Abstract: A dual drill string valve includes an actuator including a piston disposed in a housing. The housing is configured to couple at its ends to an end of a nested dual drill string segment. An upper internal conduit is mounted in the housing proximate one longitudinal end thereof. A lower internal conduit is mounted in the housing proximate the other longitudinal end thereof. The piston is slidably, sealingly engaged between the upper and lower inner conduits and defines a fluid flow passage therethrough. The upper inner conduit, the piston and the lower inner conduit define another flow passage between respective exterior surfaces thereof and an interior of the housing such that application of fluid pressure to the external flow passage causes movement of the piston away from the upper inner conduit. A rotary valve is coupled to the actuator whereby longitudinal movement thereof rotates the rotary valve.

Abstract: A control mechanism for use with a safety valve adapted to seal a wellbore is described. The control mechanism comprises at least one valve actuator for engaging with the safety valve, the at least one actuator being moveable, in use, between a valve open position in which the safety valve is open and a valve closed position, in which the safety valve is closed. The control mechanism further comprises biasing apparatus adapted to bias the at least one valve actuator to the valve closed position, wherein, in use, the at least one valve actuator extends from the safety valve up to a wellbore wellhead. In one described embodiment, the safety valve is moved between the open and closed positions by movement of the at least one valve actuator with respect to the wellbore.

Abstract: A flow restrictor device for production tubing comprising an obstructing member. The flow restrictor is arranged for movement between a first position where the obstructing member is located so as to form a seal with an edge of an aperture formed in a wall of said production tubing and is arranged to prevent fluid flow through said aperture, and a second position where the obstructing member is located so that the aperture is unobstructed. The flow restrictor further comprises a retaining arrangement for restricting possible locations of said obstructing member to said first position, second position and positions therebetween. The aperture allows fluid communication between the exterior and interior of the production tubing.

Abstract: Various embodiments of the present invention disclose enhanced and improved well production tools for increasing the stability of production zones in a wellbore. Various embodiments of the present invention generally relate to apparatuses, systems, and processes for efficiently and effectively isolating zones within a wellbore.

Abstract: A housing can be mounted adjacent an isolation valve and after a fixed number of on and off pressure cycles allow a spring to push an actuator to operate the valve to an open position. The actuator, can be reset with a tool run into the module to move the actuator back against a power spring and hold that spring force until the pressure cycling begins again. The preferred application is for a formation isolation ball valve but other valves, such as sliding sleeves, or other types of downhole tools can be actuated with the module that permits a retrofit of a hydraulic operation to a heretofore purely mechanically actuated tool. The actuation force to initially open is boosted by a secondary potential energy source that is unlocked to give an initial boost force to the indexing spring that is part of a j-slot actuation mechanism.

Abstract: A downhole oilfield tool assembly comprises a mandrel, a ball valve oriented to block downwards flow through the mandrel in a closed position, a first piston located above the ball valve and at least partly around an outside of the mandrel. The first piston is configured to develop motive force from a pressure differential between an interior of the mandrel and an exterior of the downhole oilfield tool assembly.

Abstract: Actuation assemblies include a valve assembly comprising a valve sleeve configured to rotate to selectively enable fluid flow through at least one aperture in the valve sleeve and into at least one port of an outer sleeve and a ball retention feature configured to selectively retain a ball dropped through a fluid passageway of the valve assembly in order to rotate the valve sleeve. Downhole tools include actuation assemblies. Methods for actuating a downhole tool include receiving a ball in an actuation assembly, rotating a valve sleeve of the actuation assembly to enable fluid to flow through a portion of the actuation assembly, and actuating a portion of the downhole tool with the fluid.

Abstract: A downhole activation assembly for activating a downhole component of a downhole tool positionable in a wellbore penetrating a subterranean formation. The activation assembly includes a housing operatively connectable to the downhole tool, a spring-loaded sleeve, and a ball catcher. The sleeve slidably positionable in the housing, and having a flow channel therethrough and an outer surface defining a chamber between the sleeve and the housing. The sleeve having inlets therethrough about a sleeve end thereof to permit fluid from the flow channel to pass therethrough. The ball catcher slidably positionable in the housing, and having a catcher end engageable with the sleeve end to selectively divert the fluid thereabout and a ball seat therein to receivingly engage a ball passing through the sleeve whereby the ball catcher selectively moves the downhole component between activation positions.

Abstract: An internal blowout preventer used in drilling rigs for the discovery and production of hydrocarbons from the earth is disclosed. The internal blowout preventer has two independently and remotely operable blowout preventer valves in the same body, providing for greater service life and higher reliability during drilling operations. The two valves are loaded into the internal blowout preventer housing from a single end, and are operable by an actuator assembly.

Abstract: A ball valve includes a first ball clamping assembly that defines a first seat surface in contact with an exterior of the ball. A second ball clamping assembly defines a second, sealing seat surface in contact with and adapted to seal with the exterior of the ball. The second ball clamping assembly is coupled to the first ball clamping assembly to clamp the ball between the first and second seat surfaces. The second ball clamping assembly includes a seat ring holder and a seat ring carried by the seat ring holder. The seat ring of the second ball clamping assembly has a sealing seat surface. A springing member is provided between the seat ring and the seat ring holder and springingly biases the seat ring toward the ball. The seat ring holder has a shoulder that supports the seat ring against fully compressing the springing member.

Abstract: A control mechanism for use with a safety valve adapted to seal a wellbore is described. The control mechanism comprises at least one valve actuator for engaging with the safety valve, the at least one actuator being moveable, in use, between a valve open position in which the safety valve is open and a valve closed position, in which the safety valve is closed. The control mechanism further comprises biasing apparatus adapted to bias the at least one valve actuator to the valve closed position, wherein, in use, the at least one valve actuator extends from the safety valve up to a wellbore wellhead. In one described embodiment, the safety valve is moved between the open and closed positions by movement of the at least one valve actuator with respect to the wellbore.

Abstract: A tubular string testing system for use with a tubular string having a longitudinally extending flow passage can include a valve which selectively permits and prevents fluid communication between sections of the flow passage, a bypass passage which provides fluid communication between the sections of the flow passage when the valve is closed, and a filter which filters fluid that flows through the bypass passage. A method of testing a tubular string can include permitting fluid to flow through a bypass passage which connects sections of a flow passage extending longitudinally through the tubular string, a filter filtering the fluid which flows through the bypass passage, a valve of a tubular string testing system preventing flow of the fluid between the sections of the flow passage through the valve, and flow through the bypass passage being prevented in response to a predetermined pressure differential being created across the filter.

Abstract: A ball valve comprises a ball rotatably disposed within a housing, and a trunnion plate supporting the ball. The trunnion plate comprises a trunnion plate hole, and a trunnion plate shoulder disposed on a surface of the trunnion plate about the trunnion plate hole, where the trunnion plate shoulder has a length in the axial direction of the ball valve that is greater than a width in the radial direction of the ball valve.

Abstract: A ball within a ball valve comprises a ball, an interior fluid passage extending through the ball, a first flow passage disposed in the ball that allows fluid communication between an exterior fluid and the interior fluid passage, a second flow passage disposed in the ball that extends through a wall of the ball to the interior fluid passage, where the first flow passage and the second flow passage are on opposite hemispheres of the ball, and a flow through device. The flow through device comprises a plug disposed in the second flow passage and configured to sealingly engage the ball, and a shear device configured to engage the plug and retain the plug in the second flow passage.

Abstract: A technique employs a formation isolation valve that utilizes a ball rotatably mounted within a valve housing. The valve is designed to enable rotation of the ball about a fixed axis without translation of the ball. Rotation of the ball is achieved by connecting an arm to the ball at a position offset from the axis of rotation. A movable mandrel also is connected to the arm to enable selective actuation of the ball.

Abstract: Fluid circulation valve is provided for use with a well drilling operation, so that a drill joint may be added to or removed from the drill string while continuously circulating fluid into the well. Valve housing has a central flow path therein, a housing side port, and upper and lower threaded connectors for engagement with the drill joint and the drill string, respectively. A rotatable ball is positioned within the flow path in the valve housing and a port in the ball is in fluid communication with the housing side port when the ball is closed. A coupling is provided for engaging the valve housing and sealing between an interior of the valve housing and the radially external flow line, which passes fluid into the well when a drill joint is being connecting to the upper end of the valve.

Abstract: A ball valve comprises a housing, a first seat surface, a second seat surface, and a ball rotatably movable within the housing. The ball contacts at least one of the first seat surface and the second seat surface to form a seal within the ball valve. The first seat surface and the second seat surface are fixed relative to each other, and pressure acting in a first direction and in a second direction opposite the first direction increases the contact pressure of the first seat surface and the second seat surface with the ball.

Abstract: A valve and method of use wherein the valve includes a housing having an axial flowbore defined along its length. A lateral fluid flow port is disposed through the housing. A piston sleeve is disposed within the flowbore and is selectively moveable to block flow through the lateral flow port. The valve can be moved between operating positions wherein flow through the lateral flow port is blocked or allowed and axial flow through the flowbore is blocked or permitted.

Abstract: A disposable downhole tool is disclosed. The tool is suitable for use as a frac tool. The tool includes a housing having an inner wall surface defining a bore. The tool also includes a valve structure disposed within the bore, the valve structure comprising a disposable plug seat, the disposable plug seat comprising a first natural rock material. The disposable tool may also include a disposable plug in fluid sealing engagement with the seat, the plug comprising a second natural rock material, the plug and the plug seat comprising a plug valve. The first and second natural rock materials may include sedimentary rock, such as various forms of limestone, including Carrara marble or Indiana limestone.

Abstract: A wellbore ball valve includes a ball-type valve closure having an interior, central bore. A lower ball carrying assembly defines a first annular, sealing seat surface in contact with and adapted to seal with the exterior of the valve closure. The first seat surface defines a first through hole. An upper assembly defines a second annular seat surface in contact with the exterior of the valve closure. The second seat surface defines a second through hole. The second through hole is shaped differently from the first through hole in that it at least partially overlaps with the central bore while the first through hole is sealed from the central bore.

Abstract: A tubular string testing system for use with a tubular string having a longitudinally extending flow passage can include a valve which selectively permits and prevents fluid communication between sections of the flow passage, a bypass passage which provides fluid communication between the sections of the flow passage when the valve is closed, and a filter which filters fluid that flows through the bypass passage. A method of testing a tubular string can include permitting fluid to flow through a bypass passage which connects sections of a flow passage extending longitudinally through the tubular string, a filter filtering the fluid which flows through the bypass passage, a valve of a tubular string testing system preventing flow of the fluid between the sections of the flow passage through the valve, and flow through the bypass passage being prevented in response to a predetermined pressure differential being created across the filter.

Abstract: A wellbore ball valve includes a ball-type valve closure having an interior, central bore. A lower ball carrying assembly defines a first annular, sealing seat surface in contact with and adapted to seal with the exterior of the valve closure. The first seat surface defines a first through hole. An upper assembly defines a second annular seat surface in contact with the exterior of the valve closure. The second seat surface defines a second through hole. The second through hole is shaped differently from the first through hole in that it at least partially overlaps with the central bore while the first through hole is sealed from the central bore.

Abstract: A control mechanism for use with a safety valve adapted to seal a wellbore is described. The control mechanism comprises at least one valve actuator for engaging with the safety valve, the at least one actuator being moveable, in use, between a valve open position in which the safety valve is open and a valve closed position, in which the safety valve is closed. The control mechanism further comprises biasing apparatus adapted to bias the at least one valve actuator to the valve closed position, wherein, in use, the at least one valve actuator extends from the safety valve up to a wellbore wellhead. In one described embodiment, the safety valve is moved between the open and closed positions by movement of the at least one valve actuator with respect to the wellbore.

Abstract: This invention is a top drive having an inside blowout preventer connected with a rotatable stem. The inside blowout preventer includes a hydraulically actuatable arm. An inside blowout preventer with a rotatable stem is connected to the top drive rotatable stem. The inside blowout preventer has a hydraulically actuatable arm, a hydraulic cylinder, a tubular body having a tubular bore, and a valve operator assembly surrounding the tubular body.

Abstract: The tool can run in and latch another tool such as a ball valve into a packer, for example. It has the capability of operating the valve while still engaged to the valve housing. Once the valve is operated and released a pressure test can be conducted while the tool is still engaged to the valve housing. After that a predetermined applied force allows release from the valve housing without the valve shifting mechanism still engaged. In a different configuration the tool can be a simple pulling tool to remove the valve housing without shifting it. The tool has a rotational lock to allow release from a packer by turning to the right. In another configuration it can be a latch tool for a production string that shifts the valve as it releases when the production string is pulled.

Abstract: A drilling rig with a top drive having an inside blowout preventer for drilling in a wellbore, the drilling rig having a derrick and a crown, a torque track suspended from the crown, a travelling block hanging from a cable, a drawworks for raising or lowering the travelling block, and a top drive with a rotatable stem suspended from the travelling block. The top drive has a motor mounted to the top drive housing and is connected to the rotatable stem. An inside blowout preventer with a rotatable stem is connected to the top drive rotatable stem. The inside blowout preventer has a hydraulically actuatable arm, a hydraulic cylinder, a tubular body having a tubular bore, and a valve operator assembly surrounding the tubular body.

Abstract: A pressure equalizing system allows flow past an upper seal on a movable member downhole that in turn allows pressure to be delivered from uphole into what had previously been an isolated low pressure zone. The pressure differential across the member is equalized before attempting to move the member into another position. The member is a ball in a ball valve for subterranean use.

Abstract: A valving system includes, a tubular having a seat, and a body with a bore therethrough having a surface sealably engagable with the seat, the body being rotatable relative to the tubular between at least a first position, a second position and a third position, the first position occluding flow between an inside of the tubular and the bore the second position providing fluidic communication between the inside of the tubular and the bore via at least one cavity formed in the surface and a third position providing direct fluidic communication between the inside of the tubular and the bore

Abstract: A downhole tool is hydraulically actuated through a control system that features rod piston(s) that are double acting. The piston bore is in a single housing component with an annular cavity that provides access to all piston bores to move the pistons in a first direction. The housing component that has the piston bore also includes an internal sleeve in a passage in the housing. A second control system connection communicates with a sealed annular space defined between the sleeve and the passage wall that holds the sleeve. A series of radial ports communicate from the annular space into each piston bore on the opposite side of each piston from the annular cavity so that each piston is double acting with a bore in a single housing component.

Abstract: A downhole ball valve is mounted n a string and features a rotating ball that turns on its axis as it is held against an upstream and a downstream seal by a cage. The cage accepts a slide that engages the ball off-center to rotate it between the open and closed positions. The slide is operated by a sleeve attached to a piston assembly. The sleeve is mechanically operated in opposed directions such as by a wireline shifting tool. Differential pressure on a closed ball does not affect the actuation piston because pressure across the actuating piston is balanced while holding pressure differential across the closed ball. A check valve allows the actuation piston to be in pressure balance as the ball stays closed.

Abstract: A lubricator valve assembly adapted for connection in a pipe string for use in a well includes a tubular valve body having a bore formed longitudinally therethrough; a valve seat connected to the valve body and in communication with the bore; a valve element mounted in the bore and rotatable with respect to the valve seat between positions opening and closing the bore; an operator in connection between the valve element and a hydraulic control system, the operator moving the valve element between the open and close bore positions in response to the hydraulic control system; and a system for opening the valve element upon failure of the hydraulic system.

Abstract: A well tool with combined actuation of multiple valves. A well tool includes at least two valves and an actuator which actuates each of the valves, one valve being positioned longitudinally between the other valve and the actuator, and the other valve being operable in response to displacement of an operating device by the actuator. Another well tool includes a valve with a closure which displaces when the valve is operated, a volume of a chamber which increases and a volume of another chamber which decreases when the closure displaces, and a pressure differential between the chambers being substantially zero when the closure displaces. Another well tool includes at least two valve closures which are the only displaceable components of the well tool exposed to a first internal flow passage portion when one closure prevents fluid communication between the first and a second internal flow passage portions.

Abstract: A ball type downhole barrier valve capable of bidirectional sealing features a ball rotating on its axis to open or close with control line pressure to an actuating rod piston assembly. The ball is also shiftable to a locked open position. A cage surrounds the ball and retains opposed seats to it. The cage is made from one piece and tangential holes are drilled and tapped before the piece is longitudinally split with a wire EDM cutting technique. Fasteners to rejoin the cut halves properly space them to the original one piece internal dimension. Auxiliary tools allow determination of spacing of internal components so that a desired spring preload on the seats against the ball can be achieved. Seals on the sleeves that form ball seats help prevent leakage due to ball distortion at high differential pressures when the valve is closed.

Abstract: A downhole tool for providing a pressure differential between sub-assemblies, the downhole tool including an elongated body, a tubular assembly disposed within the elongated body, the tubular assembly including a central flowbore with an inner diameter and a central longitudinal axis, a camming device, an actuator member located below the tubular assembly, having a dual-bore configuration, the actuator member including a first bore, a second bore, and a concave seating surface formed within the second bore for receiving a obstructing device, wherein the first bore and the second bore are oriented 90 degrees to one another so that fluid may flow through the actuator while it is in either a first or a second position, and a stationary sleeve concentrically disposed between the actuator member and the elongated body is disclosed.

Abstract: A completion suspension valve system is described which allows a well to be suspended and desuspended remotely without a dual bore riser to the surface. This is achieved by incorporating a remotely actuatable valve into the production bore of a tubing hanger. The valve is hydraulically operable and may be controlled via the tubing hanger running tool or via the xmas tree. The valve can be closed and tested after the tubing hanger has been installed, thereby isolating the well. The dual bore riser and running tool are retrievable and the MODU type vessel is then free to continue drilling and completion operations elsewhere. The xmas tree can therefore be deployed from a workclass supply boat instead of a MODU type vessel.

Abstract: A technique enables control over flow in a wellbore with a flow control system. The flow control system combines a flow reduction mechanism with a flow control device, such as a valve. The flow reduction mechanism comprises a closure member which can be selectively moved between an unactuated and actuated position, allowing relatively greater flow through the flow control device in the unactuated position. The flow reduction mechanism actuates prior to or in conjunction with the flow control device to reduce flow and thus reduce the loading forces that would otherwise act against the flow control mechanism upon closure of the flow control device.

Abstract: A ball type downhole lubricator valve features a ball rotating on its axis to open or close with control line pressure to an actuating piston. The ball is also shiftable to a locked open position. A cage surrounds the ball and retains opposed seats to it. The cage is made from one piece and tangential holes are drilled and tapped before the piece is longitudinally split with a wire EDM cutting technique. Fasteners to rejoin the cut halves properly space them to the original one piece internal dimension. Auxiliary tools allow determination of spacing of internal components so that a desired spring preload on the seats against the ball can be achieved.

Abstract: A technique employs a formation isolation valve that utilizes a ball rotatably mounted within a valve housing. The valve is designed to enable rotation of the ball about a fixed axis without translation of the ball. Rotation of the ball is achieved by connecting an arm to the ball at a position offset from the axis of rotation. A movable mandrel also is connected to the arm to enable selective actuation of the ball.

Abstract: Apparatus and method for a providing a completion assembly for running at an end of a completion string which provides a remotely operable tubing mounted valve used to control the flow of fluids through the tubing in hostile well conditions. The tubing mounted completion assembly has a tubular body for connection in the string below a production packer with a through bore from a first inlet and a first outlet coaxially aligned with the string; a downhole electronic actuating mechanism, a downhole hydraulic pump and a hydraulically operated ball valve member. The actuating mechanism operates the hydraulic pump to provide a hydraulic control line to control movement the valve member from a first position, where the member is open and a through bore is created between the inlet and outlet of the assembly, to a second position, where the valve seals the throughbore and, finally, back to the first position.

Abstract: A bearing mounted ball valve (10) comprises a housing (12) having a throughbore and a valve seat (16) and an apertured ball (18) mounted within the housing in continuous engagement with the valve seat. The apertured ball is rotatable by rotation means (20), about an axis of rotation, between a throughbore open position and a throughbore closed position. The bearing mounted ball valve further comprises bearing means (26) coupled between the apertured ball and the housing for constraining the rotation of the apertured ball about the axis of rotation between the throughbore open and the throughbore closed position. In the throughbore closed position, the bearing means is adapted to release the apertured ball from the axis of rotation to permit the apertured ball to float into a sealing engagement with the valve seat.

Abstract: The tool can run in and latch another tool such as a ball valve into a packer, for example. It has the capability of operating the valve while still engaged to the valve housing. Once the valve is operated and released a pressure test can be conducted while the tool is still engaged to the valve housing. After that a predetermined applied force allows release from the valve housing without the valve shifting mechanism still engaged. In a different configuration the tool can be a simple pulling tool to remove the valve housing without shifting it. The tool has a rotational lock to allow release from a packer by turning to the right. In another configuration it can be a latch tool for a production string that shifts the valve as it releases when the production string is pulled.

Abstract: A ball type downhole lubricator valve features a ball rotating on its axis to open or close with control line pressure to an actuating piston. The ball is also shiftable to a locked open position. A cage surrounds the ball and retains opposed seats to it. The cage is made from one piece and tangential holes are drilled and tapped before the piece is longitudinally split with a wire EDM cutting technique. Fasteners to rejoin the cut halves properly space them to the original one piece internal dimension. Auxiliary tools allow determination of spacing of internal components so that a desired spring preload on the seats against the ball can be achieved.

Abstract: A casing running tool comprising an integral elevation module and make-up/torque module. In accordance with one aspect or the invention, the tool is adapted to automatically engage a collared end of a tubular structure such as a casing string segment. The integral make-up/torque module is actuated by hydraulic control lines to exert compression force upon the outer diameter of a tubular, such as a casing string segment. This compression force is sufficient to enable torque to be applied to the tubular without slippage. In one embodiment, the make-up/torque module comprises an outer body carrying a plurality of hydraulically-actuable pistons, such that the tool is actuable from the rig floor to grasp the tubular with sufficient force that rotational force (torque) supplied via a drive motor in a top-drive rig. In accordance with another embodiment, the multifunction tool further includes an internal ball valve assembly for selectively allowing or restricting fluid flow through the tool.

Abstract: A well tool with combined actuation of multiple valves. A well tool includes at least two valves and an actuator which actuates each of the valves, one valve being positioned longitudinally between the other valve and the actuator, and the other valve being operable in response to displacement of an operating device by the actuator. Another well tool includes a valve with a closure which displaces when the valve is operated, a volume of a chamber which increases and a volume of another chamber which decreases when the closure displaces, and a pressure differential between the chambers being substantially zero when the closure displaces. Another well tool includes at least two valve closures which are the only displaceable components of the well tool exposed to a first internal flow passage portion when one closure prevents fluid communication between the first and a second internal flow passage portions.

Abstract: The safety valve includes a first generally tubular body 12 and a second generally tubular body 14 each having flow paths therein when the bodies are mated. A ball 20 rotates between open and closed position in a first seat 30 and a ball centering member 32 provided for engaging the ball. An outer actuator sleeve 40 is rotatable with respect to the first and second bodies, and a connecting member 50 acts between the actuator sleeve and the ball to rotate the ball.

Abstract: A hydraulic control and actuation system for downhole tools. In a described embodiment, a hydraulic control and actuation system includes an internal chamber serving as a low pressure region and a well annulus serving as an energy source. A valve assembly provides selective fluid communication between alternating opposite sides of a piston and each of the energy source and low pressure region. Displacement of the piston operates a well tool. Operation of the valve assembly is controlled via telemetry between a remote location and an electronic circuit of the system.

Abstract: The present invention provides for high volume flow from a well. A retrievable formation isolation valve allows high volume flow through the remaining casing or tubing. Alternatively, a large bore valve configuration that is not retrieved, but remains as part of the casing, can be used. The present invention also includes methods to allow for high volume flow using retrievable isolation valves or large bore valves.

Abstract: Apparatus for multi-zone wellbores that can by-pass upper hydrocarbon bearing zones and deliver fluid to lower hydrocarbon bearing zones. The apparatus can include at least one housing, and at least one port can be formed through the housing. An inner sleeve can be positioned within the housing. At least one cavity can be radially disposed on an outer diameter of the inner sleeve, and each cavity can be located within an annulus formed between the inner sleeve and the housing. A ball can be disposed within each cavity, and the ball can be adapted to selectively engage the port.

Abstract: A lubricator valve assembly adapted for connection in a pipe string for use in a well includes a tubular valve body having a bore formed longitudinally therethrough; a valve seat connected to the valve body and in communication with the bore; a valve element mounted in the bore and rotatable with respect to the valve seat between positions opening and closing the bore; an operator in connection between the valve element and a hydraulic control system, the operator moving the valve element between the open and close bore positions in response to the hydraulic control system; and a system for opening the valve element upon failure of the hydraulic system.

Abstract: A tool that is easily convertible from a frac plug to a bridge plug is disclosed. The tool comprises a mandrel with a mule shoe connected to the lower end thereof. A closing ball is disposed in a cavity defined by the mule shoe. The mandrel is threaded to receive a plug at or near the upper end thereof to convert the frac plug to a bridge plug.