U.S. patent application number 11/061460 was filed with the patent office on 2006-08-24 for fluid seals.
Invention is credited to Jean-Marc Lopez.
Application Number | 20060186601 11/061460 |
Document ID | / |
Family ID | 36889405 |
Filed Date | 2006-08-24 |
United States Patent
Application |
20060186601 |
Kind Code |
A1 |
Lopez; Jean-Marc |
August 24, 2006 |
Fluid seals
Abstract
Certain embodiments of the invention are directed to a sealing
device having greater resistance to failure when exposed to
elevated temperature or pressure conditions. A number of
embodiments of the invention include a sealing device having an
annular seal member comprising an elastomer material and at least
one cap member affixed to the seal member. In some circumstances,
when the seal member is compressed in a substantially axial
direction, at least a portion of the cap member deforms in a
substantially radial direction.
Inventors: |
Lopez; Jean-Marc; (Plano,
TX) |
Correspondence
Address: |
Terry Stalford;Fish & Richardson, P.C.
Suite 5000
1717 Main Street
Dallas
TX
75201
US
|
Family ID: |
36889405 |
Appl. No.: |
11/061460 |
Filed: |
February 18, 2005 |
Current U.S.
Class: |
277/327 |
Current CPC
Class: |
E21B 33/1208 20130101;
F16J 15/166 20130101; E21B 33/1216 20130101; E21B 33/12 20130101;
F16J 15/181 20130101; F16J 15/3236 20130101 |
Class at
Publication: |
277/327 |
International
Class: |
E21B 33/06 20060101
E21B033/06 |
Claims
1. A sealing device comprising: an annular seal member comprising
an elastomer material, the annular seal having a first seal surface
exposed on a first side and a second seal surface exposed on an
inner second side; and a cap member affixed between the first and
second seal surfaces of the seal member, the cap member formed of
material having substantially greater strength than the elastomer
material of the seal member, wherein when pressure is applied
between the seal surfaces, the seal member is compressed in a
certain direction substantially toward the cap member and causes at
least a portion of the cap member to deform substantially
perpendicular to the certain direction.
2. The sealing device of claim 1, further comprising a second cap
member affixed to the seal member opposite the first mentioned cap
member and disposed between the first and second seal surfaces, at
least a portion of the second cap member operable to deform
substantially perpendicular to the certain direction when the seal
member is compressed in the certain direction.
3. The sealing device of claim 1, wherein the cap member comprises
a thermoplastic material.
4. The sealing device of claim 1, wherein the cap member comprises
a material having a greater resistance to degradation from
temperature than the elastomer material of the seal member.
5. The sealing device of claim 1, wherein the cap member comprises
a material selected from the group consisting of:
Polyetheretherketone, Polyetherimide, Torlon.TM., and
Teflon.TM..
6. The sealing device of claim 1, wherein the seal member comprises
a material selected from the group consisting of: Hydrogenated
Nitrile Butadiene Rubber, Nitrile Butadiene Rubber, Chloroprene
Rubber, Polyisoprene, Styrene Butadiene Rubber,
Isoprene-Isobutylene Rubber, Chlorinated Butyl, Polyacrylic,
Epichlorohydrin, Thiokol Polysulfide, Silicone and Fluoro-Silicone
Rubber, Hypalon.TM., Fluoro Elastomer, Polybutadiene, Ethylene
Propylene Copolymer, Ethylene Propylene Diene Terpolymer, and TFE
Propylene.
7. The sealing device of claim 1, wherein when the seal member is
disposed between an outer body and an inner body, the cap member is
affixed to the side of the seal member proximal to a clearance
space between the outer and inner bodies.
8. The sealing device of claim 7, wherein when the seal member is
compressed in the certain direction, the cap member substantially
inhibits the seal member from extruding into the clearance
space.
9. The sealing device of claim 7, wherein when fluid between the
outer body and inner body is at a temperature operable to
deteriorate the elastomer material of the seal member, the cap
member substantially inhibits the elastomer material of the seal
member from passing into the clearance space.
10. The sealing device of claim 9, wherein when fluid between the
outer body and inner body is at least 350.degree.0 F. and at least
15,000 psi, the cap member substantially inhibits the elastomer
material of the seal member from passing into the clearance
space.
11. The sealing device of claim 7, wherein when the seal member is
disposed in a groove formed in the outer body and the inner body,
the cap member is sized to contact the outer and inner bodies so as
to substantially inhibit the seal member from blowing out of the
groove.
12. A device comprising: a first body; a second body having a
groove; and a seal in the groove adapted to substantially seal
between the first and second bodies, the seal comprising: an
annular seal member having a first substantially convex surface and
a second substantially convex surface; and a first cap member
having a first substantially concave surface affixed to the first
substantially convex surface of the seal member such that
deformable portions of the first cap member are positioned radially
on both sides of a portion of the seal member, and a second cap
member having a second substantially concave surface affixed to the
second substantially convex surface of the seal member such that
deformable portions of the second cap member are positioned
radially on both sides of a portion of the seal member.
13. The device of claim 12, wherein when the seal member is
compressed in a substantially axial direction, the deformable
portions of the first and second cap members deform in a
substantially radial direction.
14. The device of claim 13, wherein at least one of the first and
second cap members deforms to press against the first and second
bodies.
15. The device of claim 13, wherein at least one of the first and
second cap members substantially seals against the first and second
bodies.
16. The device of claim 12, wherein when the seal member is
compressed in a substantially axial direction, at least one of the
first and second cap members substantially inhibits the seal member
from extruding into a clearance space between the first and second
bodies.
17. The device of claim 12, wherein at least one of the first and
second cap members has higher resistance to degradation from
temperature than the seal member.
18. The device of claim 12, wherein the first and second bodies are
components of a well bore packer assembly.
19. The device of claim 12, wherein at least one of the first and
second cap members is sized to contact the outer and inner bodies
so as to substantially inhibit the seal member from blowing out of
the groove.
20. A method of sealing between a first body and a second body, the
second body including a groove, the method comprising: providing a
seal device in the groove having an elastomeric seal member
defining a first seal surface to press against the first body and a
second seal surface to press against the second body, the seal
device having a cap member affixed to an axial side of the seal
member and disposed radially between the first and second seal
surfaces; and in response to pressure applied to the seal between
the first and second seal surfaces, deforming the cap member to
press against the first and second bodies.
21. The method of claim 20, wherein the cap member is provided in
contact with the first and second bodies and wherein deforming the
cap member to press against the first and second bodies comprises
deforming the cap member into further contact against the first and
second bodies.
22. The method of claim 20, wherein deforming the cap member to
press against the first and second bodies comprises deforming the
cap member to substantially seal against the first and second
bodies.
23. The method of claim 20, wherein the cap member is affixed to
the axial side of the seal member proximal to a clearance space
between the first and second bodies, further comprising
substantially inhibiting the seal member from extruding into the
clearance space.
24. The method of claim 20, wherein the cap member has a higher
resistance to degradation from temperature than the elastomer
material of the seal member.
Description
TECHNICAL FIELD
[0001] This invention relates to seals that restrict or otherwise
control fluid flow.
BACKGROUND
[0002] Sealing devices, such as o-rings and the like, may be used
to form a fluid seal between two mating parts. For example, when a
metallic cylindrical plug is inserted into a metallic tubular
member to restrict fluid flow, an o-ring seal may be positioned in
a circumferential groove formed in the plug. The o-ring may have an
outer diameter that is larger than both the inner diameter of the
tubular member and the outer diameter of the plug. In such
circumstances, when the plug is inserted into the tubular member,
the o-ring is compressed between the outer circumferential surface
of the plug and the inner circumferential surface of the tubular
member. If fluid seeps in the clearance space between the plug and
the tubular member, the o-ring may form an effective seal that
prevents fluid flow through the clearance space past the plug.
[0003] In the event of seal failure, fluid leakage may
occur--requiring replacement of the sealing device or, in some
circumstances, rendering the associated machinery inoperable. The
time and costs required to repair or replace the inoperable
machinery can be significant. For example, accessing fluid control
machinery disposed in underground wells is a time-consuming and
laborious task. If such machinery is rendered inoperable by the
failure of a sealing device, considerable time and costs must be
spent in order to retrieve, repair, and restore the machinery.
Throughout the entire process, production from the well may be
completely shutdown until the machinery is restored.
[0004] The material of the seal is one design factor that affects
seal failure. For example, if a seal is exposed to sufficiently
high pressures so as to overcome the seal material's strength, the
seal may be extruded through the clearance space between the mating
parts. Also, if the seal is exposed to sufficiently high
temperatures, the seal material may deteriorate, thereby permitting
fluid to flow past the seal location.
[0005] The geometry of the seal is another design factor that
affects seal failure. If the seal is improperly sized for the
groove in which it sits, fluid may seep past the seal in the
groove. Also, if the radial clearance between the mating parts is
relatively large compared to the radial height of the seal, the
seal may be at least partially "blown out" (forced out its groove
and into the clearance space between the mating parts), thereby
permitting fluid to leak through the seal location.
SUMMARY
[0006] Certain embodiments of the invention are directed to a
sealing device having greater resistance to failure when exposed to
elevated temperature or pressure conditions.
[0007] A number of embodiments of the invention include a sealing
device. The seal device may include an annular seal member
comprising an elastomer material. The annular seal member may be
disposed radially from an axis and may have a first seal surface
exposed on an outer radial side and a second seal surface exposed
on an inner radial side. The seal device may further include a cap
member affixed to an axial side of the seal member. The cap member
may be disposed radially between the first and second seal
surfaces, and the cap member may be formed of material having
substantially greater strength than the elastomer material of the
seal member. In such embodiments, when the seal member is
compressed in a substantially axial direction that is substantially
parallel to the axis, at least a portion of the cap member deforms
in a substantially radial direction.
[0008] In some embodiments, a device includes a first body, a
second body having a groove, and a seal in the groove. The seal may
be adapted to substantially seal between the first and second
bodies. The seal may include an annular seal member having a first
substantially convex surface and a second substantially convex
surface. The seal may further include a first cap member having a
first substantially concave surface affixed to the first
substantially convex surface of the seal member such that
deformable portions of the first cap member are positioned radially
on both sides of a portion of the seal member. Also, the seal may
include a second cap member having a second substantially concave
surface affixed to the second substantially convex surface of the
seal member such that deformable portions of the second cap member
are positioned radially on both sides of a portion of the seal
member.
[0009] In another embodiment, a method of sealing between a first
body and a second body includes providing a seal device in a groove
of the second body. The seal device may have an elastomeric seal
member defining a first seal surface to press against the first
body and a second seal surface to press against the second body.
The seal device may also have a cap member affixed to an axial side
of the seal member and disposed radially between the first and
second seal surfaces. The method further includes, in response to
pressure applied to the seal between the first and second seal
surfaces, deforming the cap member to press against the first and
second bodies.
[0010] These and other embodiments may be configured to provide one
or more of the following advantages. First, even when the sealing
device is exposed to elevated temperature or pressures, the sealing
device may be configured to reduce the likelihood of extrusion
through the clearance space between the mating parts. Second, the
sealing device may have increased radial strength while maintaining
some degree of flexibility. Third, the sealing device may be
configured to reduce the likelihood of seal "blow out" or other
types of seal failure. Fourth, large quantities of the sealing
device may be cost-effectively manufactured using molding
techniques. Some or all of these and other advantages may be
provided by the devices and methods described herein.
[0011] The details of one or more embodiments of the invention are
set forth in the accompanying drawings and the description below.
Other features, objects, and advantages of the invention will be
apparent from the description and drawings, and from the
claims.
DESCRIPTION OF DRAWINGS
[0012] FIG. 1 is a perspective view of a sealing device in
accordance with an embodiment of the invention.
[0013] FIG. 2A is a cross-sectional view of the sealing device of
FIG. 1.
[0014] FIG. 2B is an exploded view of the sealing device of FIG.
2A.
[0015] FIG. 2C is a cross-sectional view of a sealing device in
accordance with another embodiment of the invention.
[0016] FIGS. 3A-B are cross-sectional views of a sealing device
disposed in a groove in accordance with an embodiment of the
invention.
[0017] FIGS. 4A-C are cross-section views of a sealing device
disposed in a groove in accordance with another embodiment of the
invention.
[0018] FIGS. 5A-B are views of a packer system having the seal
device of a FIG. 1, in accordance with some embodiments of the
invention.
[0019] Like reference symbols in the various drawings indicate like
elements.
DETAILED DESCRIPTION
[0020] Referring to FIG. 1, a sealing device 100 may include a seal
member 120 and one or more cap members 140 and 160. In a number of
embodiments, the sealing device 100 may be inserted into a groove
or otherwise positioned between two contact surfaces so as to
control fluid flow between the surfaces. The sealing member 120 may
have a shape that is generally similar the shape of the groove or
contact surfaces. In the embodiment shown in FIG. 1, the sealing
device 100 has a generally annular shape that is disposed radially
about a central axis 110. The cap members 140 and 160 are coupled
to opposing axial sides of the seal member 120. As such, the cap
members 140 and 160 comprise at least a substantial portion of the
faces 104 and 106 of the device 100. The inner exposed surface 126
and the outer exposed surface 128 of the sealing member 120 are
exposed along the inner circumferential side 102 and the outer
circumferential side 108 of the device 100. In these embodiments,
the sealing member 120 and the cap members 140 and 160 collectively
form at least a substantial portion of the inner and outer
circumferential sides 102 and 108 of the device 100.
[0021] Referring to FIGS. 2A-B, the cap members 140 and 160 may
include mating surfaces that join with complementary surfaces on
the sealing member 120. In this embodiment, the cap member 140
mates with the sealing member 120 such that extension portions 144
and 146 are disposed radially on both sides of portions of the
sealing member 120. For example, the cap member 140 may have a
mating surface 142 at least a portion of which includes a concave
curvature. The sealing member 120 has a mating surface 122 that is
joined to the mating surface 142 of the cap member 140. At least a
portion of the sealing member's mating surface 122 has a convex
curvature that substantially complements the cap member's mating
surface 142. As such, the extension portions 144 and 146 are
disposed radially on both sides of portions of the sealing member
120.
[0022] As shown in FIGS. 2A-B, the second cap member 160 may have a
similar size and shape as the first cap member 140. In the depicted
embodiment, the second cap member 160 has a mating surface 162 that
joins a mating surface 124 of the sealing member 120 on an axial
side opposite the first cap member 140. Again, the cap member 160
may mate with the sealing member 120 such that extension portions
164 and 166 are disposed radially on both sides of portions of the
sealing member 120. At least a portion of the second cap member's
mating surface 162 may have a concave curvature, which is
substantially complementary to a convex curvature on the sealing
member's mating surface 124.
[0023] Still referring to embodiment shown in FIGS. 2A-B, the cap
member 140 may be disposed radially between the inner exposed
surface 128 and an outer exposed surface 128 of the seal member
120. As such, the exposed surfaces 126 and 128 of the seal member
120 are capable of pressing against inner and outer bodies to form
a seal (described in form detail below in connection with FIGS.
3A-B). In such circumstances, the device 100 may use the exposed
surfaces 126 and 128 of the seal member 120 to form a seal between
two bodies while the cap members 140 and 160 may enhance the seal
performance.
[0024] The cap member 140 may include an inner circumferential
surface 148 and an outer circumferential surface 149. The inner
circumferential surface 148 faces in a generally radial direction
and forms a portion of the device's inner circumferential side 102.
The outer circumferential surface 149 faces in a generally radial
direction opposite that of the inner circumferential surface 148
(but not necessarily exactly opposite and parallel of the inner
circumferential surface 148). The cap 140 may have an axial-facing
surface 150 that forms a substantial portion of the sealing
device's face 104. In some embodiments, the inner and outer
circumferential surfaces 148 and 149 may be tapered at angles 152
and 154 toward to the axial-facing side 150 to compensate for
thermal expansion. As shown in FIG. 2B, for example, the
circumferential surfaces 148 and 149 are tapered at an angle of
about 1 degree to about 10 degrees--preferably about 4 degrees. The
tapering angles 152 and 154 of the circumferential surfaces 148 and
149 may vary depending on the thermal expansion of the cap member
material and the desired flow characteristics during operation. In
the embodiment depicted in FIGS. 2A-B, the cap member 140 has
beveled surfaces between the axial-facing side 150 and the
circumferential surfaces 148 and 149.
[0025] As previously described, the second cap member 160 may have
a similar size and shape as the first cap member 140. In such
embodiments, the second cap member 160 may have an inner
circumferential surface 168 and an outer circumferential surface
169 similar to those of the first cap member 140. Also, the second
cap member 160 may have a surface 170 that generally faces an
opposite axial direction from the axial-facing side 150 of the
first cap member 140. In some embodiments, the inner and outer
circumferential surfaces 168 and 169 may be tapered at angles 172
and 174 toward to the axial-facing side 170 of the second cap
member 160. The tapering angles 172 and 174 of the circumferential
surfaces 168 and 169 may vary depending on the thermal expansion of
the cap member material and the desired flow characteristics.
Furthermore, the second cap member 160 may have beveled surfaces
between the axial-facing surface 170 and the circumferential
surfaces 168 and 169.
[0026] The sealing device 100 may be manufactured using a number of
processes and various materials. Referring now to FIG. 2B, the cap
members 140 and 160 may be formed of a different material from the
sealing member 120 and bonded to the sealing member 120. The cap
members 140 and 160 may comprise a polymer material that is capable
of a substantially elastically deforming when pressure is applied
to the sealing device 100 (described in more detail below). The
type of polymer material for the cap members 140 and 160 may vary
depending on the application of the sealing device 100, the flow
temperature and pressure characteristics, the possibility of
corrosion, and other factors. For example, the cap members 140 and
160 may comprise Polyetheretherketone (PEEK), Polyetherimide (PEI),
Torlon.TM., Teflon.TM., other thermoplastic polymers, rubber
materials having a relatively high degree of hardness, rubber or
thermoplastic materials having reinforcing fibers (such as glass
fibers) embedded therein, or the like. In some circumstances, the
cap members 140 and 160 may be thermoformed to the desired shape,
and if necessary, certain machining operations may be performed on
the thermoformed parts.
[0027] The sealing member 120 may comprise an elastomer material
that has a sufficiently high operating temperature capabilities and
desired elasticity properties. The type of elastomer material for
the sealing member may vary depending on the application of the
sealing device 100, the flow temperature and pressure
characteristics, and other factors. For example the sealing member
120 may comprise Hydrogenated Nitrile Butadiene Rubber (HNBR) or
other Nitrile Butadiene Rubbers, C. R. Chloroprene Rubber,
Polyisoprene, Styrene Butadiene Rubber (SBR), Isoprene-Isobutylene
Rubber (IIR), Chlorinated Butyl (Chlorobutyl), Polyacrylic,
Epichlorohydrin (Hydrin.TM.), Thiokol Polysulfide, Silicone and
Fluoro-Silicone Rubber, Hypalon.TM., Fluoro Elastomers (e.g.,
Viton.TM. or Fluorel.TM.), Polybutadiene, Ethylene Propylene
Copolymer (ERM), Ethylene Propylene Diene Terpolymer (ERDM), TFE
Propylene (Aflas.TM.), or other like materials. In some
circumstances, the sealing member 120 may comprise an elastomer
material having reinforcing fibers of a different material (such as
glass fibers) embedded therein.
[0028] In some embodiments, the material of the cap members 140 and
160 is selected such that the cap member material has substantially
greater strength that the elastomer material of the seal member
120. In addition, the cap member material may be selected to have a
greater resistance to degradation from temperature than the
elastomer material of the seal member. In one illustrative example,
the cap members 140 and 160 may comprise a PEEK material, and the
seal member 120 may comprise a HNBR material. In this example, the
PEEK material is substantially stronger than the HNBR so as to
provide supplemental radial strength to the overall device 100.
Also in this example, the PEEK material is capable of operating a
higher temperatures than the HNBR material, which may may permit
the device 100 to maintain a seal at temperatures greater than the
normal operating temperature of the HNBR material by itself
(described in more detail below).
[0029] Still referring to FIG. 2B, a bonding agent may be applied
to the mating surfaces 142 and 162 of the cap members 140 and 160.
The bonding agent may be an adhesive that affixes the complementary
surfaces to one another. Alternatively, the bonding agent may be a
chemical agent that promotes bonding between the materials during
the in-molding process that forms the seal member 120. The cap
members 140 and 160 are attached to the seal member 120 such that,
when the seal member 120 is compressed in an axial direction (e.g.,
a direction substantially parallel to the central axis 110),
certain portions of the cap members 140 and 160 may flex or
otherwise deform in a substantially radial direction (described in
more detain below).
[0030] In some embodiments, the sealing member may be manufactured
using an in-molding process. In such circumstances, the cap members
140 and 160 may be thermoformed from a polymer material, as
previously described. Then the first cap member 140 is positioned
in a first mold half, and the second cap member 160 is disposed in
a second mold half. The mold halves include spaces to receive the
cap members 140 and 160 and other geometries that define the shape
of the seal member 120. The mold halves are pressed together such
that the cap members 140 and 160 are disposed substantially
parallel to one another with the mating surfaces 142 and 162 facing
one another. Preferably, a bonding agent is applied to the mating
surfaces 142 and 162 of the cap members 140 and 160 so as to
promote bonding between the seal member material and the cap
members 140 and 160. When the mold halves are properly positioned,
the elastomer material is injected into the space between the cap
members 140 and 160. The in-molding process continues until the
seal member 120 is formed (e.g., thermoset, thermoformed, or the
like) to the desired shape between the cap members 140 and 160.
[0031] It should be understood that the sealing device may be
formed to include geometries other than those shown in FIGS. 2A-B.
For example, alternative cap members 240 and 260 are shown in FIG.
2C. The alternative cap members 240 and 260 may include notches 245
and 265 in the mating surfaces 242 and 262, respectively. The
notches 245 and 265 may enhance the flexing motion of the extension
portions 244 and 246 of cap members 240 and 260. Furthermore, the
notches 245 and 265 may increase the surface area between the cap
member material and the seal member material, which in turn may
improve the bonding between the sealing member 220 and the cap
members 240 and 260. Such improved bonding may be more significant
when the seal member 220 is formed using an in-molding process, as
described above. The sealing member 220 may also include tongue
portions 225 that extend into the notches 245 and 265.
[0032] Still referring to FIG. 2C, the mating surfaces 242 and 262
of the alternative cap members 240 and 260 do not necessarily
include a concave curvature. Each cap member 240 and 260 may
include a V-shaped groove with substantially straight and inwardly
angled surfaces 242 and 262. The sealing member 220 may include
mating surfaces 222 and 224 that have a shape complementary to the
corresponding mating surfaces 242 and 262. As previously described,
the cap member 240 mates with the sealing member 220 such that
extension portions 244 and 246 are disposed radially on both sides
of portions of the sealing member 220. Similarly, the second cap
member 260 mates with the sealing member 220 such that extension
portions 264 and 266 are disposed radially on both sides of
portions of the sealing member 220.
[0033] In operation, the sealing device may form an effective seal
between two contact surfaces with improved resistance to seal
failure. The sealing device may be configured to reduce the
likelihood of extrusion through the clearance space between the
mating parts, even when the sealing device is exposed to elevated
temperature or pressures. Furthermore, some embodiments the sealing
device may operate as a dynamic seal while reducing the likelihood
of seal "blow out."
[0034] Referring to FIGS. 3A-B, the sealing device 100 may be
disposed in a groove 310 to provide a seal in the clearance space
305 between two contact surfaces 300 and 302. When the fluid
pressure causes the seal member 120 to be compressed in a
substantially axial direction, portions of the cap members 140 and
160 may be flexed or otherwise deformed in a substantially radial
direction to further enhance the performance of the seal. In these
cases, the fluid pressure acting upon the sealing device 100 may be
used to enhance seal performance, thereby reducing the likelihood
of seal failure under elevated pressures. In some embodiments, the
sealing device 100 may be capable of providing a fluid seal under
temperatures and pressure that would ordinarily cause an
traditional rubber o-ring to deteriorate and extrude through the
clearance space 305.
[0035] Referring now to FIG. 3A, in this embodiment the sealing
device 100 is sufficiently sized such that the sealing member 120
abuts both the circumferential surface 312 of the groove 310 and
the first contact surface 300 (e.g., the outside diameter surface
of the inner body). As previously explained, the cap members 140
and 160 may have circumferential surfaces 148, 149 and 168, 169
that are tapered. In such embodiments, the sealing device 100 may
be sized such that the tips 158, 159 and 178, 179 of the cap
members 140 and 160 abut the same surfaces as the sealing member
120. Under these circumstances, the sealing member 120 and the cap
members 140 and 160 are pressed against the surfaces 300 and 312,
which may provide a fluid seal in the clearance space 305.
[0036] Referring to FIG. 3B, the seal performance may be enhanced
when greater fluid pressure (e.g., compared to the fluid pressure
exhibited in FIG. 3A) is applied to the sealing device 100. When
the fluid pressure is acting upon the sealing device 100 in a
substantially axial direction 10, the first cap member 140 is
forced toward the second cap member 160, which is retained by at
least one wall of the groove 310. If the fluid pressure is
sufficient to compress the sealing device 100 in the substantially
axial direction 10, the elastomer material of the sealing member
120 deforms, which in turn forces portions of the polymer cap
members 140 and 160 to deform in a substantially radial direction
20. In this embodiment, at least the extension portions 144, 146
and 164, 166 (e.g., the portions of the cap members 140 and 160
that are disposed radially of both sides of portions of the seal
member 120) deform in the substantially radial direction 20. Such
deformation of the cap members 140 and 160 causes the
circumferential sides 148, 149 and 168, 169 to forcefully press
against the circumferential surfaces 300 and 312 and tightly close
off any extrusion path through which the sealing member 120 can
extrude. Furthermore, the convex shape of the mating surface 142,
162 increases the force in which the circumferential sides 148, 149
and 168, 169 press against the circumferential surfaces 300 and 312
as the pressure applied to the sealing device 100 increases. As
shown in FIG. 3B, a greater proportion of the cap members'
circumferential sides 148, 149 and 168, 169 may contact the
circumferential surfaces 300 and 312 when the fluid pressure causes
the compression of the sealing device 100. In this manner, the cap
members 140 and 160 reduce the tendency of the sealing member 120
to extrude at high pressures and/or temperatures, and enable the
sealing device 100 to seal a gap 305 that is larger than could be
sealed without the cap members 140, 160.
[0037] In some embodiments, the sealing device 100 may be capable
of providing a fluid seal under temperatures and pressure that
would ordinarily cause a traditional rubber o-ring or even the
sealing member 120 itself (i.e. without cap members 140, 160) to
deteriorate and extrude through the clearance space 305. In such
embodiments, the material of the cap members 140 and 160 may have a
greater resistance to degradation from temperature than the
elastomer material of the seal member 120. For example, in one
application a sealing device 100 comprising cap members 140 and 160
formed of PEEK thermoplastic material and a sealing member 120
formed of HNBR elastomer material is capable providing a fluid seal
when exposed to fluid at 15,000 psi and 350.degree. F. In general,
the HNBR elastomer material may break down at temperatures of about
350.degree. F., so in the same application, a traditional o-ring or
the sealing member 120 alone made of the HNBR material would likely
be extruded through the clearance space 305 when exposed to fluid
at 15,000 psi and 350.degree. F. It is believed that the polymer
cap members 140 and 160 forcefully press against the
circumferential surfaces 300 and 312 to retain the elastomer
material of the sealing member 120 when the device 100 is exposed
to fluid at 15,000 psi and 350.degree. F., thus preventing or
reducing the likelihood of extrusion of the elastomer material
through the clearance space 305.
[0038] Referring now to FIGS. 4A-C, the sealing device 100 may
operate as a dynamic seal to control fluid flow and may have a
design that reduces the likelihood of seal "blow out." For example,
the sealing device 100 may permit fluid to flow past the seal
location when a contact surface is a first position and may provide
a fluid seal when the contact surface is moved to a second position
relative to the seal location. As previously described, the energy
from the fluid pressure may be used to advantageously deform the
sealing device 100 to enhance the seal performance.
[0039] Referring to FIG. 4A, the sealing device 100 is disposed
between an inner body 400 and an outer body 401 in a groove 410
such that fluid is permitted to flow through the clearance space
405. In this embodiment, the inner body 400 and the outer body 401
are designed to move relative to one another so as to control the
fluid flow. When the first contact surface 402 is positioned as
shown in FIG. 4A, the sealing member 120 does not necessarily press
against both the circumferential surface 412 of the groove 410 and
the first contact surface 402, so fluid flow is restricted but not
necessarily sealed. (Alternatively, the sealing device 100 may be
sized so that the sealing member 120 contacts both the
circumferential surface 412 of the groove 410 and the first contact
surface 402 of the inner body 400. However, the sealing member 120
may not press against the circumferential surfaces 402 and 412 with
sufficient force so as to form a fluid-tight seal. In such
circumstances, some fluid may flow past the seal device 100.) The
fluid flow may be subsequently sealed when the chamfer 403 and the
second contact surface 404 are shifted so as to contact the seal
device 100, as described in more detail below.
[0040] Referring now to FIG. 4B, when the inner body 400 is shifted
in a substantially axial direction so that the chamfer 403 first
begins to contact the sealing member 120 of the sealing device 100,
the fluid flow becomes restricted between the chamfer 402 and the
sealing member 120. However, during this stage it is possible that
fluid may flow past the sealing device 100 along the groove surface
412, resulting in a relatively higher pressure radially outside of
the sealing device 100 than radially inside the sealing device 100
until the area between the sealing device 100 and surface 402 is
filled with fluid. In such circumstances, some traditional o-rings
would be susceptible to being "blown out" (forced out its groove
and into the clearance space between the inner and outer bodies)
due the resulting pressure differential caused by the fluid flow
along the groove surface 412 and lack of (or substantially reduced)
flow between the sealing member 120 and the chamfer 403.
[0041] The embodiment of the sealing device 100 shown in FIG. 4B
reduces the likelihood of such seal "blow outs." When the chamfer
403 contacts the sealing device, the sealing device 100 may be
shifted in a substantially radial direction, which in turn causes
portions of the cap members 140 and 160 to press against the
circumferential surface 412. When the cap members 140 and 160 are
pressed against the surface 412, the fluid flow along the groove
surface 412 may be substantially reduced. The reduced flow is less
likely to force the sealing device 100 out of the groove 410 and
reduces the likelihood of seal "blow out." Furthermore, one or both
of the cap members 140, 160 may comprise a polymer material that is
substantially more rigid than the elastomer material of the sealing
member 120. In these embodiments, the cap members 140, 160 increase
the radial rigidity of the sealing device 100 and make the sealing
device 100 less likely to be flexed into a position that can
squeezed into the clearance space 405 (i.e. the initial stages of a
"blow out" may be less likely to occur).
[0042] Referring to FIG. 4C, the inner body 400 may be shifted
further in the substantially axial direction such that the second
contact surface 404 is adjacent the first cap member 140 and the
sealing member 120. The first cap member 140 may comprise a polymer
material that is capable of substantially elastically deforming
when the second contact surface 404 is shifted to decrease the
space in the groove 410. In some circumstances, the cap member's
polymer material may be advantageous (compared to non-deformable
materials) because it can be sized to fit snugly in the space
between the first contact surface 402 and the groove surface 412
and then be substantially elastically deformed to fit in the
decreased space between the second contact surface 404 and the
groove surface 412. Similarly, the second cap member 160 may
comprise a polymer material that is capable of substantially
elastically deforming when the second contact surface 404 is fully
shifted so as to abut the second cap member 160.
[0043] When the chamfer 403 and the second contact surface 404 are
shifted toward the second cap member 160, the fluid pressure may
cause the sealing device 100 to be compressed in a substantially
axial direction. As shown in FIG. 4C, the first cap member 140 is
forced toward the second cap member 160, which is retained by at
least one wall of the groove 410. If the fluid pressure is
sufficient to compress the sealing device 100 in the substantially
axial direction 10, the elastomer material of the sealing member
120 deforms, which in turn forces portions of the polymer cap
members 140 and 160 to deform in a substantially radial direction.
In this embodiment, at least the extension portions 144, 146 and
164, 166 deform in the substantially radial direction. Such
deformation of the cap members 140 and 160 causes the cap members'
circumferential sides 148, 149 and 168, 169 to press against the
contact surfaces 402, 404 and the groove surface 412, which may
provide a fluid-tight seal. Comparing FIG. 4C to the previously
described FIG. 4A, a greater proportion of the cap members'
circumferential sides 148, 149 and 168, 169 may contact the contact
surfaces 402, 404 and the groove surface 412 when the fluid
pressure causes the compression of the sealing device 100.
Accordingly, the energy from the fluid pressure and temperature may
be used to advantageously deform the sealing device 100 to enhance
the seal performance.
[0044] Referring to FIGS. 5A-B, the previously described
embodiments of the sealing device may provide an effective fluid
seal when exposed to elevated pressures and temperatures, such as
those conditions present in some fluid control machinery disposed
in underground wells. One example of a fluid control system
disposed in underground wells is known as a packer 500. One purpose
of the packer 500 is to seal the annulus 515 between the outside of
the production tubing 520 and the inside of the well casing 510 so
as to block movement of fluids through the annulus 515 past the
packer location. As shown in FIG. 5A, the packer 500 is releasably
engaged with the bore of the well casing 510. The tubular well
casing 510 lines a well bore which has been drilled through, for
example, an oil producing formation. The packer 500 is connected to
the production tubing 520, which may lead to a wellhead for
conducting produced fluids to the surface.
[0045] Referring now to FIG. 5A, the packer 500 is releasably set
and locked against the casing 510 by one or more anchor slip
assemblies 530. The anchor slip assemblies 530 may have opposed
camming surfaces that cooperate with complementary opposed wedging
surfaces 535. In such embodiments, the anchor slip assemblies 530
are radially extendible into gripping engagement against the well
casing 510 in response to relative axial movement of the wedging
surfaces 535. In general, the anchor slip assemblies 530 are first
set against the well casing 510, and further axially compress a
seal element assembly 550 causing the seal element assembly 550 to
expand radially. The seal element assembly 550 can be expanded
against the well casing 510 to provide a fluid-tight seal between
the packer mandrel and the well casing 510. As such, pressure is
held in the well bore below the seal element assembly 550.
[0046] Referring now to FIG. 5B. the seal element assembly 550 of
the packer 500 may include the sealing device 100 described in
connection with FIGS. 1-4. In this embodiment, the sealing device
100 includes a sealing member 120 and cap members 140 and 160
affixed to opposing axial sides of the sealing member 120. The
sealing device 100 is capable of providing a substantially
fluid-tight seal such that fluid between the inner body 551 and the
outer body 552 is restricted from flowing from the first clearance
space 561 to the second clearance space 565, or vice versa. In some
circumstances, the seal device may be exposed to and seal against
fluid at pressures in excess of 15,000 psi and at temperatures
greater than 350.degree. F.
[0047] The sealing device 100 in the packer 500 may operate similar
to the embodiment shown in FIGS. 4A-C. The sealing device 100 may
be disposed in a groove 560 similar to that of groove 410. When the
inner body 551 is in the position shown in FIG. 5B, the fluid may
be permitted to seep past the sealing device 100 similar to the
process described in connection with FIG. 4A. When the inner body
551 is shifted relative to the outer body 552 such that the chamfer
563 is in contact with the first cap member 140, the fluid flow is
restricted and the fluid pressure increases. As previously
described, the sealing device 100 is design to resist "blow outs"
and other seal failures even at the increased pressure levels. A
fluid-tight seal may be formed when the inner body 551 is shifted
so that the second contact surface 564 abuts the at least the first
cap member 140 and the sealing member 120. (In some instances, the
second contact surface 564 is shifted so as to contact both cap
members 140 and 160.) As previously described in connection with
FIG. 4C, when the fluid pressure causes the sealing device 100 to
be compressed in a substantially axial direction, the cap members
140 and 160 deform in a substantially radial direction. Such
deformation of the cap members 140 and 160 causes the cap members'
circumferential sides to press against the contact surface 564 (or
both 564 and 562) and the circumferential surface of the groove
560, which may provide a fluid-tight seal. In such circumstances,
the energy from the fluid pressure may be used to advantageously
deform the sealing device 100 to enhance the seal performance in
the packer 500.
[0048] Still referring to FIG. 5B, in a presently preferred
embodiment, the sealing device 100 comprises cap members 140 and
160 formed of PEEK thermoplastic material and a sealing member 120
formed of HNBR material. Such an embodiment is capable of providing
a fluid seal in a packer 500 when the fluid has a pressure of
15,000 psi and a temperature of 350.degree., conditions that may be
generally too extreme for traditional single-material, rubber
seals. The sealing device 100 may form an effective seal in the
packer 500 with improved resistance to seal failure. Even when the
sealing device 100 is exposed to a pressure of 15,000 psi and a
temperature of 350.degree. F., the sealing device 100 performs with
a reduced likelihood of extrusion through the clearance space 565.
Furthermore, the sealing device 100 may operate as a dynamic seal
with a reduced likelihood of seal "blow out" when the chamfer 563
approaches the seal location.
[0049] It is not necessary that the sealing device 100 include two
cap members 140, 160. In some embodiments, the sealing device may
include the sealing member 120 and a single cap member 160. In such
embodiments, the energy from the fluid pressure and temperature may
be used to advantageously deform the sealing device to enhance the
seal performance.
[0050] One such embodiment is shown in FIGS. 6A-B. A sealing device
600 may include an seal member 620 and a cap member 660. The cap
member 660 may comprise a thermoplastic polymer material that is
substantially stronger than the elastomer material of the seal
member 620. In addition, the cap member 660 may comprise a material
that has greater resistance to degradation from temperature than
the elastomer material of the seal member 620. Similar to the
process described above in connection with FIGS. 3A-B, when the
fluid pressure causes the sealing device 600 to be compressed in a
substantially axial direction, the elastomer material of the
sealing member 620 deforms, which in turn forces portions of the
cap member 660 to deform in a substantially radial direction. Such
deformation of the cap member 660 causes the cap member's
circumferential sides 668 and 669 to press against the contact
surface 602 and the circumferential surface 612 of the groove 610,
which may provide a fluid-tight seal.
[0051] In such circumstances, the energy from the fluid pressure
may be used to advantageously deform the sealing device 600 to
enhance the seal performance. Furthermore, the cap member 660 may
provide increased radial strength to the sealing device 600 while
maintaining a substantial degree of elasticity and flexibility of
the overall sealing device. The sealing device 600 may form an
effective seal between two bodies with improved resistance to seal
failure. Even when the sealing device is exposed to elevated
temperature or pressures, the sealing device 600 may be configured
to reduce the likelihood of extrusion through the clearance space
605 between the mating bodies. Furthermore, the cap member 660 of
the sealing device 600 may operate reduce the likelihood of seal
"blow out," as previously described.
[0052] A number of embodiments of the invention have been
described. Nevertheless, it will be understood that various
modifications may be made without departing from the spirit and
scope of the invention. Accordingly, other embodiments are within
the scope of the following claims.
* * * * *