U.S. patent application number 13/310172 was filed with the patent office on 2013-06-06 for seal with bellows type nose ring.
This patent application is currently assigned to VETCO GRAY INC.. The applicant listed for this patent is Daniel Caleb Benson, David Lawrence Ford, Jeffrey Allen Raynal. Invention is credited to Daniel Caleb Benson, David Lawrence Ford, Jeffrey Allen Raynal.
Application Number | 20130140775 13/310172 |
Document ID | / |
Family ID | 47560664 |
Filed Date | 2013-06-06 |
United States Patent
Application |
20130140775 |
Kind Code |
A1 |
Raynal; Jeffrey Allen ; et
al. |
June 6, 2013 |
Seal With Bellows Type Nose Ring
Abstract
A wellhead assembly having concentric tubulars and a seal
assembly in an annulus between the tubulars. The seal assembly
includes an upper portion having an annular body with a U-shaped
cross section and a nose ring seal. The nose ring seal has a
bellows like cross section and provides sealing in the annulus and
exerts a lockdown force onto one of the tubulars. Metal inlays are
provided on the outer edges of the folds in the bellows and a
compressible medium is disposed between the folds.
Inventors: |
Raynal; Jeffrey Allen;
(Houston, TX) ; Benson; Daniel Caleb; (Houston,
TX) ; Ford; David Lawrence; (Houston, TX) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Raynal; Jeffrey Allen
Benson; Daniel Caleb
Ford; David Lawrence |
Houston
Houston
Houston |
TX
TX
TX |
US
US
US |
|
|
Assignee: |
VETCO GRAY INC.
Houston
TX
|
Family ID: |
47560664 |
Appl. No.: |
13/310172 |
Filed: |
December 2, 2011 |
Current U.S.
Class: |
277/328 ;
277/339 |
Current CPC
Class: |
E21B 33/047 20130101;
E21B 33/04 20130101; E21B 2200/01 20200501; E21B 33/043
20130101 |
Class at
Publication: |
277/328 ;
277/339 |
International
Class: |
E21B 33/03 20060101
E21B033/03; E21B 33/128 20060101 E21B033/128 |
Claims
1. A seal assembly for use between concentric downhole tubulars
comprising: an annular upper portion comprising a ring like outer
leg, a ring like inner leg set radially inward from the outer leg
to define an annular space between the inner leg and outer leg and
having a lower end attached to the outer leg; and a nose ring
assembly coupled to a lower end of the upper portion comprising an
annular seal body having a bellows shaped cross section that
defines folds having edges along inner and outer circumferences of
the seal body, and compressible material between the folds, so that
when the seal assembly is disposed between the concentric downhole
tubulars and an end of an energizing ring is inserted into the
annular space between the inner and outer leg, the seal body of the
nose ring transfers a lock down force onto one of the tubulars and
the edges extend radially inward and outward into sealing contact
with the downhole tubulars.
2. The seal assembly of claim 1, wherein the compressible material
comprises encapsulated gas dispersed within a medium.
3. The seal assembly of claim 2, wherein the encapsulated gas
comprises glass microspheres and the medium comprises an
elastomer.
4. The seal assembly of claim 1, wherein the seal body comprises an
elastic metal.
5. The seal assembly of claim 1, further comprising inlays that
comprise metal having a yield strength less than the downhole
tubulars, so that when the edges extend into sealing contact with
the downhole tubulars and discontinuities are present on the
downhole tubulars, the inlays conform to the discontinuities to
provide the sealing contact.
6. The seal assembly of claim 1, wherein the seal body of the nose
ring is threadingly coupled to the upper portion and further
comprises a ring like lower base projecting axially downward from
an end of a lowermost fold, wherein the lower base is in selective
contact with a casing hanger.
7. The seal assembly of claim 1, further comprising a lock nut
mounted on an inner surface of the upper end of the upper portion,
so that when the energizing ring is pulled from between the
tubulars, the seal assembly is retrieved with the energizing
ring.
8. A wellhead assembly comprising: an outer tubular; an inner
tubular inserted within the outer tubular to define an annular
space between the tubulars; and a seal assembly in the annular
space comprising: a seal body having axially projecting folds that
define a bellows and edges between adjacent folds that are in
sealing contact with an outer surface of the inner tubular and an
inner surface of the outer tubular, and an upper end engaged to one
of the outer tubular or lower tubular and a lower end engaged with
the one of the tubulars not engaged by the upper end, so that when
the seal assembly is set in the annular space, a lock down force is
transmitted between the inner and outer tubulars through the seal
body.
9. The wellhead assembly of claim 8, further comprising a
compressible material disposed between the folds.
10. The wellhead assembly of claim 9, wherein the compressible
material comprises glass microspheres dispersed in an elastomeric
medium.
11. The wellhead assembly of claim 8, further comprising an upper
portion attached to an upper end of the seal body, the upper
portion comprising an annular outer leg in engagement with the
outer tubular and an inner leg spaced radially inward from the
outer leg that has a lower end depending from the outer leg and is
in contact with the inner tubular.
12. The wellhead assembly of claim 11, further comprising a lower
base on the seal body that contacts the inner tubular and transmits
the lock down force from the inner tubular to the seal
assembly.
13. The wellhead assembly of claim 8, further comprising metal
inlays on the edges that conform to discontinuities on the
respective surfaces of the inner and outer tubulars.
14. A seal assembly for use between concentric inner and outer
downhole tubulars comprising: an annular lockdown portion
comprising a ring like outer leg, a ring like inner leg set
radially inward from the outer leg to define an annular space
between the inner leg and outer leg and having a lower end attached
to the outer leg; a nose ring assembly coupled to a lower end of
the lockdown portion comprising: a bellows like annular seal body
that defines folds that are obliquely angled to adjacent folds,
edges formed at interfaces between adjacent folds that extend along
inner and outer circumferences of the seal body, and compressible
material between the folds that comprises an elastomeric substrate
with glass microspheres dispersed in the substrate, so that when
the seal assembly is disposed between the concentric downhole
tubulars and an end of an energizing ring is inserted into the
annular space between the inner and outer leg, the seal body of the
nose ring transfers a lock down force onto one of the tubulars and
the edges extend radially inward and outward into sealing contact
with the downhole tubulars.
15. The seal assembly of claim 14, wherein the seal body comprises
an elastic metal.
16. The seal assembly of claim 14, further comprising inlays that
comprise metal having a yield strength less than the downhole
tubulars, so that when the edges extend into sealing contact with
the downhole tubulars and discontinuities are present on the
downhole tubulars, the inlays conform to the discontinuities to
provide the sealing contact.
17. The seal assembly of claim 14, wherein the seal body of the
nose ring is threadingly coupled to the lockdown portion and
further comprises a ring like lower base projecting axially
downward from an end of a lowermost fold, wherein the lower base is
in selective contact with a casing hanger.
Description
BACKGROUND
[0001] 1. Field of Invention
[0002] The invention relates generally to a wellbore assembly. More
specifically, the invention relates to a bellows shaped nose ring
for an annulus seal having pliable material in the folds of the
bellows and malleable metal inlays on the edges of its outer
folds.
[0003] 2. Description of Prior Art
[0004] Seals are typically inserted between inner and outer
wellhead tubular members to contain internal well pressure. The
inner wellhead member is generally a hanger for supporting either
casing or tubing that extends into the well. Outer wellhead members
are usually one of a wellhead housing, or can be a casing hanger
when the inner member is a tubing hanger. A variety of seals
located between the inner and outer wellhead members are known.
Examples of known seals are elastomeric, metal, and combinations
thereof and elastomeric rings. The seals may be set by a running
tool, or they may be set in response to the weight of the string of
casing or tubing. One type of metal-to-metal seal has seal body
with inner and outer walls separated by a cylindrical slot, forming
a "U" shape. An energizing ring is pushed into the slot in the seal
to deform the inner and outer walls apart into sealing engagement
with the inner and outer wellhead members, which may have wickers
formed thereon. The energizing ring is typically a solid
wedge-shaped member. The deformation of the seal's inner and outer
walls exceeds the yield strength of the material of the seal ring,
making the deformation permanent.
[0005] Thermal growth between the casing or tubing and the wellhead
may occur, particularly with wellheads located at the surface,
rather than subsea. The well fluid flowing upward through the
tubing heats the string of tubing, and to a lesser degree the
surrounding casing. The temperature increase may cause the tubing
hanger and/or casing hanger to move axially a slight amount
relative to the outer wellhead member. During the heat up
transient, the tubing hanger and/or casing hanger can also move
radially due to temperature differences between components and the
different rates of thermal expansion from which the component
materials are constructed. If the seal has been set as a result of
a wedging action where an axial displacement of energizing rings
induces a radial movement of the seal against its mating surfaces,
then sealing forces may be reduced if there is movement in the
axial direction due to pressure or thermal effects. A reduction in
axial force on the energizing ring results in a reduction in the
radial inward and outward forces on the inner and outer walls of
the seal ring, which may cause the seal to leak. A loss of radial
loading between the seal and its mating surfaces due to thermal
transients may also cause the seal to leak. One approach to
preventing this type of movement is through the use of lockdown
C-rings on the seal that rest in a machined pocket on the
energizing ring. The C-ring engages the hanger when the seal is
set, locking the seal to the hanger. Another approach has been to
use the sealing element itself as a locking mechanism. In these
approaches, lockdown is thus provided by the seal. Further, a
lockdown style hanger may be utilized to lock the casing hanger in
place. This requires an extra trip to lower the lockdown style
hanger.
SUMMARY OF THE INVENTION
[0006] An example of a seal assembly for use between concentric
downhole tubulars is described that includes an annular upper
portion that has a ring like outer leg, a ring like inner leg set
radially inward from the outer leg that defines an annular space
between the inner leg and outer leg, and a lower end attached to
the outer leg. The seal assembly includes a nose ring assembly
coupled to a lower end of the upper portion. The nose ring assembly
includes an annular seal body having a bellows shaped cross
section. The seal body has folds with edges along inner and outer
circumferences of the seal body. Metal inlays are on the edges and
compressible material is between the folds. When the seal assembly
is disposed between the concentric downhole tubulars and an end of
an energizing ring is inserted into the annular space between the
inner and outer leg, the seal body of the nose ring transfers a
lock down force onto one of the tubulars and the edges extend
radially inward and outward into sealing contact with the downhole
tubulars. Optionally, the compressible material has encapsulated
gas dispersed within a medium. In one example, glass microspheres
form the encapsulated gas and the medium is made of an elastomer.
In one alternate embodiment, the seal body is made of an elastic
metal. The metal inlays can be made from a metal having a yield
strength less than the downhole tubulars, so that when the edges
extend into sealing contact with the downhole tubulars and
discontinuities are present on the downhole tubulars, the inlays
conform to the discontinuities to provide the sealing contact. The
seal body of the nose ring may be threadingly coupled to the upper
portion. Optionally, the seal assembly can further include a ring
like lower base projecting axially downward from an end of a
lowermost fold, wherein the lower base is in selective contact with
a casing hanger. A lock nut may be optionally included that is
mounted on an inner surface of the upper end of the upper portion,
so that when the energizing ring is pulled from between the
tubulars, the seal assembly is retrieved with the energizing
ring.
[0007] Also provided herein is an example of a wellhead assembly
that includes an outer tubular, an inner tubular inserted within
the outer tubular to define an annular space between the tubulars;
and a seal assembly in the annular space. The seal assembly
includes a seal body having axially projecting folds that define a
bellows and edges between adjacent folds that are in sealing
contact with an outer surface of the inner tubular and an inner
surface of the outer tubular. An upper end of the folds is engaged
to one of the outer tubular or lower tubular and a lower end
engaged with the one of the tubulars not engaged by the upper end.
When the seal assembly is set in the annular space, a lock down
force is transmitted between the inner and outer tubulars through
the seal body. A compressible material may be disposed between the
folds. In one example, the compressible material is made up of
glass microspheres dispersed in an elastomeric medium. An upper
portion may be included that is attached to an upper end of the
seal body. The upper portion may include an annular outer leg in
engagement with the outer tubular and an inner leg spaced radially
inward from the outer leg that has a lower end depending from the
outer leg and is in contact with the inner tubular. Optionally, a
lower base may be included on the seal body that contacts the inner
tubular and transmits the lock down force from the inner tubular to
the seal assembly. In an example embodiment, metal inlays are
provided on the edges that conform to discontinuities on the
respective surfaces of the inner and outer tubulars.
[0008] Also provided herein is an example of a seal assembly for
use between concentric inner and outer downhole tubulars that
includes an annular lockdown portion having a ring like outer leg
and a ring like inner leg set radially inward from the outer leg
that defines an annular space between the inner leg and outer leg.
A lower end of the outer leg attaches to the outer leg. A nose ring
assembly couples to a lower end of the lockdown portion that is
made up of a bellows like annular seal body that with folds that
are at an oblique angle to adjacent folds. Edges are formed at
interfaces between adjacent folds that extend along inner and outer
circumferences of the seal body. Metal inlays are provided on the
edges and compressible material is set between the folds. The
compressible material is made of an elastomeric substrate with
glass microspheres dispersed in the substrate. In this way when the
seal assembly is disposed between the concentric downhole tubulars
and an end of an energizing ring is inserted into the annular space
between the inner and outer leg, the seal body of the nose ring
transfers a lock down force onto one of the tubulars and the edges
extend radially inward and outward into sealing contact with the
downhole tubulars. The seal body can be made of an elastic metal.
In one example embodiment, the metal inlays are made from a metal
having a yield strength less than the downhole tubulars so that
when the edges extend into sealing contact with the downhole
tubulars and discontinuities are present on the downhole tubulars,
the inlays conform to the discontinuities to provide the sealing
contact. The seal body of the nose ring can be threadingly coupled
to the lockdown portion and may further include a ring like lower
base projecting axially downward from an end of a lowermost fold,
wherein the lower base is in selective contact with a casing
hanger.
BRIEF DESCRIPTION OF DRAWINGS
[0009] Some of the features and benefits of the present invention
having been stated, others will become apparent as the description
proceeds when taken in conjunction with the accompanying drawings,
in which:
[0010] FIG. 1 is a side partial sectional view of an example
embodiment of a seal assembly between downhole tubulars in
accordance with the present invention.
[0011] FIG. 2 is a detailed portion of the embodiment of FIG.
1.
[0012] FIG. 3 is a sectional view of an embodiment of the seal
assembly of FIG. 1 in a locked configuration in accordance with the
present invention.
[0013] FIG. 4 is a side partial sectional view of a wellhead
assembly having an embodiment of a seal assembly in accordance with
the present invention.
[0014] While the invention will be described in connection with the
preferred embodiments, it will be understood that it is not
intended to limit the invention to that embodiment. On the
contrary, it is intended to cover all alternatives, modifications,
and equivalents, as may be included within the spirit and scope of
the invention as defined by the appended claims.
DETAILED DESCRIPTION OF INVENTION
[0015] The method and system of the present disclosure will now be
described more fully hereinafter with reference to the accompanying
drawings in which embodiments are shown. The method and system of
the present disclosure may be in many different forms and should
not be construed as limited to the illustrated embodiments set
forth herein; rather, these embodiments are provided so that this
disclosure will be thorough and complete, and will fully convey its
scope to those skilled in the art. Like numbers refer to like
elements throughout.
[0016] It is to be further understood that the scope of the present
disclosure is not limited to the exact details of construction,
operation, exact materials, or embodiments shown and described, as
modifications and equivalents will be apparent to one skilled in
the art. In the drawings and specification, there have been
disclosed illustrative embodiments and, although specific terms are
employed, they are used in a generic and descriptive sense only and
not for the purpose of limitation. Accordingly, the improvements
herein described are therefore to be limited only by the scope of
the appended claims.
[0017] An example embodiment of a wellhead assembly 20 is shown in
a side partial sectional view in FIG. 1. In the example of FIG. 1,
the wellhead assembly 20 is shown having an annular hanger 22
coaxially disposed within an annular housing 24. The hanger 22 may
be one of a casing hanger or a tubing hanger, wherein the housing
24 can be one of a high pressure housing or casing hanger. A seal
assembly 26 is shown set within an annular space between the
concentric hanger 22 and housing 24. The seal assembly 26 includes
a seal member 28 on its upper end. In the example of FIG. 1, part
of the seal member 28 is a ring-like outer leg that runs
substantially in an axial direction and adjacent an inner surface
of the housing 24. An inner leg is included with the seal member 28
that is set radially inward from the outer leg to define a space
therein. The inner leg is connected to the outer leg by a lower end
that projects radially inward from the outer leg and then axially
upward to the inner leg.
[0018] A nose ring assembly 30 is shown mounted on a lower end of
the seal member 28 and beneath the inner leg. Partially coaxially
within the seal member 28 is an annular energizing ring 32, having
a lower wedge-shaped extension shown inserted in the space between
the outer and inner legs of the seal member 28. In the example of
FIG. 1, ridge-like wickers 34 are shown formed respectively on the
outer surface of the hanger 22 and inner surface of the housing 24.
An annular lug ring 37 is shown threadingly secured to an upper end
of the seal member 28 that extends radially inward from the seal
member 28. As described in more detail below, by axially urging the
nose ring 32 downward so its lower end inserts into the space
between the inner and outer legs of the seal member 28, sealing may
take place within the annular space between the hanger 22 and
housing 24. Moreover, the lug ring 37 extends radially inward from
the seal member 28 and interferes with a ledge on the energizing
ring 32 when the energizing ring 32 is pulled upward to also pull
on the seal member 28.
[0019] Referring now to FIG. 2, a portion of the embodiment of FIG.
1 is shown in a side partial sectional view and in greater detail.
More specifically, FIG. 2 depicts that a bellows-like nose ring
body 38 is included with the nose ring assembly 30 along with a
lower base 40 on the lower end of the body 38. In the example of
FIG. 2, the lower base 40 is a generally ring-like annular member
and configured to land on a ledge 41 (FIG. 1) provided on the
hanger 22. An upper base 42 is shown mounted on an upper end of the
nose ring body 38 and is also a generally ring-like annular member.
A portion of the upper base 42A is threaded for attachment to the
seal member 28. In the example of FIG. 2, the nose ring body 38 is
made up of a series of folds 44 shown arranged generally oblique to
each adjacent fold 44. Edges 45 are defined on the body 38 where
the adjacent folds 44 join. On the outer surface of the edges 45
are optional metal inlays 46 that in an example are formed from a
metal that is softer (i.e., having a lower yield strength) than
that of the hanger 22 and housing 24. In one example embodiment,
the metal inlay 46 includes tin indium. In the embodiment of FIG.
2, a mid portion of the edges 45 is recessed for receiving the
inlays 46, the recesses define points 47 on the upper and lower
ends of the edges 45 that penetrate into and grip the hanger 22 and
housing 24 when the body 38 axially compresses.
[0020] Each adjacent fold 44 defines a wedge-shaped space in which
is disposed a compensating material 38. The compensating material
38 provides a barrier to debris and other undesirable material that
may otherwise enter into the space between the folds 44. In one
example embodiment, the compensating material 48 is shown having a
series of spheres 50 that are dispersed within a substrate 52.
Examples of spheres 50 include a compressible fluid, such as a gas,
encapsulated inside of a load-bearing housing, such as a glass
microsphere. The substrate 52 may include elastomeric materials,
such as foam, rubber, composites, and the like.
[0021] In the example embodiment of FIG. 3 the seal assembly 26 is
in an energized and sealing configuration. As shown, the energizing
ring 32 is axially inserted within the legs of the seal member 28
thereby projecting the legs of the seal member 28 radially apart
from one another and into contact with the housing 24 and also the
hanger 22. In a typical installation, the wickers 34, 36 in the
housing 24 and the hanger 22 form corresponding grooves 54, 56 on
the inner and outer legs of the seal member 28. Additionally, the
downward urging of the lockdown ring 32 transmits a lock down force
through the seal member 28 and onto the nose ring assembly 30 for
preventing respective axial movement of the hanger 22 and housing
24. Referring back to FIG. 2, in an example embodiment, the contact
between the upper and lower bases 40, 42 of the nose ring body 38
transmits force from the hanger 22 and the housing 24. While the
bellows portion of the nose ring body 38 axially deforms,
sufficient axial stresses remain within the nose ring assembly 30
to maintain the lockdown force between the hanger 22 and housing
24.
[0022] When the seal assembly 26 is in the set position of FIG. 3,
the axial deformation of the nose ring body 38 allows the edges 45
to move radially inward and outward into contact with the
respective outer and inner surfaces of the hanger 22 and housing
24. With sufficient inward and outward radial force, the softer
metal inlays 46 on the edges 45 deform and create sealing contact
between the nose ring body 38 and surfaces of the hanger 22 and
housing 24. Discontinuities 58, such as scratches, scores or other
damage, may be present on one of the sealing surfaces of the hanger
22 or housing 24. The deforming metal inlays 46 can fill the space
of the discontinuity 58, thereby ensuring a sealing surface within
the annulus between the hanger 22 and housing 24. Moreover, the
spheres 50 within the compensating material 48 may collapse and the
encapsulated gas in the spheres 50 will compress in response to the
forces (and pressures) encountered while energizing the seal
assembly 26. The collapsing spheres 50 and compression of the gas
allows axial compression of the nose ring body 38. Thus, should any
liquid 59, such as from the wellbore, enter the space between
adjacent folds 44, the compensating material 48 compresses to make
up for the presence of the liquid 59 so that movement of the folds
44 is not restricted when the seal assembly 26 is being
energized.
[0023] FIG. 4 illustrates a side partial sectional view of one
example of a wellhead assembly 20 that is mounted over a wellbore
60. In the example of FIG. 4, the wellhead assembly includes a
production tree 62 mounted on a wellhead housing 64. Casing 66
depends downward from the wellhead assembly 20 and into the
wellbore 60. The casing 66 is shown concentrically around a string
of production tubing 68 that also depends into the wellbore 60. In
the example of FIG. 4, the seal assembly 26 is inserted between the
casing hanger, on which the casing 66 is supported and a high
pressure wellhead housing 24. In one example of use, the seal
assembly 26 described herein may be used in an emergency situation
wherein an initial seal has failed. In such an example,
deformations, such as the discontinuities 58 of FIG. 3, may be
present within one or more of the tubulars in the wellbore 60.
Moreover, the wickers 34, 36 may have also been damaged, thereby
compromising the sealing ability of a seal, such as seal member 28.
In this example, implementing a nose ring as described herein can
provide sealing capabilities to overcome the sealing problems
encountered. An advantage of the nose ring described herein is that
it can be integrated with the standard seal member 28 and installed
using steps typically undertaken to install the seal member 28.
[0024] The present invention described herein, therefore, is well
adapted to carry out the objects and attain the ends and advantages
mentioned, as well as others inherent therein. While a presently
preferred embodiment of the invention has been given for purposes
of disclosure, numerous changes exist in the details of procedures
for accomplishing the desired results. These and other similar
modifications will readily suggest themselves to those skilled in
the art, and are intended to be encompassed within the spirit of
the present invention disclosed herein and the scope of the
appended claims.
* * * * *