Note: Descriptions are shown in the official language in which they were submitted.
CA 02536616 2006-02-15
Fluid Seals
TECHNICAL FIELD
This invention relates to seals that restrict or otherwise control fluid flow.
BACKGROUND
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 circtunferential 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.
In the event of seal faihu-e, fluid leakage may occurrequiring 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.
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.
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
CA 02536616 2006-02-15
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
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. 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 axed 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.
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.
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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.
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.
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
FIG. 1 is a perspective view of a sealing device in accordance with an
embodiment of the invention.
FIG. 2A is a cross-sectional view of the sealing device of FIG. 1.
FIG. 2B is an exploded view of the sealing device of FIG. 2A.
FIG. 2C is a cross-sectional view of a sealing device in accordance with
another
embodiment of the invention.
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FIGS. 3A-B are cross-sectional views of a sealing device disposed in a groove
in
accordance with an embodiment of the invention.
FIGS. 4A-C are cross-section views of a sealing device disposed in a groove in
accordance with another embodiment of the invention.
FIGS. SA-B are views of a packer system having the seal device of a FIG. 1, in
accordance with some embodiments of the invention.
FIGS. 6A-B are cross-sectional views of a sealing device disposed in a groove
in
accordance with another embodiment of the invention.
Like reference symbols in the various drawings indicate like elements.
DETAILED DESCRIPTION
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. l, 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.
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
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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.
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.
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.
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 imler
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
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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 degreespreferably 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.
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.
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,
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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), TorlonTM, TeflonTM, 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.
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
(HydrinTM), Thiokol
Polysulfide, Silicone and Fluoro-Silicone Rubber, HypalonTM, Fluoro Elastomers
(e.g.,
VitonTM or FluorelTM), Polybutadiene, Ethylene Propylene Copolymer (ERM),
Ethylene
Propylene Diene Terpolymer (ERDM), TFE Propylene (AflasTM), 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.
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
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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).
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).
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.
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
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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.
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.
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."
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
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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.
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.
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
CA 02536616 2006-02-15
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.
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°F.
In general, the HNBR elastomer material may break down at temperatures of
about
350°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°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°F, thus preventing or reducing
the likelihood of
extrusion of the elastomer material through the clearance space 305.
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
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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
S sealing device 100 to enhance the seal performance.
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.
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)
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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.
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).
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.
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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.
Referring to FIGS. SA-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 SA, 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.
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CA 02536616 2006-02-15
Referring now to FIG SA, 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 caroming 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 fL~rther 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.
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
I 5 140 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°F.
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
SB, 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
CA 02536616 2006-02-15
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.
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°, 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°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.
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.
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
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CA 02536616 2006-02-15
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.
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.
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.
17
