Patent Application
20170198558
Field of the Invention
The present invention relates to an expansion tool and method for expanding the diameter of an expandable tubular liner disposed within a targeted interval of a bore of a casing in an earthen well. More specifically, the present invention relates to an expansion tool and a method to expand an expandable tubular liner along its full length. The expansion tool and method of the present invention provide for an improved installation of an expandable liner to seal with the casing without the necessity and expense of recovering a residual and/or non-expanded portion of the tubular liner from the well to prevent well obstruction. The present invention further relates to an expansion tool and a method for positioning and then restraining the expandable liner within the targeted installation interval of the casing during a stepwise or staged expansion of the liner to engage and seal the targeted interval of the casing.
Background of the Related Art
Various tools and methods have been devised for expanding a tubular disposed in an earthen well including, but not limited to, those disclosed in U.S. Pat. Nos. 7,225,880, 7,278,492 and 8,132,627. Some tools are intended to provide a tubular patch in a well, as disclosed in U.S. Pat. Nos. 6,622,788, 6,763,893 and 6,814,143.
An expandable tubular liner used for lining a targeted interval of a well casing may be installed within a casing to provide added structural and/or sealing integrity to an unstable or leaking interval of a casing. An expandable liner may be installed in a targeted interval of casing to isolate a previously perforated, leaking or otherwise open interval of the casing to prevent fluid exchange between the well and one or more adjacent geologic formations penetrated by the well.
Expandable liners may be installed within a targeted interval of a well casing by running an undersized (unexpanded) liner into the targeted interval of the well casing and radially outwardly expanding the liner in-situ. Conventional liner expansion tools include a pulling mandrel that pulls an expander, larger in diameter than the unexpanded liner, from a distal (downhole) end of the liner towards a proximal (uphole) end of the liner. Other liner expansion tools include pushing a mandrel that pushes a connected expander from a proximal end of the liner towards a distal end of the liner. Still other expansion tools rely on hydraulic pressure to generate a force sufficient to displace an expander through the bore of a liner without the use of a mandrel to pull or push the expander.
The liner material and the liner dimensions are generally selected to yield radially outwardly as the expander is moved through the bore to radially expand the liner and to engage the expanded liner with the bore of the targeted casing interval without rupture. The elastic limit of the liner material is exceeded to produce plastic deformation of the liner and to cause the liner to retain an expanded diameter engaged with the bore of the casing. It will be understood that the liner may be expanded slightly beyond the intended diameter in order to elastically resist a residual collapsing force applied by the casing after the expander passes. This mode of installation is optimal for improving the sealing integrity between the exterior surface of the expanded liner and the interior bore of the casing.
Some conventional expansion tools and method involve pulling or pushing the expander through the bore of the expandable liner by engaging the expander on a distal end of an elongate mandrel that is slidably received through a bore of a housing. The mandrel may be hydraulically displaced within the housing to pull the expander into and then through the bore of a liner disposed axially intermediate an expander, connected at the distal end of the mandrel, and a reaction assembly on the expansion tool to oppose movement of the liner during expansion. The expansion tool may be secured or coupled within the casing using a gripping device. The housing and the mandrel may each include a variety of additional features including, but not limited to, annular pistons, annular chambers, connectors, fittings, ball seats and apertures.
A shortcoming of conventional liner expansion tools is that if the slips of the tool are set within the bore of the expandable liner, and if the expandable liner is expanded beginning at an end of the expandable liner that is spaced apart from the portion of the expandable liner in which the slips are set to secure the expandable liner in position, the slips must be eventually displaced from the bore of the liner. This presents a problem because the expandable liner cannot be secured in position for expansion of the full length of the expandable liner, and a portion of the expandable liner will remain in the unexpanded condition. The unexpanded portion may require an additional trip into the well to retrieve the unexpanded portion of the liner.
Those skilled in the metallurgical arts will understand that a metal liner that is radially outwardly expanded to a larger diameter exhibits a predictable amount of axial shrinkage. As the diameter of the liner is expanded, the wall thickness of the liner is substantially reduced and the length of the liner shortens to compensate. This shrinkage may complicate the liner expansion process where slips are set in the bore of the casing above the top of the expandable liner and are used to secure the liner in position against the expander. Shrinkage of the liner may cause unwanted movement or shifting of an expanded portion of the liner within the casing if the reaction assembly cannot be favorably repositioned to compensate for axial shrinkage of the liner, thereby compromising the sealing integrity of the expanded liner. Conventional expansion tools that grip the bore of the expandable liner during liner expansion include reaction assemblies that remain in a fixed position within the liner during liner expansion, resulting in a loss of sealing integrity between the expanded liner and the casing due to the axial shrinkage that occurs during expansion of the liner bore.
The disadvantages of the prior art are overcome by the present invention, an improved downhole tubular expander and method are herein disclosed.
An expandable liner provides optimal structural and sealing integrity if it is radially expanded along its full length to radially engage the bore of a targeted interval of casing, and if expanded portions of the liner remain engaged with the wall of the casing as the remaining length of the liner is thereafter expanded. An expandable liner provides improved structural and sealing integrity if the expansion tool is adapted to self-adjust to prevent shifting or movement of a partially-expanded portion of the liner within the targeted interval of the casing. This occurs when slips are set in the casing in which the expandable liner is being expanded as the expansion tool is repeatedly stroked to expand an interval of the expandable liner, and then re-cocked prior to each subsequent stroke that is needed until the entire expandable liner is expanded in the casing. It will be understood that, at some point during the expansion process, enough of the expandable liner will be expanded so that sufficient frictional engagement between the expanded portion of the expandable liner and the casing prevents movement of the expandable liner during expansion of the remaining, unexpanded portion. When this threshold is achieved, the remaining, unexpanded portion of the expandable liner may be expanded by using the draw works on the rig to pull the expansion tool in the uphole direction, thereby causing the expander to move through the bore of the expandable liner until the entire expandable liner is expanded. However, in the event that a tight spot requires an excessive amount of force to applied to the tubular string by the draw works, the draw works can be stopped and the tubular string can be again pressurized to stroke the hydraulic section of the expansion tool to hydraulically move the expander within the bore of the expandable liner without placing too much stress on the draw works. After the tight spot is expanded, the draw works may then be re-engaged to resume expansion.
Embodiments of the expansion tool and method of the present invention employ slips that are sized and adapted to be set within the casing in which the expandable liner is to be expanded and installed. This enables the expansion tool to retain radially expanded portions of a partially-expanded liner in position within the casing and to prevent unwanted shifting or sliding of a partially expanded portion of the expandable liner within the casing during the expansion process. Embodiments of the expansion tool of the present invention engage an unexpanded proximal end of the liner with a self-adjusting reaction assembly that is coupled to a slip cage that is, in turn, coupled to a housing of the expansion tool. The self-adjusting reaction assembly engages the proximal end of the expandable liner to oppose an axial displacing force applied by movement of the expander into and through the distal end of the bore of the expandable liner that is the first portion of the expandable liner to be expanded. The reaction assembly self-adjusts to enable re-cocking of the expansion tool for stepwise or staged expansion of the liner starting from the distal end and progressing stepwise to the proximal end. A portion of the self-adjusting ratcheting reaction assembly called a ratcheting component is eventually detached from the proximal end of the bore of the expandable liner before the expander exits the bore of the fully expanded liner.
One embodiment of the expansion tool and method of the present invention provides an expansion tool that uses a self-adjusting ratcheting reaction assembly to secure an unexpanded liner in a run-in configuration on the expansion tool. The expansion tool receives and secures the expandable liner to the expansion tool in a run-in configuration at the surface. The expandable liner is received onto the expansion tool to engage the ratcheting component of the self-adjusting ratcheting reaction assembly with a proximal end of the expandable liner and to surround a substantial portion of the elongate ratchet rack extending distally to the original starting position of a ratcheting component movably received on the exterior of the ratchet rack through which the pulling mandrel passes. The expander is then connected to a distal end of the pulling mandrel to axially capture the unexpanded liner on the expansion tool between the expander, engaging the distal end of the expandable liner, and the ratcheting component of the self-adjusting reaction assembly at the proximal end of the expandable liner. The pulling mandrel is slidably received through a bore of the tubular ratchet rack which terminates short of the distal end of the pulling mandrel to allow for stroking of the pulling mandrel towards the ratchet rack during each expansion stroke. This configuration is referred to herein as the run-in configuration of the expansion tool.
The expansion tool and the unexpanded liner are run into a well casing on the end of a tubular work string stepwise extended into the well from a rig at the earth's surface. The expansion tool and liner are positioned within a casing section to be reinforced, stabilized, patched or sealed with an expanded liner.
Embodiments of the expansion tool of the present invention include a tubular housing having a proximal end connected to a distal end of a tubular work string and a distal end coupled to a slip cage and a rack retainer. The housing includes a bore through which an upper portion of a pulling mandrel passes. The bore of the housing includes a plurality of annular cylinders defined by radially inwardly extending and spaced apart annular stops. The pulling mandrel has a bore and a plurality of radially outwardly extending annular pistons that are reciprocatably received within the annular cylinders defined within the bore of the housing. This axially aligned arrangement of hydraulic cylinders is known in the art.
The rack retainer is coupled to the slip cage which is coupled to the distal end of the housing. The rack retainer includes a bore through which a portion of the pulling mandrel passes. The rack retainer movably secures the self-adjusting reaction assembly to the slip cage and to the housing. The rack retainer threadably cooperates with the ratcheting component to permit uni-directional movement of the ratcheting component from a retracted position, proximal to the slip cage and the housing, to an extended position that is distal to the slip cage and the housing to vary (increase) the distance from the ratcheting component, which is connected to the proximal end of the expandable liner, to the slip cage and housing during the expansion process. The reaction assembly of the expansion tool of the present invention includes an elongate ratchet rack having a threaded exterior and a bore through which the lower portion of the pulling mandrel passes. The reaction assembly further includes a ratcheting component having a ratchet ring housed within a ring housing. The ratchet ring includes a radially interior threaded portion and a longitudinal slot that is spring biased to engage the interior threaded portion with the threaded exterior portion of the ratchet rack. The ring housing includes an interior chamber that accommodates cyclic expansion and contraction of the ratchet ring therewithin, and that surrounds the spring-biased ratchet ring. The ratchet housing is secured to the proximal end of the expandable liner using, for example, threaded fasteners. The ratchet ring includes a bore with buttress threads adapted to cooperate with the buttress threads along the exterior of the elongate ratchet rack to resist movement of the ratchet rack in a distal direction relative to the ratcheting component and the expandable liner connected thereto, but to allow movement of the ratchet rack in a proximal direction relative to the ratcheting component and the expandable liner connected thereto. The ratcheting component may comprise an exterior surface adapted for being releasably engaged with the unexpanded proximal end of the bore of the liner. For example, the ring housing of the ratcheting component may include external threads or other surface gripping structures and/or bonding agents. In one embodiment, the ring housing of the ratcheting component is secured to the unexpanded proximal end of the expandable liner with threaded and headless fasteners, as illustrated in the appended drawings. The uni-directional movement of the ratchet rack within and relative to the ratcheting component (including the ratchet ring and the ring housing that surrounds the ratchet ring) can, in one embodiment, be provided by the use of buttress threads disposed along the ratchet rack and cooperating buttress threads disposed within the bore of the slotted ratchet ring. The slot of the ratchet ring resiliently opens (expands) and closes (contracts) to allow the ratchet rack to move within the ratchet ring and the ring housing in the proximal direction (relative movement), but to prevent movement of the ratchet rack within the ratchet ring and the ring housing in the distal direction (relative movement). It will be understood that cooperative sets of buttress teeth can provide for this ratcheting function. These features are discussed in more detail below and illustrated in the appended drawings.
The self-adjusting reaction assembly of embodiments of the expansion tool of the present invention allows the housing and the hydraulic annular cylinders formed therein, along with the slip cage and the slips movably captured therein, to be repositioned further uphole between each stage of hydraulically assisted liner expansion without disengaging the reaction assembly from the proximal end of the liner. At the onset and during the earlier stages of the liner expansion process, the pulling mandrel is hydraulically displaced proximally within the bore of the housing and the slip cage to first set the slips to secure the expansion tool within the casing, and then to pull the expander through a portion or an interval of the bore of the expandable liner. The ratcheting component reacts against the proximal end of the liner to oppose any shifting or movement of the liner within the casing due to the axial component of the force applied to the liner by the expander. During an expansion stroke of the pulling mandrel and the expander connected thereto, the ratcheting component may move in a distal direction relative to the ratchet rack to compensate for axial shrinkage of the expandable liner occurring during radial expansion by the expander. It will be understood by persons knowledgeable in metallurgy that the expansion of a slender tubular member generally results in a corresponding reduction in the length, or shrinkage, of the tubular member to compensate for radial expansion which reduces wall thickness.
The expansion tool of the present invention includes slips to grip the bore of the casing and to secure the housing, the slip cage, the rack retainer, and the reaction assembly in a position within the casing. As explained above, the reaction assembly prevents axial movement of the liner, except for the capacity of the reaction assembly to accommodate liner shrinkage. Hydraulic pressurization of the bore of the pulling mandrel results in axial displacement of the pulling mandrel relative to the housing. At the very onset of hydraulic pressurization of the hydraulic section of the expansion tool, the pulling mandrel may move in a proximal direction while the housing may move in a distal direction. That is, until the slips are set within the casing, the housing may also be slightly movable upon pressurization of the tubular string, probably less than about one inch (2.54 cm), in a downhole direction opposite to the initial movement of the pulling mandrel. However, once the slip actuator engages and displaces the slips radially outwardly through windows of the slip cage to engage a gripping face of each of the slips with the interior bore of the casing, the slip cage and the housing coupled to the slip cage become secured in position in the casing. Further movement of the pulling mandrel in the proximal direction pulls the expander through a distal portion of the bore of the expandable liner, which is secured against movement in the proximal direction by the reaction assembly, slips and slip cage.
After completion of an expansion stroke, the annular pistons on the pulling mandrel are hydraulically displaced in a proximal direction to proximal ends of the annular cylinders formed within the housing. The expander on the distal end of the pulling mandrel is sized so that when it is drawn through a portion of the bore of the expandable liner, it remains lodged at the end of a stroke within a freshly expanded portion of the expandable liner which is, in turn, lodged in the bore of the casing in which the expandable liner is to be expanded. The pressure of the fluid in the bore of the pulling mandrel and in the portions of the annular cylinders distal to the annular pistons is relieved. The draw works on the rig at the surface then pulls the tubular string that is connected at its distal end to the housing of the liner expansion tool and, through the housing, it also pulls the slip cage in a proximal direction, or uphole, to unseat the slips. The draw works on the rig is then used to pull the housing further in an uphole direction to reposition the housing, the annular cylinders therein and the rack retainer in a proximal direction, or uphole, to restore each of the annular pistons on the lodged pulling mandrel to their original “cocked” positions at the distal ends of each of the annular cylinders of the housing. This process uses the frictional resistance to movement of the lodged expander, the expanded portion of the expandable liner disposed around the expander and the pulling mandrel to which the expander is connected to re-cock the hydraulic section of the housing by moving the housing relative to the pulling mandrel.
The pulling mandrel is again hydraulically actuated by fluid pressurization of the bore of the tubular string to again deploy the slips to grip the bore of the casing at a position spaced uphole from the first gripping position, and further to displace the expander in a proximal direction, relative to the housing and the slip cage, through a second portion of the expandable liner. The expander is again lodged within the freshly expanded portion of the expandable liner which is, in turn, lodged within the casing in which the liner is being expanded. The process is repeated and the expandable liner is stepwise expanded, interval by interval, with each expanded interval of the liner being generally equal in length to the stroke of a plurality of annular pistons on the pulling mandrel within the corresponding plurality of annular cylinders of the housing. This stepwise expansion process continues until the entire length of the expandable liner is expanded and the reaction assembly is disconnected from the proximal end of the expandable liner.
The bore of the pulling mandrel includes a plurality of strategically positioned apertures immediately distal to each of the annular pistons on the pulling mandrel. Pressurization of the fluid in the bore of the tubular string that is used to position the expandable liner expansion tool in the well and of the bore of the pulling mandrel in fluid communication with the work string provides fluid pressure through the apertures into adjacent annular cylinders of the housing. The fluid pressure provides the power to fluidically displace the annular pistons on the pulling mandrel in a proximal direction within the annular cylinders of the housing. Similarly, there are vents in the housing at the proximal end of each of the annular cylinders that allow fluid to be displaced from the annular cylinders as the annular pistons on the pulling mandrel are hydraulically displaced by the pressure in the distal portion of each annular cylinder.
It will be understood that the bore of the pulling mandrel is open as the expansion tool is run into the well and positioned within the casing at the targeted liner expansion location. The open bore of the pulling mandrel enables the operator of the well to maintain well control at all times during running and positioning of the expansion tool. The bore of the pulling mandrel can be closed to enable the bore of the pulling mandrel, and the annular pistons in fluid communication with the bore of the pulling mandrel, to be pressurized in order to stroke the expansion tool and displace the pulling mandrel and expander relative to the housing. The pulling mandrel includes a ball seat disposed intermediate the plurality of apertures that provide fluid pressure to the annular cylinders of the housing and the expander at the distal end of the pulling mandrel. The ball seat is adapted to receive a ball introduced into the tubular string and pumped through the tubular string and the bore of the pulling mandrel to engage and seal with the ball seat. The ball is deployed from the rig through the tubular string and into the bore of the pulling mandrel after the expansion tool and the liner are favorably positioned in the casing. Once the ball engages and seals with the ball seat, pressurized fluid pumped through the work string and into the bore of the pulling mandrel communicates through the apertures to the annular cylinders to apply fluid pressure against the distal face of the annular pistons on the pulling mandrel.
After the expansion tool is stroked to draw the expander into the bore of the expandable liner to expand an initial and distal portion of the expandable liner, the fluid pressure within the tubular string and the bore of the pulling mandrel is relieved. Relieving the pressure in the bore of the pulling mandrel relieves the pressure urging the slips into the gripping position with the bore of the casing. The draw works of the rig is used to pull the tubular string and the housing of the expansion tool connected to the tubular string towards the surface end of the well as the lodged expander, pulling mandrel and partially expanded liner remain in place in the casing. The slips are thereby unseated and retract to allow the housing, slip cage and the rack retainer coupled thereto to be repositioned uphole. Repositioning of the housing, slip cage and rack retainer, with the pulling mandrel and expander remaining in place in the casing, re-cocks the expansion tool and positions the pulling mandrel for another stroke to further expand an additional interval of the liner. During the re-cocking process, the housing and the annular chambers formed therein move in a proximal direction relative to the stationary annular pistons that remain in place with the lodged expander, the partially expanded liner and the pulling mandrel to which the expander is connected. Once the expander is drawn into the bore of the expandable liner, the expander remains lodged in an interference fit with the expanded portion of the expandable liner, and the expanded portion of the liner is circumferentially trapped between the exterior of the expander and the bore of the casing in which the expandable liner is being installed. The interference fit advantageously lodges the expander, the pulling mandrel, the annular pistons on the pulling mandrel and the partially expanded liner in position within the bore of the casing as the housing, slip cage and rack retainer are moved in a proximal direction with the tubular string. The ratcheting component, however, remains engaged with the proximal end of the expandable liner and it ratchets in a distal direction along the ratchet rack as the housing, the annular chambers and the ratchet rack are pulled uphole during the re-cocking step.
After re-cocking of the expansion tool in preparation for another expansion stroke, the expansion tool is again capable of being hydraulically stroked by pressurizing the work string and the bore of the pulling mandrel to hydraulically displace the pulling mandrel and the expander through another expansion stroke to expand another interval of the expandable liner. Upon hydraulic pressurization of the bore of the work string and the bore of the pulling mandrel, the slips are initially set to grip the bore of the casing to secure the housing and the rack retainer in place within the casing. The expander is then drawn through another interval of the bore of the expandable liner as the ratcheting component remains engaged with the proximal end of the expandable liner to resist movement of the partially expanded liner in a proximal direction relative to the ratchet rack. The ratcheting component thereby provides a reaction force against the expandable liner to prevent unwanted axial shifting or movement of the partially expanded liner during each expansion stroke.
In one embodiment, a reaction assembly, meaning at least one of the ratcheting component and the ratchet rack, may include one or more spring elements that bias one or more dogs into engagement with a series of buttress threads disposed along the other of the ratcheting component and ratchet rack. Spring biased elements may be disposed circumferentially within the ratcheting component. In other embodiments, the ratcheting component may comprise a circumferentially expandable slotted ratchet ring with a threaded bore. The longitudinal slot of the ratchet ring allows the threaded bore of the ratchet ring to elastically expand in response to an applied expanding force. The ratchet rack includes an exterior having cooperating threads. In a preferred embodiment, the threads along the exterior surface of the ratchet rack are buttress threads on which the proximal side of each thread is ramped and the distal side of each thread is steep, and the buttress threads of the interior bore of the cooperating slotted ratchet ring are ramped on the distal side and steep on the proximal side. This arrangement of cooperating buttress threads on the bore of the ratchet ring and the exterior surface of the ratchet rack allows the ratchet ring to ratchet in a distal direction along the ratchet rack as the ramped sides of the mating threads slidably engage to elastically and circumferentially expand the bore of the ratchet ring. Expansion of the slot of the ratchet ring allows the threads of the internal bore of the ratchet ring to skip over and slide past threads of the ratchet rack and to move, or ratchet, in a distal direction along the ratchet rack. This ratcheting movement of the ratchet ring occurs as the housing, the slip cage and the ratchet rack are pulled in a proximal direction as the ratchet ring remains secured to the proximal end of the partially expanded liner to re-cock the hydraulic section of the expansion tool. At the onset of the subsequent expansion stroke, the axial force applied by the expander to the liner forces the liner and the ratchet ring coupled to the proximal end of the liner in a proximal direction relative to the ratchet rack, and into binding engagement with the ratchet rack as the steep sides of the cooperating threads engage to oppose expansion and movement of the ratchet ring. It will be understood that at some point during the staged expansion process, the expanded portion of the expandable liner will be sufficiently long so that the frictional engagement between the expanded portion of the expandable liner and the casing becomes sufficient to prevent movement of the expandable liner in response to further movement of the expander through the bore of the expandable liner. At this juncture, the operator may choose to use the draw works on the rig to pull the expansion tool to finish expanding the expandable liner.
In embodiments of the liner expansion tool of the present invention, an expansion stroke initially causes the ratchet rack to be displaced, along with the ratchet ring and relative to the housing and the work string, until the slip actuator is moved relative to the slips to displace the slips radially outwardly through the windows in the slip cage to engage with the bore of the casing to prevent movement of the housing, the slip cage and the ratchet rack. Once the slips are firmly engaged with the bore of the casing, further displacement of the pulling mandrel within the housing and the slip cage causes the expander to be pulled through an interval of the expandable liner to radially expand the liner within the casing bore.
In addition to enabling the liner expansion tool to be re-cocked, the ratcheting component, which includes the ratchet ring and ring housing, can also move in a distal direction relative to and along the ratchet rack to compensate for the axial shrinkage in the expandable liner that occurs as a result of the radial expansion of the expandable liner resulting from movement of the expander. Each time the expansion tool is re-cocked, the ratcheting component remains engaged with the proximal end of the partially expanded liner as the ratchet rack moves in a proximal direction relative to the ratcheting component to re-cock the expansion tool. The ratcheting component, which includes the ratchet ring and ratchet housing, therefore serves the dual functions of enabling the tool to be re-cocked between expansion strokes and also compensating for axial shrinkage of the expandable liner occurring during an expansion stroke.
The setting of the slips of the expansion tool of the present invention to grip the interior wall of a casing occurs at the onset of an expansion stroke. At the onset of a stroke of the hydraulic section of the liner expansion tool, the slip actuators, coupled to the housing, are moved in a proximal direction relative to the slips and the slip housing in which the slips are axially captured. The slip actuators slidably engage and radially outwardly deploy the slips to engage and grip the interior bore of the casing. The slip cage is coupled to the ratchet rack, and the ratchet rack is thereby secured within the casing by deployment of the slips to the gripping position. The limited amount of relative movement between the housing, coupled to the slip actuators, and the ratchet rack, coupled to the slips, is enabled by a collet assembly having a collet, with a bore therethrough, that is releasably seated within a collet cage, which also has a bore to receive the collet. The collet cage retains the collet within a limited range of axial movement within the collet cage. In one embodiment, the collet includes at least one radially inwardly directed protrusion, or a series of radially inwardly directed protrusions, that is releasably seated within at least one corresponding radially outwardly extending notch, or a series of radially outwardly directed notches, in the exterior of the pulling mandrel that passes through the bore of the collet. The collet is in a seated position within the collet cage when the radially inwardly directed notch of the collet is engaged with the radially outwardly directed notch in the pulling mandrel. The collet cage is coupled to the slip cage and to the ratchet rack. Upon pressurization of the bore of the pulling mandrel, the collet can be moved only a limited distance within the collet cage and then forcibly disengaged from the pulling mandrel by application of a sufficient force applied through the ratchet rack to cause the at least one radially inwardly directed protrusion on the collet to unseat from the corresponding at least one notch in the exterior of the pulling mandrel. The application of force to the collet is provided upon stroking of the hydraulic section of the expansion tool to pull the expander on the distal end of the pulling mandrel against the distal end of the expandable liner which, in turn, bears against the ratcheting component engaged with the proximal end of the expandable liner to lock the ratcheting component on the ratchet rack due to the ratcheting component being forced in a proximal direction along the ratchet rack. The ratcheting component resists movement in a proximal direction along the ratchet rack due to the unidirectional ratchet ring and, therefore, transfers the force applied by the expander to the expandable liner through the ratcheting component to the ratchet rack, urging the ratchet rack in the proximal direction against the collet. The ratchet rack bears against the collet which bears against the slips to set the slips by urging them up and radially outward of the slip actuator. Once the slips are set, the collet is held in place and the force applied to the pulling mandrel becomes sufficient to unseat the pulling mandrel from the collet, and the pulling mandrel then continues to move in a proximal direction relative to the housing and the slips to pull the expander through an interval of the expandable liner.
The drawings that are appended to this application illustrate one embodiment of the expansion tool and method of the present invention. It will be understood that other embodiments may also be within the scope of the present invention, which is limited only by the claims.
Stroking of the expansion tool 10 from the run-in configuration or cocked configuration, illustrated in
The second annular stop 118 shown in
Returning to
Returning to
Alternately, the ratcheting function of the ratchet ring 57, as it moves in one (the distal) direction only, can also be provided by a conventional spring-biased dog provided on the ratchet ring 57 in lieu of the slot 57A. The spring-biased dog engages and rides along the thread profile 56 of the ratchet rack 55 with the spring biasing the dog to remain engaged with the threads on the ratchet rack 55. Each time a force is applied to move the ratchet ring 57 in the distal direction, the dog will be displaced radially outwardly against the spring element and away from the ratchet rack 55 as the dog clears a thread peak 83. After the dog clears the thread peak 83, the biasing of the spring element restores the dog into a valley between two adjacent thread peaks to re-engage the dog with the steep side of the thread and to prevent movement of the ratchet ring 57 in the proximal direction. It will be understood that a spring-biased dog is the same apparatus used in many conventional ratcheting apparatuses such as, for example, a ratchet tool and a bumper jack used to lift an automotive vehicle. It will be understood that a large variety of elastically deformable components could be included within a ratchet ring 57 to provide the elastic restoring function of the slotted ratchet ring 57 or the spring-biased ratchet ring described above.
The ball 72 is introduced into the tubular string (not shown) at the rig, and pumped through the bore 44 of the pulling mandrel 40 and displaced to the distal end 73 of the liner expansion tool 10 to sealably engage the ball seat 75.
Once the slips 47 engage the casing 99, the continued introduction of pressurized fluid into the bore of the pulling mandrel causes the pulling mandrel 40 to be displaced in a proximal direction within the bore of the housing 11 and to pull the expander 87 into the bore of the distal end 64 of the liner 62. The resulting expansion of the expandable liner 62 continues until the stroke of the annular pistons 48 and 148 is completed. At this juncture, the expander 87 is securely lodged within the partially expanded bore of the expandable liner 62 and the exterior surface of the expandable liner 62, in the portion of the expandable liner 62 that has been expanded, is in engagement with the casing 99.
The remaining unexpanded portion of the expandable liner 62 that has not yet been expanded by movement of the expander 87 through the bore of the distal end 64 of the expandable liner 62 can be expanded by subsequent strokes of the liner expansion tool 10. Subsequent strokes require that the liner expansion tool 10 be re-cocked to reset the hydraulic section of the liner expansion tool 10, which means that the pulling mandrel 40 and the annular pistons 48 and 148 thereon must be restored to their original “run-in” positions relative to the housing 11 and the annular chambers defined by the stops 18 and 118 provided within the housing 11 for reciprocal movement of the annular pistons 48 and 148.
The liner expansion tool 10 can be re-cocked by first relieving the fluid pressure within the bore 44 of the pulling mandrel 40 to relieve force applied to each of the annular pistons 48 and 148 disposed on the pulling mandrel 40 by the fluid pressure within each of the annular chambers defined by the stops 18 and 118. It will be understood that relieving the pressure within the bore 44 of the pulling mandrel 40 requires control of the pumps that pump fluid into the bore 44 of the pulling mandrel 40 by pumping down the tubular string to the housing 11. With the hydraulic pressure in the bore 44 of the pulling mandrel 40 relieved, and with the expander 87 securely lodged within the partially expanded expandable liner 62, the expanded portion of which engages the casing 99, the liner expansion tool 10 can be re-cocked by using the draw works on the rig to pull the tubular string (not shown) and the proximal end 12 of the housing 11 of the liner expansion tool 10 to which it is threadably connected in a proximal direction within the casing 99 to displace the annular pistons 48 and 148 back to their original locations within the annular chambers defined by the annular stops 18 and 118 of the proximally displaced housing 11. It will be understood that the pulling mandrel 40 and the expander 87 to which it is connected will remain stationary during the re-cocking process, and also that the ball 72 does not disengage the ball seat 75 during this re-cocking step as long as the pressure within the bore 44 of the pulling mandrel 40 does not fall below the pressure within the casing 99. Once the housing 11 of the liner expansion tool 10 is displaced relative to the pulling mandrel 40 and the expander 87 by using the draw works to pull the proximal end 12 of the housing 11, the liner expansion tool 10 is re-cocked and ready for being hydraulically stroked to set the slips 47 and then to expand an additional interval of the expandable liner 62.
Subsequent pressurization of the tubular string and of the bore 44 of the pulling mandrel 40 causes the slips 47 to again be engaged to grip the casing 99, and further pressurization causes the expander 87 to be drawn in a proximal direction further within the bore of the expandable liner 62 to expand another portion of the expandable liner 62. It will be understood that with each stroke of the liner expansion tool 10, the axial length of the expanded portion of the expandable liner 62 increases. It will be further understood that since the expanded portion of the expandable liner 62 engages the casing 99, each stroke of the liner expansion tool 10 increases the overall surface area of frictional engagement between the exterior surface of the expanded portion of the expandable liner 62 and the casing 99 in which the expandable liner 62 is installed. It will be further understood that the expandable liner 62 is initially, during the early stages of expansion of the expandable liner 62, secured in place by the ratchet ring 57, the ring housing 50 and the ratchet rack 55, and by the arrangement of buttress threads within the bore of the ratchet ring 57 and on the exterior surface of the ratchet rack 55. However, once a sufficient amount of frictional engagement between the expanded portion of the expandable liner 62 and the casing 99 exists, the ratchet ring 57 and cooperating ratchet rack 55 will no longer continue to be loaded during strokes of the expander 87 within the bore of the expandable liner 62 since movement of partially expanded expandable liner 62 within the casing 99 will be prevented by the steadily increasing frictional engagement between the expanded portion of the expandable liner 62 and the casing 99 in which it is expanded. At some point during the expansion of the expandable liner 62, the use of the hydraulic components (annular pistons 48 and 148, annular chambers defined by stops 18 and 118, etc.) and the gripping components (slips 47 and slip actuator 46) of the liner expansion tool 10 can be terminated, and the draw works of the rig from which the tubular string is run can be used to pull the liner expansion tool 10 and the expander 87 coupled thereto to expand the remaining unexpanded portion of the partially expanded liner 62. If the weight on the draw works were to exceed a safe threshold beyond which the draw works or the tubular string may be damaged, the hydraulic components such as the annular pistons 48 and 148 and the annular stops 18 and 118, and the gripping components of the liner expansion tool 10 such as the slips 47 and the slip actuator 46 can be again engaged to continue expanding the expandable liner 62 one stroke at a time.
One embodiment of the method of the present invention includes the step of providing elastomeric seals 82 on the exterior surface 65 of the expandable liner 62 to engage the casing 99 upon expansion of the expandable liner 62.
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, components and/or groups, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. The terms “preferably,” “preferred,” “prefer,” “optionally,” “may,” and similar terms are used to indicate that an item, condition or step being referred to is an optional (not required) feature of the invention.
The corresponding structures, materials, acts, and equivalents of all means or steps plus function elements in the claims below are intended to include any structure, material, or act for performing the function in combination with other claimed elements as specifically claimed. The description of the present invention has been presented for purposes of illustration and description, but it is not intended to be exhaustive or limited to the invention in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the invention. The embodiment was chosen and described in order to best explain the principles of the invention and the practical application, and to enable others of ordinary skill in the art to understand the invention for various embodiments with various modifications as are suited to the particular use contemplated.
