An expansion system is assembled by coupling a piston assembly and a solid cone assembly to an adjustable cone assembly within an expandable tubular having inner sleeve disposed in a portion thereof. The expansion system is run into a wellbore. The piston assembly is activated to move the solid cone assembly downward through the inner sleeve so as to expand the inner sleeve and the portion of the expandable tubular having the inner sleeve. The adjustable cone assembly is shifted from a retracted position to an expansion position within the inner sleeve. The adjustable cone assembly is moved upward through expandable tubular while leaving the solid cone assembly and the inner sleeve coupled to expandable tubular. The solid cone assembly and the inner sleeve may be drilled or milled.

BACKGROUND

This disclosure relates generally to methods and apparatus for drilling a wellbore. More specifically, this disclosure relates to methods and apparatus for installing an expandable tubular that has, after expansion, essentially the same diameter as a previous base casing.

In the oil and gas industry, expandable tubulars are often used for casing, liners and the like. To create a casing, for example, an expandable tubular is installed in a wellbore and subsequently expanded by displacing an expansion cone through the expandable tubular. The expansion cone may be pushed or pulled using mechanical means, such as by a support tubular coupled thereto, or driven by hydraulic pressure. As the expansion cone is displaced axially within the expandable tubular, the expansion cone imparts radial force to the inner surface of the expandable tubular. In response to the radial force, the expandable tubular is plastically deformed, thereby permanently increasing both its inner and outer diameters. In other words, the expandable tubular expands radially.

Expandable tubulars often include a shoe assembly coupled to the lower end of the tubular that enables cementing operations to be performed through the expandable tubular. Once the expandable tubular is installed, the shoe assembly has to be removed to allow drilling to continue. This is often accomplished by milling or drilling out the shoe assembly. The shoe assembly may be constructed from composite materials, cast iron, or other materials that simplify the removal of the shoe assembly.

In certain expandable tubular applications, a portion of the expandable tubular adjacent to the shoe assembly is left unexpanded while the tubular above that portion is expanded. The unexpanded portion creates a diametrical constriction that must also be removed before drilling ahead. Removing both the unexpanded portion and the shoe assembly has conventionally involved multiple trips into the wellbore for milling and fishing, or the utilization of complex tools that may be prone to malfunction.

Thus, there is a continuing need in the art for methods and apparatus for providing a shoe assembly that reduces the time needed to prepare the wellbore prior to restarting drilling operations.

SUMMARY OF THE DISCLOSURE

In one or more aspects, the present disclosure relates to an expansion system comprising an adjustable cone assembly having a plurality of cone segments slidably coupled to a mandrel. The expansion system further comprises a solid cone assembly coupled to the mandrel and a piston assembly coupled to the mandrel. The adjustable cone assembly is disposed between the piston assembly and the solid cone assembly. The expansion system further comprises an expandable tubular disposed about the adjustable cone assembly, the solid cone assembly, and the piston assembly. The expansion system further comprises an inner sleeve disposed within the expandable tubular adjacent to one end of the expandable tubular.

In some example, the adjustable cone assembly may have a retracted position wherein the cone segments have an expansion diameter less than an unexpanded inner diameter of the expandable tubular and an expansion position wherein the cone segments have an expansion diameter greater than the unexpanded inner diameter of the expandable tubular. The adjustable cone assembly may be shifted from the retracted position to the expansion position by moving the mandrel axially relative to the plurality of cone segments. The mandrel may include a bore having a seal seat therein. The adjustable cone assembly may further include a cone lock that limits axial movement of the plurality of cone segments relative to the expandable tubular. The solid cone assembly may be formed from a drillable material. The expansion system may further comprise a plurality of longitudinal slots formed in a portion of the solid cone assembly. The expansion system may further comprise a plurality of longitudinal slots formed in a portion of the inner sleeve. The expansion system may further comprise a locking member that selectively couples the solid cone assembly to the one end of the expandable tubular. The locking member may be located above a maximum expansion diameter of the solid cone assembly. The expansion system may further comprise a seal member coupled to the solid cone assembly which forms a seal between the solid cone assembly and the inner sleeve after expansion of the expandable tubular and may also form a seal between the solid cone assembly and expandable tubular before expansion. The piston assembly may be configured so that working fluid supplied to the piston assembly creates an axial force that moves the mandrel downward. A portion of the solid cone assembly may be disposed within the inner sleeve. The inner sleeve may comprise a castellation for engaging the solid cone assembly. The inner sleeve may comprise a segmented ring adjacent the one end of the expandable tubular. The inner sleeve may comprise a threaded portion including retaining threads engaging complementary retaining thread on the expandable tubular. The inner sleeve may comprise an inwardly tapered portion adjacent the one end of the expandable tubular.

In one or more aspects, the present disclosure relates to a method involving assembling an expansion system by coupling a piston assembly and a solid cone assembly to an adjustable cone assembly within an expandable tubular having inner sleeve disposed in a portion thereof. The method further involves running the expansion system into a wellbore, and activating the piston assembly to move the solid cone assembly downward through the inner sleeve so as to expand the inner sleeve and the portion of the expandable tubular having the inner sleeve. The method further involves shifting the adjustable cone assembly from a retracted position to an expansion position within the inner sleeve, and moving the adjustable cone assembly upward through expandable tubular while leaving the solid cone assembly and the inner sleeve coupled to expandable tubular.

In some examples, the piston assembly may be activated by dropping an actuation member into engagement with a seal seat within the solid cone assembly. The expansion system may include a casing lock that selective locks the piston assembly to the expandable tubular, and the casing lock may be disengaged before the adjustable cone assembly is shifted from the retracted position to the expansion position. The expansion system may include a cone lock that selectively limits the axial movement of the adjustable cone assembly relative to the expandable tubular, and the cone lock may be disengaged once the adjustable cone has been shifted from the retracted position to the expansion position. The adjustable cone assembly may be shifted from the retracted position to the expansion position within the inner sleeve by moving a mandrel relative to cone segments of the adjustable cone assembly.

DETAILED DESCRIPTION

Referring initially toFIG. 1, an expansion system10includes a solid cone assembly20, an adjustable cone assembly30, and an actuator assembly40. In general, the solid cone assembly20is configured to move downward to expand a lower portion of an expandable tubular14. Once the solid cone assembly20has expanded the lower portion of the expandable tubular14, the adjustable cone assembly30is configured to move upward and expand the remainder of the expandable tubular14. The configuration and sequential operation of the solid cone assembly20and the adjustable cone assembly30allow for the expansion system10to have a minimal external diameter prior to expansion and simplifies drill out of the portions of the assembly that remain in the wellbore following expansion.

FIG. 1illustrates the expansion assembly10in an assembled, or running, mode in which the expansion system10is coupled to a work string12and disposed within an expandable tubular14. A shoe18is coupled to the lower end of the expandable tubular14. A receptacle, for example an inner sleeve16, extends upward into the expandable tubular14from the shoe18. In certain embodiments, the expandable tubular14may have a uniform outer diameter and thickness along its entire length. In some embodiments, the lower end of the expandable tubular14may include a launcher portion15that has larger inner and outer diameters than the expandable tubular14. The inner sleeve16and the shoe18may be constructed from drillable materials such as aluminum, brass, bronze, cast iron or other low strength steel, composites such as filament wound plastics, or other drillable materials.

The solid cone assembly20forms the lower portion of the expansion system10and includes a solid expansion cone102. The solid expansion cone102has an expansion surface103that is oriented downward and has an expansion diameter that is larger than the unexpanded inner diameter of the inner sleeve16but smaller than the unexpanded inner diameter of the expandable tubular14. One or more locking members104are coupled to a lower end of the solid expansion cone. The solid cone assembly20includes a seal member106that sealingly engages the expandable tubular14, and/or the inner sleeve16after expansion. The solid cone assembly20also includes an axial bore108with a seal seat110that allows fluid to pass through the solid cone assembly20.

Adjustable cone assembly30includes an adjustable cone112, a mandrel114, and a cone lock116. In certain embodiments, the adjustable cone112includes a plurality of primary segments118that are coupled to the mandrel114and a plurality of secondary segments120that are disposed adjacent to the primary segments118. The secondary segments120are axially translatable relative to the mandrel114and the primary segments118. The mandrel114includes an axial bore122that is fluidically coupled to the axial bore108of the solid cone assembly20.

Actuator assembly40includes a seal124, a casing lock126, and hydraulic piston assemblies128. Seal124sealingly engages the expandable tubular14. Casing lock126is coupled to the hydraulic piston assemblies128and selectively engages the expandable tubular14so as to axially couple the expansion system10to the expandable tubular14. Hydraulic piston assemblies128include one or more pistons that are coupled to the mandrel114so that working fluid supplied to the hydraulic piston assemblies128creates an axial force that moves the mandrel114.

The operation of expansion system10is illustrated inFIGS. 2A-2D.FIG. 1shows the expansion system10in a running configuration that is used when running the expansion system to a desired location in a wellbore (not shown). In the running position, working fluid can be pumped from the drilling rig through the work string12, axial bore122of the mandrel114, axial bore108of the adjustable cone assembly30, and through shoe18. When the expansion system10is in the proper location for installation, an actuation member130(such as a dart or a ball), is inserted into, and pumped through, the work string12until it engages seal seat110, as is shown inFIG. 2A.

As shown inFIG. 2A, once actuation member130engages seal seat110, fluid from the work string12is redirected to the hydraulic piston assemblies128. The hydraulic piston assemblies128generate an axial force on mandrel114that pushes the solid cone assembly20downward through the inner sleeve16, causing the radial expansion of both the inner sleeve16and the expandable tubular14, as shown inFIG. 2B. During this expansion, the casing lock126is engaged with the expandable tubular14, preventing axial movement of the expandable tubular14relative to the expansion system10. The solid cone assembly20will move downward expanding the inner sleeve16and expandable tubular14until the hydraulic piston assemblies128fully actuate, at which time the locking members104of the solid cone assembly20engage the shoe18. The final position of the solid cone assembly20is controlled by the stroke length of the hydraulic piston assemblies128. The length of the shoe18may be matched with the stroke length of the hydraulic piston assemblies128. So when the piston bottoms out after the complete stroke length, the shoe18may be fully expanded and the solid cone assembly20may be locked in place.

Towards the end of the top-down expansion, casing lock126disengages from the expandable tubular14., and the hydraulic piston assemblies128may bottom out on an internal shoulder (in an end of stroke position). As shown inFIG. 2B, the portion of the expandable tubular14adjacent to the shoe18is fully expanded and the seal member106is sealingly engaged with the now expanded portion of the expandable tubular14. With locking members104engaged with the shoe18, further movement of the solid cone assembly20is prevented. Further supply of working fluid through work string12and increasing pressure within the mandrel114will cause a port (not shown) to open and allow working fluid to enter region of the expandable tubular14between the seal124and the seal member106. As the pressure within this region increases, the mandrel114will separate from the solid cone assembly20and begin moving upward relative to the expandable tubular14.

As the mandrel114begins moving, the cone lock116remains engaged with the expandable tubular14, thus maintaining the axial position of the secondary segments120relative to the expandable tubular14. As the mandrel114moves, the primary segments118, being coupled to the mandrel114, move upward and engage the secondary segments120. This engagement pushes the secondary segments120outward until the adjustable cone assembly30reaches its full expansion diameter, as is shown inFIG. 2C. Once the adjustable cone assembly30has reached its full expansion diameter, cone lock116disengages the expandable tubular14and locks the secondary segments120in place.

As shown inFIG. 2D, continued supply of working fluid through the work string12will push the adjustable cone assembly30upward, radially expanding the expandable tubular14. This expansion may continue until the expandable tubular14is entirely expanded. In certain embodiments, mandrel114includes a seal seat132that can accept a seal member134(such as a ball or dart) that will prevent working fluid from passing through the mandrel114. Once the mandrel is blocked, continued supply of working fluid to the mandrel114will move the mandrel114downward and move the primary segments118out of engagement with the secondary segments120, thus allowing the adjustable cone assembly30to reduce its expansion diameter. This reduction in expansion diameter may allow for the adjustable cone assembly30to be pulled axially through an unexpanded portion of the expandable tubular14.

Referring now toFIGS. 3 and 4A, an expansion system300includes a solid cone assembly302, an adjustable cone assembly304, and a hydraulic actuator assembly (not shown). The expansion system300is disposed within an expandable tubular306that is coupled to a lower shoe308. A receptacle, for example an inner sleeve310is disposed within the expandable tubular306proximate the lower shoe308. The solid cone assembly302includes an expansion cone312, seal members314, and locking members316. The adjustable cone assembly304includes adjustable cone segments318mounted on a mandrel328and a cone lock320. The expansion system300also includes a seal322above the adjustable cone assembly304.

Referring now toFIG. 4B, a dart324has been dropped into a seal seat326near the top of the solid cone assembly302. The dart324blocks the flow of working fluid through the expansion system300and initiates activation of the hydraulic actuator assembly (not shown) that applies an axial force that moves the solid cone assembly302and the adjustable cone assembly304downward relative to the expandable tubular306. For example, the hydraulic actuator assembly includes one or more pistons that are coupled to the mandrel426so that working fluid supplied to the hydraulic actuator assembly creates an axial force that moves the mandrel426. As the solid cone assembly302moves downward, the expansion cone312radially expands the inner sleeve310and the expandable tubular306.

The solid cone assembly302and adjustable cone assembly304continue moving downward until the locking members316of the solid cone assembly302engage the lower shoe308. Once the solid cone assembly302is locked to the lower shoe308, the mandrel328of the adjustable cone assembly304moves upward relative to the adjustable cone segments318, which pushes the adjustable cone segments318outward to their full expansion diameter. In the full expansion diameter, the adjustable cone assembly304continues to move upward, through hydraulic force or by pulling on the mandrel328, and radially expands the expandable tubular306.

In certain embodiments, the inner sleeve310includes a plurality of longitudinal slots330that reduce the forces needed to radially expand that section of the inner sleeve310and allow for a more complete drill out once expansion is complete. Referring back toFIG. 4B, it can be seen that the adjustable cone segments318are moved outward along the mandrel328while still disposed within the inner sleeve310. Therefore, once the adjustable cone assembly304is adjusted to its full expansion diameter, the expandable tubular306will be “over-expanded” to an inner diameter equal to the expansion diameter of the adjustable cone assembly304plus twice the thickness of the inner sleeve310. In contrast, the portions of the expandable tubular306above the inner sleeve310and below the location at which the adjustable cone assembly304is adjusted will only be expanded to an inner diameter equal to the full expansion diameter of the adjustable cone assembly304.

In certain embodiments, this may cause an issue when the solid cone assembly302and lower shoe308are drilled out of the installed expandable tubular306as the tools used for this process may not fully engage the inner wall of the “over-expanded” portion of the expandable tubular306. The slots330may be configured so as to span the entire length of the “over-expanded” portion of the expandable tubular306so that, once the remainder of the inner sleeve310is removed, the slotted portion will simply fall away from the expandable tubular306.

Referring now toFIG. 5, one embodiment of a solid cone assembly500includes a cone body502, upward-facing cup seal504, downward-facing cup seal506, and locking members508. The cone body502includes a bore510having a seal seat512. A flapper valve514and shear tube516may also be disposed within the cone body502.

Before cementing operations, a ball is dropped to sealingly engage the shear tube516. Differential pressure acting across the ball then breaks the shear tube516so that the shear tube falls out of the flapper valve514and allows the flapper518to close, preventing flow back into the bore510from the surrounding wellbore. Downward-facing cup seal506provides a seal between the solid cone assembly500and a surrounding tubular member, such as the expandable tubular14ofFIG. 1, that prevents cement slurry from flowing around the outside of the solid cone assembly500.

Cone body502may be constructed from an easily drillable or millable material such as aluminum, brass, bronze, cast iron or other low strength steel, or a composite material such as filament wound plastics. Cone body502also includes an expansion surface519that gradually increases in outer diameter from its leading edge520to a maximum expansion diameter522. In certain embodiments, a plurality of longitudinal slots524may be formed through a portion of the cone body502to make later removal of the cone body502easier. Locking members508may include biasing members526that urge the locking members508outward.

In certain embodiments, the expansion surface519may have two distinct profiles. As shown inFIGS. 6 and 7, a cone body502may have a circular expansion profile528, which has a circular cross-section, and a faceted expansion profile530which has one or more facets532formed on the expansion surface519. The circular expansion profile528may be formed on a first portion of the expansion surface519. The faceted expansion profile530may be formed on a second portion of the expansion surface519that is located between the leading edge520of the expansion surface519and the portion. When in the pre-expansion running position, as shown inFIG. 7, the faceted expansion profile530may be disposed in a receptacle of the expandable tubular, for example in the upper end of the inner sleeve534. As can be seen inFIG. 7A, the inner sleeve534may be formed to have an inner profile536with flat sections538that correspond to the facets532. In this manner, the cone body502is rotationally locked to the inner sleeve534. Alternatively, the cone body502and the faceted expansion profile530may be pushed into the receptacle of the expandable and may deform it to generate an inner profile with flat sections that correspond to the facets of the cone body502.

The inner sleeve534may be effectively locked to the expandable tubular14, for example with an adhesive between the inner sleeve534and the expandable tubular14, and/or with retaining threads on the inner sleeve534engaging complementary retaining thread on the expandable tubular14. This rotational lock facilitates the milling or drilling of at least the upper part of the cone body502, the lower part disintegrating in small debris separated by the plurality of longitudinal slots524. In addition, a torque transfer ring on the adjustable cone assembly304allows for torque to be transmitted from the work string into the expandable tubular14and allows for rotation of the expandable tubular14while the tubular is being run into a wellbore.

Referring now toFIGS. 8 and 9, one embodiment of an adjustable cone assembly200includes a plurality of cone segments202that are slidably coupled to a mandrel204. The cone segments202include three primary cone segments206that are interleaved with three secondary cone segments208. Slots210on the primary cone segments206engage with tabs212on the secondary cone segments208to maintain alignment and limit axial offset between the cone segments202. Mandrel204also includes guide rails213that engage and align the primary cone segments206with the mandrel. The secondary cone segments208include retention tabs215that engage with a housing (not shown) that limits the axial travel of the secondary cone segments208.

The adjustable cone assembly200has a retracted position that is shown inFIGS. 8 and 8Ain which the secondary cone segments208are axially offset from the primary cone segments206. The adjustable cone assembly200can be disposed within an expandable tubular214and run into a wellbore in the retracted position. The adjustable cone assembly200is transitioned to an expansion position ofFIGS. 9 and 9Aby axially translating the mandrel204relative to the cone segments202.

As transition of the adjustable cone assembly200is initiated, the cone segments202are held in a substantially stationary axial position by engagement of the secondary cone segments208with the housing (not shown) and the contact between the primary cone segments206and the inner diameter of the expandable tubular214. The relative axial translation of the mandrel204causes the primary cone segments206to move radially outward and expand the expandable tubular214. Continued movement of the mandrel204causes the secondary cone segments208to move radially outward and expand the expandable tubular214into a circular cross-sectional shape. Once adjustable cone assembly200has fully transitioned to an expansion position, the cone segments202form an expansion cone that can be translated through and radially expand an extended length of the expandable tubular214. In certain embodiments, guide rails213and the primary cone segments206are configured so that the movement of the mandrel204in the opposite direction can also transition the assembly200from the expansion position back to the retracted position.

Turning now toFIGS. 10A and 10B, an expansion system400includes a solid cone assembly402, an adjustable cone assembly404, and a hydraulic actuator assembly (not shown). The expansion system400is disposed within an expandable tubular406. A shoe408including a nose is coupled to a lower end of the expandable tubular406. A receptacle, for example an inner sleeve410is disposed within the expandable tubular406at the shoe408. The solid cone assembly402includes a cone body416, seal members418, and locking members420. The cone body416includes an expansion surface that gradually increases in outer diameter from its leading edge to a maximum expansion diameter. The adjustable cone assembly404includes adjustable cone segments424mounted on a mandrel426, which, in certain embodiments, may be similar to the primary cone segments206and secondary cone segments208shown inFIGS. 8 and 9. The expansion system400may also include a seal (not shown) above the adjustable cone assembly404to provide hydraulic force to move the adjustable cone assembly upward and radially expands the expandable tubular406.

In the example ofFIGS. 10A and 10B, the solid cone assembly402includes a castellation422having faces configured to engage corresponding faces of a castellation434provided on the inner sleeve410. The castellation422may be located below the leading edge of the expansion surface of the cone body416. When engaged, the castellations422and434provide a rotational lock between the solid cone assembly402and the inner sleeve410. This rotational lock facilitates the milling or drilling of the cone body416. The solid cone assembly may also include locking members420that, in the example shown inFIGS. 10A and 10B, are located above the maximum diameter of the cone body416. As such, the amount of material of the shoe408that is not drilled and may fall into the wellbore is reduced. The locking members may include a plurality of dogs expanding into groove located in the shoe408. The dogs may include spring loaded cone segments that expand radially at an acute angle relative to the shoe inner surface.

In certain embodiments, the inner sleeve410includes a plurality of longitudinal slots432that reduce the forces needed to radially expand that section of the inner sleeve410and allow for a more complete drill out once expansion is complete. The slots432may be configured so that, once the remainder of the inner sleeve410is removed by drilling, the slotted portion will simply fall away from the expandable tubular406. The inner sleeve410may further be effectively locked to the expandable tubular406, for example via a threaded portion440including retaining threads on the inner sleeve410engaging complementary retaining thread on the expandable tubular406. The threads may be configured to prevent parts of the inner sleeve410from falling in the wellbore as the inner sleeve410is milled after expansion of the expandable tubular406. In other words, the retaining threads may be used to retain the slotted portion of the inner sleeve410against the expandable tubular406as long as possible during drilling so as to minimize the size of debris falling away from the expandable tubular406. The inner surface of the expandable tubular406may further include a corresponding threaded portion that engages the threaded portion440of the inner sleeve410.

The inner sleeve410may further include a segmented ring436located adjacent to bottom end of the expandable tubular406. The segmented ring436may permit uniform expansion of the expandable tubular406down to the bottom of the expandable tubular406by providing radial support to expand the expandable tubular406while reducing hoop stress. The inner sleeve410may further include a inwardly tapered portion442located adjacent to bottom end of the expandable tubular406, and adjacent to the segmented ring436. The tapered portion442may also permit uniform expansion of the expandable tubular406down to the bottom of the expandable tubular406while keeping the solid cone assembly402locked within an interior of the expandable tubular406where it can be milled after expansion of the expandable tubular.

In use, a dart (no shown) is dropped into a seal seat430near the top of the solid cone assembly402. The dart blocks the flow of working fluid through passageway428in the expansion system400and initiates activation of the hydraulic actuator assembly (not shown) that applies an axial force that moves the solid cone assembly402and the adjustable cone assembly404downward relative to the expandable tubular406. For example, the hydraulic actuator assembly includes one or more pistons that are coupled to the mandrel426so that working fluid supplied to the hydraulic actuator assembly creates an axial force that moves the mandrel426. As the solid cone assembly402moves downward, the cone body416radially expands the inner sleeve410and the expandable tubular406, as illustrated inFIG. 10A.

The solid cone assembly402and adjustable cone assembly404continue moving downward until the locking members420of the solid cone assembly402engage a groove438located in shoe408as illustrated inFIG. 10B. At the end top-down expansion, the engagement of the locking members420and the shoe408prevents further upward movement of the solid cone assembly20. Also, the solid cone assembly402may abut a wall section on the inner sleeve410that may by sufficiently thick so that the expansion forces are sufficiently high to prevent further downward movement of the solid cone assembly402. Once the solid cone assembly402is locked to the shoe408, the mandrel426of the adjustable cone assembly404moves upward relative to the adjustable cone segments424, which deploys the adjustable cone segments424outward to their full expansion diameter. In the full expansion diameter, the adjustable cone assembly404continues to move upward, through hydraulic force or by pulling on the mandrel426, and radially expands the expandable tubular406.

While the disclosure is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and description. It should be understood, however, that the drawings and detailed description thereto are not intended to limit the disclosure to the particular form disclosed, but on the contrary, the intention is to cover all modifications, equivalents and alternatives falling within the spirit and scope of the present disclosure.