U.S. patent application number 10/325718 was filed with the patent office on 2004-06-24 for expansion assembly for a tubular expander tool, and method of tubular expansion.
Invention is credited to Jackson, Stephen L., Lauritzen, J. Eric, MacKay, A. Craig, Pluckeck, Clayton, Simpson, Neil A.A., Vickers, Caswell D. III.
Application Number | 20040118571 10/325718 |
Document ID | / |
Family ID | 32593860 |
Filed Date | 2004-06-24 |
United States Patent
Application |
20040118571 |
Kind Code |
A1 |
Lauritzen, J. Eric ; et
al. |
June 24, 2004 |
Expansion assembly for a tubular expander tool, and method of
tubular expansion
Abstract
An improved expansion assembly for an expander tool is provided,
and a method for expanding a surrounding tubular body within a
wellbore. The expansion assembly first comprises a piston disposed
within a recess of the expander tool. The top surface of the piston
closely receives a body. The bearing body includes one or more
races which house at least one bearing. In one arrangement, at
least one bearing is provided which rotationally resides within a
single race. In another arrangement, a plurality of bearings are
provided that recirculate within one or more races. In this
arrangement, the bearing body is preferably a tapered, cylindrical
roller actuated into contact with the surrounding tubular by
hydraulic pressure applied from within the bore of the expander
tool. These arrangements reduce the geometric size of the expansion
assembly, affording a larger inner diameter for the hollow bore of
the expander tool itself.
Inventors: |
Lauritzen, J. Eric;
(Kingwood, TX) ; Pluckeck, Clayton; (Tomball,
TX) ; MacKay, A. Craig; (Aberdeen, GB) ;
Simpson, Neil A.A.; (Aberdeen, GB) ; Vickers, Caswell
D. III; (Houston, TX) ; Jackson, Stephen L.;
(Richmond, TX) |
Correspondence
Address: |
MOSER, PATTERSON & SHERIDAN, L.L.P.
3040 POST OAK BOULEVARD, SUITE 1500
HOUSTON
TX
77056-6582
US
|
Family ID: |
32593860 |
Appl. No.: |
10/325718 |
Filed: |
December 19, 2002 |
Current U.S.
Class: |
166/384 ;
166/207 |
Current CPC
Class: |
E21B 43/105
20130101 |
Class at
Publication: |
166/384 ;
166/207 |
International
Class: |
E21B 023/02 |
Claims
1. An expansion assembly for an expander tool for expanding a
surrounding tubular body, the expansion assembly being disposed
within a recess in the body of the expander tool, and the expander
tool having a bore therethrough, the expansion assembly comprising:
a piston disposed within the recess of the expander tool, the
piston having a bottom surface and a top surface, the bottom
surface being exposed to a radially outward force within the bore
of the expander tool, and the piston being outwardly extendable
from the body of the expander tool within the recess in response to
the radially outward force; and a bearing body residing in close
proximity to the top surface of the piston, the bearing body having
at least one race for receiving at least one bearing for engaging
the surrounding tubular body when the piston is extended away from
the body of the expander tool.
2. The expansion assembly of claim 1, wherein the at least one
bearing defines a plurality of recirculating bearings.
3. The expansion assembly of claim 2, wherein the bearing body
defines a tapered, non-circular body.
4. The expansion assembly of claim 3, wherein the bearing body
comprises: a first substantially flat surface residing upon the top
surface of the piston; and a second arcuate surface above the first
substantially flat surface.
5. The expansion assembly of claim 3, wherein the at least one race
defines at least two elongated, non-parallel races.
6. The expansion assembly of claim 3, wherein the at least one race
defines an elongated, non-linear race.
7. The expansion assembly of claim 3, wherein the at least one race
defines at least two substantially linear, substantially parallel
races.
8. The expansion assembly of claim 6, wherein the bearing body is
substantially rotationally fixed relative to the top surface of the
piston.
9. The expansion assembly of claim 3, further comprising a mounting
arrangement for supporting the bearing body upon the top surface of
the piston.
10. The expansion assembly of claim 9, wherein the mounting
arrangement comprises: a first bracket affixed to the top surface
of the piston for supporting the bearing body at a first end; and a
second bracket affixed to the top surface of the piston for
supporting the bearing body at a second opposite end.
11. The expansion assembly of claim 10, wherein each of the first
and second brackets receives a connector for connecting the first
and second brackets to the respective first and second opposite
ends of the body.
12. The expansion assembly of claim 11, wherein the connector
comprises: a plate secured to the bracket; and a tongue extending
from the bracket and received within the bearing body at an
end.
13. The expansion assembly of claim 12, wherein each of the first
and second brackets receives a connector for connecting the first
and second brackets to the respective first and second opposite
ends of the body.
14. The expansion assembly of claim 13, wherein the connector
comprises: a plate secured to the bracket; and a tongue extending
from the bracket and received within the bearing body at an
end.
15. The expansion assembly of claim 5, wherein the top surface of
the piston comprises a plurality of scallops, each scallop sized
and configured to receive the plurality of bearings as they
recirculate within the at least two races.
16. The expansion assembly of claim 3, wherein the orientation of
the bearing body is skewed relative to the longitudinal center axis
of the bore of the expander tool.
17. The expansion assembly of claim 3, wherein the radially outward
forces are hydraulic forces from within the bore of the expander
tool.
18. The expansion assembly of claim 17, wherein the piston
sealingly resides within the recess of the body of the
expander.
19. The expansion assembly of claim 1, wherein: the at least one
race comprises a first race and a second adjacent race; and the at
least one bearing comprises first and second bearings received
within the first and second adjacent races, respectively.
20. The expansion assembly of claim 19, wherein the first bearing
is larger than the second bearing.
21. The expansion assembly of claim 1, wherein the bearing body
comprises one race, and one bearing received within the race.
22. The expansion assembly of claim 21, wherein the radially
outward forces are hydraulic forces from within the bore of the
expander tool.
23. The expansion assembly of claim 22, wherein the bearing body is
integral to the piston.
24. An expansion assembly for a hydraulic expander tool for
expanding a surrounding tubular body, the expansion assembly being
sealingly disposed within a recess in the body of the expander
tool, and the expander tool having a bore therethrough, the
expansion assembly comprising: a piston residing within the recess
of the expander tool, and being outwardly extendable from the body
of the expander tool within the recess in response to hydraulic
pressure within the bore of the expander tool, the piston
comprising a bottom surface exposed to fluid pressure within the
expander tool, and a top surface; a bearing body residing upon the
top surface of the piston, the roller having at least one race for
receiving at least one bearing that engages a surrounding tubular
body when the piston is extended away from the body at the expander
tool; and a mounting arrangement for supporting the bearing body
upon the top surface of the piston such that the roller is
substantially rotationally fixed relative to the top surface of the
piston.
25. The expansion assembly of claim 24, wherein: the bearing body
is integral to the piston; the at least one race defines a single
race; and the at least one bearing defines a single bearing that
rotationally resides within the single race.
26. The expansion assembly of claim 24, wherein the bearing body
defines a tapered eccentric body comprising: a first substantially
flat surface residing upon the top surface of the piston; and a
second arcuate surface above the first substantially flat
surface.
27. The expansion assembly of claim 26, wherein: the at least one
race defines at least two substantially linear, substantially
parallel races; the at least one bearing defines a plurality of
bearings that recirculate within the races; and the top surface of
the piston comprises a plurality of scallops, each scallop sized
and configured to receive the plurality of bearings as they
recirculate within the at least two races.
28. The expansion assembly of claim 27, wherein the mounting
arrangement comprises: a first bracket affixed to the top surface
of the piston for supporting the bearing body at a first end; and a
second bracket affixed to the top surface of the piston for
supporting the bearing body at a second opposite end.
29. The expansion assembly of claim 28, wherein the orientation of
the bearing body is skewed relative to the longitudinal center axis
of the bore of the expander tool.
30. The expansion assembly of claim 29, wherein each of the first
and second brackets receives a connector for connecting the first
and second brackets to the respective first and second opposite
ends of the roller, the connector comprising: a plate secured to
the bracket; and a tongue extending from the bracket and received
within the roller at an end.
31. A method for expanding a tubular body within a hydrocarbon
wellbore, comprising the steps of: attaching an expander tool to
the lower end of a working string, the expander tool having a body
and a plurality of recesses within the body, each recess receiving
an expansion assembly, each expansion assembly comprising: a piston
disposed within the recess of the expander tool, the piston having
a bottom surface and a top surface, the bottom surface being
exposed to a radially outward force within the bore of the expander
tool, and the piston being outwardly extendable from the body of
the expander tool within the recess in response to the radially
outward force; a bearing body residing in close proximity to the
top surface of the piston, the bearing body having at least one
race for receiving at least one bearing that engages the
surrounding tubular body when the piston is extended away from the
body of the expander tool; and a mounting arrangement for
supporting the bearing body upon the top surface of the piston such
that the bearing body is substantially rotationally fixed relative
to the top surface of the piston; running the working string with
the expander tool into a wellbore; and rotating the working string
in order to radially expand a section of the surrounding tubular
body within the wellbore.
32. The method for expanding a tubular body within a wellbore of
claim 31, wherein the at least one bearing defines a plurality of
bearings that recirculate within the races.
33. The method for expanding a tubular body within a wellbore of
claim 32, wherein the bearing body comprises: a first substantially
flat surface residing upon the top surface of the piston; and a
second arcuate surface above the first substantially flat
surface.
34. The method for expanding a tubular body within a wellbore of
claim 33, wherein the mounting arrangement comprises: a first
bracket affixed to the top surface of the piston for supporting the
roller at a first end; and a second bracket affixed to the top
surface of the piston for supporting the roller at a second
opposite end.
35. The method for expanding a tubular body within a wellbore of
claim 33, wherein the at least one race defines at least two
substantially linear, substantially parallel races.
36. The method for expanding a tubular body within a wellbore of
claim 35, wherein the top surface of the piston comprises a
plurality of scallops, each scallop sized and configured to receive
the plurality of bearings as they recirculate within the at least
two races.
37. The method for expanding a tubular body within a wellbore of
claim 35, wherein the orientation of the roller is skewed relative
to the longitudinal center axis of the bore of the expander
tool.
38. The method for expanding a tubular body within a wellbore of
claim 35, wherein the radially outward forces are hydraulic forces
from within the bore of the expander tool.
39. The method for expanding a tubular body within a wellbore of
claim 31, wherein: the at least one race defines a single race; the
at least one bearing defines a single bearing rotationally residing
within the single race; and the bearing body is integral to the
piston.
40. The method for expanding a tubular body within a wellbore of
claim 31, wherein: the at least one race defines two separate but
adjacent races; the at least one bearing defines a single bearing
rotationally residing within each of the two respective races; and
the bearing body is integral to the piston.
41. An expander tool for expanding a surrounding tubular body in a
wellbore, comprising: a body; at least one radially expandable
member; and at least one rotatable member disposed on an outer
surface of the expandable member for engaging the surrounding
tubular body when the radially extendable member is extended away
from the body of the expander tool.
42. A method of expanding a tubular in a wellbore comprising:
running an expander tool into the wellbore to a predetermined
location adjacent the tubular to the expander, the expander tool
comprising: a body; at least one radially expandable member
disposed along the body; and at least one rotatable member disposed
on an outer surface of the expandable member; and actuating the
expander tool, thereby urging the at least one rotatable member
into contact with the surrounding tubular member, thereby expanding
the tubular member past its elastic limits.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to wellbore completion. More
particularly, the invention relates to an apparatus and method for
expanding a tubular body. More particularly still, the apparatus
relates to an expander tool for expanding a section of tubulars
within a wellbore.
[0003] 2. Description of the Related Art
[0004] Hydrocarbon and other wells are completed by forming a
borehole in the earth and then lining the borehole with steel pipe
or casing to form a wellbore. After a section of wellbore is formed
by drilling, a string of casing is lowered into the wellbore and
temporarily hung therein from the surface of the well. Using
apparatus known in the art, the casing is cemented into the
wellbore by circulating cement into the annular area defined
between the outer wall of the casing and the borehole. The
combination of cement and casing strengthens the wellbore and
facilitates the isolation of certain areas of the formation behind
the casing for the production of hydrocarbons.
[0005] It is common to employ more than one string of casing in a
wellbore. In this respect, a first string of casing is set in the
wellbore when the well is drilled to a first designated depth. The
first string of casing is hung from the surface, and then cement is
circulated into the annulus behind the casing. The well is then
drilled to a second designated depth, and a second string of
casing, or liner, is run into the well. The second string is set at
a depth such that the upper portion of the second string of casing
overlaps the lower portion of the first string of casing. The
second liner string is then fixed or "hung" off of the existing
casing by the use of slips which utilize slip members and cones to
wedgingly fix the new string of liner in the wellbore. The second
casing string is then cemented. This process is typically repeated
with additional casing strings until the well has been drilled to
total depth. In this manner, wells are typically formed with two or
more strings of casing of an ever decreasing diameter.
[0006] Apparatus and methods are emerging that permit tubular
bodies to be expanded within a wellbore. The apparatus typically
includes an expander tool that is run into the wellbore on a
working string. The expander tool includes radially expandable
members, or "expansion assemblies," which are urged radially
outward from a body of the expander tool, either in response to
mechanical forces, or in response to fluid injected into the
working string. The expansion assemblies are expanded into contact
with a surrounding tubular body. Outward force applied by the
expansion assemblies cause the surrounding tubular to be expanded.
Rotation of the expander tool, in turn, creates a radial expansion
of the tubular.
[0007] Multiple uses for expandable tubulars are being discovered.
For example, an intermediate string of casing can be hung off of a
string of surface casing by expanding an upper portion of the
intermediate casing string into frictional contact with the lower
portion of surface casing therearound. Additionally, a sand screen
can be expanded into contact with a surrounding formation in order
to enlarge the inner diameter of the wellbore. Additional
applications for the expansion of downhole tubulars exist.
[0008] An exemplary embodiment of an expander tool previously known
as of the filing of this continuation-in-part application is shown
in FIG. 1. FIG. 1 is an exploded view of an exemplary expander tool
100. FIG. 2 presents the same expander tool 100 in cross-section,
with the view taken across line 2-2 of FIG. 1.
[0009] The expander tool 100 has a body 102 which is hollow and
generally tubular. The central body 102 has a plurality of recesses
114 to hold a respective expansion assembly 110. Each of the
recesses 114 has substantially parallel sides and holds a
respective piston 120. The pistons 120 are radially slidable, one
piston 120 being slidably sealed within each recess 114. The back
side of each piston 120 is exposed to the pressure of fluid within
a hollow bore 115 of the expander tool 100. In this manner,
pressurized fluid provided from the surface of the well can actuate
the pistons 120 and cause them to extend outwardly.
[0010] Disposed above each piston 120 is a roller 116. In one
embodiment of the expander tool 100, the rollers 116 are near
cylindrical and slightly barreled. Each of the rollers 116 is
supported by a shaft 118 at each end of the respective roller 116
for rotation about a respective axis. The rollers 116 are generally
parallel to the longitudinal axis of the tool 100. In the
arrangement of FIG. 1, the plurality of rollers 116 is radially
offset at mutual 120-degree circumferential separations around the
central body 102. In the arrangement shown in FIG. 1, two offset
rows of rollers 116 are shown. However, only one row, or more than
two rows of roller 116, may be incorporated into the body 102.
[0011] As sufficient pressure is generated on the bottom piston
surface behind the expansion assembly 110, the tubular being acted
upon (not shown) by the expander tool 110 is expanded past its
point of elastic deformation. In this manner, the diameter of the
tubular is increased within the wellbore. By rotating the expander
tool 100 in the wellbore and/or moving the expander tool 100
axially in the wellbore with the expansion assemblies 110 actuated,
a tubular can be expanded into plastic deformation along a
predetermined length. Where the expander tool 100 is translated
within the wellbore, the shaft 118 serves as a thrust bearing.
[0012] One disadvantage to known expander tools, such as the
hydraulic tool 100 shown in FIGS. 1-2, is the inherently restricted
size of the hollow bore 115. In this respect, the dimension of the
bore 115 is limited by the size of the expansion assemblies 110
radially disposed around the body 102 of the tool 100. The
constricted bore 115 size, in turn, imposes a limitation on the
volume of fluid that can be injected through the working string at
any given pressure. Further, the dimension of the bore 115 in known
expander tools places a limit on the types of other tools which can
be dropped through the expander tool 100. Examples of such tools
include balls, darts, retrieving instruments, fishing tools, bridge
plugs and other common wellbore completion tools.
[0013] In addition, the tubulars being expanded within a wellbore
generally define a thick-walled, high-strength steel body. To
effectively expand such tubulars, a large cross-sectional geometry
is required for the roller body 116. This further limits the inner
bore diameter, thereby preventing adequate flow rates, and
minimizing the space available to run equipment through the inner
bore 115. Also, the stresses required to expand the material are
very high; hence, reducing the roller body size to accommodate a
larger inner bore diameter would mechanically weaken the roller
mechanism, thereby compromising the functionality of the expansion
assembly.
[0014] Therefore, a need exists for an expander tool which provides
for a larger configuration for the hollow bore 115 therein.
Further, a need exists for an expander tool which reduces the size
of the expansion assemblies 110 around the tool 100 so as to allow
for a greater bore 115 size without reducing the size of the roller
body. Further, a need exists for an expander tool having expansion
assemblies which do not rely upon rollers 116 rotating about a
shaft 118 at a spaced apart distance from the piston member
120.
SUMMARY OF THE INVENTION
[0015] The present invention provides an apparatus for expanding a
surrounding tubular body. More specifically, an improved expansion
assembly for a radially rotated expander tool is disclosed. In
addition, a method for expanding a tubular body, such as a string
of casing within a hydrocarbon wellbore, is provided, which employs
the improved expansion assembly of the present invention.
[0016] The expansion assembly first comprises a piston. The piston
is preferably an elongated wafer-shaped body which is sealingly
disposed within an appropriately configured recess of an expander
tool. The piston has a top surface and a bottom surface. The top
surface is configured to receive a bearing body. In the expansion
assembly of the present invention, the bearing body preferably is
not a roller body, and does not rotate about a shaft; instead, the
bearing body resides in close proximity to the top surface of the
piston. This reduces the overall size of the expansion assembly,
allowing more room for the hollow bore within the expander
tool.
[0017] To aid in rotation of the expansion assembly, the bearing
body includes one or more bearings along the roller body surface.
In one embodiment, a plurality of recirculating bearings are
employed. The bearings are preferably spherical in shape, and are
held within a plurality of races arranged in rows. The races are
sized to permit the bearings to recirculate therein.
[0018] In one aspect, the top surface of the piston includes a
series of grooves, or "scallops," that correspond to the races in
the bearing body. The scalloped surface allows the bearing body to
rest immediately upon the top surface of the piston, with the
scallops receiving the bearings as they recirculate.
[0019] In another embodiment, a single bearing is disposed within
the bearing body. The bearing is preferably spherical in shape, and
resides within a single race in the bearing body. The single race
is sized to permit the ball to freely rotate as it engages a
surrounding tubular.
[0020] Where a plurality of bearings is employed, the bearing body
is preferably tapered. This more easily allows the expander tool to
both rotate and translate within the wellbore simultaneously. The
bearing body is mounted onto the top surface of the piston. In one
aspect, mounting is by brackets affixed to the top surface of the
piston at opposite ends. The brackets receive connectors that
connect the bearing body to the brackets. In this way, the bearing
body resides intermediate the two opposite brackets.
[0021] In one arrangement, the bottom surface of the piston is
exposed to fluid pressure within the bore of the expander tool. The
piston is moved radially outward from the body of the expander tool
but within the recess in response to fluid pressure or other
outward force within the bore. Because the bearing body is held
closely to the piston, greater space is accommodated for the bore
within the expander tool.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] So that the manner in which the above-recited features of
the present invention are attained and can be understood in detail,
a more particular description of the invention, briefly summarized
above, may be had by reference to the appended drawings (FIGS.
3-14). It is to be noted, however, that the appended drawings
illustrate only typical embodiments of this invention and are
therefore not to be considered limiting of its scope, for the
invention may admit to other equally effective embodiments.
[0023] FIG. 1 is an exploded view of an expander tool previously
known as of the time of the filing of this continuation-in-part
application. The roller is consistent with an embodiment described
in the pending parent application. Visible in FIG. 1 is an
expansion assembly having a roller which rotates about a shaft.
[0024] FIG. 2 is a cross-sectional view of the expander tool of
FIG. 1, taken across line 2-2 of FIG. 1.
[0025] FIG. 3 is an exploded view of an expansion assembly of the
present invention, in one embodiment. The expansion assembly is
shown in perspective view. The expansion assembly is designed to
operate within a body of an expander tool, such as a hydraulically
actuated expander tool.
[0026] FIG. 4 is a side, cross-sectional view of the expansion
assembly of FIG. 3.
[0027] FIG. 5 is a top view of the expansion assembly of FIG.
3.
[0028] FIG. 6 is an exploded view of an expander tool which
includes expansion assemblies of the present invention.
[0029] FIG. 7 is a cross-sectional view of the expander tool of
FIG. 6, taken across line 7-7 of FIG. 6.
[0030] FIG. 8 is an exploded view of an alternate embodiment of an
expansion assembly. In this arrangement, a single bearing is
employed. The assembly is exploded from an expander tool.
[0031] FIG. 9 is a cross-sectional view of the expander tool of
FIG. 8, taken across line 9-9 of FIG. 8. A single bearing is shown
residing on the top surface of each piston.
[0032] FIG. 10A is a cross-sectional view of the expansion assembly
of FIG. 8, taken across a line perpendicular to the longitudinal
axis of the expansion assembly. FIG. 10B is a cross-sectional view
of the expansion assembly of FIG. 8, taken across the longitudinal
axis of the expansion assembly.
[0033] FIG. 11 is a cross-sectional view of a wellbore. The
wellbore includes an upper string of casing, and a lower string of
casing having been hung off of the upper string of casing. In this
view, the lower string of casing serves as a tubular body to be
expanded.
[0034] FIG. 12 presents the wellbore of FIG. 11. In the view, an
expander tool which includes expansion assemblies of the present
invention is being lowered into the wellbore on a working
string.
[0035] FIG. 13 presents the wellbore of FIG. 11, with the expander
tool being actuated in order to expand the lower string of casing
into the upper string of casing, thereby further hanging the liner
from the upper string of casing.
[0036] FIG. 14 presents the wellbore of FIG. 13, in which the lower
string of casing has been expanded into the upper string of casing
along a desired length. The expander tool is being removed from the
wellbore.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0037] FIG. 3 presents a perspective view of an expansion assembly
210 of the present invention, in one embodiment. The expansion
assembly 210 is designed to be utilized within an expander tool
(shown in FIG. 6) for expanding a surrounding tubular body
(demonstrated in FIGS. 12-14). The parts of the expansion assembly
210 are presented in an exploded view for ease of reference.
[0038] The expansion assembly 210 first comprises a piston 220. As
will be discussed, the piston 220 resides within a recess of an
expander tool 200. In the arrangement shown in FIG. 3, the piston
220 defines an elongated, wafer-shaped member capable of sliding
outwardly from the expander tool in response to hydraulic pressure
within the bore 215 of the expander tool 200. A piston body recess
223 is circumferentially formed around the piston 220 in order to
receive a seal (not shown).
[0039] The piston 220 has a top surface and a bottom surface. The
bottom surface is exposed to hydraulic pressure within the bore 215
of the expander tool 200. The top surface of the piston 220 is
configured to receive a bearing body 216. In the expansion assembly
of the present invention, the bearing body 216 does not rotate
about a shaft; instead, the bearing body 216 fixedly resides in
close proximity to the top surface of the piston 220. In the
arrangement of FIG. 3, the bearing body 216 does not roll or skid
along the top surface of the piston 220.
[0040] To aid in rotation of the expander tool 200 with the
expansion assemblies 210, the bearing body 216 includes a plurality
of bearings 218 along the body surface. The bearings 218 are
preferably spherical in shape, but may also be cylindrical or
egg-shaped. The bearings 218 are held within a plurality of races
214 arranged in rows. The races 214 are sized to permit the
bearings 218 to recirculate therein.
[0041] In the arrangement shown in FIGS. 3 and 5, the races 214 are
arranged in a plurality of parallel rows. Five separate, parallel
rows are provided. However, it is within the scope of the present
invention to employ additional or fewer rows, so long as the
bearing body 216 is able to effectively expand a surrounding
tubular body. In this respect, it is the bearings 218 that provide
the primary engagement between the expander tool 200 and the
surrounding tubular during an expansion operation. In addition, it
is within the spirit of this invention to utilize any configuration
of races 214, such as a nonlinear or a nonparallel arrangement (not
shown).
[0042] It is preferred that a hardened substrate be fabricated into
the bearing body 216 along the races 214. A material of appreciable
strength and toughness is employed such that the high hertzian
stresses applied during an expansion operation do not detrimentally
deform the races 214. Examples include ceramics and tungsten
carbide.
[0043] The bearing body 216 is mounted onto the top surface of the
piston 220. Any mounting arrangement may be employed. In the
embodiment shown in FIG. 3, a pair of brackets 230a, 230b is
affixed to the top surface of the piston 220 at opposite ends of
the piston 220a, 220b. The brackets 230a, 230b receive respective
connectors 232a, 232b that connect the bearing body 216 to the
brackets 230a, 230b. One or more bolts 250 is provided to secure
each connector 232a, 232b to its corresponding bracket 230a, 230b.
The body 216, brackets 230a, 230b and connectors 232a, 232b may be
of a unitary construction with the piston 220, or may be separate
pieces as shown in FIG. 3. In any of such arrangements, the bearing
body 216 preferably resides and remains rotationally fixed
intermediate the two opposite brackets 230a, 230b.
[0044] In the arrangement of FIG. 3, each connector 232a, 232b
includes a plate 236 and a tongue 234. The tongue 234 defines an
elongated, substantially flat member that extends into a recess 236
within the bearing body 216 at an end. The tongue 234 aids in
stabilizing the bearing body 216 relative to the piston 220. The
tongue 234 is best shown in the exploded view of FIG. 3. In this
view, it can be seen that the tongue 234 does not serve as an axle
so that the bearing body 216 in the expansion assembly 210 does not
significantly rotate relative to the piston 220. Removal of the
shaft 118 from the previous embodiment of an expansion assembly 110
(FIG. 1) allows the overall diameter of the body 202 of the new
expander tool 200 (shown in FIG. 6) to be increased, thereby saving
valuable space within the bore 215 of the expander tool 200.
[0045] In an alternative embodiment, the body 216 is arranged to
rotate as with the roller body of the prior art, thereby providing
an additional rotation means to the tool. In such an arrangement, a
swivel connection (not shown) is preferably provided between the
brackets 230a, 230b and the body 216.
[0046] To further aid in the space-saving function of the expansion
assembly 210, the bearing body 216 is disposed immediately upon the
top surface of the piston 220. To accommodate the integral bearing
mechanism defined by the bearings 218, "scallops" 226 are
fabricated into the piston 220. In FIGS. 3-5, the scallops 226 are
shown along the top surface of the piston 220. Each scallop 226
defines a groove that is sized and configured to correspond to a
race 214 along the bearing body 216. The scalloped piston surface
220 allows the bearing body 216 to rest immediately upon the top
surface of the piston 220, with the scallops 226 receiving the
bearings 218 and permitting recirculation thereof.
[0047] The configuration of the roller 116 shown in the prior art
drawing of FIG. 1 is somewhat barrel-shaped. It also has a
cross-sectional shape that is generally cylindrical. Such a
configuration may be used in the bearing body 216 for the improved
expansion assembly 210 of the present invention. Of course, it is
to be appreciated that other roller shapes may be used, including
semi-spherical, multifaceted, elliptical or any other cross
sectional shape suited to the expansion operation to be conducted
within a tubular. However, to further aid in the space-saving
function of the expansion assembly 210, a tapered eccentric
(non-circular) bearing body 216 shape is provided, as shown in FIG.
3.
[0048] The configuration of the novel bearing body 216 is best seen
in the side cross-sectional view of FIG. 4. The surface of the
bearing body 216 proximate to the piston 220 is essentially flat,
permitting the bearings 218 to closely ride within the scalloped
226 top piston surface 220. In contrast, the portion of the bearing
body 216 that contacts the surrounding tubular body, e.g., casing,
is arcuate. In one aspect, the arcuate surface of the bearing body
216 is also tapered in diameter. The tapered shape allows the
expander tool 200 to both rotate and translate within the wellbore
simultaneously. In this respect, the expander tool 200 is
preferably urged within the wellbore in the direction of the
bearing body 216 end having the reduced diameter.
[0049] In the configuration of the bearing body 216 shown in FIG.
4, opening 213 is provided for loading the bearings 218 into the
races 214. The opening 213 is disposed on the surface of the
bearing body 216 proximate to the piston 220. In one aspect, each
race 214 has a bearing opening 213.
[0050] The tapered bearing body 216 and the bearings 218 are
fabricated from a material of appreciable strength and toughness in
order to withstand the high hertzian stresses imposed during an
expansion operation. Preferably, the bearing body 216 and bearings
218 are fabricated from a ceramic or other hardened composite
material. Alternatively, a steel or other hard metal alloy may be
used. In any arrangement, it is understood that some sacrifice of
the material of the bearings 218 may occur due to the very high
stresses required to expand a surrounding metal tubular.
[0051] In one aspect, the orientation of the tapered bearing body
216 is skewed relative to the longitudinal center axis of the bore
of the expander tool 200. To accomplish this, the recess 214 in the
expander tool body 202 is tilted so that the longitudinal axis of
the body 216 is out of parallel with the longitudinal axis of the
tool 200. Preferably, the angle of skew is only approximately 1.5
degrees. The advantage is that simultaneous rotation and
translation of the expander tool 200 allows the body 216 to
predominantly roll against the surrounding casing being expanded,
without skidding against it. This, in turn, causes the thrust
system, i.e., the mechanism for raising or lowering the expander
tool 200 within the wellbore, to operate more efficiently.
[0052] It is understood that "skewing" of the bearing body 216 is
an optional feature. Further, the degree of tilt of the bearing
body 216 is a matter of designer's discretion. In any event, the
angle of tilt must be away from the direction of rotation of the
tool 200 so as to enable the tool 200 to more freely be translated
within the wellbore. By employing such an angle, the body 216 will
tend to pull itself into the casing as it is expanded (depending on
the direction of `skew` and rotation). This again reduces the
thrust load required to push the roller into the casing during
translation. Tilting the body 216 further causes the body 216 to
gain an increased projected depth to expand the casing. This is
true for both parallel and tapered rollers.
[0053] FIG. 5 presents a top view of the expansion assembly of FIG.
3. In this view, the configuration of the bearing body 216, and the
disposition of the bearing body 216 upon the top surface of the
piston 220 can be more fully seen. The preferred tapered
configuration of the bearing body 216 is also more fully
demonstrated.
[0054] Referring now to FIG. 6, FIG. 6 presents a perspective view
of an expander tool 200 as might be used with the expansion
assembly 210 of the FIG. 3. The view in FIG. 6 shows the piston
220, the bearing body 216, the mounting brackets 230, and the
connectors 232 in exploded arrangement above a recess 214. A
plurality of recesses 214 is fabricated into the body 202 of the
expander tool 200.
[0055] The body 202 of the expander tool 200 defines a tubular
body. A bore 215 is seen running through the body 202. It is to be
observed that the diameter of the bore 215 of the improved expander
tool 200 is larger than the diameter of the bore 115 of the
previously known expander tool 100, shown in FIG. 1.
[0056] Tubular connector members 225, 235 are shown disposed at
either end of the expander tool 200. An upper connector 225 is
typically connected to a working string, as will be shown in a
later figure. A lower connector 235 may be used for connecting the
expander tool 200 to other tools further downhole. Alternatively,
connector 235 may simply define a deadhead.
[0057] FIG. 7 presents a cross-sectional view of the expander tool
200 of FIG. 6. The view is taken across line 7-7 of FIG. 6. More
visible in this view is the enlarged dimension of the bore 215
permitted by the novel expansion assembly 210 of the present
invention.
[0058] FIG. 8 presents a perspective view of an expansion assembly
810 of the present invention, in an alternate embodiment. As with
the first embodiment of an expansion assembly 210, the second
embodiment 810 is designed to be utilized within an expander tool
for expanding a surrounding tubular body (not shown in FIG. 8). The
expansion assembly 810 is shown exploded away from of an expander
tool 200. The expander tool 200 once again includes a tubular body
202 having a plurality of recesses 214 for receiving the expansion
assemblies 810.
[0059] FIG. 9 presents a cross-sectional view of the expander tool
200 of FIG. 8. The view is taken across line 9-9 of FIG. 8. FIG. 9
more clearly shows the bore 215 within the expander tool 200, and
the radial placement of the expansion assemblies 810.
[0060] As with the expansion assembly 210 of FIG. 3, the expansion
assembly 810 of FIG. 8 includes a piston 820 having a top surface
and a bottom surface. A piston recess 823 is also formed around the
piston 820 for receiving a seal (not shown). The expansion assembly
810 also includes a bearing body 816 residing upon the top surface
of the piston 820. However, unlike the bearing body 216 in the
expansion assembly 210 of FIG. 3, the bearing body 816 in the
expansion assembly 810 of FIG. 8 is preferably integral to the
piston 820. With this design, no separate connectors are required.
In such an arrangement, the bearing body 816 is directly fastened
or otherwise fabricated into the piston 820, as the mounting
arrangement.
[0061] The bearing body 816 is fabricated with a race 814 therein.
The race 814 is sized to receive a single, large bearing 818.
Further, the bearing 818 is permitted to rotate in any direction
within the race 814. The relative configurations of the bearing 818
and of the race 814 are shown in the cross-sectional view of FIGS.
10A and 10B. FIG. 10A is a cross-sectional view of the expansion
assembly of FIG. 8, taken across a line perpendicular to the
longitudinal axis of the expansion assembly. FIG. 10B is a
cross-sectional view of the expansion assembly of FIG. 8, taken
across the longitudinal axis of the expansion assembly.
[0062] As can be seen from the cross-sectional views of FIGS. 10A
and 10B, the single bearing 818 is loaded into the top of the race
814. During an expansion operation, the bearing 818 engages the
inner surface of a surrounding tubular to be expanded. As with the
plurality of bearings 218 in the first expansion assembly, the
single bearing 818 is fabricated from a material of appreciable
strength and toughness such that the high hertzian stresses applied
during an expansion operation do not detrimentally deform the
bearing 818. An example of such a material is tungsten carbide.
[0063] In addition to the single bearing arrangement shown in FIG.
8, the body 816 may be configured to hold two or more bearings,
including bearings of different sizes located at different relative
heights on the surface of the body. Such bearings would reside in
separate but adjacent races. The smaller race is disposed on the
expander tool in the direction of the expansion operation so as to
aid expansion.
[0064] In order to demonstrate the operation of an expander tool of
the present invention, FIGS. 11-14 have been provided. FIG. 11
provides a cross-sectional view of a wellbore 10. The wellbore 10
is cased with an upper string of casing 25. The upper string of
casing 25 has been cemented into a surrounding formation 15 by a
slurry of cement 20. The wellbore 10 also includes a lower string
of casing 30, sometimes referred to as a "liner." The lower string
of casing 30 has an upper portion 30U which has been positioned in
the wellbore 10 at such a depth as to overlap with a lower portion
25L of the upper string of casing 25. It can be seen that the lower
string of casing 30 is also cemented into the wellbore 10. A packer
35 is shown schematically in FIG. 11, providing support for the
lower string of casing 30 within the upper string of casing 25
before the cement 20 behind the lower sting of casing 25 is
cured.
[0065] FIG. 12 presents the wellbore of FIG. 11, with a working
string WS being lowered into the wellbore 10. Affixed at the bottom
of the working string WS is an expander tool 200. The expander tool
200 includes improved expansion assemblies 210. In this view, the
expansion assemblies 210 have not yet been actuated.
[0066] Turning now to FIG. 13, the expander tool 200 has been
lowered to a depth within the wellbore 10 adjacent the overlapping
strings of casing 25L, 30U. The expansion assemblies 210 of the
expander tool 200 have been actuated. In this manner, the upper
portion 30U of the lower string of casing 30 can be expanded into
frictional engagement with the surrounding lower portion 25L of the
upper string of casing 20.
[0067] In order to actuate the expander tool 200, fluid is injected
into the working string WS. Fluid under pressure then travels
downhole through the working string WS and into the perforated
tubular bore 215 of the tool 200. From there, fluid contacts the
bottom surfaces of the pistons 220. As hydraulic pressure is
increased, fluid forces the pistons 220 outwardly from their
respective recesses 214. This, in turn, causes the bodies 216 to
make contact with the inner surface of the liner 30L. With a
predetermined amount of fluid pressure acting on the piston surface
220, the lower string of expandable liner 30L is expanded past its
elastic limits. Fluid exits the expander tool 200 through the
bottom connector 235 at the base of the tool 200.
[0068] It will be understood by those of ordinary skill in the art
that the working string WS shown in FIGS. 12 and 13 is highly
schematic. It is understood that numerous other tools may and
commonly are employed in connection with a well completion
operation. For example, the lower string of casing 30 would
typically be run into the wellbore 10 on the working string WS
itself. Other tools would be included on the working string WS and
the liner 30, including a cement shoe (not shown) and a wiper plug
(also not shown). Numerous other tools to aid in the cementing and
expansion operation may also be employed, such as a swivel (not
shown) and a collet or dog assembly (not shown) for connecting the
working string WS with the liner 30.
[0069] FIG. 14 presents the lower string of casing 30 having been
expanded into frictional engagement with the surrounding upper
string of casing 25 along a desired length. In this view, the upper
portion 30U of the lower string of casing 30 has utility as a
polished bore receptacle. Alternatively, a separate polished bore
receptacle can be landed into the upper portion 30U of the lower
string of casing 30 with greater sealing capability. Further, a
larger diameter of tubing (not shown) may be landed into the liner
30 due to the expanded upper portion 30U of the liner 30. It is
understood that the depictions in FIGS. 12, 13, and 14 are simply
to demonstrate one of numerous uses for an expander tool 200, and
to demonstrate the operation of the expansion assembly 210.
[0070] As demonstrated, an improved expansion assembly 210 for an
expander tool 200 has been provided. In this respect, the bodies
216 of the expansion apparatus 210 are able to reside in close
proximity to the surface of a piston 220. In this way, the shaft of
previous embodiments of an expander tool has been removed, and a
bearing system has been provided in its place. The entire bearing
system can be angled to allow the expansion assembly 210 to be
rotated and axially translated simultaneously with lower forces
applied against the bearing body 216. In one aspect, no shaft or
thrust bearing apparatus is needed. In another aspect, a
non-circular bearing body 216 is employed, with the bearing body
216 residing immediately upon the surface of the piston 220. With
these features, the expansion assembly components 210 are
geometrically reduced, thereby affording a larger inner diameter
for the bore 215 of the expander tool 200.
[0071] The above description is provided in the context of a
hydraulic expander tool. However, it is understood that the present
invention includes expander tools in which the pistons are moveable
in response to other radially outward forces, such as mechanical
forces. While the foregoing is directed to embodiments of the
present invention, other and further embodiments of the invention
may be devised without departing from the basic scope thereof, and
the scope thereof is determined by the claims that follow.
* * * * *