U.S. patent application number 10/349432 was filed with the patent office on 2004-07-22 for expansion apparatus having resistive medium.
This patent application is currently assigned to Weatherford/Lamb, Inc.. Invention is credited to Maguire, Patrick G., Tran, Khai.
Application Number | 20040140086 10/349432 |
Document ID | / |
Family ID | 32712731 |
Filed Date | 2004-07-22 |
United States Patent
Application |
20040140086 |
Kind Code |
A1 |
Tran, Khai ; et al. |
July 22, 2004 |
Expansion apparatus having resistive medium
Abstract
An apparatus for expanding a portion of a tubular within a
wellbore. The expansion assembly first comprises an expander tool.
The expander tool is preferably a rotary expander tool which is
lowered into the wellbore at the lower end of a working string. In
one aspect, the rotary expander tool defines a tubular body having
recesses, with each recess containing a compliant roller. The
expansion assembly further comprises a chamber having a resistive
medium therein. In one arrangement, the medium is a clean oil
loaded into the chamber before being run into the wellbore. The
fluid chamber is sized and configured to sealingly receive an
elongated lower portion of the body of the expander tool. As the
body of the expander tool travels into the fluid chamber, it
encounters resistance from the fluid loaded therein. The fluid
serves as a resistant force to the downward movement of the drill
string and the expander tool during the expansion process, thereby
preventing any rapid springing of the pipe string above it.
Inventors: |
Tran, Khai; (Pearland,
TX) ; Maguire, Patrick G.; (Cypress, TX) |
Correspondence
Address: |
MOSER, PATTERSON & SHERIDAN, L.L.P.
3040 POST OAK BOULEVARD, SUITE 1500
HOUSTON
TX
77056-6582
US
|
Assignee: |
Weatherford/Lamb, Inc.
|
Family ID: |
32712731 |
Appl. No.: |
10/349432 |
Filed: |
January 22, 2003 |
Current U.S.
Class: |
166/55 ;
166/207 |
Current CPC
Class: |
E21B 43/105
20130101 |
Class at
Publication: |
166/055 ;
166/207 |
International
Class: |
E21B 023/02 |
Claims
1. An apparatus for expanding a tubular in a wellbore, the
apparatus being disposed on a working string, the apparatus
comprising: an expander tool, the expander tool having an elongated
tubular body; a chamber for receiving a portion of the elongated
tubular body when the expander tool is lowered during expansion
operations; and a resistive medium within the chamber for providing
resistance against the body of the expander tool as the body enters
the chamber.
2. The apparatus of claim 1, wherein the chamber comprises an outer
wall having a side surface; and the resistive medium is disposed
within the outer wall.
3. The apparatus of claim 2, wherein: said chamber further
comprises an inner wall; said inner wall and said outer wall are
connected by a connecting surface portion of said outer wall; and
said resistive medium is disposed between the inner wall and the
outer wall.
4. The apparatus of claim 3, wherein said resistive medium is a
fluid.
5. The apparatus of claim 4, wherein said resistive medium is
oil.
6. The apparatus of claim 2, wherein said resistive medium is a
powerful spring.
7. The apparatus of claim 4, wherein said chamber further
comprises: at least one valve disposed proximate to the connecting
surface, each valve being designed to prevent fluid from entering
the chamber, but to open so as to permit fluid to exit the chamber
once pressure within the chamber reaches a designated level.
8. The apparatus of claim 7, wherein the at least one valve is
sized to permit the resistive fluid medium to slowly bleed from the
chamber after the valve has been opened and as the body of the
expander tool advances into the chamber.
9. The apparatus of claim 8, wherein the at least one valve
includes a diaphragm.
10. The apparatus of claim 8, wherein the at least one valve
defines a one-way valve.
11. An apparatus for expanding a tubular in a wellbore, the
apparatus being disposed on a working string, the apparatus
comprising: an expander tool, the expander tool having an elongated
tubular body; a chamber for receiving a portion of the elongated
tubular body when said expander tool is lowered during expansion
operations, the chamber comprising an inner wall and an outer wall;
and a resistive medium disposed between the inner wall and the
outer wall of the chamber for providing resistance against the body
of the expander tool as the body enters the chamber.
12. The apparatus of claim 11, wherein said resistive medium is a
fluid.
13. The apparatus of claim 12, wherein said resistive medium is
oil.
14. The apparatus of claim 11, wherein said resistive medium is a
powerful spring.
15. The apparatus of claim 13, wherein said chamber further
comprises: a connecting surface connecting the inner wall and the
outer wall; and at least one valve disposed proximate to the
connecting surface each valve being designed to prevent fluid from
entering the chamber, but to open so as to permit fluid to exit the
chamber once pressure within the chamber reaches a designated
level.
16. The apparatus of claim 15, wherein the at least one valve
comprises an opening that is sized to permit the resistive fluid
medium to slowly bleed from the chamber after the valve has been
opened and as the body of the expander tool advances into the
chamber.
17. The apparatus of claim 16, wherein the at least one valve
defines at least two valves, the at least two valves being opened
in response to different pressure levels in order to incrementally
throttle advancement of the body into the chamber.
18. The apparatus of claim 16, wherein the at least one valve
includes a pressure-sensitive diaphragm.
19. The apparatus of claim 11, wherein the length of the chamber
defines and controls the length of tubular that gets expanded.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to methods for wellbore
completion. More particularly, the invention relates to an
apparatus for expanding a tubular in 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
to form a wellbore. After a section of wellbore is formed by
drilling, joints of pipe are lowered into the wellbore and
temporarily hung therein from the surface of the well. Using
apparatus known in the art, the joints of pipe, or "casing," are
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, sometimes referred to as a "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 second pipe string in the
wellbore. The second pipe string, or liner, is then cemented. This
process is typically repeated with additional liner 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 tubulars to
be expanded in situ. The apparatus typically includes expander
tools which are run into the wellbore on a working string. The
expander tools include radially expandable members which are urged
outward radially from the body of the expander tool and into
contact with a tubular therearound. The expander tools may be
actuated either mechanically, or they may be fluid powered. In the
case of a hydraulic system, fluid pressure is applied to a piston
surface located at the back of the expansion members. As sufficient
pressure is generated on the respective piston surfaces, the
expansion members move radially outward from the expander tool body
and against the inner surface of a surrounding tubular. The tubular
being acted upon by the expansion tool is then expanded past its
point of elastic deformation. In this manner, the inner and outer
diameter of the surrounding tubular is increased in the wellbore.
By rotating the actuated expander tool in the wellbore and moving
the expander tool axially, a tubular can be radially expanded into
plastic deformation along a predetermined length in a wellbore.
[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 string into frictional contact with the lower portion
of surface casing therearound. This allows for the hanging of a
string of casing without the need for a separate slip assembly as
described above. Additional applications for the expansion of
downhole tubulars exist, such as the use of an expandable sand
screen.
[0008] There are problems associated with the expansion of
tubulars. One problem particularly associated with the use of
rotary expander tools is the likelihood of obtaining an uneven
expansion of a tubular. In this respect, the inner diameter of the
tubular that is expanded tends to initially assume the shape of the
compliant rollers of the expander tool, including imperfections in
the rollers. Moreover, as the working string is rotated from the
surface, the expander tool may temporarily stick during expansion
of a tubular, then turn quickly, and then stop again. This
spring-type action in the working string further creates
imperfections in the expansion job.
[0009] Another obstacle to smooth expansion relates to the
phenomenon of pipe stretch. Those of ordinary skill in the art will
understand that raising a working string a selected distance at the
surface does not necessarily translate in the raising of a tool at
the lower end of a working string by that same selected distance.
The potential for pipe stretch is great during the process of
expanding a tubular. Once the expander tool is actuated at a
selected depth, an expanded profile is created within the expanded
tubular. This profile creates an immediate obstacle to the raising
or lowering of the expander tool. Merely raising the working string
a few feet from the surface will not, in many instances, result in
the raising of the expander tool; rather, it will only result in
stretching of the working string. Applying further tensile force in
order to unstick the expander tool may cause a sudden recoil,
causing the expander tool to move uphole too quickly, leaving gaps
in the tubular to be expanded.
[0010] The same problem exists in the context of pipe compression.
In this respect, the lowering of the working string from the
surface does not typically result in a reciprocal lowering of the
expander tool at the bottom of the hole. This problem is
exacerbated by rotational sticking, as discussed above. The overall
result of these sticking problems is that the inner diameter of the
expanded tubular may not have a uniform circumference.
[0011] There is a need, therefore, for an improved apparatus for
expanding a portion of casing or other tubular within a wellbore.
Further, there is a need for an apparatus which will aid in the
expansion of a tubular downhole and which avoids the potential of
pipe-stretch/pipe-compression by the working string.
Correspondingly, there is a need for an expansion apparatus which
will enable a rotary expander tool to be axially translated
downhole without substantial risk of uneven tubular expansion
caused by pipe-compression.
[0012] There is yet a further need for an apparatus which employs
at least one valve and at least one sized orifice for controlling
the rate of translation of an expander tool during a tubular
expansion operation.
SUMMARY OF THE INVENTION
[0013] The present invention provides an apparatus for expanding a
tubular within a wellbore. According to the present invention, an
expansion assembly is introduced into a wellbore. The expansion
assembly is lowered downhole on a working string, such as a string
of drill pipe. At the same time, the expansion assembly may be
releasably connected to the lower string of casing or other tubular
to be expanded. In this way, the expandable tubular is optionally
lowered into the wellbore by the working string as well.
[0014] The expansion assembly first comprises an expander tool. The
expander tool is preferably a rotary expander tool which is lowered
into the wellbore at the lower end of a working string. The rotary
expander tool defines a tubular body having recesses, with each
recess containing a compliant roller. The rollers are expandable
outwardly against the inner surface of a tubular to be expanded
upon actuation. In one aspect, the expander tool is hydraulically
actuated. In this respect, the application of fluid pressure from
the surface, through the working string, and into a perforated
inner bore of the expander tool generates pressure behind the
rollers so as to expand them outwardly. The rollers are then placed
into contact with the inner surface of the surrounding tubular to
be expanded.
[0015] The expansion assembly of the present invention further
comprises a fluid chamber. The fluid chamber is loaded with an
amount of clean fluid, such as oil, before being run into the
wellbore. The fluid chamber is sized to receive the body of the
expander tool. In one arrangement, the fluid chamber is disposed
below the body of the expander tool and receives a lower elongated
portion of the expander tool body. In this arrangement, the fluid
chamber defines an outer wall, an inner wall, and a bottom wall,
and receives the lower body portion of the expander tool. Seals are
provided within the fluid chamber and/or circumferentially around
the elongated body portion of the expander tool to enable the body
of the expander tool to be sealingly received within the inner and
outer walls of the fluid chamber.
[0016] In operation, the expansion assembly of the present
invention is lowered into the wellbore along with the tubular to be
expanded. The expander tool is actuated by the injection of fluid
under pressure into the drill string. As the rollers are forced
outwardly against the tubular to be expanded, the drill string is
rotated. This, in turn, rotates the rotary expander tool and
provides for initial radial expansion of the surrounding tubular.
Thereafter, the drill string is slowly lowered further into the
wellbore, causing the body of the expander tool to be further
inserted into the fluid chamber. As the body of the expander tool
travels into the fluid chamber, it encounters resistance from the
fluid loaded therein. The fluid serves as a resistant force to
sudden downward movement of the drill string, thereby preventing
any rapid springing of the pipe string above it.
[0017] One or more valves is placed in the outer wall of the fluid
chamber. Each of the valves defines a sized orifice which serves as
a through-opening in the outer wall. The valves include a
pressure-sensitive diaphragm. As additional downward force is
applied against the fluid in the fluid chamber, the diaphragms
rupture, allowing fluid to exit the fluid chamber. At the same
time, resistive pressure is maintained within the fluid chamber due
to the constricted configuration of the valves. Thus, fluid is
permitted to only slowly bleed from the fluid chamber as the
expander tool is lowered downhole. In this manner, rapid springing
of the pipe string caused by pipe-compression is further
resisted.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] 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 embodiments thereof which are
illustrated in the appended drawings. 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.
[0019] FIG. 1 is a cross-sectional view of a wellbore having an
upper string of casing, and a lower string of casing being lowered
into the upper string of casing. In this view, the lower string of
casing serves as the expandable tubular. Also depicted in FIG. 1 is
an expansion apparatus of the present invention for translating an
expander tool.
[0020] FIG. 2 is a cross-sectional view of the expansion apparatus
of the present invention, taken across line 2-2 of FIG. 1.
[0021] FIG. 3 presents an exploded view of an expander tool as
might be translated by a slow-bleed expansion apparatus of the
present invention.
[0022] FIG. 4 presents a portion of the expander tool of FIG. 3 in
cross-section, with the view taken across line 4-4 of FIG. 3.
[0023] FIG. 5 is an enlarged sectional view of a fluid chamber for
an expansion apparatus of the present invention. In this view, the
surrounding upper string of casing and formation are not shown.
[0024] FIG. 6 depicts the wellbore of FIG. 1. In this view, the
expander tool has been actuated so as to begin expanding the lower
string of casing.
[0025] FIG. 7 depicts the wellbore of FIG. 6. Here, the expander
tool has been lowered further so as to expand the upper portion of
the lower string of casing along a desired length.
[0026] FIG. 8 is a partial section view of the wellbore of FIG. 7,
with the slow-bleed expansion apparatus of the present invention
having been removed. In this view, the lower string of casing has
been expanded into frictional and sealing engagement with the
surrounding upper string of casing.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0027] FIG. 1 presents a cross-sectional view of a wellbore 100
having an upper string of casing 110 and a lower string of casing
120. The lower string of casing 120, or liner, is being lowered
into the wellbore 100 co-axially with the upper string of casing
110. The lower string of casing 120 is positioned such that an
upper portion 120U of the lower string of casing 120 overlaps with
a lower portion 110L of the upper string of casing 110.
[0028] In the example of FIG. 1, the lower string of casing 120
serves as an expandable tubular. The lower string of casing 120
will be hung off of the upper string of casing 110 by expanding the
upper portion 120U of the lower string of casing 120 into the lower
portion 110L of the upper string of casing 110. However, it is
understood that the apparatus and method of the present invention
may be utilized to expand downhole tubulars other than strings of
casing.
[0029] A sealing member 222 is preferably disposed on the outer
surface of the lower string of casing 120. Preferably, the sealing
member 222 defines a matrix formed in grooves (not shown) on the
outer surface of the lower string of casing 120U. However, other
configurations are permissible, including one or more simple rings
formed circumferentially around the lower string of casing 120.
[0030] The sealing member 222 is fabricated from a suitable
material based upon the service environment that exists within the
wellbore 100. Factors to be considered when selecting a suitable
sealing member 222 include the chemicals likely to contact the
sealing member, the prolonged impact of hydrocarbon contact on the
sealing member, the presence and concentration of corrosive
compounds such as hydrogen sulfide or chlorine, and the pressure
and temperature at which the sealing member must operate. In a
preferred embodiment, the sealing member 222 is fabricated from an
elastomeric material. However, non-elastomeric materials or
polymers may be employed as well, so long as they substantially
prevent production fluids from passing upwardly between the outer
surface of the lower string of casing 120 and the inner surface of
the upper string of casing 110 after the expandable section 120U of
the casing 120 has been expanded.
[0031] Also positioned on the outer surface of the lower string of
casing 120 is at least one slip member 224. The slip member 224 is
used to provide an improved grip between the expandable tubular
120U and the upper string of casing 110 when the lower string of
casing 120 is expanded. In this example, the slip member 224
defines a plurality of carbide buttons interspersed within the
matrix of the sealing member 222. However, any suitable placement
of a hardened material which provides a gripping means for the
lower string of casing 120 into the upper string of casing 110 may
be used. For example, a simple pair of rings having grip surfaces
(not shown) formed thereon for engaging the inner surface of the
upper string of casing 110 when the lower string of casing 120 is
expanded would be suitable. The size, shape and hardness of the
slips 224 are selected depending upon factors well known in the art
such as the hardness of the inner wall of casing 110, the weight of
the casing string 120 being hung, and the arrangement of slips 224
used.
[0032] In order to expand the lower string of casing 120 seen in
FIG. 1, the present invention provides an expansion assembly 500.
The expansion assembly 500 of the present invention defines two
primary components--(1) an expander tool 300; and (2) a chamber 400
which receives the expander tool 300. The two components 300 and
400 are shown together within the wellbore 100 of FIG. 1, defining
an expansion assembly 500. FIG. 2 is also provided, which shows the
expansion assembly 500 of FIG. 1 in cross-section, with the view
being taken across line 2-2 of FIG. 1.
[0033] In FIG. 1, the expander tool 300 is shown positioned above
the chamber 400. In this respect, the working string 170 will be
lowered, causing the expander tool 300 to be received in the
chamber 400. However, it is to be understood that the scope of the
present invention permits the expander tool portion 300 to be
positioned below the fluid chamber portion 400. In such an
arrangement, the working string 170 is axially translated towards
the surface of the well, causing the expander tool 300 to be raised
or otherwise pulled into the fluid chamber 400.
[0034] As noted, the expansion assembly of the present invention
500 first comprises an expander tool 300. An exploded view of the
expander tool 300 of FIG. 1 is seen in FIG. 3. This presents an
exemplary hydraulic expander tool 300. In this embodiment, the
expander tool 300 first has a body 330. The body 330 is preferably
an elongated tubular member defining a bore 305 there through. As
will be discussed further below, the body 330 is elongated in order
to be sealingly received within a chamber 400 there below. A
connector 304 is provided at an upper end of the body 330 for
connection to the working string 170. The connector 304 is
typically of a reduced diameter (compared to the outside diameter
of the body 330 of the tool 300).
[0035] The expander tool 300 next provides an inner mandrel 310.
The inner mandrel 310 runs longitudinally through the body 330.
Where the expander tool 300 is a hydraulically actuated, the inner
mandrel 310 is perforated. The perforations permit fluid to fill an
annular region defined between the inner mandrel 310 and the outer
body 330, or to otherwise act on a plurality of roller members 316.
FIG. 4 presents a portion of the expander tool 300 of FIG. 3 in
cross-section, with the view taken across line 4-4. A portion of
the perforated tubular mandrel 310 is more closely seen.
[0036] The central body 330 has a plurality of recesses 314 for
holding the respective rollers 316. In one arrangement, each of the
recesses 314 has parallel sides and holds a roller 316 capable of
extending radially from the perforated tubular core 305 of the tool
300. The rollers 316 illustrated in FIG. 3 have generally
cylindrical or barrel-shaped cross sections; however, it is to be
appreciated that other roller shapes are possible. For example, a
roller 316 may have a cross sectional shape that is conical,
truncated conical, semi-spherical, multifaceted, elliptical or any
other cross sectional shape suited to the expansion operation to be
conducted within the tubular 120. It is understood that any
cross-sectional shape suitable for engaging the surrounding tubular
may be employed.
[0037] In the arrangement for an expander tool 300 shown in FIG. 3,
each of the rollers 316 is supported by a shaft 318 at each end of
the respective roller 316. The shaft 318, in turn, is supported by
a piston 312. In this manner, the rollers 316 may rotate above the
respective pistons 312 about a defined rotational axis. However,
the present invention is not limited to the manner in which the
roller members 316 are mounted. Alternatively, the roller members
316 may define solid bodies that reside directly on the outer
piston surface. In such an arrangement, the roller members 316 may
define non-rotating members that are integral to the piston, or
they may define roller bodies that partially roll and partially
skid on the piston 312. And still alternatively, the roller members
316 may define one or more bearings that reside in one or more
respective races above the piston 312.
[0038] The rollers 316 are generally parallel to the longitudinal
axis of the tool 300. It is permissible, however, to skew the
orientation of the roller members 316 at a one or two degree offset
in order to aid in the axial movement of the expander tool 300. The
plurality of rollers 316 are radially offset at mutual
circumferential separations around the central body 330. In the
arrangement shown in FIG. 3, two rows of three rollers 316 are
employed. However, additional rows may be incorporated into the
body 330, or only one may be utilized. Various numbers of roller
members 316 may be employed.
[0039] As shown in FIG. 3, the pistons 312 are radially slidable,
one piston 312 being slidably sealed within each radially provided
recess 314. The back side of each piston 312 is exposed to the
pressure of fluid within the hollow bore 305 of the inner mandrel
310. In this manner, pressurized fluid provided from the surface of
the well can actuate the pistons 312 and cause them to extend
outwardly whereby the rollers 316 contact the inner surface of the
surrounding tubular to be expanded, e.g., tubular 120U.
[0040] The expander tool 300 is preferably designed for use at or
near the end of a working string 170. In order to actuate the
expander tool 300 shown in FIG. 3, fluid is injected into the
working string 170. Fluid under pressure then travels downhole
through the working string and into the perforated tubular bore 305
of the tool 300. From there, fluid contacts the backs of the
pistons 312. As hydraulic pressure is increased, fluid forces the
pistons 312 from their respective recesses 314. This, in turn,
causes the rollers 316 to make contact with the inner surface of
the liner 120U. Fluid finally exits the expander tool 300 at the
base of the mandrel 310. The circulation of fluids to and within
the expander tool 300 is preferably regulated so that the contact
between and the force applied to the inner wall of liner 120U is
controlled. In this respect, fluid passing from the mandrel 310
encounters a sized orifice (not shown) at the base of or below the
tool 500. The pressurized fluid causes the piston assembly 312 to
extend radially outward so as to place the rollers 316 into contact
with the inner surface of the lower string of casing 120U. With a
predetermined amount of fluid pressure acting on the piston surface
312, the lower string of casing 120U is expanded past its elastic
limits.
[0041] Below the expander tool 300 is a chamber 400. The chamber of
FIG. 1 is seen more fully in the enlarged cross-sectional view of
FIG. 5. As can be seen, the chamber 400 is comprised of an outer
wall 450 and an inner wall 430. A connecting surface 460 is also
shown. The outer wall 450, the inner wall 430, and the connecting
surface 460 define a chamber 400 for containing a resistive medium.
Preferably, the resistive medium is a viscous fluid such as a clean
oil, but may be any liquid material. The oil is loaded into the
chamber 400 before the chamber 400 is run into the wellbore 100. In
this arrangement, the chamber 400 defines a fluid chamber.
[0042] The fluid chamber 400 is sized and configured to receive the
elongated tubular body 330 of the expander tool 300. A portion of
the body 330 can be seen in FIG. 5. In this view, the body 330
remains only partially inserted into the chamber 400, as the
expander tool 300 has not yet been fully lowered into fluid chamber
400. Two seal rings 320 and 340 are disposed around the body 330.
Seal ring 320 defines an inner seal ring, and is disposed
circumferentially internal to the body 330, while seal ring 340
defines an outer seal ring, and is disposed circumferentially
external to the body 330. The seal rings 320 and 340 enable the
body 330 to be sealingly received within the fluid chamber 400 as
the expander tool 300 is lowered during expansion operations.
[0043] An additional seal 355 is optionally provided between the
mandrel 310 and the inner wall 430. In one aspect, the seal 355 is
attached circumferentially to the inner surface of the inner wall
430. The optional seal 355 is also seen in FIG. 5.
[0044] In operation, the expansion apparatus 500 of the present
invention is run into the wellbore 100 on the lower end of a
working string 170. In order to accomplish the expansion operation
in a single trip, the working string 170 also is temporarily
connected to the lower string of casing 120. In this manner, the
lower string of casing 120 can be introduced into the wellbore 100
at the same time as the expander tool 300. In FIG. 1, a collet 160
is presented as the releasable connection. The collet 160 is shown
near the end of the working string 170. The collet 160 is landed
into a radial profile 165 within the lower string of casing 120 so
as to support the lower string of casing 120. The collet 160 is
mechanically or pneumatically actuated as is known in the art, and
supports the lower string of casing 120 until such time as the
lower string of casing 120 has been expandably set by actuation of
the expander tool 300.
[0045] When expansion of the surrounding tubular 120U is desired,
the rollers 316 of the expander tool 300 are actuated as disclosed
above. At about the same time, the rotary expander tool 300 is
rotated within the expandable tubular 120. It is contemplated in
FIG. 1 that rotation of the expander tool 300 is accomplished by
rotating the working string, i.e., drill pipe 170, from the
surface. However, rotation may also be achieved by activation of a
downhole hydraulic or electric rotary motor, such as a mud motor
(not shown).
[0046] Once the initial section of expandable tubular 120U is
expanded, the expander tool 300 is translated. In the arrangement
depicted in FIG. 1, the expander tool 300 is moved downwardly by
slacking off the weight of the drill string 170 from the surface.
This has the effect of lowering the expander tool 300 within the
wellbore 100 so as to expand a desired length of tubular 120U. As
the expander tool 300 is lowered, the body 330 of the tool 300 is
received within the fluid chamber 400. The resistant medium within
the chamber 400 resists entry of the body 330 into the chamber 400.
However, as additional weight is slacked off of the drill string
170 by the operator, the body 330 is urged further downward.
[0047] In accordance with the present invention, at least one valve
member 480 is disposed proximate to the bottom connecting surface
460 of the inner and outer walls 430, 450. In the enlarged view of
FIG. 5, a pair of valves 480 is depicted in the connecting surface
460 of the outer wall 450. The valves 480 define through-openings
having pressure-sensitive diaphragms 485 designed to be penetrated
at a given elevated pressure within the fluid chamber 400.
Preferably, the valves 480 include a one-way internal member (not
shown) for permitting fluid to flow from the fluid chamber 400 at a
designated elevated pressure, but prohibiting wellbore fluid from
flowing into the chamber 400. Thus, when pressure reaches a certain
anticipated level caused by the advancement of the expander tool
body 330 into the fluid chamber 400, the valves 480 open,
permitting fluid to be released.
[0048] As a further feature of the present invention, the valves
480 are specially sized to restrict the rapid release of fluid from
the fluid chamber 400. In this respect, the valves 480 are sized so
that oil is released slowly, thereby prohibiting a rapid drop of
the expander tool body 330 into the fluid chamber 400. This, in
turn, protects against any downward pipe spring caused by pipe
compression and release. Thus, a "slow-bleed" expansion apparatus
is provided.
[0049] As the body 330 of the expander tool 300 continues to
advance into the chamber 400, fluid will continue to be pushed
through the at least one valve 480. The operator may discontinue
axial translation of the expander tool 300 before the body 330 of
the expander tool 300 reaches the connecting surface 460.
Alternatively, the operator may push (or pull) the body 330 to the
end of the chamber 400. In this approach, the length of the chamber
400 defines the length of the surrounding tubular 120 that gets
expanded.
[0050] It should be noted that the slow-bleed expansion apparatus
500 of the present invention permits of other arrangements and
embodiments. For example, other media besides oil may be utilized,
although it is preferred that the media be viscous. The medium may
even be in a gaseous phase rather than a liquid phase. Further, a
plurality of valves designed to be opened at ever-increasing
pressures may be employed. In this arrangement, a first valve would
open at a first designated pressure, while a second valve would
later open at a second higher designated pressure. Further, the
size of the through-opening attendant to the second valve may be
smaller or larger than the size of the first through-opening,
subject to design consideration. Yet an alternate arrangement for a
slow-bleed apparatus employs a subsea downhole motion compensator
system. Such a system is currently used to eliminate the effect of
rig heave during offshore operations, such as from a floating
vessel. For example, the subsea downhole motion compensator allows
the operator to control weight-on-bit during sensitive milling
operations. Finally, the fluid chamber may define a single,
cylindrical receptacle for entirely receiving the body of the
expander tool. The cylindrical receptacle would have the resistive
medium therein.
[0051] It is also understood that other arrangements which do not
employ a fluid medium may be used. For example, the resistive
medium can be a powerful spring (not shown). In this arrangement,
the spring is disposed within the chamber 400 for providing
resistance against the downward-moving expander tool body 330. In
such an arrangement, the use of valves is not needed.
[0052] FIG. 6 depicts the wellbore of FIG. 1. In this view, the
expander tool 300 has been actuated so as to begin expanding the
lower string of casing 120U. Expansion is accomplished radially by
rotating the actuated expander tool 300, such as by rotating the
working string 170. In such an arrangement, a swivel 150 is placed
in the working string 170 below the expansion apparatus 500. The
swivel 150 permits the expander tool 300 to rotate without rotating
other tools downhole, including the collet 160. The swivel 150 is
shown schematically in FIG. 1 as a separate downhole tool. However,
it is preferred that the swivel 150 simply be incorporated into the
lower end of the fluid chamber 400 using a bearing-type connection
(not shown).
[0053] FIG. 7 depicts the wellbore of FIG. 6. Here, the expander
tool 300 has been lowered further into the fluid chamber 400 so as
to expand the upper portion of the lower string of casing 120U
along a desired length. As explained above, actuation of the
expander tool 300 is by injection of fluid under pressure into the
working string 170. Fluid travels from the surface, down the
working string 170, through the bore 305 of the mandrel 310, and
through the perforations behind the pistons 312 of the expander
tool 300.
[0054] Following expansion operations, hydraulic pressure from the
surface is relieved, allowing the pistons 312 to return to the
recesses 314 within the body 330 of the tool 300. The releasable
connection 160 with the liner 120 is also released. The expander
tool 300 and the fluid chamber 400 can then be withdrawn from the
wellbore 100 by pulling the run-in tubular 170. FIG. 8 is a partial
section view of the wellbore of FIG. 7, with the slow-bleed
expansion apparatus 500 of the present invention having been
removed. In this view, the lower string of casing 120 has been
expanded into frictional and sealing engagement with the upper
string of casing 110. This, in turn, results in an effective
hanging and sealing of the lower string of casing 120 upon the
upper string of casing 110 within the wellbore 100. Thus, the
apparatus 500 enables a lower string of casing 120 to be hung onto
an upper string of casing 110 by expanding the lower string 120
into the upper string 110 while avoiding the problem of pipe-spring
discussed above.
[0055] It can be seen in FIG. 8 that the seal member 222 and the
slip member 224 are engaged with the inner surface of the upper
string of casing 110. Further, the annulus 135 between the lower
string of casing 120 and the upper string of casing 110 has been
filled with cement, excepting that portion of the annulus which has
been removed by expansion of the lower string of casing 120U. This
is part of an effective well completion enabled by the apparatus
500 of the present invention.
[0056] As a further aid in the expansion of the lower casing string
120, a torque anchor may optionally be utilized. Those of ordinary
skill in the art may perceive that the radially outward force
applied by the rollers 316, when combined with rotation of the
expander tool 300, might cause some unwanted rotation of the casing
120. The torque anchor (not shown) serves to prevent rotation of
the lower string of casing 120 during the expansion process.
[0057] 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.
* * * * *