Patent Grant
9051812
This application claims the benefit under 35 U.S.C. §119 of the filing date of International Application No. PCT/US2009/058516, filed Sep. 28, 2009. The entire disclosure of this prior application is incorporated herein by this reference.
This invention relates, in general, to equipment utilized in conjunction with operations performed in a subterranean well and, in particular, to a downhole tool that is positioned in a subterranean well to isolate a lower portion of the well from an upper portion of the well.
Bridge plugs are well tools that are typically lowered into a cased oil or gas well and set at a desired location inside the casing to isolate pressure between two zones in the well. Retrievable bridge plugs are used during drilling and workover operations to provide a temporary separation of zones. Permanent bridge plugs are used when it is desired to permanently close off the well above a lower zone or formation when, for example, that lower zone has become non-productive but one or more upper zones remain productive. In such cases, a through tubing bridge plug may be installed without the need for pulling the tubing or killing the well. Such through tubing bridge plugs may be lowered through the tubing string on a conveyance such as a wireline, coiled tubing or the like and then set by axially compressing the packing elements of the through tubing bridge plug to expand them into contact with the inner surface of the casing to provide a seal. Once in the sealing configuration, a significant pressure differential can be created across the through tubing bridge plug. Accordingly, conventional through tubing bridge plugs include one or more anchoring assemblies that are designed to support the through tubing bridge plug in the casing. More specifically, the anchoring assemblies are required to hold the through tubing bridge plug in the casing for a sufficient time period to allow cement to be added above the through tubing bridge plug and for the cement to cure to form a permanent plug.
It has been found, however, that the use of through tubing bridge plugs is limited to wells that require only a relatively small expansion ratio between the sealing configuration of the through tubing bridge plug and the running configuration of the through tubing bridge plug. Accordingly, a need has arisen for a through tubing bridge plug that is operable to isolate pressure between two zones in the well. A need has also arisen for such a through tubing bridge plug that is operable to anchor within the casing for a sufficient time period to allow cement to be added and for the cement to cure. Further, a need has arisen for such a through tubing bridge plug that is operable to be installed in wells that require a relatively large expansion ratio between the sealing configuration of the through tubing bridge plug and the running configuration of the through tubing bridge plug.
The present invention disclosed herein is directed to a through tubing bridge plug that is operable to isolate pressure between two zones in the well. In addition, the through tubing bridge plug of the present invention is operable to anchor within the casing for a sufficient time period to allow cement to be added and for the cement to cure. Further, the through tubing bridge plug of the present invention is operable to be installed in wells that require a relatively large expansion ratio between the gripping and sealing configuration of the through tubing bridge plug and the running configuration of the through tubing bridge plug.
In a first aspect, the present invention is directed to a through tubing bridge plug for providing a gripping and sealing engagement with a casing string of a wellbore. The through tubing bridge plug includes an actuation rod, an anchor assembly disposed about the actuation rod, a pair of compression assemblies disposed about the actuation rod, each including a support assembly and an anti extrusion assembly and a packing assembly disposed about the actuation rod between the compression assemblies. The through tubing bridge plug is operated responsive to longitudinal movement of the actuation rod. This longitudinal movement is operable to actuate the anchor assembly establishing the gripping engagement with the casing string. In addition, this longitudinal movement radially deploys the compression assemblies such that the anti extrusion assemblies are operable to compress the packing assembly. Further, this longitudinal movement is operable to actuate the packing assembly establishing the sealing engagement with the casing string.
In a second aspect, the present invention is directed to a method for establishing a gripping and sealing engagement of a bridge plug with a casing string of a wellbore. The method includes conveying the bridge plug through a tubing string in the wellbore to a target location in the casing string, longitudinally shifting an actuation rod of the bridge plug, radially expanding an anchor assembly of the bridge plug to establish the gripping engagement with the casing string, radially deploying a pair of compression assemblies of the bridge plug such that an anti extrusion assembly of each compression assembly and a support assembly of each compression assembly are deployed and radially expanding a packing assembly disposed about the actuation rod and between the compression assemblies by longitudinally compressing the packing assembly with the compression assemblies to establish the sealing engagement with the casing string.
In a third aspect, the present invention is directed to an actuation assembly for a downhole tool having a tool housing and an actuation member. The actuation assembly includes a downhole power unit having a power unit housing and a moveable shaft. The actuation assembly also includes a stroke extender having an extender housing and an extender mandrel longitudinally movable within the extender housing. The power unit housing is operably associated with the extender housing. The moveable shaft is operably associated with the extender mandrel. The extender housing is operably associated with the tool housing and the actuation member. The extender mandrel is operably associated with the actuation member such that oscillatory movement in first and second longitudinal directions of the moveable shaft relative to the power unit housing causes oscillatory movement in the first and second longitudinal directions of the extender mandrel relative to the extender housing which causes progressive movement in the first direction of the actuation member relative to the tool housing, thereby actuating the downhole tool.
In a fourth aspect, the present invention is directed to a method for actuating a downhole tool having a tool housing and an actuation member. The method involves providing a downhole power unit having a power unit housing and a moveable shaft, providing a stroke extender having an extender housing and an extender mandrel, operably associating the power unit housing with the extender housing and operably associating the moveable shaft with the extender mandrel, operably associating the extender housing with the tool housing and the actuation member and operably associating the extender mandrel with the actuation member, oscillating the moveable shaft in first and second longitudinal directions relative to the power unit housing, oscillating the extender mandrel in the first and second longitudinal directions relative to the extender housing and progressively shifting the actuation member in the first direction relative to the tool housing, thereby actuating the downhole tool.
In a fifth aspect, the present invention is directed to an actuation assembly for setting a through tubing bridge plug having an adaptor and an actuation rod. The actuation assembly includes a downhole power unit having a power unit housing and a moveable shaft. The actuation assembly also includes a stroke extender having a extender housing and an extender mandrel longitudinally movable within the extender housing. The power unit housing is operably associated with the extender housing and the moveable shaft is operably associated with the extender mandrel. The extender housing is operably associated with the adaptor and the actuation rod. The extender mandrel is operably associated with the actuation rod such that oscillatory uphole and downhole movement of the moveable shaft relative to the power unit housing causes oscillatory movement of the extender mandrel relative to the extender housing which shifts the actuation rod in the uphole direction relative to the adaptor, thereby setting the through tubing bridge plug.
In a sixth aspect, the present invention is directed to an anchor assembly for anchoring a downhole tool in a tubular disposed in a wellbore. The anchor assembly includes a first slip assembly having a first sleeve and a plurality of first arms rotatably associated with the first sleeve. The first arms have teeth on an end distal from the first sleeve. A second slip assembly has a second sleeve and a plurality of second arms rotatably associated with the second sleeve. The second arms have teeth on an end distal from the second sleeve. At least one hinge member couples respective first arms with second arms such that the distal ends of respective first and second arms are hingeable relative to one another. The anchor assembly has a running configuration in which the first and second arms are substantially longitudinally oriented and an operating configuration in which respective first and second arms form an acute angle relative to one another such that the teeth of the first and second arms define the radially outermost portion of the anchor assembly.
In an seventh aspect, the present invention is directed to an anchor assembly for anchoring a downhole tool in a tubular disposed in a wellbore. The anchor assembly includes a plurality of slip arm assemblies each including first and second arms hingeably coupled together. The first and second arms each have teeth on one end. A first sleeve is rotatably associated with each of the first arms. A second sleeve is rotatably associated with each of the second arms. The anchor assembly has a running configuration in which the slip arm assemblies are substantially longitudinally oriented and an operating configuration in which the first and second arms of each slip arm assembly form an acute angle relative to one another such that the teeth of the first and second arms define the radially outermost portion of the anchor assembly.
In a eighth aspect, the present invention is directed to a method for operating an anchor assembly to create a gripping engagement with a casing string of a wellbore. The method includes conveying the anchor assembly through a tubing string in the wellbore to a target location in a casing string, applying a compressive force between first and second slip assemblies of the anchor assembly, rotating a plurality of first arms with teeth relative to a first sleeve of the first slip assembly and rotating a plurality of second arms with teeth relative to a second sleeve of the second slip assembly such that the anchor assembly shifts from a running configuration in which the first and second arms are substantially longitudinally oriented to a gripping configuration in which the respective first and second arms form an acute angle relative to one another and the teeth of the first and second arms contact the casing string to establish a gripping engagement therewith.
In a ninth aspect, the present invention is directed to a compression assembly for actuating packing elements of a through tubing bridge plug in a casing string of a wellbore. The compression assembly includes a support assembly having a plurality link arm assemblies each including a short arm pivotably mounted to a long arm. The support assembly has a running configuration in which the link arm assemblies are substantially longitudinally oriented and an operating configuration in which the short arms are pivoted relative to the long arms such that the short arms form a support platform. The compression assembly also includes an anti extrusion assembly that is operably associated with the support assembly. The anti extrusion assembly includes a base member and a plurality of petals rotatably mounted to the base member. The anti extrusion assembly has a running configuration in which the petals are substantially perpendicular to the base member and nested relative to one another and an operating configuration in which the petals are radially outwardly disposed substantially filling gaps between the short arms.
In an tenth aspect, the present invention is directed to an anti extrusion assembly for actuating packing elements of a through tubing bridge plug in a casing string of a wellbore. The anti extrusion assembly includes a base member having a plurality of eccentrically extending pins and a plurality of petals rotatably mounted to the pins of the base member. The anti extrusion assembly has a running configuration in which the petals are substantially perpendicular to the base member and nested relative to one another and an operating configuration in which the petals are rotated such that the petals and the base member substantially lie in the same plane.
In a eleventh aspect, the present invention is directed to a method for actuating packing elements of a bridge plug in a casing string of a wellbore. The method includes conveying the bridge plug through a tubing string in the wellbore to a target location in the casing string, applying a compressive force between a pair of compression assemblies of the bridge plug, operating a support assembly of each compression assembly from a running configuration in which link arm assemblies are substantially longitudinally oriented to an operating configuration in which short arms are pivoted relative to long arms of the link arm assemblies to form a support platform, operating an anti extrusion assembly of each compression assembly from a running configuration in which petals are substantially perpendicular to a base member and nested relative to one another to an operating configuration in which the petals are radially outwardly disposed substantially filling gaps between the short arms and actuating the packing elements into sealing contact with the casing string.
For a more complete understanding of the features and advantages of the present invention, reference is now made to the detailed description of the invention along with the accompanying figures in which corresponding numerals in the different figures refer to corresponding parts and in which:
While the making and using of various embodiments of the present invention are discussed in detail below, it should be appreciated that the present invention provides many applicable inventive concepts which can be embodied in a wide variety of specific contexts. The specific embodiments discussed herein are merely illustrative of specific ways to make and use the invention, and do not delimit the scope of the present invention.
Referring initially to
A tubing string 34 extends from wellhead 36 to a location below formation 16 but above formation 14 and provides a conduit for production fluids to travel to the surface. A pair of packers 38, 40 provides a fluid seal between tubing string 34 and casing 26 and directs the flow of production fluids from formation 16 to the interior of tubing string 34 through, for example, a slotted liner. Disposed within tubing string 34 is a wireline 42 used to convey a tool system including a downhole power unit 44 and a through tubing bridge plug 46 as well as a locating device such as a gamma ray tool and other tools (not pictured). Even though downhole power unit 44 and through tubing bridge plug 46 are depicted as being deployed on a wireline, it is to be understood by those skilled in the art that downhole power unit 44 and through tubing bridge plug 46 could be deployed on other types of conveyances, including, but not limited to a slickline, coiled tubing, jointed tubing, a downhole robot or the like, without departing from the principles of the present invention.
In the illustrated embodiment shown
As will be described in more detail below, a particular implementation of downhole power unit 44 includes an elongated housing, a motor disposed in the housing and a sleeve connected to a rotor of the motor. The sleeve is a rotational member that rotates with the rotor. A moveable member such as the above-mentioned moveable shaft is received within the threaded interior of the sleeve. Operation of the motor rotates the sleeve which causes the moveable shaft to move longitudinally. Accordingly, when downhole power unit 44 is operably coupled with through tubing bridge plug 46 and the moveable member is activated, longitudinal movement is imparted to the actuation rod of through tubing bridge plug 46.
In one implementation, a microcontroller made of suitable electrical components to provide miniaturization and durability within the high pressure, high temperature environments which can be encountered in an oil or gas well is used to control the operation of downhole power unit 44. The microcontroller is preferably housed within the structure of downhole power unit 44, it can, however, be connected outside of downhole power unit 44 but within the associated tool string moved into wellbore 24. In whatever physical location the microcontroller is disposed, it is operationally connected to downhole power unit 44 to control movement of the moveable member when desired. The microcontroller may include a microprocessor which operates under control of a timing device and a program stored in a memory. The program in the memory includes instructions which cause the microprocessor to control the downhole power unit 44.
The microcontroller operates under power from a power supply which can be at the surface or, preferably, contained within the microcontroller, downhole power unit or otherwise within a downhole portion of the tool string of which these components are a part. The power source provides the electrical power to both the motor of downhole power unit 44 and the microcontroller. When downhole power unit 44 is at the target location, the microcontroller commences operation of downhole power unit 44 as programmed. For example, with regard to controlling the motor that operates the sleeve receiving the moveable member, the microcontroller sends a command to energize the motor to rotate the sleeve in the desired direction to either extend or retract the moveable member at the desired speed. One or more sensors monitor the operation of downhole power unit 44 and provide responsive signals to the microcontroller. When the microcontroller determines that a desired result has been obtained, it stops operation of downhole power unit 44, such as by de-energizing the motor. Alternatively, the operation of downhole power unit may be controlled from the surface wherein command signals may be provided to downhole power unit 44 via a wired or wireless communication protocol. Similarly, power may be provided to downhole power unit 44 from the surface via an electrical conductor.
Even though
Referring now to
In the illustrated embodiment, power assembly 104 includes a self-contained power source, eliminating the need for power to be supplied from an exterior source, such as a source at the surface. A preferred power source comprises a battery assembly 114 which may include a plurality of batteries such as alkaline batteries, lithium batteries or the like. Alternatively, however, power may be provided to downhole power unit 100 from the surface via an electrical conductor.
Connected with power assembly 104 is the force generating and transmitting assembly. The force generating and transmitting assembly of this implementation includes a direct current (DC) electric motor 116, coupled through a gearbox 118, to a jackscrew assembly 120. A plurality of activation mechanisms 122, 124 and 126, as will be described, can be electrically coupled between battery assembly 114 and electric motor 116. Electric motor 116 may be of any suitable type. One example is a motor operating at 7500 revolutions per minute (rpm) in unloaded condition, and operating at approximately 5000 rpm in a loaded condition, and having a horsepower rating of approximately 1/30th of a horsepower. In this implementation, motor 116 is coupled through the gearbox 118 which provides approximately 5000:1 gear reduction. Gearbox 118 is coupled through a conventional drive assembly 128 to jackscrew assembly 120.
Jackscrew assembly 120 includes a threaded shaft 130 which moves longitudinally, rotates or both, in response to rotation of a sleeve assembly 132. Threaded shaft 130 includes a threaded portion 134, and a generally smooth, polished lower extension 136. Threaded shaft 130 further includes a pair of generally diametrically opposed keys 138 that cooperate with a clutch block 140 which is coupled to threaded shaft 130. Clutch housing 110 includes a pair of diametrically opposed keyways 142 which extend along at least a portion of the possible length of travel. Keys 138 extend radially outwardly from threaded shaft 130 through clutch block 140 to engage each of keyways 142 in clutch housing 110, thereby selectively preventing rotation of threaded shaft 130 relative to housing 110.
Rotation of sleeve assembly 132 in one direction causes threaded shaft 130 and clutch block 140 to move longitudinally upwardly relative to housing assembly 110 if shaft 130 is not at its uppermost limit. Rotation of the sleeve assembly 132 in the opposite direction moves shaft 130 downwardly relative to housing 110 if shaft 130 is not at its lowermost position. Above a certain level within clutch housing 110, as indicated generally at 144, clutch housing 110 includes a relatively enlarged internal diameter bore 146 such that moving clutch block 140 above level 144 removes the outwardly extending key 138 from being restricted from rotational movement. Accordingly, continuing rotation of sleeve assembly 132 causes longitudinal movement of threaded shaft 130 until clutch block 140 rises above level 144, at which point rotation of sleeve assembly 132 will result in free rotation of threaded shaft 130. By virtue of this, clutch assembly 112 serves as a safety device to prevent burn-out of the electric motor, and also serves as a stroke limiter. In a similar manner, clutch assembly 112 may allow threaded shaft 130 to rotation freely during certain points in the longitudinal travel of threaded shaft 130.
In the illustrated embodiment, downhole power unit 100 incorporates three discrete activation assemblies, separate from or part of the microcontroller discussed above. The activation assemblies enable jackscrew 120 to operate upon the occurrence of one or more predetermined conditions. One depicted activation assembly is timing circuitry 122 of a type known in the art. Timing circuitry 122 is adapted to provide a signal to the microcontroller after passage of a predetermined amount of time. Further, downhole power unit 100 can include an activation assembly including a pressure-sensitive switch 124 of a type generally known in the art which will provide a control signal, for example, once the switch 124 reaches a depth at which it encounters a predetermined amount of hydrostatic pressure within the tubing string or experiences a particular pressure variation or series of pressure variations. Still further, downhole power unit 100 can include a motion sensor 126, such as an accelerometer or a geophone that is sensitive to vertical motion of downhole power unit 100. Accelerometer 126 can be combined with timing circuitry 122 such that when motion is detected by accelerometer 126, timing circuitry 122 is reset. If so configured, the activation assembly operates to provide a control signal after accelerometer 126 detects that downhole power unit 100 has remained substantially motionless within the well for a predetermined amount of time.
Working assembly 102 includes an actuation assembly 148 which is coupled through housing assembly 106 to be movable therewith. Actuation assembly 148 includes an outer sleeve member 150 which is threadably coupled at 152 to housing assembly 106. Threaded shaft 130 extends through actuation assembly 148 and has a threaded end 154 for coupling to other tools such as a stroke extender or a through tubing bridge plug as will be described below.
In operation, downhole power unit 100 is adapted to cooperate directly with a through tubing bridge plug or indirectly with a through tubing bridge plug via a stroke extender depending upon the particular implementation. Specifically, prior to run in, outer sleeve member 150 of downhole power unit 100 is operably associated with a mating tubular of a stroke extender or a through tubing bridge plug as described below. Likewise, shaft 130 of downhole power unit 100 is operably associated with a mating component of a stroke extender or a through tubing bridge plug as described below. As used herein, the term operably associated with shall encompass direct coupling such as via a threaded connection, a pinned connection, a frictional connection, a closely received relationship and may also including the use of set screws or other securing means. In addition, the term operably associated with shall encompass indirect coupling such as via a connection sub, an adaptor or other coupling means. As such, an upward longitudinal movement of threaded shaft 130 of downhole power unit 100 exerts an upward longitudinal force upon the component to which it is operably associated that initiates the operation of either a stroke extender or a through tubing bridge plug that is associated therewith as described below.
As will be appreciated from the above discussion, actuation of motor 116 by activation assemblies 122, 124, 126, and control of motor 116 by the microcontroller results in the required longitudinal movement of threaded shaft 130. In the implementation wherein a stroke extender is used, threaded shaft 130 is only required to move a reciprocate short distance in the upward direction followed by a relatively short distance in the downward direction for the number of strokes necessary to install the through tubing bridge plug. In the implementation wherein a stroke extender is not used, threaded shaft 130 is required to move a relative long distance in the upward direction to install the through tubing bridge plug. In either case, downhole power unit 100 may be preprogrammed to perform the proper operations prior to deployment into the well. Alternatively, downhole power unit 100 may receive power, command signals or both from the surface via an umbilical cord. Once the through tubing bridge plug is installed, downhole power unit 100 and the stroke extender, if present, may be retrieved to the surface.
Even though a particular embodiment of a downhole power unit has been depicted and described, it should be clearly understood by those skilled in the art that other types of downhole power devices could alternatively be used with the through tubing bridge plug of the present invention such that the through tubing bridge plug of the present invention may establish a gripping and sealing relationship with the interior of a downhole tubular.
Referring now to
Positioned below anchor assembly 212 is a support assembly 216. As described in greater detail below, support assembly 216 includes ten hingeable support arms 218, only two of which are visible in
Positioned below anti extrusion assembly 220 is a packing assembly 224. Packing assembly 224 includes a plurality of packing elements 226 that are preferably formed from a polymer material such as an elastomer, a thermoplastic, a thermoset or the like. In the illustrated embodiment, packing elements 226 are directionally arranged about a center element 228 to aid in the predictability of the expansion of packing assembly 224 upon activation of through tubing bridge plug 200. As illustrated, center element 228 is closely received around actuation rod 208. In addition, center element 228 has beveled ends such that its outermost portions have a radially reduced outer diameter. The other packing elements 226 have a spaced apart relationship with actuation rod 208 and also have beveled ends, however, one end is concave and one end is convex to enable nesting of packing elements 226 during run in and longitudinal movement relative to one another during installation. In the illustrated embodiment, one or more washers or centralizers 229 are positioned in the area between actuation rod 208 and the interior of packing elements 226. Centralizers 229 are preferably formed from a polymer material such as an elastomer, a thermoplastic, a thermoset or the like including swellable polymers such as those described below. Use of centralizers 229 further enhances the predictability of the expansion of packing assembly 224.
Actuation rod 208 includes an upper section 230 and a lower section 232 that are threadably coupled together at 234. Lower section 232 has a radially reduced section 236 that enables retrieval of the downhole power unit and upper portion 230 of actuation rod 208 after installation of through tubing bridge plug 200. Positioned below packing assembly 224 is an anti extrusion assembly 238. Anti extrusion assembly 238 includes ten rotatably mounted petals 240 that operate like those discussed above. Operably associated with anti extrusion assembly 238 is a support assembly 242 that includes ten hingeable support arms 244, only two of which are visible in
In operation, a tool string including through tubing bridge plug 200 is run to its target location in the wellbore through the tubing string on a conveyance. The tool string may include a plurality of tools, for example, a locating device such as a gamma ray tool and an electromechanical setting device such as downhole power unit 100. Specifically, the upper end of upper adaptor 202 of through tubing bridge plug 200 is operable to receive the lower end of outer sleeve member 150 of downhole power unit 100. In addition, actuation rod 208 of through tubing bridge plug 200 is threadably coupled to shaft 130 of downhole power unit 100 such that through tubing bridge plug 200 and downhole power unit 100 are secured together. Once through tubing bridge plug 200 is properly positioned in the desired location in the casing string, the activation process may begin.
Through tubing bridge plug 200 is operated from its running configuration, as best seen in
One of the benefits of the present invention is that the process of longitudinally compressing and radially expanding packing elements 226 is a controlled process that proceeds slowly compared to prior art hydraulic and explosive setting techniques. The controlled nature of this process allows packing elements 226 to deform in a more uniform manner and to move relative to one another such that stress concentrations and extrusion can be avoided. In addition, the use of support assemblies 216, 242 and anti extrusion assemblies 220, 238 further enhance the control over the movement of packing elements 226. Once packing elements 226 are fully compressed, upward movement of actuation rod 208 ceases. During this process, slip members 206 allow for the upward movement of actuation rod 208 but prevent any downward movement of actuation rod 208 after through tubing bridge plug 200 is set in the casing. Continued upward movement of shaft 130 then causes radially reduced section 236 of actuation rod 208 to fail in tension. At this point, through tubing bridge plug 200 is fully installed and has established a gripping and sealing relationship with the casing. Thereafter, downhole power unit 100 and upper portion 230 of actuation rod 208 may be retrieved to the surface and, in a permanent bridge plug implementation, cement may be placed above through tubing bridge plug 200 to permanently plug the well. Alternatively, in a temporary bridge plug implementation, the sealing and gripping relation of through tubing bridge plug 200 with the casing is suitable to provide the desired plugging function.
In certain implementations wherein the expansion ratio of through tubing bridge plug 200 is relatively large, the length of packing assembly 224 must be relative long. In the embodiment discussed above wherein the through tubing bridge plug expands from a two and one eighth inch outer diameter running configuration to a seven inch outer diameter gripping and sealing configuration, the length of the packing assembly 224 may be six feet or more. In such cases, if downhole power unit 100 is used to directly move actuation rod 208, downhole power unit 100 would need to be at least three times the length of the desired compression of packing assembly 224 or in this case about twenty feet long. In certain situations, it may be undesirable to have a downhole power unit of that length. As best seen in
Stroke extender 300 includes an outer housing 302 that is operable to receive the lower end of outer sleeve member 150 of downhole power unit 100. Preferably, stroke extender 300 and downhole power unit 100 are securably coupled together using pins, set screws, a threaded connection or the like. The upper end of upper adaptor 202 of through tubing bridge plug 200 is operable to receive the lower end of outer housing 302 of stroke extender 300. Stroke extender 300 includes an extender mandrel depicted as an actuation tubular 304 that is longitudinally movable within outer housing 302. Actuation tubular 304 has an upper connector 306 that is threadably coupled to shaft 130 of downhole power unit 100. Actuation tubular 304 also includes a set of one way slips 308 that are operably to selectively secure actuation rod 208 therein. Likewise, a set of one way slips 310 is disposed within outer housing 302 to selectively secure actuation rod 208 therein.
In operation, stroke extender 300 allows for the use of a downhole power unit 100 with a stroke that is shorter than the required compression length of packing assembly 224. Specifically, once the tool string including downhole power unit 100, stroke extender 300 and through tubing bridge plug 200 is at the target location in the wellbore, oscillatory operation of downhole power unit 100 may be used to install through tubing bridge plug 200.
As best seen in
In certain embodiments, instead of reversing the motor of downhole power unit 100 to enable a down stroke, a clutch may be operated such that shaft 130 may be mechanically or hydraulically shifted downwardly without motor operation, thereby reducing the duration of the down stroke. One of the benefits of using a stroke extender is the ease of adjusting its length. This is achieved by adding or removing tubular sections from outer housing 302 and actuation tubular 304. This modularity of stroke extender 300 eliminates the need to have different downhole power units of the same outer diameter with different stroke lengths.
Even though a particular embodiment of a stroke extender has been depicted and described, it should be clearly understood by those skilled in the art that other types of stroke extenders could alternatively be used in conjunction with the downhole power unit and through tubing bridge plug without departing from the principles of the present invention.
Referring next to
Anchor assembly 400 further includes an upper base member 432, visible in
One or more hinge members are used to connect an upper anchor assembly with a lower anchor assembly. In the illustrated embodiment, adjacent upper and lower slip arms 412, 414 are operably coupled together with two hinge members 438. In this manner, an upper slip arm 412, a pair of hinge members 438 and a lower slip arm 414 may be considered a slip arm assembly. Hinge members 438 are secured to each of the upper and lower slip arms 412, 414 with a plurality of fasteners depicted as three bolts. Even though bolts have be shown as fastening hinge members 438 to the upper and lower slip arms 412, 414, those skilled in the art will understand that other fastening techniques could alternatively be used, including, but not limited to, pins, rivets, welding and the like. As best seen in
In operation and referring again to the primary embodiment, as downhole power unit 100 is operated to actuate through tubing bridge plug 200 as described above, anchor assembly 400 is operated from its small diameter running configuration, wherein the outer surfaces of adjacent upper and lower slip arms 412, 414 lie substantially in the same plane such that upper and lower slip arms 412, 414 are substantially longitudinally oriented (see
Even though a particular embodiment of an anchor assembly has been depicted and described, it should be clearly understood by those skilled in the art that other types of anchor assemblies could alternatively be used in conjunction with the downhole power unit and through tubing bridge plug without departing from the principles of the present invention. Likewise, the anchor assembly of the present invention could be used to secure other devises within a wellbore
Referring next to
As best seen in
In operation, when downhole power unit 100 is operated to actuate through tubing bridge plug 200 as described above, compression assembly 500 is operated from its small diameter running configuration, wherein the outer surfaces of adjacent upper and lower link arms 514, 520 lie substantially in the same plane such that upper and lower link arms 514, 520 are substantially longitudinally oriented and petals 536 are nested (see
Even though a particular embodiments of a compression assembly, a support assembly and an anti extrusion assembly have been depicted and described, it should be clearly understood by those skilled in the art that other types of compression assemblies, support assemblies and anti extrusion assemblies could alternatively be used in conjunction with the downhole power unit and through tubing bridge plug described herein without departing from the principles of the present invention. For example, it may be desirable to have the petals form a conical configuration rather than a substantially planar configuration in their fully deployed state. In this embodiment, the upper surfaces of the upper link arms may also have a conical configuration in order to provide support to the petals. Alternatively, the petals could be supported by the casing wall instead of the upper link arms. As another example, each of the petals could alternatively be supported by one of the upper link arms instead of by two upper link arms. Also, instead of rotating the petals from the running to the deployed configuration, the pin ends of the petals could alternatively be deformable to allow the petals to operate from the running to the deployed configuration. In addition, even though a single layer of petals is depicted, the anti extrusion assembly of the present invention could alternatively have two or more layers of petals, wherein the petals of each layer lie in substantially the same plane or wherein each of the layers forms a conical configuration.
Referring next to
The eccentric arrangement of pins 538, the curvature of petals 536 and the flexibility of webbing elements 560 enables petals 536 and webbing elements 560 to nest together in the running position to minimize the outer diameter of anti extrusion assembly 550, as best seen in
Referring next to
In the illustrated embodiment, each petal 574 is independently coupled to its adjacent petals 574 by connecting members depicted as two radially spaced apart metal wires 580, 582. Alternatively, one or more wires could weave through all of the petals 574 to circumferentially extend around the entire anti extrusion assembly 570. As such, one or more circumferentially extending wires, one or more sets of connecting members or other similar system may be considered to be a stabilizer assembly. Even though a particular number of radially spaced apart connecting members has been described in the present embodiment, it is to be understood by those skilled in the art that other numbers of radially spaced apart connecting members both greater than and less than that specified are possible and are considered to be within the scope of the present invention. As depicted in the deployed position, each of the petals 574 is supported by two upper link arms 514 of a support assembly, as described above, and each petal 574 substantially fills the gap between the two supporting upper link arms 514. As such, petals 574 and upper link arms 514 cooperate together to substantially fill the entire cross section of the wellbore to enable compression and prevent extrusion of packing assembly 224. In addition, metal wires 580, 582 add to the hoop strength and stability of the petal system preventing any undesired movement of individual petals 574 caused by, for example, stress concentrations during compression of packing assembly 224.
Referring next to
In the illustrated embodiment, each of the anti extrusion elements 592 is formed from a flexible material such as sheet metal, composite fabric have metal wire embedded therein for resilience or the like. Anti extrusion elements 592 have a slot 594 and a central opening 596. In the relaxed state, anti extrusion elements 592 take the form of a relatively flat ring shaped element, as best seen in
Referring next to
As best seen in
Preferably, packing elements 600 are formed from a polymer material such as an elastomer, a thermoset, a thermoplastic or the like. For example, the polymer material may be polychloroprene rubber (CR), natural rubber (NR), polyether eurethane (EU), styrene butadiene rubber (SBR), ethylene propylene (EPR), ethylene propylene diene (EPDM), a nitrile rubber, a copolymer of acrylonitrile and butadiene (NBR), carboxylated acrylonitrile butadiene (XNBR), hydrogenated acrylonitrile butadiene (HNBR), commonly referred to as highly-saturated nitrile (HSN), carboxylated hydrogenated acrylonitrile butadiene (XHNBR), hydrogenated carboxylated acrylonitrile butadiene (HXNBR) or similar material. Alternatively, the polymer material may be a flurocarbon (FKM), such as tetrafluoroethylene and propylene (FEPM), perfluoroelastomer (FFKM) or similar material. As another alternative, the polymer material may be polyphenylene sulfide (PPS), polyetherketone-ketone (PEKK), polyetheretherketone (PEEK), polyetherketone (PEK), polytetrafluorethylene (PTFE), polysulphone (PSU) or similar material. In addition, packing elements 600 may have an anti-friction coating on their inner surface, their outer surface or both to further enhance the predictability or the compression process.
As depicted in
In certain embodiments, packing elements 610 are formed from a material that swells in response to contact with an activating fluid. Various techniques may be used for contacting the swellable material with appropriate activating fluid for causing swelling of swellable material. For example, the activating fluid may already be present in the well when, in which case swellable material preferably includes a mechanism for delaying the swelling of swellable material such as an absorption delaying or preventing coating or membrane, swelling delayed material compositions or the like. Alternatively, the activating fluid may be circulated through the well to swellable material after installed of through tubing bridge plug 200 in the well.
The swellable material may be formed from one or more materials that swell when contacted by an activation fluid, such as an inorganic or organic fluid. For example, the material may be a polymer that swells multiple times its initial size upon activation by an activation fluid that stimulates the material to expand. In one embodiment, the swellable material is a material that swells upon contact with and/or absorption of a hydrocarbon, such as an oil or a gas. The hydrocarbon is absorbed into the swellable material such that the volume of the swellable material increases creating a radial expansion of the swellable material.
Some exemplary swellable materials include elastic polymers, such as EPDM rubber, styrene butadiene, natural rubber, ethylene propylene monomer rubber, ethylene propylene diene monomer rubber, ethylene vinyl acetate rubber, hydrogenized acrylonitrile butadiene rubber, acrylonitrile butadiene rubber, isoprene rubber, chloroprene rubber and polynorbornene. These and other swellable materials swell in contact with and by absorption of hydrocarbons so that the swellable materials expand. In one embodiment, the rubber of the swellable materials may also have other materials dissolved in or in mechanical mixture therewith, such as fibers of cellulose. Additional options may be rubber in mechanical mixture with polyvinyl chloride, methyl methacrylate, acrylonitrile, ethylacetate or other polymers that expand in contact with oil.
In another embodiment, the swellable material is a material that swells upon contact with water. In this case, the swellable material may be a water-swellable polymer such as a water-swellable elastomer or water-swellable rubber. More specifically, the swellable material may be a water-swellable hydrophobic polymer or water-swellable hydrophobic copolymer and preferably a water-swellable hydrophobic porous copolymer. Other polymers useful in accordance with the present invention can be prepared from a variety of hydrophilic monomers and hydrophobically modified hydrophilic monomers. Examples of particularly suitable hydrophilic monomers which can be utilized include, but are not limited to, acrylamide, 2-acrylamido-2-methyl propane sulfonic acid, N,N-dimethylacrylamide, vinyl pyrrolidone, dimethylaminoethyl methacrylate, acrylic acid, trimethylammoniumethyl methacrylate chloride, dimethylaminopropylmethacrylamide, methacrylamide and hydroxyethyl acrylate.
A variety of hydrophobically modified hydrophilic monomers can also be utilized to form the polymers useful in accordance with this invention. Particularly suitable hydrophobically modified hydrophilic monomers include, but are not limited to, alkyl acrylates, alkyl methacrylates, alkyl acrylamides and alkyl methacrylamides wherein the alkyl radicals have from about 4 to about 22 carbon atoms, alkyl dimethylammoniumethyl methacrylate bromide, alkyl dimethylammoniumethyl methacrylate chloride and alkyl dimethylammoniumethyl methacrylate iodide wherein the alkyl radicals have from about 4 to about 22 carbon atoms and alkyl dimethylammonium-propylmethacrylamide bromide, alkyl dimethylammonium propylmethacrylamide chloride and alkyl dimethylammonium-propylmethacrylamide iodide wherein the alkyl groups have from about 4 to about 22 carbon atoms.
Polymers which are useful in accordance with the present invention can be prepared by polymerizing any one or more of the described hydrophilic monomers with any one or more of the described hydrophobically modified hydrophilic monomers. The polymerization reaction can be performed in various ways that are known to those skilled in the art, such as those described in U.S. Pat. No. 6,476,169 which is hereby incorporated by reference for all purposes.
Suitable polymers may have estimated molecular weights in the range of from about 100,000 to about 10,000,000 and preferably in the range of from about 250,000 to about 3,000,000 and may have mole ratios of the hydrophilic monomer(s) to the hydrophobically modified hydrophilic monomer(s) in the range of from about 99.98:0.02 to about 90:10.
Other polymers useful in accordance with the present invention include hydrophobically modified polymers, hydrophobically modified water-soluble polymers and hydrophobically modified copolymers thereof. Particularly suitable hydrophobically modified polymers include, but are not limited to, hydrophobically modified polydimethylaminoethyl methacrylate, hydrophobically modified polyacrylamide and hydrophobically modified copolymers of dimethylaminoethyl methacrylate and vinyl pyrollidone.
As another example, the swellable material may be a salt polymer such as polyacrylamide or modified crosslinked poly(meth)acrylate that has the tendency to attract water from salt water through osmosis wherein water flows from an area of low salt concentration, the formation water, to an area of high salt concentration, the salt polymer, across a semi permeable membrane, the interface between the polymer and the production fluids, that allows water molecules to pass therethrough but prevents the passage of dissolved salts therethrough.
Even with the controlled compression process and directional orientation of packing elements discussed above, it may be desirable to further engineer the deformation characteristics of the packing elements in packing assembly 224. As best seen in
As discussed above, it may also be desirable to have certain of the packing elements formed from one material or having certain material properties with other of the packing elements formed from another material or having different material properties. In the following example, a central packing element 640 is described but, it is to be understood by those skilled in the art that any of the packing elements or groups of packing elements could utilize different materials. Packing elements 640 are preferably formed from a rigid material such as a metal or hard plastic. Packing elements 640 have a generally cylindrical shape with an outer diameter 642 sized to allow passage of packing elements 640 through tubing. Packing elements 640 have a pair of convex ends 644 that are designed to nest with a concave end of an adjacent packing element in packing assembly 224. In addition, packing elements 640 have an inner diameter 646 sized to have a closely received relationship with actuation rod 208. In addition, packing elements 640 includes a pair of perpendicular holes 648 that pass through the center of packing element 640. Preferably, swellable polymer elements 650, formed from a material described above, are positioned within holes 648. The combination of the rigid material and the swellable elements helps to insure predictable compression of the packing assembly 224 and a complete seal with the casing wall.
Referring next to
As best seen in
Referring next to
In the illustrated embodiment, each of the packing elements 702 is formed from a material capable of sealing with the casing such as those polymeric materials discussed above. Packing elements 702 have a slot 704 and a central opening 706. In the relaxed state, packing elements 702 take the form of a relatively flat ring shaped element, as best seen in
While this invention has been described with reference to illustrative embodiments, this description is not intended to be construed in a limiting sense. Various modifications and combinations of the illustrative embodiments as well as other embodiments of the invention will be apparent to persons skilled in the art upon reference to the description. It is, therefore, intended that the appended claims encompass any such modifications or embodiments.
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