mandrel. In particular embodiments, the apparatus may be
mounted or otherwise secured to the mandrel. In particular
embodiments, the apparatus may comprise end rings for use in
securing the apparatus to the mandrel.
[0085] According to a further aspect of the present invention,
there is provided a method comprising:
[0086] locating a sealing apparatus according to the first aspect
in a bore;
[0087] activating the apparatus from a first configuration to a
second expanded configuration to engage the bore wall.
[0088] The method may further comprise de-activating the
apparatus.
[0089] In some embodiments, the method may further comprise
retrieving the apparatus from the bore.
[0090] According to a further aspect of the present invention,
there is provided a back-up assembly for use with a sealing
apparatus used to establish a seal in an annulus between a mandrel
and a bore wall, the back-up assembly comprising: [0091] a ring
member; [0092] a support member arranged to extend over at least an
end of a seal element of the sealing apparatus; and [0093] a collar
having a seal-engaging surface arranged to engage the end of the
seal element, the collar interposable between the end of the seal
element and the support member.
[0094] According to a further aspect of the present invention,
there is provided an assembly comprising a plurality of the
apparatus according to the first aspect of the invention.
[0095] It should be understood that the features defined above in
accordance with any aspect of the present invention or below in
relation to any specific embodiment of the invention may be
utilised, either alone or in combination, with any other defined
feature, in any other aspect or embodiment of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0096] These and other aspects of the present invention will now be
described, by way of example only, with reference to the
accompanying drawings, in which:
[0097] FIG. 1 is a perspective view of a sealing apparatus
according to an embodiment of the present invention;
[0098] FIG. 2 is an enlarged perspective view of part of the
apparatus of FIG. 1;
[0099] FIG. 3 is a diagrammatic longitudinal section view of the
apparatus shown in FIGS. 1 and 2;
[0100] FIG. 4 is a cut-away view of part of the apparatus shown in
FIGS. 1, 2 and 3;
[0101] FIG. 5 is a longitudinal section view of an apparatus
according to another embodiment of the present invention;
[0102] FIG. 6 is an enlarged view of part of the apparatus shown in
FIG. 5;
[0103] FIG. 7 is a longitudinal section view of an apparatus
according to another embodiment of the present invention;
[0104] FIG. 8 is an enlarged view of part of the apparatus shown in
FIG. 7;
[0105] FIG. 9 is an end view of an apparatus according to another
embodiment of the present invention;
[0106] FIG. 10 is a longitudinal section view of section A-A of
FIG. 9; and
[0107] FIG. 11 is an enlarged view of part of the apparatus shown
in FIGS. 9 and 10.
DETAILED DESCRIPTION OF THE DRAWINGS
[0108] Referring first to FIG. 1, there is shown a perspective view
of a sealing apparatus 10 according to an embodiment of the present
invention. In use, the apparatus 10 establishes a seal in an
annulus 12 between a mandrel 14 and a bore wall, such as a wellbore
or bore-lining tubular bore wall (shown diagrammatically by at
16).
[0109] The apparatus 10 is provided on the mandrel 14, the mandrel
forming part of a tubing string such as a drill string, production
conduit or the like (not shown).
[0110] In use, the apparatus 10 is run into the bore wall 16 on the
mandrel 14 in a first, retracted, configuration before being
activated to a second, expanded, configuration in which the
apparatus 10 sealing engages the bore wall 16.
[0111] The apparatus 10 includes an annular seal element 18 mounted
on the mandrel 14 and, in use, it is the seal element 18 which
expands to sealingly engage the bore wall 16.
[0112] In the embodiment shown in FIG. 1, the seal element 18 is
bonded to the mandrel 14. However, it will be recognised that the
seal element 18--or indeed any other component of the apparatus
10--may alternatively be a slip on component and the apparatus 10
may be located over a tubular string component, such as a drill
string, completion string or the like.
[0113] Referring now also to FIG. 2, which shows an enlarged
perspective view of part of the apparatus 10 with the mandrel
removed for clarity, annular gauge rings 20, 22 are provided at
respective ends of the apparatus 10. As shown most clearly in FIG.
2, the gauge rings 20, 22 having radially extending holes defining
bores 24 for receiving grub screws (not shown). The bores 24 are
provided in an annular portion 26 of the gauge rings 20, 22 which
also have a tapered portion 28 at their distal ends.
[0114] As shown in FIG. 2, and referring also to FIGS. 3 and 4
which show a diagrammatic longitudinal section view and a cut-away
view of part of the apparatus 10, a back-up assembly 30 for
supporting an end 32 of the seal element 18 is provided at one end
of the apparatus 10. In the embodiment shown in FIGS. 1 to 4, a
single back-up assembly 30 is provided. However, it will be
recognised that in other embodiments (such as will be described
with reference to FIGS. 5, 6, 7 and 8), back-up assemblies may be
provided at both ends of the seal element 18.
[0115] The back-up assembly 30 is provided around the mandrel 14
and between the gauge ring 20 and around the end 32 of the seal
element 18. In use, the back-up assembly 30 amongst other things
supports the expanding seal element 18 in maintaining sealing
engagement with the bore wall 16 and prevents or resists extrusion
of the seal element 18 which may otherwise reduce performance or
risk failure of the seal.
[0116] The back-up assembly 30 comprises an annular ring member 34
mounted on the mandrel 14. A seal recess or groove 36 is provided
on an inner surface 38 of the ring member 34, the seal groove 36
receiving a seal element in the form of a o-ring (not shown),
although other seal elements may be used where appropriate. In use,
the o-ring prevents fluid leakage between the ring member 34 and
the mandrel 14.
[0117] The back-up assembly 30 further comprises a support member
40 which supports the end 32 of the seal element 18. During
expansion of the seal element 18, the support member 40 supports
the expanding seal element 18 in maintaining sealing engagement
with the bore wall 16 and prevents or resists extrusion of the seal
element 18 into the annulus 12.
[0118] In the embodiment shown in FIGS. 1 to 4, the support member
40 is formed from two elements or layers, a first back-up element
42 and a second back-up element 44. The first back-up element 42
has an annular portion 46 and a slotted portion defining a number
of petals 48. The petals 48 extend over the end 32 of the seal
element 18 and bend or pivot radially outwards towards the bore 16
as the seal element 18 expands. The second back-up element 44 is
provided within the first back-up element 42 and between the first
back-up element 42 and the seal element 18 and has an annular
portion 50 and a slotted portion defining a number of petals 52. In
use, the second back-up element 44 is formed and arranged to cover,
deform into, or otherwise fill the gaps created between the petals
48 of the first back-up element 42 as they extend.
[0119] The annular portions 46, 50 of the support member 40 are
provided between the ring member and the mandrel 14 and may be used
to secure the support member to the other parts of the apparatus
10.
[0120] Interposed between the support member 40 and the end 32 of
the seal element 18, an annular insert or collar 54 is positioned
on the mandrel 14. In the embodiment shown in FIGS. 1 to 4, the
collar 54 comprises a first diameter portion 56, a second diameter
portion 58 having a diameter greater than the first diameter
portion 56 and a seal-engaging surface 60. The collar 54 defines a
curved tapering outer surface between the first diameter portion
and the second diameter portion. In use, the collar 54 prevents
damage to the support member 40 from seal element 18, in particular
from axial forces transmitted through or generated in the seal
element 18 during use and which may otherwise result in reduced
performance, control or failure of the seal.
[0121] As shown in FIG. 4, the seal element 18 in this embodiment
comprises a first inner seal member 62 and a second outer seal
member 64. The seal members 62, 64 may be formed separately and
bonded or moulded together to define the seal element 18 of the
apparatus 10. The second outer seal member 64 beneficially is
constructed from a material of greater hardness than the first seal
member 62 and, in use, provides an anti-extrusion effect at a
selected region or regions of the seal element, in particular at
the end region 32 of the seal element.
[0122] Referring now to FIGS. 5 and 6, there is shown an apparatus
110 according to another embodiment of the present invention, FIG.
5 showing a longitudinal section view and FIG. 6 showing an
enlarged view of part of the apparatus 110. The apparatus 110 is
similar to the apparatus 10 shown and described with reference to
FIGS. 1 to 4 and, for brevity and ease of reference, like
components of the apparatus are represented by like numerals
incremented by 100.
[0123] In this embodiment, the apparatus 110 comprises two back-up
assemblies 130 located at ends 132 of a seal element 118 and, in
use, the apparatus 110 is activated by compression, whereby
relative movement of the back-up assemblies 130 towards each other
(or of one assembly 130 moving closer to the other) results in
axial compression and radial expansion of the seal element 118 into
sealing engagement with the bore.
[0124] As shown most clearly in FIG. 6, the annular collar 154 of
this embodiment comprises a first diameter portion 156 and a second
diameter portion 158 and a seal-engaging surface 160. However, in
this embodiment the first diameter portion 156 does not extend
axially beyond the end face of ring member 120. Also, the collar
154 defines a distinct radial step between the first diameter
portion 156 and the second diameter portion 158.
[0125] In the illustrated embodiment, the seal element 118
comprises a single seal member 162. However, it will be recognised
that the seal element 118 may also comprise a second seal member
similar or identical to the seal element 18 described above.
[0126] Referring now to FIGS. 7 and 8, there is shown an apparatus
210 according to another embodiment of the present invention, FIG.
7 showing a longitudinal section view and FIG. 8 showing an
enlarged view of part of the apparatus 210. The apparatus 210 is
similar to the apparatus previously described and, for brevity and
ease of reference, like components of the apparatus are represented
by like numerals incremented by 200.
[0127] In this embodiment, the apparatus 210 comprises two back-up
assemblies 230 located at ends 232 of a seal element 218 and, in
use, like the apparatus 110 the apparatus 210 is activated by
compression, whereby relative movement of the back-up assemblies
230 towards each other (or of one assembly 230 moving closer to the
other) results in axial compression and radial expansion of the
seal element 218 into sealing engagement with the bore.
[0128] As shown most clearly in FIG. 6, the annular collar 254 of
this embodiment comprises a first diameter portion 256 and a second
diameter portion 258 and a seal-engaging surface 260. Like the
embodiment of FIGS. 1 to 4, in this embodiment the collar 254
defines a curved tapering outer surface between the first diameter
portion 256 and the second diameter portion 258. In this
embodiment, however, in addition to being axially interposed
between the end 232 of the seal element 218 and the support member
240, the collar 254 is also radially interposed between the support
member 240 and the mandrel 214 and, in use, the collar 254 may be
utilised to retain the support member 240.
[0129] As in the embodiment shown and described with reference to
FIGS. 5 and 6, in this embodiment the seal element 218 comprises a
single seal member 262. However, it will again be recognised that
the seal element 218 may also comprise a second seal member similar
or identical to the seal element 18 described above. The
illustrated seal element 118 further comprises internal and
external grooves.
[0130] Referring now to FIGS. 9, 10 and 11, there is shown an
apparatus 310 according to another embodiment of the present
invention, FIG. 9 showing an end view, FIG. 10 showing a
longitudinal section view along A-A, and FIG. 11 showing an
enlarged view of part of the apparatus 310. The apparatus 310 is
similar to the apparatus previously described and, for brevity and
ease of reference, like components of the apparatus are represented
by like numerals incremented by 300.
[0131] In this embodiment, the apparatus 310 comprises a single
back-up assembly 330 located at an end 332 of seal element 318 and,
in use, the apparatus 310 is activated to define a cup seal with
the bore.
[0132] Referring in particular to FIG. 11, in this embodiment the
annular collar 354 comprises a first diameter portion 356 and a
second diameter portion 358 and a seal-engaging surface 360. In
this embodiment, the first diameter portion 356 extends axially
towards and into a recess in the inner surface of in a similar
manner to the collars 54, 254. In common with the collar 154, the
collar 354 also defines a distinct radial step between the first
diameter portion 356 and the second diameter portion 358.
[0133] In this embodiment, in addition to being axially interposed
between the end 332 of the seal element 318 and the support member
340 and radially interposed between the support member 340 and the
mandrel 314, the collar 354 is also radially interposed between the
seal element 318 and the mandrel and is bonded, moulded or
otherwise secured to the seal element 318. To facilitate this
further interpositioning, the collar 354 comprises a third diameter
portion. In the illustrated embodiment, the third diameter portion
has a greater diameter than the first diameter portion 356 and a
smaller diameter than the second diameter portion 358.
[0134] Referring again to all of FIGS. 9, 10 and 11, the seal
element 318 comprises a second seal member (as shown most clearly
in FIG. 11) and a third seal member positioned adjacent to seal
member. As described above, the seal members may be of different or
similar construction and made from different or similar materials,
as required.
[0135] As described above, this embodiment differs from those shown
and described in FIGS. 5 to 8 in that the apparatus 310 defines a
cup seal with the bore.
[0136] As can be seen in FIGS. 9 and 10, gauge ring 322 comprises
bores which permit fluid passage between the inner surface of the
seal element 318 and the mandrel 314. In use, following initial
activation of the apparatus 310 fluid may be directed through the
bores and between the inner surface of the seal element 318 and the
mandrel, thereby providing an additional inflation force to
assisting in setting and maintenance of the seal.
[0137] It should be understood that the embodiment described herein
is merely exemplary and that various modifications may be made
thereto without departing from the scope of the invention.
[0138] For example, the apparatus may further comprise an
intermediate layer between the first back-up element and the/each
second back-up element. The intermediate layer may extend above and
below the first back-up element upper edge. The intermediate layer
may comprise a strong flexible material, and in particular
embodiments the intermediate layer may comprise a woven steel mesh.
Using a flexible intermediate layer such as a woven steel mesh
further minimises the existence of gaps between the first and
second back-up elements in the second, expanded, configuration. The
flexible material fills gaps which may exist between the first and
second back-up elements. The intermediate layer may be thinner than
either or both of the first and second back-up elements and, in
some embodiments, the intermediate layer may be wrapped over an
upper edge of the second back-up element. In alternative
embodiments, the intermediate layer may be wrapped over the upper
edge of the first back up element.
* * * * *