U.S. patent application number 10/253114 was filed with the patent office on 2004-03-25 for positive displacement apparatus for selectively translating expander tool downhole.
This patent application is currently assigned to Weatherford/Lamb, Inc.. Invention is credited to Maguire, Patrick G., Tran, Khai.
Application Number | 20040055786 10/253114 |
Document ID | / |
Family ID | 31993097 |
Filed Date | 2004-03-25 |
United States Patent
Application |
20040055786 |
Kind Code |
A1 |
Maguire, Patrick G. ; et
al. |
March 25, 2004 |
Positive displacement apparatus for selectively translating
expander tool downhole
Abstract
The present invention provides a positive displacement apparatus
for selectively translating a completion tool, such as an expander
tool, downhole. The positive displacement apparatus comprises a set
of three essentially concentric tubular members. The three tubulars
represent (1) an outer sleeve, (2) an inner mandrel, and (3) a
middle displacement piston between the sleeve and the mandrel.
These three tubular members are nested within the expandable liner
or other tubular to be expanded within a wellbore. A fluid transfer
chamber is provided below the middle displacement piston. Rotation
of the positive displacement apparatus serves to draw fluid into
the fluid transfer chamber. This fluid, in turn, is pumped into a
fluid transfer channel and forces the displacement piston upward
between the outer sleeve and the inner mandrel. The displacement
piston then acts against the rotary expander tool. In this manner,
the displacement piston translates the rotary expander tool axially
within the wellbore.
Inventors: |
Maguire, Patrick G.;
(Cypress, TX) ; Tran, Khai; (Pearland,
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: |
31993097 |
Appl. No.: |
10/253114 |
Filed: |
September 24, 2002 |
Current U.S.
Class: |
175/50 ;
166/207 |
Current CPC
Class: |
E21B 43/105 20130101;
E21B 43/103 20130101; E21B 4/18 20130101 |
Class at
Publication: |
175/050 ;
166/207 |
International
Class: |
E21B 047/00 |
Claims
1. An apparatus for translating an expander tool axially within a
wellbore in order to facilitate the expansion of a first tubular
into a surrounding second tubular, the apparatus comprising: a
fluid chamber having a first end and a second end; a displacement
piston having a first end and a second end, the first end of the
displacement piston acting upon the expander tool, and the second
end being in communication with the fluid chamber; a rotor piston
having a first end and a second end, the first end of the rotor
piston sealingly residing within the fluid chamber; and the fluid
chamber sized and configured such that reciprocal movement of the
rotor piston causes axial movement of the displacement piston
within the wellbore.
2. The apparatus of claim 1, further comprising a fluid medium that
is applied under pressure against the second end of the
displacement piston in order to translate the expander tool within
the wellbore.
3. The apparatus of claim 2, wherein the first tubular defines a
lower string of casing, and the second tubular defines an upper
string of casing.
4. The apparatus of claim 3, wherein the rotor piston has a bottom
face at its second end, the bottom face having a wave form
configuration; and the first end of the rotor piston is
reciprocated axially within the fluid transfer chamber by rotating
the rotor piston.
5. The apparatus of claim 4, further comprising a stator member,
the stator member having a top face having a wave form
configuration; and wherein the bottom face of the rotor piston
rides on the top face of the stator member such that rotation of
the rotor piston causes the rotor piston to reciprocate
axially.
6. The apparatus of claim 5, wherein the stator member is
stationary within the wellbore while the rotor piston is being
rotated.
7. The apparatus of claim 6, further comprising a biasing member
disposed in the fluid chamber, the biasing member biasing the rotor
piston to ensure essentially continuous contact between the bottom
face of the rotor piston and the top face of the stator member.
8. The apparatus of claim 7, further comprising: an inner mandrel,
the inner mandrel defining a tubular body nested essentially
concentrically within the displacement piston; an outer sleeve, the
outer sleeve defining a tubular body surrounding the displacement
piston such that the displacement piston is nested essentially
concentrically within the outer sleeve; and wherein the fluid
medium is loaded in an annular region defined between the
expandable first tubular and the outer sleeve.
9. The apparatus of claim 8, further comprising: an annular feed
channel placing the annular region and the fluid chamber in fluid
communication; an inflow valve permitting fluid to flow from the
annular region into the fluid chamber; and an outflow valve
permitting fluid to flow from the fluid chamber against the second
end of the displacement piston in response to rotational movement
of the rotor piston.
10. The apparatus of claim 9, wherein the displacement piston is
connected to the outer sleeve by a splined connection, allowing the
displacement piston to move axially relative to the outer
sleeve.
11. The apparatus of claim 10, wherein the displacement piston is
connected to the inner mandrel by a splined connection, allowing
the displacement piston to move axially relative to the inner
mandrel.
12. The apparatus of claim 9, further comprising at least one seal
at the first end of the rotor piston to provide a fluid seal
between the rotor piston and the fluid chamber.
13. The apparatus of claim 12, further comprising at least one seal
at the second end of the displacement piston to provide a fluid
seal between the displacement piston and the inner mandrel on an
inner surface of the displacement piston, and between the
displacement piston and the outer sleeve on an outer surface of the
displacement piston.
14. An apparatus for translating an expander tool axially within a
wellbore in order to facilitate the expansion of an upper portion
of a liner string into a surrounding string of casing, the
apparatus comprising: a fluid transfer chamber having an upper end
and a lower end; a displacement piston having an upper end and a
lower end, the upper end of the displacement piston acting upon the
expander tool, and the lower end being in communication with the
fluid chamber; an inner mandrel, the inner mandrel defining a
tubular body nested essentially concentrically within the
displacement piston; an outer sleeve, the outer sleeve defining a
tubular body surrounding the displacement piston such that the
displacement piston is nested essentially concentrically within the
outer sleeve; a rotor piston having an upper end and a lower end,
the upper end of the rotor piston sealingly residing within the
fluid transfer chamber; oil, the oil loaded in an annular region
defined between the expandable liner string and the outer sleeve;
an annular feed channel placing the annular region and the fluid
chamber in fluid communication; an inflow valve permitting the oil
to flow from the annular region into the fluid chamber; an outflow
valve permitting the oil to flow from the fluid chamber against the
lower end of the displacement piston in response to rotational
movement of the rotor piston; and the fluid chamber sized and
configured such that reciprocal movement of the rotor piston causes
axial movement of the displacement piston within the wellbore.
15. The apparatus of claim 14, wherein the rotor piston has a
bottom face at its lower end, the bottom face having a wave form
configuration; the second end of the rotor piston is reciprocated
axially within the fluid transfer chamber by rotating the rotor
piston;
16. The apparatus of claim 15, further comprising a stationary
stator member, the stator member having a top face having a wave
form configuration; and wherein the bottom face of the rotor piston
rides on the top face of the stator member such that rotation of
the rotor piston imparts an upstroke and a downstroke to the rotor
piston, causing the rotor piston to reciprocate axially within the
fluid transfer chamber such that oil is drawn into the fluid
transfer chamber on the downstroke of the rotor piston, and oil is
extruded under pressure against the displacement piston on the
upstroke, thereby imparting axial movement to the displacement
piston and to the expander tool within the wellbore.
17. The apparatus of claim 16, further comprising a spring disposed
in the fluid transfer chamber, the spring biasing the rotor piston
to ensure essentially continuous contact between the bottom face of
the rotor piston and the top face of the stator member.
18. The apparatus of claim 17, wherein the displacement piston
moves axially relative to the outer sleeve.
19. The apparatus of claim 18, wherein the displacement piston
moves axially relative to the inner mandrel.
20. The apparatus of claim 15, further comprising a stationary
stator member, the stator member having a top face having a wave
form configuration; and wherein the bottom face of the rotor piston
rides on the top face of the stator member such that rotation of
the rotor piston imparts a downstroke and an upstroke to the rotor
piston, causing the rotor piston to reciprocate axially within the
fluid transfer chamber such that oil is drawn into the fluid
transfer chamber on the upstroke of the rotor piston, and oil is
extruded under pressure against the displacement piston on the
downstroke, thereby imparting axial movement to the displacement
piston and to the expander tool within the wellbore.
21. An apparatus for translating an expander tool axially within a
wellbore in order to facilitate the expansion of an upper portion
of a liner string into a surrounding string of casing, the
apparatus comprising: a fluid transfer chamber having an upper end
and a lower end; a displacement piston having an upper end and a
lower end, the upper end of the displacement piston acting upon the
expander tool, and the lower end being in communication with the
fluid chamber; a rotor piston having an upper end and a lower end,
the upper end of the rotor piston sealingly residing within the
fluid transfer chamber, and the lower end having a bottom face, the
bottom face having a wave form configuration; a spring disposed in
the fluid transfer chamber, the spring biasing the rotor piston to
ensure essentially continuous contact between the bottom face of
the rotor piston and the top face of the stator member; a stator
having an upper face having a wave form configuration which mates
with the bottom face of the rotor piston; and wherein the bottom
face of the rotor piston rides on the top face of the stator member
such that rotation of the rotor piston imparts an upstroke and a
downstroke to the rotor piston, causing the rotor piston to
reciprocate axially within the fluid transfer chamber such that oil
is drawn into the fluid transfer chamber on the downstroke of the
rotor piston, and oil is extruded under pressure against the
displacement piston on the upstroke, thereby imparting axial
movement to the displacement piston and to the expander tool within
the wellbore.
22. The apparatus of claim 21, further comprising a plurality of
check valves, the check valves being constructed and arranged to
allow the oil to enter the fluid transfer chamber on the downstroke
of the rotor piston, and to exit the fluid transfer chamber on the
upstroke of the rotor piston.
23. The apparatus of claim 22, further comprising a plurality of
check valves, the check valves being constructed and arranged to
allow the oil to enter the fluid transfer chamber on the upstroke
of the rotor piston, and to exit the fluid transfer chamber on the
downstroke of the rotor piston.
24. The apparatus of claim 22, further comprising: an inner
mandrel, the inner mandrel defining a tubular body nested
essentially concentrically within the displacement piston; an outer
sleeve, the outer sleeve defining a tubular body surrounding the
displacement piston such that the displacement piston is nested
essentially concentrically within the outer sleeve; and wherein the
fluid medium is loaded in an annular region defined between the
expandable liner string and the outer sleeve.
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 selectively translating a completion tool, such as an
expander tool, downhole.
[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 section 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 tubulars to
be expanded in situ. The apparatus typically includes expander
tools that are run into the wellbore on a working string. The
expander tools include a plurality of expansion assemblies that are
urged radially outward into contact with a tubular therearound. The
expansion assemblies typically comprise a piston disposed within a
recess of the expander tool body, and a roller member positioned on
or above an external piston surface. In some arrangement's, the
expansion assemblies are urged outward from the body of the
expander tool by mechanical force. More commonly, the back surface
of the expansion assembly is exposed to hydraulic pressure from
within the bore of the tool. Fluid pressure is provided either by
injecting fluid under pressure into the wellbore from the surface,
or by activating a dedicated fluid reservoir associated with the
tool.
[0007] As sufficient pressure is generated on the piston surface
behind the expansion assemblies, the tubular being acted upon by
the expander tool is expanded past its point of elastic
deformation. In this manner, the inner and outer diameter of the
tubular is increased in the wellbore. By rotating the expander tool
in the wellbore and/or moving the expander tool axially in the
wellbore with the expansion assemblies actuated, a tubular can be
expanded into plastic deformation along a predetermined length in a
wellbore.
[0008] 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.
[0009] 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.
[0010] 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 into 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.
[0011] 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 pipe drag caused by friction between the drill pipe
and the casing. Because of pipe drag, it is not known how much
weight is actually reaching the tools down hole. The overall result
of these drag problems is that the inner diameter of the expanded
tubular may not have a uniform circumference along the desired
length.
[0012] 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 reduces the potential of
pipe-stretch/pipe-compression by the working string.
Correspondingly, there is a need for a method for expanding a
tubular which avoids the risk of uneven expansion of the tubular
caused by pipe-stretch incident to raising the working string.
Still further, a need exists for an apparatus which will
selectively translate a completion tool such as a rotary expander
tool axially downhole without requiring that the working string be
raised or lowered.
[0013] There is yet a further need for an apparatus which
translates a rotary expander tool by means of a piston selectively
driven through positive displacement.
SUMMARY OF THE INVENTION
[0014] The present invention provides an apparatus and method for
selectively translating a completion tool, such as an expander
tool, downhole. According to the present invention, a translation
apparatus is introduced into a wellbore. The translation apparatus
is lowered downhole on a working string along with an expander
tool, and along with a lower string of casing or other tubular to
be expanded. The expander tool includes compliant rollers which are
expandable radially outward against the inner surface of the
tubular upon actuation.
[0015] The translation apparatus of the present invention utilizes
positive displacement to translate the expander tool. The positive
displacement translation apparatus first defines a set of three
essentially concentric tubular members which reside below the
expander tool. The three concentric tubulars represent (1) an outer
sleeve, (2) an inner mandrel, and (3) a middle displacement piston
nested between the sleeve and the mandrel. These three tubular
members are disposed within the expandable liner or other tubular
to be expanded.
[0016] A fluid transfer chamber is provided below the middle
displacement piston. Rotation of the positive displacement
apparatus serves to draw fluid into the fluid transfer chamber.
This fluid is applied against the base of the displacement piston
in order to force the displacement piston upward between the outer
sleeve and the inner mandrel. This, in turn, causes the
displacement piston to act against the rotary expander tool. In
this manner, the displacement piston translates the expander tool
incrementally upward within the wellbore.
[0017] In order to fill the fluid transfer chamber with fluid, a
positive displacement mechanism is provided. First, a stator member
is provided below the middle displacement piston. The stator member
has a top face at its top end configured in a wave form. In one
aspect, the wave form is sinusoidal. At the same time, a rotor
piston is provided below the displacement piston. The rotor piston
has a bottom face which rides upon the wave form face of the stator
member. Preferably, the bottom face of the rotor piston also has a
sinusoidal wave form shape. Rotation of the expander tool and the
positive displacement apparatus, including the rotor piston, serves
to reciprocate the rotor piston in an up-and-down manner. By this
reciprocating motion, fluid is drawn into the fluid transfer
chamber and fed against the base of the displacement piston. This,
in turn, causes the expander tool to be translated upwardly within
the wellbore. In this manner, the expander tool can be raised
without raising the working string itself.
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 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
a positive displacement apparatus of the present invention for
translating an expander tool.
[0020] FIG. 2 is a more detailed view of a scribe as might be
placed in the lower string of casing. The scribe serves as a point
of structural weakness in the lower string of casing, permitting
severance upon expansion of the casing.
[0021] FIG. 3 is an enlarged view of the fluid transfer chamber in
an exemplary positive displacement apparatus of the present
invention.
[0022] FIG. 4 is a cross-sectional view of a positive displacement
apparatus of the present invention, taken across line 4-4 of FIG.
1.
[0023] FIG. 5 is a cross-sectional view of the positive
displacement apparatus of FIG. 1. In this view, oil is being
transferred from the fluid transfer chamber, up the transfer
chamber channel, and into the piston feed channel. Visible in this
view is the initial translation of the middle displacement
piston.
[0024] FIG. 6 presents an exploded view of an expander tool as
might be translated by the positive displacement pump/piston
apparatus of the present invention.
[0025] FIG. 7 presents a portion of the expander tool of FIG. 5 in
cross-section, with the view taken across line 7-7 of FIG. 6.
[0026] FIG. 8 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. Further, the torque anchor has been actuated so
as to stabilize the lower string of casing and to prevent
rotational movement during expansion.
[0027] FIG. 9 depicts the wellbore of FIG. 8. In this view, the
expander tool remains actuated by hydraulic pressure from the
surface. The working string has been rotated so as to begin raising
the expander tool within the wellbore. In this respect, rotation of
the positive displacement apparatus serves to actuate the piston
within the apparatus. This in turn, causes the expander tool to be
translated co-axially within the wellbore.
[0028] FIG. 10 depicts the wellbore of FIG. 9. Here, the expander
tool has been raised further within the wellbore so as to expand
the lower string of casing into the surrounding upper string of
casing along a desired length. The portion of the lower string of
casing having a scribe has been expanded, causing severance of the
lower string of casing.
[0029] FIG. 11 is a sectional view of the wellbore of FIG. 10. In
this view, the torque anchor and the expander tool have been
de-actuated and the lower collet has been released from the liner.
Also, the expansion assembly is being removed from the wellbore.
Removal of the expansion assembly brings with it the severed upper
portion of the lower casing string.
[0030] FIG. 12 is a sectional view of the wellbore of FIG. 11, with
the positive displacement 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 upper
string of casing.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0031] 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 expandable portion 120E of the lower string of casing 120
overlaps with a lower portion 110L of the upper string of casing
110.
[0032] 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 an
upper portion 120E of the lower string of casing 110 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.
[0033] A sealing member 222 is preferably disposed on the outer
surface of the lower string of casing 120. In one embodiment, the
sealing member 222 defines a matrix formed in grooves (not shown)
on the outer surface of the lower string of casing 120. However,
other configurations are permissible, including one or more simple
rings formed circumferentially around the lower string of casing
120. In the arrangements of FIG. 1, a single ring 222 is shown.
[0034] 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 erosive 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 120L and the inner surface of
the upper string of casing 110L after the expandable section 120L
of the casing 120 has been expanded.
[0035] 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
120E and the upper string of casing 110L 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.
[0036] In order to expand the lower string of casing 120 seen in
FIG. 1, an expander tool 400 is provided. An expander tool as might
be used in the expansion assembly is seen more fully in FIG. 6.
FIG. 6 is an exploded view of an exemplary expander tool 400. FIG.
7 presents the same expander tool 400 in cross-section, with the
view taken across line 7-7 of FIG. 6.
[0037] The expander tool 400 has a body 402 which is hollow and
generally tubular. The central body 402 has a plurality of recesses
414 to hold a respective roller 416. Each of the recesses 414 has
parallel sides and holds a respective piston 420. The pistons 420
are radially slidable, one piston 420 being slidably sealed within
each recess 414. The back side of each piston 420 is exposed to the
pressure of fluid within the hollow bore 415 of the tool 400. In
this manner, pressurized fluid provided from the surface of the
well can actuate the pistons 420 and cause them to extend outwardly
whereby the rollers 416 contact the inner surface of the tubular
120L to be expanded.
[0038] It is understood that the expander tool 400 shown in the
referenced illustrations is merely exemplary. Any arrangement for
an expander tool may be employed with the translation apparatus of
the present invention 100. These include not only hydraulic
expander tools, but mechanically activated expander tools as well.
Further, the utility of the present invention is not limited to
hydraulical expander tools that rely upon hydraulic pressure from
the surface, but includes hydraulic expander tools that utilize a
dedicated fluid reservoir associated with the tool. For example, a
sealed fluid reservoir may be provided between concentric tubulars
downhole. Fluid from this reservoir may be applied against the
expansion assemblies within an expander tool, thereby urging them
outwardly to expand a surrounding tubular. Alternatively, a blended
system may be adopted having a mechanically advanced piston or
other roller carrier that rides on a ramp, and has a hydraulic
assist.
[0039] Disposed within each piston 420 is a roller 416. In one
embodiment of the expander tool 400, rollers 416 are
near-cylindrical and slightly barreled. Each of the rollers 416 is
supported by a shaft 418 at each end of the respective roller 416
for rotation about a respective rotational axis. The rollers 416
are preferably tilted at a very slight angle of approximately two
degrees relative to the longitudinal axis of the tool 400. This
aids in translation of the expander tool upward. In the arrangement
of FIG. 6, the plurality of rollers 416 are radially offset at
mutual 120-degree circumferential separations around the central
body 402. In the arrangement shown in FIG. 6, only a single row of
rollers 416 is employed. However, additional rows may be
incorporated into the body 402, as shown in FIG. 1.
[0040] The rollers 416 illustrated in FIG. 6 have generally
cylindrical or barrel-shaped cross sections; however, it is to be
appreciated that other roller shapes are possible. For example, the
roller 416 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. In addition, at least one portion
of the roller surface is preferably tapered. In some instances,
solid pads will take the place of rollers in an assembly.
[0041] The expander tool 400 is preferably designed for use at or
near the end of a working string 170. In the arrangement of FIG. 1,
connection between the working string 170 and the expander tool 400
is by a mandrel 340'. The mandrel 340' defines an elongated tubular
body that extends into and through the expander tool 400. The
mandrel portion above the expander tool 400 is shown at 340', while
the mandrel portion below the expander tool is shown at 340. The
upper mandrel 340' includes a spline 337 which is received within a
profile (not shown) within the expander tool body 402. In this way,
rotation of the working string 170 and the upper mandrel 340'
imparts rotation to the expander tool 400. At the same time, and as
will be described below, the upper mandrel 340' is able to radially
receive the expander tool 400 when the tool 400 is translated
upward by a positive displacement apparatus 300.
[0042] In order to actuate the exemplary expander tool 400 of FIG.
6, fluid is injected into the working string 170. Fluid under
pressure then travels downhole through the working string 170 and
into the perforated tubular bore 415 of the tool 400. From there,
fluid contacts the backs of the pistons 420. As hydraulic pressure
is increased, fluid forces the pistons 420 outwardly from their
respective recesses 414. This, in turn, causes the rollers 416 to
make contact with the inner surface of the liner 120L. Fluid
finally exits the expander tool 400 through the mandrel 340 at the
base of the tool 400. The circulation of fluids to and within the
expander tool 400 is preferably regulated so that the contact
between and the force applied to the inner wall of the liner 120E
is controlled. The pressurized fluid causes the piston assembly 420
to extend radially to place the rollers 416 into contact with the
inner surface of the lower string of casing 120E. With a
predetermined amount of fluid pressure acting on the piston surface
420, the lower string of expandable liner 120E is expanded past its
elastic limits. Of course, as noted previously, other means for
activating the pistons of the expander tool may be employed.
[0043] In the arrangement of FIG. 1, the lower end of the expander
tool 400 is connected to a positive displacement apparatus 300. The
positive displacement apparatus 300 generally defines a tubular
assembly which is able to translate the expander tool 400 upwardly
in the wellbore 100 when the expander tool 400 and the positive
displacement apparatus 300 are rotated.
[0044] In the arrangement shown in FIG. 1, the positive
displacement apparatus 300 first comprises a set of three
essentially concentric tubular members which reside below the
expander tool 400. The three tubulars represent (1) an outer sleeve
330, (2) an inner mandrel 340, and (3) a middle displacement piston
355 nested between the sleeve 330 and the mandrel 340. These three
tubular members 330, 355, 340 are disposed proximate the expandable
liner 120 or other tubular to be expanded. Hence, four separate
tubulars 120, 340, 355, 330 are disposed essentially concentrically
within the upper casing string 100.
[0045] FIG. 4 is a cross-sectional view of a positive displacement
apparatus 300 of the present invention, taken across line 4-4 of
FIG. 1. The relative placement of the liner string 120 and of the
three tubulars 340, 355, 330 of the present invention is seen more
fully in this view. It can be seen that an annular region is formed
between the inner mandrel 340 and the displacement piston 355.
Likewise, an annular region is found between the displacement
piston 355 and the outer sleeve 330. Also, an annular region is
created between the sleeve 330 and the liner string 120. Finally, a
hollow bore 345 is defined within the inner mandrel 340.
[0046] Each of the three tubulars 340, 355, 330 of the positive
displacement apparatus 300 has an upper end and a lower end. The
upper end of the displacement piston 355 is connected to the
expander tool 400. Connection is preferably by a threaded
connection.
[0047] In order to impart rotation to the expander tool 400, and as
noted above, a splined connection 337 is provided between the upper
mandrel 340' and the expander tool body 402. The splined connection
337 is in the nature of a traveling spline.
[0048] A fluid transfer chamber 348 is provided below the
displacement piston 355. The fluid transfer chamber 348 and its
related components are seen more fully in the enlarged view of FIG.
3. As shown, the fluid transfer chamber 348 is defined by the inner
mandrel 340 on the inside, and by a fluid transfer chamber housing
346 on the outside. The purpose of the fluid transfer chamber 348
is to serve as a reservoir through which oil may be transferred
from the annular space 325 (shown in FIG. 4) outside of the sleeve
330 to the base of the displacement piston 355, thereby fluidly
forcing the displacement piston 355 upward. The annulus 325 is
loaded with a clean, lightweight liquid medium such as oil. A
cement bushing (not shown) positioned at a lower end of the
positive displacement apparatus 300 supports the column of fluid
outside of the sleeve 330 and within the liner 120. As seen in FIG.
3, the fluid transfer chamber 348 is placed in fluid communication
with the annulus 325 by means of an annular feed channel 324. The
annular feed channel 324 has a through-opening 324' at one end
which is in open communication with the annulus 325. At its
opposite end, the annular feed channel 324 has a check valve
opening 324" which delivers oil to an inflow check valve 374.
[0049] The inflow check valve 374 permits oil to flow into the
fluid transfer chamber 348, but does not permit oil to flow out of
the fluid transfer chamber 348. In the arrangement shown in FIG. 3,
the inflow check valve 374 is a bullet nose check valve. However,
any suitable one-way valve may be used.
[0050] As shown in FIG. 3, more than one check valve is employed
for the positive displacement apparatus 300. In addition to the
inflow check valve 374, an outflow check valve 372 is also
provided. As with the inflow check valve 374, the outflow check
valve 372 is a one-way check valve. However, the outflow check
valve 372 permits oil to flow out of the fluid transfer chamber
348, but does not permit oil to flow into the fluid transfer
chamber 348. In the arrangement shown in FIG. 3, the inflow check
valve 372 is a bullet nose check valve. However, any suitable
one-way valve may be used, or none at all. As oil is delivered
through the inflow check valve 374, the fluid transfer chamber 348
is filled. As additional oil is pumped into the fluid transfer
chamber 348, pressure is created therein. Ultimately, oil is forced
out of the fluid transfer chamber 348 through the outflow check
valve 372. Oil flows from the outflow check valve 372 and into a
piston feed channel 334. This oil, in turn, provides a force
against the lower end of the middle displacement piston 355,
forcing it upward with respect to the outer sleeve 330 and the
inner mandrel 340. Because the displacement piston 355 is connected
to the lower end of the expander tool 400, upward displacement of
the displacement piston 355 translates the expander tool 400 upward
within the expandable tubular 120E.
[0051] The arrangement of FIG. 3 also presents a transfer chamber
channel 364. The transfer chamber channel 364 provides a path of
fluid communication between the check valves 374 and 372, and the
fluid transfer chamber 348 itself. In this arrangement, the
transfer chamber channel 364 resides within a fluid transfer
channel housing 365. The fluid transfer channel housing 365 defines
the top of the fluid transfer chamber 348, and also houses the
check valves 374 and 372. It is understood, however, that other
arrangements may be provided for channeling fluid from the fluid
transfer chamber 348, through the outflow check valve 372, and
against the displacement piston 355.
[0052] A means is needed to draw oil from the annular space 325
into the fluid transfer chamber 348. In the present invention, the
drawing of oil is accomplished through positive displacement. In
accordance with the present invention, a stator member 210 is first
provided. The stator member 210, in one aspect, defines a tubular
body which is disposed below the fluid transfer chamber 348. The
stator member 210 has a top surface which serves as a face 385. The
face 385 is configured in a wave form. Preferably, the wave form is
sinusoidal. The stator member 210 remains stationary, while the
mandrel 340' rotates through it.
[0053] As seen in FIG. 1, a lower portion of the mandrel 340"
extends below the stator 210. This lower mandrel 340" also rotates
in response to rotation imparted by the working string 170. A
swivel, shown schematically as a sub at 150, is positioned between
the lower mandrel 340" and the collet 160 to further facilitate
rotation of the inner mandrel 340 and the lower mandrel 340".
[0054] Fixed between the fluid transfer chamber 348 and the tubular
body 210 is a rotor piston 357. The rotor piston 357 is rotated as
part of the positive displacement apparatus 300. In this respect, a
key or other splined-type connection 335 connects the mandrel 340
to the rotor piston 357 to impart rotation to the rotor piston 357.
In the arrangement of FIG. 3, the fluid transfer channel housing
365 also includes separate split rings 332 and 362 which provide a
locating shoulder between the outer sleeve 330, the fluid transfer
channel housing 365, and the inner mandrel 340. These split rings
332, 362 ensure that the components of the positive displacement
apparatus 300 remain axially stationary relative to the rotor
piston 357. It is understood, however, that the present invention
is not limited to any particular manner in which the rotor piston
357 is connected to the positive displacement apparatus 300, so
long as the rotor piston 357 is able to reciprocate in response to
the wave form on the face 385 of the stator member 210.
[0055] The rotor piston 357 has an upper end which defines the
bottom of the fluid transfer chamber 348. The rotor piston 357
further has a lower end that includes a face 380 configured in a
wave form similar to the face 385 on the tubular body 210. The face
380 of the rotor piston 357 rides upon the face 385 of the stator
member 210 as the rotor piston 357 is rotated. Preferably, the
rotor piston face 380 and the stator member face 385 are each
sinusoidal, though other wave forms may be used. This means that
rotation of the rotor piston 357 by 90 degrees creates a single
stroke length. In the preferred arrangement, the stroke length is
approximately one-half inch (1.27 cm). Thus, rotation of the
expander tool 400 and the positive displacement apparatus 300,
including the rotor piston 357, serves to reciprocate the rotor
piston 357 in an up-and-down manner along a stroke length of
approximately one-half of an inch. As will be shown, it is this
reciprocating stroke that produces the positive displacement used
to translate the expander tool 400.
[0056] As noted, the positive displacement apparatus 300 includes a
fluid transfer chamber 348. The fluid transfer chamber 348 is sized
and configured such that reciprocal movement of the rotor piston
357 causes translational movement of the displacement piston 355.
During the first half of the stroke cycle, the rotor piston 357
moves upwards, thereby reducing the volume of the fluid transfer
chamber 348. Reduction of the volume of the fluid transfer chamber
348 extrudes oil from the fluid transfer chamber 348 and into the
piston feed channel 334. This injection of oil moves the
displacement piston 355 upward within the expandable tubular
120E.
[0057] A biasing member 342 is housed inside the fluid transfer
chamber 348. The biasing member 342 biases the rotor piston 357 in
its downward position to ensure essentially continuous contact
between the bottom face 380 of the rotor piston 357 and the top
face 385 of the stator member 210. Preferably, the biasing member
342 is a spring. The spring 342 becomes compressed during the first
half of the stroke cycle when the rotor piston 357 is thrust
upward. During the second half of the rotor piston's 357 stroke
cycle, the rotor piston 357 moves back into phase with the face 385
of the stator member 210. The spring 342 pushes the rotor piston
357 back downward, re-expanding the volume of the fluid transfer
chamber 348. The second half of the stroke cycle occurs after an
additional 90 degree rotation of the rotor piston 357. This
movement downward of the rotor piston 357 creates a vacuum within
the fluid transfer chamber 348, thereby drawing fluid, e.g., oil,
into the chamber 348 from the piston-sleeve annulus 325. With
continued cycles, the transfer chamber 348 becomes filled with
fluid under pressure. Ultimately, the oil is extruded out of the
transfer chamber 348 and against the base of the displacement
piston 355.
[0058] FIG. 5 presents a cross-sectional view of the positive
displacement apparatus 300 of FIG. 1. In this view, oil is being
transferred from the fluid transfer chamber 348, up the transfer
chamber channel 364, and into the piston feed channel 334. Visible
in this view is the initial translation of the middle displacement
piston 355. Continued rotation of the positive displacement
apparatus 300 will raise the displacement piston 355 further within
the expandable tubular 120E. This, in turn, causes the expander
tool 400 to be translated upwardly. In this manner, the expander
tool 400 can be raised without raising the working string 170
itself.
[0059] In order to effectuate the transfer of oil from the annulus
325, into the fluid transfer chamber 348, and against the
displacement piston 355, it is desirable to utilize various seals
between the components of the positive displacement apparatus 300.
FIG. 5 presents a variety of seals. These include a first sealing
member 356 at the lower end of the displacement piston 355. The
sealing member 356 creates a fluid seal between the displacement
piston 355 and the tubulars 330, 340, thereby allowing all the
fluid in the piston feed channel 334 to fully act upon the
displacement piston 355. A second sealing member 359 is disposed at
the lower end of the transfer channel housing 365. The second
sealing member 359 creates a fluid tight seal for the transfer
channel housing 365 between the transfer chamber housing 346 and
the mandrel 340, thereby preventing a leakage from the upper end of
the fluid transfer chamber 348. A third sealing member 358 is
disposed at the upper end of the rotor piston 357. The sealing
member 358 creates a fluid tight seal for the rotor piston 357
housed between the transfer chamber housing 346 and the mandrel
340, thereby preventing any fluid leakage from the lower end of the
fluid transfer chamber 348.
[0060] Seals are additionally positioned inside and outside of the
outer sleeve 330 at the lower end. First, seal 337 seals the
interface between the outer sleeve 330 and the inner mandrel 340.
Second, seal 353 seals the annular area between the outer sleeve
330 and the fluid transfer channel housing 365. These seals 337,
353 assist in maintaining fluid within the annular feed channel 324
during the translation process. The seals 337, 353 are seen in
FIGS. 3 and 5.
[0061] The present invention is not limited in scope to any single
arrangement of seals. In this respect, various means are known for
providing a fluid seal between nested tubulars. Any sealing
arrangement may be utilized, so long as the reciprocation of the
rotor piston 357 within the fluid transfer chamber 348 is able to
draw oil in during a first stroke, and extrude oil during an
opposite second stroke. In the arrangement shown in FIGS. 3 and 5,
oil is drawn into the fluid transfer chamber 348 on the downstroke,
and extruded during the upstroke. Of course, the apparatus 300 can
also be configured to draw oil on the upstroke and to discharge on
the downstroke.
[0062] In operation, the positive displacement apparatus 300 of the
present invention is run into the wellbore 100 on the lower end of
the working string 170. As seen in FIG. 1, the positive
displacement apparatus 300 is connected to the expander tool 400 at
one end. In the arrangement shown in FIG. 1, the apparatus 300 is
connected to the bottom of the expander tool 400. However, it will
be appreciated that the positive displacement apparatus 300 will
also function if the positive displacement apparatus 300 is above
the expander tool 400. In this regard, the check valves 374, 372
and associated chamber 348 and channel 364 would be positioned
above the displacement piston 355.
[0063] 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 400 and the apparatus 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 hydraulically 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 400.
[0064] FIG. 8 depicts the wellbore of FIG. 1, in which the expander
tool 400 has been actuated. It can be seen that an initial portion
of the lower string of casing 120 has been expanded. As explained
above, actuation of the expander tool 400 is by injection of fluid
under pressure into the working string 170. Fluid travels from the
surface, down the working string 170, and through the bore 415 of
the expander tool 400.
[0065] FIG. 9 depicts the wellbore 100 of FIG. 8. In this view, the
expander tool 400 remains actuated. This allows the expander tool
400 to move within the expandable tube 120E relative to the running
tool collet 160. Also, in FIG. 9, the working string 170 has been
rotated so as to begin raising the expander tool 400 within the
expandable tubular 120E. As described above, rotation of the
working string 170 causes the displacement piston 355 and,
therewith, the expander tool 400 to be translated axially within
the wellbore 100. FIG. 9 thus demonstrates the expander tool 400
being raised within the expandable tubular 120E by actuation of the
positive displacement apparatus 300.
[0066] It is contemplated in FIG. 1 that rotation of the rotor
piston 357 and of the expander tool 400 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
rotary motor, such as a mud motor (not shown).
[0067] FIG. 10 depicts the wellbore 100 of FIG. 9. Here, the
actuated expander tool 400 has been raised further within the
wellbore 100 so as to expand the lower string of casing 120 into
the surrounding upper string of casing 110 along a desired length.
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 300 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, and
without raising or lowering the working string 170 from the surface
during expansion operations. It is understood, however, that the
working string 170 may optionally be raised and lowered while the
expander tool 400 is still actuated and after the initial expansion
has taken place, i.e., after the expander tool 400 has been
initially actuated. Using this procedure, the collet 160 would
first need to be released from the liner 120.
[0068] Following expansion operations, hydraulic pressure from the
surface is relieved, allowing the pistons 420 to return to the
recesses 414 within the body 402 of the tool 400. The expander tool
400 and the positive displacement apparatus 300 can then be
withdrawn from the wellbore 100 by pulling the run-in tubular 170.
FIG. 11 is a partial section view of the wellbore 100 of FIG. 10.
In this view, the expander tool 400 has been de-actuated and is
being removed from the wellbore 100 along with the positive
displacement apparatus 300. In addition, the collet 160 or other
releasable connection must be released from the liner 120, as shown
in FIG. 11.
[0069] In one procedure for utilizing the positive displacement
apparatus 300 of the present invention, the liner 120 is expanded
to its top end. However, the length of expansion is discretionary.
An upper non-expanded portion 120S of the liner 120 can be severed
after a portion 120E is expanded. The severed portion 120S of the
lower string of casing 120 above the expander tool 400 must then be
removed from the wellbore 100. To accomplish this, typical casing
severance operations may be conducted. This would be done via a
subsequent trip into the wellbore 100. However, as an alternative
shown in FIG. 11, the severed portion 120S of the lower string of
casing 120 may be removed from the wellbore 100 at the same time as
the expander tool 400 after the collet 160 has been released from
the liner 120. In order to employ this method, a novel scribe 130
is formed on the outer surface of the lower string of casing
120.
[0070] An enlarged view of the scribe 130 in one embodiment is
shown in FIG. 2. The scribe 130 defines a cut made into the outer
surface of the lower string of casing 120. The scribe 130 is
preferably placed around the casing 120 circumferentially. The
depth of the scribe 130 needed to cause the break is dependent upon
a variety of factors, including the tensile strength of the
tubular, the overall deflection of the material as it is expanded,
the profile of the cut, and the weight of the tubular being hung.
The scribe 130 must be shallow enough that the tensile strength of
the tubular 120 supports the weight below the scribe 130 during
run-in. The arrangement shown in FIG. 2 employs a single scribe 130
having a V-shaped profile so as to impart a high stress
concentration onto the casing wall. However, other profiles may be
employed.
[0071] The scribe 130 creates an area of structural weakness within
the lower casing string 120. When the lower string of casing 120 is
expanded at the depth of the scribe 130, the lower string of casing
120 is cleanly severed. The severed portion 120U of the lower
casing string 120 can then be easily removed from the wellbore 100.
Thus, the scribe 130 may serve as a release mechanism for the lower
casing string 120. Other means for severing the tubular 120 upon
expansion may be developed as well.
[0072] In order to remove the severed portion 120S of the lower
string of casing 120 from the wellbore 100, a second connection
must be provided with the severed portion of the lower string of
casing 120. In the arrangement of FIGS. 8-11, a releasable
connector 124 is shown. The connector 124 is demonstrated as a
collet 124 to be landed into a radial profile 125 within the lower
string of casing 120. The collet 124 is mechanically or
pneumatically actuated as is known in the art, and supports the
severed portion 120S of the lower string of casing 120 while the
apparatus 300 and the expander tool 400 are being removed from the
wellbore 100. Removal of the working string 170 with the expander
tool 400 brings with it the severed portion 120S of the lower
casing string 120. It is, of course, understood that other means
may be employed for removing a non-expanded upper portion of liner
120, and that the arrangement shown in FIGS. 8-11 is purely
exemplary.
[0073] FIG. 12 is a partial section view of the wellbore 100 of
FIG. 11. In this view, the positive displacement apparatus 300 of
the present invention and the expander tool 400 have been removed.
It can be seen that the expandable portion 120E of the lower string
of casing 120 has been expanded into frictional and sealing
engagement with the upper string of casing 110. The seal member 222
and the slip member 224 are engaged to 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 optionally filled with cement, excepting that portion of the
annulus which has been removed by expansion of the lower string of
casing 120E.
[0074] As a further aid in the expansion of the lower casing string
120, a torque anchor 200 may optionally be utilized. The torque
anchor 200 serves to prevent rotation of the stator 210 during the
expansion process. The torque anchor 200 shown in FIG. 1 includes
radially extendable cleating mechanism 240 for engaging the inner
surface of the casing 110. The torque anchor 200 is actuated during
initial expansion of the expandable portion 120E of the liner 120.
The torque anchor 200 may be released after initial expansion, as
shown in FIG. 11.
[0075] 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.
* * * * *