U.S. patent application number 15/735823 was filed with the patent office on 2019-10-03 for improved sealing apparatus.
The applicant listed for this patent is RUBBERATKINS LIMITED. Invention is credited to Nicholas ATKINS, Vijay AVANASHIAPPAN, Craig SPALDING.
Application Number | 20190301263 15/735823 |
Document ID | / |
Family ID | 53784584 |
Filed Date | 2019-10-03 |
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United States Patent
Application |
20190301263 |
Kind Code |
A1 |
ATKINS; Nicholas ; et
al. |
October 3, 2019 |
IMPROVED SEALING APPARATUS
Abstract
The present invention provides a pressure control device (10)
suitable to be mounted on a rigid mandrel or the like and to form a
seal in an oilwell, for example, in order to deploy a zonal control
system. The pressure control device comprises a flexible sealing
element (18), a first support member (30, 32) and a second support
member (34, 36). One of the support members (34, 36) comprises a
composite material.
Inventors: |
ATKINS; Nicholas;
(Aberdeenshire, GB) ; AVANASHIAPPAN; Vijay;
(Aberdeenshire, GB) ; SPALDING; Craig;
(Aberdeenshire, GB) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
RUBBERATKINS LIMITED |
Aberdeenshire |
|
GB |
|
|
Family ID: |
53784584 |
Appl. No.: |
15/735823 |
Filed: |
June 10, 2016 |
PCT Filed: |
June 10, 2016 |
PCT NO: |
PCT/GB2016/051715 |
371 Date: |
December 12, 2017 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
E21B 33/1216
20130101 |
International
Class: |
E21B 33/12 20060101
E21B033/12 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 12, 2015 |
GB |
1510285.8 |
Claims
1. A pressure control device for mounting on a mandrel, the device
comprising: a flexible sealing element; a first support member; and
a second support member comprising a composite, wherein the
pressure control device is adapted to move from a run in position
to an expanded position when exposed to a source of pressure, the
flexible sealing element being adapted to form a seal against a
bore wall in the expanded position, the first and second support
members being adapted, in the expanded position, to resist
extrusion of the flexible sealing element, in use, along the bore
wall away from the source of pressure, the second support member
being further adapted to resist extrusion into the first support
member.
2. A pressure control device according to claim 1 wherein a portion
of the flexible sealing element, the first support member and/or
the second support member are arranged concentrically.
3. A pressure control device according to claim 1 wherein the first
support member comprises a helical spring, the helical spring being
biased to the run-in position.
4. (canceled)
5. A pressure control device according to claim 1 wherein the first
support member is located at an outer portion of the flexible
sealing element.
6. A pressure control device according to claim 1 wherein the first
support member is urged outwardly against a bore wall, in use, to
help to create a seal.
7. (canceled)
8. (canceled)
9. A pressure control device according to claim 1 wherein the first
support member comprises a circumferential first spring with a
second spring in its interior.
10. A pressure control device according to claim 1 wherein the
first support member comprises a circumferential first spring with
a second spring in its interior wherein the second spring is
mounted within the first spring such that the helix of one spring
is wound in the opposite direction to the spiral of the other
spring in order to resist canting of the first support member under
high pressure.
11. A pressure control device according to claim 1 wherein the
first support member is located so as to abut the second support
member.
12. A pressure control device according to claim 1 comprising a
rigid body adapted for mounting on a mandrel or the like, the rigid
body comprising an annular member, the first support member being
mounted to the annular member, the rigid body definging a cammed
surface adapted to be engaged by the first support member.
13. (canceled)
14. (canceled)
15. (canceled)
16. (canceled)
17. (canceled)
18. A pressure control device according to claim 1 wherein the
first support member is bonded to the second support member.
19. A pressure control device according to claim 1 wherein the
first support member is located on or adjacent the second support
member.
20. A pressure control device according to claim 1 wherein the
second support member comprises a composite of greater hardness
than the flexible sealing element located at an outer portion of
the flexible sealing element.
21. A pressure control device according to claim 1 wherein the
composite of the second support member comprises a composite matrix
and a reinforcing material, the reinforcing material being more
rigid than the composite material, the reinforcing material
comprising a plurality of separate members, particles or fibres and
a metal wire mesh.
22. (canceled)
23. (canceled)
24. (canceled)
25. (canceled)
26. (canceled)
27. (canceled)
28. (canceled)
29. A pressure control device according to claim 1 wherein the
second support member is urged outwardly against a bore wall, in
use, to help create a seal.
30. A pressure control device according to claim 1 wherein the
second support member is located adjacent the first support member
at an outer portion of the flexible sealing element.
31. A pressure control device according to claim 1 wherein at least
a portion of the second support member extends radially inwards of
the first support member.
32. A pressure control device according to claim 1 wherein the
second support member comprises a free end which is not bonded to
the flexible sealing element.
33. A pressure control device according to claim 1 wherein the
second support member comprises an end which is bonded to the
flexible sealing element.
34. (canceled)
35. A pressure control device according to claim 1 wherein the
flexible sealing element is selectively bonded to the body of the
first and/or second support member.
36. A pressure control device according to claim 1 wherein a
portion of the flexible sealing element is bonded to a portion of
the first support member and a further portion of the flexible
sealing element is bonded to a portion of the second support
member.
Description
FIELD OF THE INVENTION
[0001] The present invention belongs to the field of oil and gas
wells drilling and production of oil and gas from wells drilled on
the earth. More particularly it relates to the field of zonal
isolation wherein different sections of an oil or gas well are
sealingly isolated from other well sections to avoid
cross-contamination with fluids such as water, undesired pressure
transmission between sections or for other reasons.
BACKGROUND TO THE INVENTION
[0002] In the oil and gas exploration and extraction industries it
is often desirable to be able to modulate downhole pressure when
required. For example, it may be desirable to isolate a section of
well bore to create sections of differential pressure within the
bore. A sealing device may be used to create a seal within the
bore, such that fluid pressure on one side of the seal increases
relative to fluid pressure on the other side. Further, a temporary
decrease in well pressure can be used to initiate flow from the
reservoir in a process known as `swabbing`. One means of doing this
is to make use of a swab cup, which is a cup-shaped resilient
member which is lowered on a mandrel into the well. As a pressure
differential develops across the cup, the walls of the cup are
pushed into contact with the well tubing or bore wall, thereby
sealing a portion of the well. Thus, the pressure below the cup may
decrease, while the pressure above may increase.
[0003] Similarly constructed pressure cups are also used in a wide
variety of other sealing and fluid lifting applications. For
example, variations in pressure may also be used to actuate or to
control other downhole tools and instruments which rely on fluid
pressure for their operation. Such cups may be constructed with an
outer diameter slightly less than the bore diameter, such than an
initial inflation is required before a seal is created, or may have
an outer diameter slightly larger than that of the bore, such that
a seal is present even when the cup is not inflated.
[0004] Alternatively, a pressure differential may be achieved by
means of a packer. The sealing element on a packer is compressed
and activated via a setting load caused by mechanical or hydraulic
or other forces. These are used to isolate different parts of the
well for numerous downhole operations, such as well testing or
completions.
[0005] Conventional pressure seals suffer from a number of
disadvantages. The seals are usually made from rubber or other
elastomer, which must be made relatively thick in order to resist
the pressures downhole. This means that such seals may be
unsuitable for use at relatively low pressures, since they will not
seal the well effectively under these conditions. The relatively
thick elastomer can also suffer from slow recovery times after
pressure has been removed. Seals may be reinforced in order to
resist higher pressures with metal or wire hoops or rings embedded
within the elastomer; however, this can lead to shear failure of
the elastomer, with the reinforcing wire cutting through the
elastomer.
[0006] In addition, conventional seals may only operate over a
restricted range of pressures and temperatures, and with a small
gap between the seal and the bore wall. If the gap between the seal
and the bore is increased, the pressure that the seal will hold
drops considerably.
[0007] Further, elastomers under pressure can flow or extrude in
certain conditions. This may arise in seals or packers, and will
reduce the effectiveness of such seals or packers, because
elastomer flows or extrudes while the seal is under pressure. Any
tendency to flow or extrude is also exacerbated at higher
temperatures.
SUMMARY OF THE INVENTION
[0008] According to a first aspect of the present invention, there
is provided a pressure control device for mounting on a mandrel,
the device comprising:
[0009] a flexible sealing element;
[0010] a first support member; and
[0011] a second support member comprising a composite,
[0012] wherein the pressure control device is adapted to move from
a run in position to an expanded position when exposed to a source
of pressure, the flexible sealing element is adapted to form a seal
against a bore wall in the expanded position, the first and second
support members being adapted, in the expanded position, to resist
extrusion of the flexible sealing element, in use, along the bore
wall away from the source of pressure, the second support member
being further adapted to resist extrusion into the first support
member.
[0013] In at least one embodiment of the present invention an
apparatus as described above is able to sealingly isolate two
sections of an oil or gas well and at the same time maintain its
integrity under wellbore pressure differentials, thus preventing
extrusion and deformation of the flexible sealing element and of
the second support member and therefore maintaining the seal
leak-free. This invention is particularly suitable to achieve
effective zonal isolation under extreme pressures and temperatures,
such as those encountered in high pressure, high temperature wells
(HPHT wells).
[0014] Furthermore, by provision of a second support member in the
form of a composite, extrusion into the first support member of
flexible sealing element material or second support member material
is resisted, allowing for greater recovery of the first support
member, when the source of pressure is released, towards the run in
position.
[0015] The pressure control device may be a cup seal or a swab
cup.
[0016] Alternatively, the pressure control device may be a packer
or any suitable pressure control device comprising a flexible
sealing element.
[0017] A portion of the flexible sealing element, the first support
member and/or the second support member may be arranged
concentrically.
[0018] The first support member may further comprise a
circumferential spring.
[0019] The circumferential spring may be biased to the run-in
position.
[0020] The first support member may be located at an outer portion
of the flexible sealing element. Such an arrangement assists in
recovery of the flexible sealing element from the expanded position
to the run in position, when source of pressure is reduced or
eliminated.
[0021] In certain embodiments of the invention, the first support
member may also be urged outwardly against the bore wall, in use,
to help to create the seal.
[0022] In at least one embodiment of the present invention the
spring is a helical spring.
[0023] In other embodiments the spring may be a garter spring.
[0024] In some embodiments the spring may comprise a first spring
with a second spring in its interior. The second spring may be
mounted within the first spring such that the helix of one spring
is wound in the opposite direction to the spiral of the other
spring in order to resist canting of the first support member under
high pressure. In some embodiments this arrangement of the springs
also confers benefits for reducing the extrusion of the second
support member into the first support member.
[0025] Alternative spring forms and/or arrangements may be used
without departing from the principles of the invention.
[0026] The first support member may alternatively or additionally
comprise a petal arrangement.
[0027] The petals may be overlapping. In moving from the run-in
position to the expanded position, the petals open up but still
form a continuous surface to resist extrusion of the flexible seal
element along the bore wall away from the source of pressure.
[0028] The first support member may be located so as to abut the
second support member. Such an arrangement restricts movement of
the first support member to some degree when the device is
pressurised, and may be used to direct movement of the first
support member to improve formation of a seal.
[0029] The pressure control device may comprise a rigid body
adapted for mounting on a mandrel or the like.
[0030] The rigid body may comprise an annular member.
[0031] The first support member may be mounted to the annular
member.
[0032] The rigid body may comprise a cammed surface adapted to be
engaged by the first support member.
[0033] The cammed surface may be arranged to direct the first
support member radially outward when the device is under pressure.
This may be achieved by the cammed surface being inclined axially
downwardly from the centre of the device and radially outward. Such
an arrangement also provides further integrity of sealing by
ensuring the first support member has to overcome both the pressure
within the pressure control device and the direction of the cammed
surface to return to the run-in position.
[0034] Alternatively, the cammed surface may be inclined upwardly,
or may be generally horizontal; these arrangements may be used to
delay or restrain expansion of the first support member and/or
flexible sealing element, which may be useful in certain
applications.
[0035] The first support member may be bonded to the second support
member.
[0036] In alternative embodiments the first support member may be
located on or adjacent the second support member.
[0037] In at least one embodiment of the present invention the
second support member comprises a composite of greater hardness
than the flexible sealing element located at an outer portion of
the flexible sealing element. When the composite portion is of
greater hardness than the flexible sealing element itself, it will
be less susceptible to flow or extrusion due to the pressure, so
improving effectiveness of the device. This feature also allows the
flexible sealing element to be made of somewhat thinner or less
hard material than in previous devices.
[0038] The composite of the second support member may comprise a
composite matrix and a reinforcing material.
[0039] The reinforcing material may be more rigid than the
composite matrix material. In at least one embodiment of the
present invention the reinforcing material adds rigidity to the
second support member and improves its anti-extrusion properties at
high pressures. This is of benefit because when in use, it will
resist extrusion into the first support member and therefore it
will not hamper the recovery of the cup or packer original size and
shape upon removal or reduction of deforming pressure.
[0040] In at least one embodiment of the present invention the
reinforcing material may comprise a plurality of separate members,
particles or fibres.
[0041] In other embodiments the reinforcing material may comprise
at least one aggregated member. In at least one embodiment of the
present invention one or more aggregated members provide(s)
enhanced anti-extrusion properties to the second support member and
also helps resist better the extrusion of the flexible sealing
element by providing better tensile strength.
[0042] The/each aggregated member may comprise a mesh.
[0043] The mesh may comprise metal wire. Other semi-rigid materials
may be used for the mesh without departing from the principles of
the invention. Metal wire meshes are easily available at affordable
prices and provide the required mechanical and anti-extrusion
properties to the second support member in conjunction with the
composite matrix.
[0044] The mesh may be a diamond shape mesh.
[0045] Alternatively, the mesh may be a chicken-wire style mesh
(hexagonal mesh).
[0046] Other mesh shapes may be used without departing from the
principles of the present invention.
[0047] In some embodiments the second support member may also be
urged outwardly against the bore wall, in use, to help create a
seal.
[0048] Suitable materials for the various components include, but
are not limited to elastomers such as nitrile, hydrogenated
nitrile, fluoroelastomers, perfluoroelastomers, thermoplastic
materials, EPDM, polyurethane, and the like for the flexible
sealing element and/or the composite matrix; metals such as steel,
brass, or the like, or polymeric materials such as PEEK, nylon,
Kevlar and/or metal fabrics or the like for the first support
member and/or the composite reinforcing material.
[0049] The second support member may be located adjacent the first
support member at an outer portion of the flexible sealing
element.
[0050] At least a portion of the second support member may extend
radially inwards of the first support member.
[0051] The second support member may comprise a free end which is
not bonded to the flexible sealing element.
[0052] The second support member may comprise a free end and a
bonded end, which is bonded to the flexible sealing element. The
free end allows movement and expansion of the flexible sealing
element relative to the second support member, while the bonded end
serves to both retain the second support member in place relative
to the flexible sealing element, and further reduces the risk of
flow and/or extrusion of the flexible sealing element.
[0053] The first support member may be located adjacent to the free
end of the second support member. In at least one embodiment of the
present invention this arrangement allows the combination of the
first support member and the second support member to move relative
to the flexible sealing element when under pressure.
[0054] Preferably, the flexible sealing element is selectively
bonded to the body of the first and/or second support member.
[0055] A portion of the flexible sealing element may be bonded to a
portion of the first support member and a further portion of the
flexible sealing element may be bonded to a portion of the second
support member.
[0056] Any suitable means may be used to bond the components of the
device; for example, glue or other adhesive, welding,
vulcanisation, heat treatment, mechanical fasteners, bonding
agents, and the like.
BRIEF DESCRIPTION OF THE DRAWINGS
[0057] An embodiment of the present invention will now be described
with reference to the accompanying drawings in which:
[0058] FIG. 1 is a section through a pressure control device for
sealing an annulus between a mandrel and a wellbore, according to a
first embodiment of the present invention, the pressure control
device shown in a run-in configuration;
[0059] FIG. 2 is a close-up of part of the pressure control device
of FIG. 1 in the run-in configuration;
[0060] FIG. 3 is a close-up of part of the pressure control device
of FIG. 1 in the set configuration;
[0061] FIG. 4 is a perspective view of a section of the deformable
reinforcing element, and
[0062] FIG. 4A shows a close-up of part of the section of the
reinforcing element.
DETAILED DESCRIPTION OF THE DRAWINGS
[0063] Reference is first made to FIG. 1, a section through a
pressure control device 10 for sealing an annulus 12 between a
mandrel 14 and a wellbore 16, according to a first embodiment of
the present invention; the pressure control device 10 is shown in a
run-in configuration. The pressure control device 10 is a packer
and comprises a flexible sealing element 18 comprising an upper
flexible sealing element portion 20, a central flexible sealing
element portion 22 and a lower flexible sealing element portion 24.
The central flexible sealing element portion 22 is separated from
the upper flexible sealing element 20 and the lower flexible
sealing element 24 by first and second seal rings 26, 28
respectively. The sealing element portions 20, 22, 24 comprise an
elastomer, particularly nitrile butadiene rubber.
[0064] The pressure control device 10 further comprises two first
support members 30, 32 and two second support members 34, 36. The
structure and operation of the first and second support members 30,
32, 34, 36 will be discussed in due course.
[0065] The pressure control device 10 further comprises an upper
setting disc 38 and a lower setting disc 40, the discs 38, 40 being
adapted to be moved towards each other and move the sealing element
portions 20, 22, 24 from the run-in configuration shown in FIG. 1
to a set configuration shown in and discussed in connection with
FIG. 3.
[0066] Referring to FIG. 2, which illustrates a close-up of part of
the pressure control device 10 of FIG. 1 in the run-in
configuration, the structure of the first support members 30, 32
and the second support members 34, 36 will be discussed with
particular reference to the lower pair of support members 32,
36.
[0067] The first support member 32 comprises a circular helical
spring 42. The helical spring 42 rests on a cammed surface 44
defined by the lower setting disc 40 and is embedded in the matrix
46 of a composite material 48 which makes up the second support
member 36.
[0068] The matrix 46 of the composite material 48 is an elastomer
such as nitrile butadiene rubber and is reinforced by a deformable
reinforcing element 50.
[0069] FIG. 4 shows a perspective view of a section of the
deformable reinforcing element 50 and FIG. 4A shows a close-up of
part of the section of the reinforcing element 50. The reinforcing
element 50 is frusto-conical in shape and is made from a length of
steel mesh 52 wrapped around a former (not shown) around forty to
fifty times.
[0070] As can be seen from FIG. 4A, the steel mesh 52 defines voids
54. Between adjacent layers of mesh 52, there is partial but not
complete alignment of the voids 54 through the reinforcing element
50. The reason for this partial alignment will now be
discussed.
[0071] During manufacture of the second support member 36 the
matrix material 46 is adapted to permeate into the reinforcing
element voids 54 as the reinforcing element 50 is embedded in the
second support member 36 as the second support member 36 is
pressure formed around the reinforcing element 50.
[0072] The pressure control device 10 is moved from the run-in
configuration to the set configuration by applying a force to the
setting discs 38, 40 to move the setting discs towards each other,
compressing the flexible sealing elements 20, 22, 24. Due to the
presence of the mandrel 14, the sealing elements 20, 22, 24 can
only expand radially outwardly and expand into engagement with a
wellbore wall 56 (best seen in FIG. 3, a close-up of part of the
pressure control device 10 of FIG. 1 in the set configuration).
[0073] In the set configuration, the flexible sealing portions 20,
22, 24 are engaged with the wellbore wall 56 and under pressure and
temperature in the wellbore 16 would be inclined to extrude into
the gap indicated by the letter "A" on FIG. 3.
[0074] As can be seen from FIG. 3, however, the first support
member 32 has travelled down the cammed surface 44 as the second
seal element 24 is compressed, to substantially fill the gap A. In
addition, because the first support member 32 is substantially
encased within the second support member 36, the softer elastomer
of the seal element 24 is prevented from seeping through the
interface 60 between the first support member 32 and the cammed
surface 44 or the interface 62 between the first support member 32
and the wellbore wall 56. The harder elastomer of the second
support member 36 is selected so that seepage through the
interfaces 60, 62 is negligible under normal operating
pressures.
[0075] Continuing to refer to FIG. 3, the second support member 36
also comes into engagement with the wellbore wall 56 due to the
reinforcing element 50 deforming under the setting pressure.
[0076] As previously stated, the first support member 32 is in the
form of a helical spring 42. The spring 42 is biased to the run-in
position and is in an expanded state in the set position. In the
set position adjacent coils will, therefore, be separated with a
gap between. The use of a harder elastomer for the matrix 46 of the
second support member 36 and the presence of the reinforcing
element 50 reduces seepage of the second support member 36 into the
gaps between the separated coils. This allows the first support
member 32 to recover to the run-in configuration when the setting
pressure is removed.
[0077] Various modifications and improvements may be made to the
above-described embodiments without departing from the scope of the
invention. For example, in low-temperature environments, a
mechanical force could be applied to move the seal element to the
sealed position.
[0078] Although the support element is shown as being a conical
multilayer mesh construction, other materials such as Kevlar could
be used and other shapes such a cylindrical can be adopted.
[0079] Similarly, although the embodiments shown a packer type
pressure control device, a further embodiment comprising a pressure
control device comprising a flexible cup would also fall within the
scope of the invention.
* * * * *