US20040055786A1

US20040055786A1 - Positive displacement apparatus for selectively translating expander tool downhole

Info

Publication number: US20040055786A1
Application number: US10/253,114
Authority: US
Inventors: Patrick Maguire; Khai Tran
Original assignee: Weatherford Lamb Inc
Current assignee: Weatherford Lamb Inc
Priority date: 2002-09-24
Filing date: 2002-09-24
Publication date: 2004-03-25

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.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

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.

2. Description of the Related Art

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.

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.

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.

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.

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.

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.

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.

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.

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.

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

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.

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.

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.

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

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. [0018]
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. [0019]
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. [0020]
FIG. 3 is an enlarged view of the fluid transfer chamber in an exemplary positive displacement apparatus of the present invention. [0021]
FIG. 4 is a cross-sectional view of a positive displacement apparatus of the present invention, taken across line [0022] 4-4 of FIG. 1.
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. [0023]
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. [0024]
FIG. 7 presents a portion of the expander tool of FIG. 5 in cross-section, with the view taken across line [0025] 7-7 of FIG. 6.
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. [0026]
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. [0027]
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. [0028]
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. [0029]
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.[0030]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 1 presents a cross-sectional view of a [0031] 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.
In the example of FIG. 1, the lower string of [0032] 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.
A sealing [0033] 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.
The sealing [0034] 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.
Also positioned on the outer surface of the lower string of [0035] 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.
In order to expand the lower string of [0036] 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.
The [0037] 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.
It is understood that the [0038] 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.
Disposed within each [0039] 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.
The [0040] 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.
The [0041] 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.
In order to actuate the [0042] 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.
In the arrangement of FIG. 1, the lower end of the [0043] 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.
In the arrangement shown in FIG. 1, the [0044] 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.
FIG. 4 is a cross-sectional view of a [0045] 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.
Each of the three [0046] 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.
In order to impart rotation to the [0047] 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.
A [0048] 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.
The [0049] 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.
As shown in FIG. 3, more than one check valve is employed for the [0050] 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.
The arrangement of FIG. 3 also presents a [0051] 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.
A means is needed to draw oil from the [0052] 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.
As seen in FIG. 1, a lower portion of the [0053] 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″.
Fixed between the [0054] 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.
The [0055] 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.
As noted, the [0056] 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.
A biasing [0057] 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.
FIG. 5 presents a cross-sectional view of the [0058] 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.
In order to effectuate the transfer of oil from the [0059] 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.
Seals are additionally positioned inside and outside of the [0060] 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.
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 [0061] 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.
In operation, the [0062] 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.
In order to accomplish the expansion operation in a single trip, the working [0063] 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.
FIG. 8 depicts the wellbore of FIG. 1, in which the [0064] 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.
FIG. 9 depicts the [0065] 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.
It is contemplated in FIG. 1 that rotation of the [0066] 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).
FIG. 10 depicts the [0067] 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.
Following expansion operations, hydraulic pressure from the surface is relieved, allowing the [0068] 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.
In one procedure for utilizing the [0069] 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.
An enlarged view of the [0070] 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.
The [0071] 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.
In order to remove the severed [0072] 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.
FIG. 12 is a partial section view of the [0073] 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.
As a further aid in the expansion of the [0074] 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.
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. [0075]

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 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 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

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 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

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:

wherein the fluid medium is loaded in an annular region defined between the expandable liner string and the outer sleeve.