Apparatus and method for cutting a tube in an oil or gas well

Abstract

A cutting tool is provided for use in an oil or gas well. The cutting tool includes a battery powered power assembly that allows the tool to be used downhole without power from the surface. In use, the power assembly rotates the drive shaft and varies fluid pressure within the cutting tool. A drive shaft rotates a cutting wheel assembly including a cutting wheel that rotates about the shaft. The cutting wheel may radially extend and retract in response to changes in fluid pressure. A corresponding method of cutting a pipe using a cutting tool is described.

Description

[0001] The present application generally relates to an apparatus and method involving a cutting tool and method for cutting a tubular member in a downhole environment. Background Art

[0002] During downhole recovery operations, it may be necessary to retrieve segments of tubular components, such as casing, bushings, drill pipe, mandrels, and other pipes. In order to more easily recover these parts to the surface, tubular components are typically cut into manageable lengths to be pulled out of the wellbore.

[0003] Conventional cutting tools include shears, milling tools or lathe-like cutters that run downhole on an e-line. These tools need to be supplied with a high level of direct current (DC) power in order to provide the rotational power coupled with the applied force required to cut through the wall of the downhole tubular member. The use of an e-line provides the tool with effectively unlimited power to cut through the target during the cutting operation. However, due to the increased risks associated with the high voltages provided, for example, e-line operation requires personnel to have a higher level of training to operate tools powered in this manner.

[0004] Such conventional cutting tools may require some time to penetrate the wall of the tubular member, and the demand for power increases as the cutting operation lasts longer, resulting in higher heat generation. In particular, conventional cutting tools may generate chips and / or splaying at the edges of the cut, which may interfere with subsequent operations.

[0005] Additionally, current cutting tools must be conveyed downhole in predetermined settings, and if an operating parameter needs to be changed (e.g., a setting increment is increased to the maximum radial extension of the cutting device to allow it to cut further into the tubular wall), several trips to the target location may be required to complete the cutting operation.

[0006] Due to the limitations of conventional cutting tools, it would be beneficial to provide an alternative power source for the cutting tool that does not need to be run on a power cable and therefore does not have additional cumbersome training requirements. This would allow a greater number of operators to use such tools.

[0007] It would also be beneficial to provide a cutting tool that is as compact as possible (in terms of its longitudinal length).More compact tools are desirable by operators because they generally reduce the cost and time involved in running in / pulling out of a wellbore.

[0008] Additionally, further improvements in the performance of conventional cutting tools and in reducing the cost of such conventional cutting tools would be highly desirable, particularly in the oil and gas industry where costs need to be minimized. Summary of the invention

[0009] According to the present invention, there is provided a cutting tool for an oil well or a gas well, the cutting tool comprising:

[0010] a battery powered power assembly, wherein operation of the power assembly causes the drive shaft to rotate and change the fluid pressure within the cutting tool;

[0011] wherein the drive shaft is configured to rotate a cutting wheel assembly;

[0012] wherein the cutting wheel assembly comprises a cutting wheel configured to rotate about an axis; and

[0013] Wherein the cutting wheel is actuated to move radially in response to changes in the fluid pressure.

[0014] Optionally, the power assembly includes a battery pack and a motor. Optionally, the power assembly includes a power control module (PCM), which includes a battery pack and a motor. Optionally, the power assembly includes a gearbox. Optionally, the power assembly includes a PCM, which includes a battery pack, an electric motor and a gearbox.

[0015] The PCM, motor and gearbox can be of any type configured to work with a linear actuator. Preferred examples of PCMs, motors and gearboxes are described in WO2019 / 180462A1, the entire contents of which are incorporated herein by reference, and are provided by Aberdeen, UK Made and available for purchase from.

[0016] The PCM can be used as the sole power source for the cutting tool. In other words, the cutting tool can be powered entirely by the battery pack within the PCM.

[0017] Thus, the cutting tool may advantageously be operated on a cable, wireline, wire cable, electrical cable or any other suitable type of conveying method. Alternatively, if the cutting tool is operated on a cable, the cable may be used as a means of transmitting commands and / or data between the tool and the surface of the wellbore into which the tool is operated. Alternatively, the tool may be pre-programmed with, for example, timed operations that instruct the tool, for example, to start a motor, without necessarily requiring any instructions or signals to be sent from the surface.

[0018] Advantageously, using the battery pack as the sole power source, rather than powering the tool via the Easy Cable, means that no rectifier is required. Normally, a rectifier would be used to power the motor via the Easy Cable, but the use of the battery pack means that the tool can operate regardless of the power conversion state.

[0019] In particular, the battery pack in the PCM can selectively provide electrical energy to the electric motor in the motor subassembly. Optionally, when power is supplied to the electric motor, the motor starts to rotate.

[0020] The electric motor may be connected to the gearbox via a first end of an input shaft. Rotation of the motor may cause the input shaft to rotate, thereby rotating the gearbox. Optionally, the input shaft is coupled to a drive shaft at its second end. Optionally, the input shaft is coupled to a drive coupling assembly at its second end. Optionally, the drive coupling assembly is coupled to the drive shaft. Optionally, the rotational motion of the electric motor is transmitted to the drive shaft through the gearbox and the drive coupling, which then rotates.

[0021] Optionally, the drive shaft is part of a rotating assembly, the rotating assembly further comprising a linear actuator. Optionally, the rotating assembly further comprises a piston, optionally a hydraulic piston.

[0022] Preferably, the linear actuator includes a lead screw and a lead screw nut, but this is not limiting and alternative configurations of the linear actuator may be used. For example, alternatively, the linear actuator may include a ball screw and a ball nut (where lead screw, lead screw nut, and lead screw assembly are used in this disclosure, these terms may be replaced with ball screw, ball nut, and ball screw assembly, and vice versa unless otherwise stated). Optionally, the lead screw assembly includes a housing, a lead screw, and a lead screw nut.

[0023] Optionally, the drive shaft comprises at least one clutch.

[0024] Optionally, the clutch may be a slip clutch, for example in the form of at least one tolerance ring on the outer surface of the shaft. Optionally, the at least one tolerance ring is a circlip, or alternatively a full ring. Optionally, the at least one tolerance ring comprises a circumferential protrusion, such as a ridge, or a wave-like structure. Optionally, the drive shaft comprises a portion having a protrusion, such as a ridge or wave, on the outer surface of the drive shaft, wherein the protrusion of the drive shaft portion corresponds to the protrusion of the tolerance ring. Optionally, the engagement between the protrusion of the tolerance ring and the drive shaft holds the one or more tolerance rings in place.

[0025] Optionally, one or more tolerance rings provide friction between the drive shaft and the lead screw in the lead screw assembly. Optionally, one or more tolerance rings are press-fitted between the drive shaft and the lead screw. Optionally, a slip clutch is pressed outwardly against the inner surface of the lead screw using a spring force, thereby providing friction. Optionally, the slip clutch is configured to allow the drive shaft and the lead screw to slide relative to each other rotationally when the drive shaft provides a threshold level of torque. Optionally, the slip clutch is configured so that when the threshold level of torque is reached, it exceeds the spring force of the slip clutch, thereby allowing relative motion between the drive shaft and the lead screw. Optionally, when the maximum pressure is reached in the cutting tool, the slip clutch allows the drive shaft and the lead screw to slide through each other, as described in more detail below.

[0026] Alternatively, the clutch may be an optional torque limiting clutch, such as a synchronous torque limiting clutch, and may be optionally arranged in a different configuration within the cutting tool. A suitable clutch may be the 10 ... Obtained clutch.

[0027] Alternatively, the clutch may be disposed at one end of the rotating assembly, rather than between the drive shaft and the lead screw. Alternatively, the clutch is at least partially engaged with the drive shaft, for example, the clutch may be clamped to a portion of the drive shaft. Alternatively, one end of the clutch is configured to engage with the lead screw. Alternatively, the clutch is attached, optionally fixedly attached to an adapter, which is disposed between the clutch and the lead screw and is optionally configured to engage the lead screw. Alternatively, one end of the adapter includes a protrusion that engages with a castellation on a corresponding end of the lead screw.

[0028] Optionally, the clutch is configured to slip at a predetermined threshold level of torque (e.g., in the range of 10-50 Nm, but this can be set as desired). Initially, the clutch is used to rotate the drive shaft and the lead screw together. Once the threshold level of torque is reached and / or exceeded, the clutch is configured to slip, thereby allowing relative movement between the drive shaft and the lead screw. As described above, optionally, when maximum pressure is reached in the cutting tool, the clutch allows the drive shaft and the lead screw to slide past each other, as described in more detail below.

[0029] Optionally, the lead screw comprises a through hole through which the drive shaft of the linear actuator passes. Optionally, the drive shaft and the lead screw are coaxially arranged. Optionally, the lead screw surrounds at least a portion of the length of the drive shaft.

[0030] Optionally, when the drive shaft rotates, engagement with the lead screw simultaneously causes rotation of the lead screw. Optionally, the lead screw includes a threaded portion on its outer surface. Optionally, the entire outer surface of the lead screw can be threaded. Alternatively, the lead screw can be at least partially threadless.

[0031] Optionally, the screw nut includes a through hole, and the screw nut surrounds at least a portion of the screw so that at least a portion of the length of the screw is located within the through hole of the screw nut, and optionally, the screw nut, the screw and the drive shaft are coaxial with the axis of the cutting tool.

[0032] Optionally, the inner surface of the lead screw nut comprises a threaded portion. Optionally, the threaded portion of the lead screw nut engages with the threaded portion of the lead screw and is optionally complementary to the threaded portion of the lead screw.

[0033] In the case of using a ball screw assembly, optionally, the threaded section of the ball nut forms a raceway for a bearing, preferably a spherical bearing, together with the ball screw. Optionally, the ball nut also includes a recirculation mechanism to recirculate the spherical bearing.

[0034] Optionally, when the drive shaft rotates, the lead screw rotates due to frictional engagement with one or more tolerance rings of the drive shaft.When the lead screw rotates, the lead screw nut moves axially along the lead screw.

[0035] Optionally, the rotating assembly is balanced with the well pressure. Optionally, the rotating assembly is configured to convert the rotating motion into fluid pressure, optionally hydraulic.

[0036] Optionally, the lead screw nut is coupled to the piston at one end, optionally at its lower end (i.e., the end of the lead screw nut closer to the cutting wheel assembly). Optionally, the lead screw nut and the piston are in a locked configuration. Optionally, the lead screw nut and the piston are connected together by a screw or other fixing.

[0037] Optionally, the piston comprises a central hole having a first inner diameter. Optionally, the end of the piston comprises an opening having a second inner diameter less than the first inner diameter. The opening is optionally sized to allow a drive shaft to pass through the opening. The opening optionally also comprises at least one inner seal, optionally comprising an annular seal, such as an O-ring. Optionally, the inner annular seal or each inner annular seal is at least partially disposed in a recess formed in the inner surface of the opening. Optionally, the seal forms a sealing engagement between the opening and the drive shaft. Optionally, the O-ring is used to prevent fluid from entering or flowing out of either side of the piston.

[0038] Optionally, within the rotating assembly, there is a piston chamber between the hydraulic piston and the cutting wheel assembly and / or the anchoring module. The piston chamber may contain a fluid to be compressed by the hydraulic piston.

[0039] Optionally, when the lead screw nut moves axially, the piston travels with the lead screw nut due to the locking configuration. Optionally, when the gearbox rotates in one direction (e.g., counterclockwise), the lead screw nut travels axially toward the cutting wheel assembly. Optionally, when the gearbox rotates in the opposite direction (e.g., clockwise), the lead screw nut travels axially away from the cutting wheel assembly.

[0040] Optionally, the piston comprises at least one seal, optionally an annular seal, such as an O-ring, on the outer surface of the piston. Optionally, the outer annular seal or each outer annular seal is at least partially arranged in a recess formed on the outer surface of the piston. Optionally, the piston also comprises at least one seal, optionally an annular seal, in the inner surface of the piston. Optionally, at least one seal on the inner surface of the piston is in sealing engagement with the drive shaft.

[0041] Optionally, the housing of the screw assembly includes at least one annular groove formed on its inner surface. Optionally, the housing of the screw assembly includes at least a first annular groove and a second annular groove formed on its inner surface. Optionally, the first annular groove and the second annular groove are axially spaced apart. Optionally, the housing of the screw assembly includes a segment having a narrower inner diameter disposed between the first annular groove and the second annular groove. Optionally, the piston chamber includes an inner diameter narrower than the first annular groove and / or the second annular groove. Optionally, the inner diameter of the piston chamber is the same as the inner diameter of the segment of the screw housing between the first annular groove and the second annular groove.

[0042] Optionally, the piston is initially aligned with the second annular groove before any movement of the piston occurs. Optionally, when the lead screw nut advances axially and moves the piston, the piston moves through the second annular groove into the piston chamber. Optionally, an outer annular seal on the outer surface of the piston is in sealing engagement with the inner surface of the piston chamber.

[0043] Optionally, the drive shaft includes a spline end. Optionally, the spline end is configured to be connected to the cutting wheel assembly. Optionally, the cutting wheel assembly includes a corresponding spline opening, in which the spline end of the drive shaft is inserted. Optionally, the spline engagement between the drive shaft and the cutting wheel assembly transmits the rotation of the drive shaft to the cutting wheel assembly. In other words, the drive shaft and the cutting wheel assembly are rotationally engaged so that when the drive shaft (in either direction) rotates, the cutting wheel assembly also rotates. Optionally, the rotation of the cutting wheel assembly revolves around the longitudinal axis of the cutting tool.

[0044] Alternatively, the cutting wheel assembly may include a ratchet and pawl configuration. Optionally, one or more pawls may be narrower at one end, optionally narrower at an end engaging with the ratchet, and optionally thicker at an opposite end. Optionally, one or more pawls may be paddle-shaped or blade-shaped. Optionally, one or more pawls are each retained in or adjacent to a cavity formed in the cutting wheel assembly. Optionally, the cavity includes a biasing device. Optionally, the biasing device is configured to bias the pawl or each pawl toward the drive shaft of the tool.

[0045] Optionally, the drive shaft includes ridges or teeth configured to engage with at least one pawl in the cutting wheel assembly. Optionally, the end of the drive shaft acts as a ratchet. Optionally, the ridges or teeth on the end of the drive shaft are configured to rotate past the at least one pawl when rotating in one direction, and are configured to engage with the at least one pawl when rotating in another direction. Optionally, when the drive shaft rotates in a first direction, the engagement of the at least one pawl with the ridge / tooth on the end of the drive shaft drives the rotation of the cutting wheel assembly.

[0046] Alternatively, the rotation of the drive shaft in a second direction opposite to the first direction causes the drive shaft to slide through or inertially slide through at least one pawl. Optionally, when the drive shaft passes through the pawl or each pawl, the pawl or each pawl is pushed against the biasing device by the ridge / tooth on the drive shaft. Optionally, the pawl or each pawl can be hinged or similarly fixed to the cutting wheel assembly, and is optionally arranged so that when the drive shaft moves through the pawl or each pawl, the free end of the pawl or each pawl moves along an arc in the cavity. This allows the drive shaft to rotate without a corresponding rotation of the cutting wheel assembly. Optionally, the rotation of the drive shaft in the second direction retracts the hydraulic piston by reversing the direction of travel of the linear actuator.

[0047] The advantage provided by the ratchet and pawl arrangement is that if the cutting wheel / cutting wheel assembly becomes stuck or stalled in the wellbore, the drive shaft can be rotated in a second direction causing the piston to retract and the fluid pressure within the tool to decrease. Once the fluid pressure is released, in the event that the cutting wheel becomes stuck, the cutting wheel can be vibrated to release the tool from the tubular and allow the tool to be retrieved to the surface.

[0048] Optionally, the cutting tool also includes an anchoring module, which is optionally arranged between the rotating assembly and the cutting wheel assembly. Optionally, the anchoring module is in fluid communication with the rotating assembly and / or the cutting wheel assembly (optionally, the fluid communication is selected). Optionally, the anchoring module includes a plurality of anchors. Optionally, the anchors are symmetrically arranged around the circumference of the anchor module. Alternatively, the anchor may be arranged in another part of the cutting tool.

[0049] Optionally, the anchor is in the form of a grooved button that moves radially outward from the tool, such as from the anchor module, to anchor the cutting tool. Alternatively, the anchor can be an anchor pad. Optionally, the anchor pad or anchor button is radially arranged around the anchor module, optionally in a symmetrical configuration. Optionally, the anchor is actuated by fluid pressure, which is enhanced within the anchor module due to the movement of the piston. Optionally, the anchor is configured to engage with the inner surface of the target tubular to be cut (e.g., casing, liner, etc.).

[0050] The anchor is configured to rotationally secure the cutting tool relative to the target tubular, thereby allowing the cutting wheel to rotate while preventing the remainder of the tool from rotating during the cutting operation.

[0051] Optionally, the anchor module comprises an anchor module pressure relief valve, and optionally a check valve. Optionally, the cutting wheel assembly comprises an anchor module pressure relief valve, and optionally a check valve.

[0052] Optionally, when the pressure in the anchor module is below a first predetermined threshold, the anchor module pressure relief valve prevents fluid communication between the anchor module and the cutting wheel assembly. Optionally, the anchor is configured to radially extend at a pressure greater than zero but less than a first predetermined threshold. This provides the advantage of the anchor being deployed and in place before starting a cutting operation as further described below.

[0053] Optionally, the first predetermined threshold may be in the range of 100-1000 psi (or greater than or equal to 100 psi; or less than or equal to 1000 psi). In this example of the invention, this wide range includes a suitable pressure for the first predetermined threshold and the anchor may be deployed at this pressure. Optionally, the first predetermined threshold may be in the range of 100-500 psi (or greater than or equal to 100 psi; or less than or equal to 500 psi), which includes the pressure at which the first predetermined threshold is preferably set and the pressure at which the anchor may be deployed. Optionally, the first predetermined threshold may be in the range of 100-300 psi (or greater than or equal to 100 psi; or less than or equal to 300 psi). This range is particularly suitable for deploying the anchor before starting the cutting operation.

[0054] Optionally, as the lead screw rotates and the piston moves toward the cutting wheel assembly, the pressure behind the anchor module pressure relief valve increases.Once the pressure exceeds a first predetermined threshold, fluid may begin to enter the cutting wheel assembly through the anchor module pressure relief valve.

[0055] Optionally, when fluid flows into the cutting wheel assembly, the fluid pressure in the cutting wheel assembly increases. Optionally, the fluid pressure increases to a second predetermined threshold, wherein the second predetermined threshold is higher than the first predetermined threshold. Optionally, the second predetermined threshold can be in the range of 200-1500psi (or greater than or equal to 200psi; or less than or equal to 1500psi). This wide range includes pressures that are suitable for radially extending the cutting wheel and applying a force for a cutting operation. Optionally, the second predetermined threshold can be in the range of 400-1200psi (or greater than or equal to 400psi; or less than or equal to 1200psi). This range includes pressures that are suitable for radially extending the cutting wheel and applying a force for a cutting operation. Optionally, the second predetermined threshold can be in the range of 800-1200psi (or greater than or equal to 800psi; or less than or equal to 1200psi). This range is particularly useful for cutting operations due to the force provided to the cutting wheel by these fluid pressures (and / or the potential pressure differential between the first predetermined pressure threshold and the second predetermined pressure threshold, allowing the anchor to deploy at relatively low pressures, with the second predetermined threshold set at a suitably high pressure).

[0056] Optionally, when the fluid pressure reaches a second predetermined threshold, the clutch is configured to allow the drive shaft to effectively disengage from the lead screw so that the drive shaft can rotate without further rotation of the lead screw as described above. Optionally, when the clutch is actuated and the drive shaft and lead screw lose mutual friction, the fluid pressure within the cutting wheel assembly can decrease (due to the increased volume as the cutting wheel and rollers extend radially outward), or alternatively, it can remain at or very close to the second predetermined threshold.

[0057] Advantageously, by preventing the fluid pressure within the cutting wheel assembly from exceeding the second predetermined threshold, the risk of damage to the cutting tool or more specifically the cutting wheel itself (e.g., stalling or breaking of the wheel) is significantly reduced. Furthermore, the fluid pressure is maintained at a sufficiently high level to allow the cutting wheel to engage the tubular to be cut - if the fluid pressure is too low, the cutting wheel may not apply sufficient pressure to the tubular and the cutting process may be adversely affected.

[0058] Alternatively, the tool may not include an anchor module pressure relief valve or check valve and may have a single predetermined pressure threshold at which the drive shaft and leadscrew disengage.Alternatively, the anchor may be actuated simultaneously with the cutting wheel and cutting wheel housing.

[0059] Alternatively, in addition to or in lieu of the clutch, the cutting tool may include a piston relief valve (PRV) to control pressure within the tool. Optionally, the piston PRV is located at the distal end of the piston. Optionally, the piston PRV extends parallel to the longitudinal axis of the cutting tool. Optionally, the piston PRV is disposed within the wall of the piston. Optionally, the piston PRV controls fluid communication between the piston chamber and the rotating assembly.

[0060] Where a piston PRV is used in place of a clutch mechanism, the lead screw may be fixedly attached to the drive shaft. For example, the lead screw may be attached by a screw or other fixture extending at least partially radially into the drive shaft. Optionally, each complete rotation of the drive shaft advances the piston a distance equal to the pitch of the lead screw.

[0061] Optionally, the piston PRV is configured to maintain a constant pressure supplied to the anchor and cutting wheel assembly. Optionally, the desired pressure can be in the range of 200-1500psi, for example 800-1200psi. Optionally, the desired pressure is set to a particularly preferred value, for example: 1000psi; 1100psi; or 1200psi. Optionally, if the fluid pressure in the piston chamber exceeds a predetermined pressure, the piston PRV opens, and optionally, fluid passes from the piston chamber into the central bore of the piston, and / or into the space between the piston and the screw assembly housing.

[0062] Optionally, the cutting wheel assembly comprises at least one roller. Optionally, the at least one roller is configured to stabilize the cutting wheel assembly, optionally to center the cutting wheel assembly. Optionally, the at least one roller mitigates rotation of the cutting wheel assembly. Optionally, the at least one roller is disposed relative to the cutting wheel. Optionally, the roller or each roller comprises a roller wheel that rotates about a roller axis. Optionally, the axis is aligned with the axis of the cutting tool. Optionally, the roller axis comprises a bearing to facilitate rotation.

[0063] Optionally, each of the roller and the roller shaft is arranged in a roller shell. Optionally, the roller shell or each roller shell is movable, optionally radially movable. Optionally, the cutting wheel assembly includes a chassis in which the cutting wheel and the roller or each roller are arranged. Optionally, the roller shell or each roller shell is arranged in one or more cavities, hereinafter referred to as a roller cavity / multiple roller cavities formed in the chassis of the cutting wheel assembly. Optionally, the roller or each roller includes at least one resilient device, which is configured to bias the roller shell towards a retracted configuration and resist radial extension of the roller or each roller.

[0064] Optionally there is a fluid path from the anchor module pressure relief valve and / or check valve to the or each roller cavity. Optionally there is no anchor module pressure relief valve or check valve and pressure is controlled by a clutch and / or piston PRV.

[0065] Optionally, when fluid pressure is increased in the anchor module and / or the cutting wheel assembly, fluid may flow into the or each roller cavity. Optionally, when fluid flows into the or each roller cavity, the fluid pressure pushes the or each roller shell. Optionally, when the fluid pressure increases, the biasing effect of the one or more resilient devices is overcome and the or each roller shell may move radially outwardly. Optionally, when the roller shell moves radially outwardly, the roller wheel housed within the roller shell then extends beyond the circumference of the cutting wheel assembly chassis and may contact the inner surface of the target pipe to be cut.

[0066] Optionally, the cutting wheel assembly includes two rollers arranged directly opposite the cutting wheel and positioned so that the rollers are located on either side of the cutting axis of the cutting wheel. In other words, the rollers can be optionally arranged to contact the inner surface of the target pipe on either side of the pipe being cut.

[0067] Optionally, the cutting wheel is mounted on a cutting wheel shaft in the cutting wheel housing. Optionally, the cutting wheel shaft is aligned with the longitudinal axis of the cutting tool. Optionally, the cutting wheel is configured to rotate around the cutting wheel shaft. Optionally, the cutting wheel shaft includes a bearing that is convenient for rotation. Optionally, the cutting wheel, the cutting wheel shaft and the cutting wheel housing are arranged in another cavity, hereinafter referred to as the cutting wheel cavity. Optionally, there is a fluid path from a pressure relief valve and / or a check valve to the cutting wheel cavity. Optionally, when fluid pressure is strengthened in the anchoring module and / or the cutting wheel assembly, the fluid can flow into the cutting wheel cavity or each cutting wheel cavity. Optionally, when the fluid flows into the cutting wheel cavity or each cutting wheel cavity, the fluid pressure pushes the cutting wheel housing and moves the cutting wheel housing radially outward. When the cutting wheel housing moves radially outward, the cutting wheel contained in the cutting wheel housing then extends beyond the circumference of the cutting wheel assembly chassis to contact the inner surface of the target pipe to be cut.

[0068] Optionally, the cutting wheel housing (and therefore the cutting wheel) extends radially outwardly in increments. Optionally, the cutting wheel moves radially outwardly by a first increment under fluid pressure. Optionally, when the fluid pressure continues to increase beyond a (optionally, a second) predetermined pressure threshold, the clutch (e.g., a slipping clutch) and / or the piston PRV actuates and the pressure decreases, or optionally remains at a constant level. Optionally, when the fluid pressure decreases, the cutting wheel housing substantially remains in the position of the first increment.

[0069] The position of the first increment may be sufficient to begin to form a first incision in the wall of the tubular. Optionally, the cutting wheel extends at least partially into the wall of the tubular. When the cutting wheel assembly rotates around the axis of the cutting tool, the cutting wheel also rotates around the cutting wheel axis. Optionally, when the cutting wheel assembly rotates around the axis of the cutting tool, the cutting wheel may thereby at least partially cut the wall of the tubular for a first 360 degrees.

[0070] Optionally, when the pressure drops below a (optionally second) predetermined threshold, the drive shaft and the leadscrew reengage and the fluid pressure increases again as the piston begins to move axially toward the cutting wheel assembly and / or the anchoring module. The increased fluid pressure optionally moves the cutting wheel housing radially outward by a second increment.

[0071] When the second incremental position optionally extends the cutting wheel housing (and thus the cutting wheel) further radially outward from the cutting wheel assembly, the cutting wheel may cut further into the wall of the tubular to form a deeper 360 degree cut in the wall of the tubular.

[0072] Optionally, when the fluid pressure again continues to increase above a (optionally second) predetermined threshold, the slip clutch / clutch / piston PRV is actuated again and the pressure is slightly reduced, or optionally maintained at a constant level. Optionally, the continued radial extension of the cutting wheel and rollers acts to increase the available volume of fluid within the cutting wheel assembly, which stabilizes the fluid pressure. Optionally, as the fluid pressure drops, the housing of the cutting wheel remains substantially in the position of the second increment. Optionally, the housing of the cutting wheel continues to extend outwardly in response to the fluid pressure and allows the cutting wheel to dig further into the wall of the tubular as the cut made by the cutting wheel deepens.

[0073] This process may optionally be repeated until the cutting wheel has completely cut through the wall of the tubing with a 360 degree cut to sever the tubing.

[0074] Optionally, the cutting tool may be pre-programmed with, for example, a run time that has been predetermined to provide sufficient time to complete the cutting operation.

[0075] When the cutting operation is completed and the cutting tool is to be removed from the wellbore, optionally, the cutting wheel and one or more rollers can be retracted. Optionally, to achieve this, the rotating assembly can be changed from a driving configuration to a retracted configuration.

[0076] Where the drive shaft includes a splined end that engages a splined opening in the cutting wheel assembly, reversal of the direction of rotation of the drive shaft causes the cutting wheel assembly to rotate in the same direction. In examples of the invention that include a ratchet and pawl arrangement, reversal of the drive shaft causes the cutting wheel assembly to disengage from the drive shaft, and the drive shaft rotates independently of the cutting wheel assembly.

[0077] Optionally, in the retraction configuration, the direction of rotation of the drive shaft is reversed. Since the slip clutch provides friction between the drive shaft and the lead screw, the reversal of the rotation of the drive shaft similarly reverses the rotation of the lead screw. Then, the lead screw nut optionally moves axially in a direction away from the cutting wheel assembly / anchoring module. Optionally, the hydraulic piston is connected to the lead screw nut, and the axial travel of the lead screw nut optionally also causes the hydraulic piston to retract from the cutting wheel assembly or the anchoring module. Optionally, when the piston retracts, the volume of the piston chamber in the rotating assembly increases. Optionally, when the piston retracts, the piston crosses the second annular groove, which allows fluid to pass through the piston. Optionally, the piston then passes through the narrower section of the housing between the first and second annular grooves and reseals the inner surface of the housing. Optionally, the piston continues to retract until the seal of the piston is aligned with the first annular groove. Optionally, aligning with the first annular groove allows the fluid to move in the space formed between the outer annular seal and the first annular groove. Alternatively, once the piston is aligned with the first annular groove, the piston cannot return to the second annular groove and must reset at the surface.

[0078] Optionally, when the cutting tool includes a piston PRV, when the cutting operation is completed and the rotation of the drive shaft is reversed, the fluid can be discharged through the piston in the return direction. For example, the piston can include a one-way lip seal that allows the fluid to be discharged in the return direction. In this example, when the piston is retracted, the discharge of the fluid through the piston seal (and / or through the PRV) provides the advantage that large forces are not intensified during the retraction phase of the tool, which may cause damage to the tool components.

[0079] Optionally, when the piston moves away from the cutting wheel assembly / anchoring module, the fluid pressure behind the piston (and in the anchoring module / cutting wheel assembly) decreases. Optionally, the fluid flows through a check valve into a piston chamber within the rotating assembly. When the fluid pressure in the cutting wheel assembly decreases, one or more rollers and the cutting wheel retract into the chassis of the cutting wheel assembly. The retraction of one or more cutting wheels and rollers is used to reduce the risk of the cutting tool getting stuck downhole, which would require intervention measures with associated losses in operating time and cost.

[0080] Alternatively, the cutting wheel assembly may include one or more resilient devices, such as a spring return mechanism configured to retract the cutting wheel. The use of a resilient device biased toward retraction of the cutting wheel may be useful in shallow cutting applications where there is little / no hydrostatic pressure to assist in retraction of the cutting wheel.

[0081] Optionally, when the rotating assembly is in the retracted configuration and the cutting wheel assembly is retracting, the first predetermined threshold is also the maximum pressure difference allowed during retraction. Optionally, during retraction, the check valve can allow fluid to flow freely between the cutting wheel assembly and the anchoring module. Optionally, the check valve is set to a very low pressure, such as about 1-5psi, such as 2psi, in which case, once the pressure in the anchoring module and / or the cutting wheel assembly exceeds the very low pressure, the fluid can flow freely through the check valve. This can ensure that all hydraulic / pneumatics are released simultaneously during the retraction of the cutting wheel assembly (and the subsequent retraction of the anchor), thereby reducing the risk of forming a large pressure difference and potentially damaging the tool.

[0082] Optionally, the pressure within the tool, more specifically the pressure applied by the piston, is regulated by one or more of a clutch, a pressure relief valve and a reversible actuator.

[0083] Optionally, the tool includes a shear release configuration that allows emergency ventilation of the tool when the tool fails. Optionally, the shear release configuration can be set at one end of the anchor module. Optionally, the shear release configuration can include one or more frangible fasteners, optionally threaded fasteners, such as shear screws. Optionally, the frangible fastener passes through an opening in one end of the screw assembly housing and enters the end of the anchor module connected to the end of the screw assembly housing (optionally, the anchor module is assembled within the inner diameter of the screw assembly housing). Optionally, the frangible fastener extends partially into the wall of the anchor module.

[0084] Optionally, the shear release configuration further comprises a rotating bushing located in a recess formed by the connection between the anchor module and the screw assembly housing. Optionally, the screw assembly housing comprises a milled end which forms an outer recess and an inner recess in the end of the screw assembly housing when the connection with the anchor module is formed. Optionally, the rotating bushing is arranged to surround the end of the screw assembly housing and is optionally located in the outer recess of the housing. Optionally, the shear release configuration further comprises a retaining ring which is arranged to surround the end of the anchor module and is optionally located in the inner recess formed by the end of the screw assembly housing. Optionally, the inner recess is axially wider than the retaining ring. Optionally, the retaining ring is arranged so that in the normal configuration of the shear release configuration, the retaining ring is located at the end of the inner recess closest to the anchor module.

[0085] The end of the anchor module optionally further comprises an annular seal, such as an O-ring, disposed in a groove around the outer circumference of the anchor module. The annular seal is optionally positioned adjacent to the frangible fastener, optionally on a side of the frangible fastener opposite the rotating bushing and the snap ring.

[0086] Optionally, in the event of tool failure - for example, the tool stops, or the tool is trapped or stuck in a tubular - the tool can be vibrated upward (toward the surface). Vibrating the tool will damage the removable fasteners between the screw assembly housing and the anchoring module. Optionally, the screw assembly housing can then move relative to the anchoring module. Optionally, the screw assembly housing partially moves axially away from the anchoring module while remaining connected to the anchoring module. Optionally, a shear release configuration including a retaining ring and a rotating bushing moves in an upward direction with the screw assembly housing. Optionally, an opening through the screw assembly housing (in which the removable fasteners are provided) is at least partially aligned with an annular seal around the end of the anchoring module, thereby disengaging the annular seal from the groove. This allows the fluid within the tool to be discharged into the wellbore. In the case where the cutting wheel and roller include elastic devices such as springs, these elastic devices bias the cutting wheel and roller to radially retract into the cutting wheel assembly. Similarly, the anchor button and / or anchor pad may include resilient means to bias the anchor button and / or anchor pad to retract radially into the anchor module.The tool may then be retrieved to the surface.

[0087] Optionally, the current supplied to the tool by the battery pack may be monitored during cutting operation. In some cases, such as when the pipe is in compression or moving during cutting operation, this may also cause the cutting wheel to become trapped or stuck in the pipe. This may be detected by a spike in the current reaching the tool (e.g., 1-2A quickly spikes to 3-5A during normal use).

[0088] In the event that the cutting wheel is stuck, it is undesirable to continue to increase the fluid pressure and apply force to the cutting wheel as this may result in damage to the tool. Therefore, optionally, a threshold value for the current is pre-set (optionally within the tool, such as within the PCM). Optionally, when the current exceeds a predetermined threshold, the rotation of the motor is reversed for a first predetermined period. In particular, in the case of using a ratchet and pawl configuration in a cutting wheel assembly as described above, the first predetermined period can be set so that the drive shaft rotates past the nearest pawl. As an example, if three pawls are equidistantly spaced around the drive shaft, the drive shaft can optionally be arranged to rotate in opposite directions for a first time period, the first time period being equal to a rotation of 120 degrees to pass through a first adjacent pawl.

[0089] Optionally, the reversal of the motor and thus the reverse rotation of the drive shaft reduces the fluid pressure in the tool due to the retraction of the piston. Optionally, the reduction in fluid pressure allows the cutting wheel to at least partially retract. Optionally, the reversal of the motor and drive shaft reduces the force applied by the fluid pressure on the cutting wheel.

[0090] Optionally, once the first predetermined period has ended and the drive shaft has optionally passed an adjacent pawl, the cutting operation may be restarted. Optionally, after the first predetermined period has been completed, but before the cutting operation is restarted, there may be an additional period of time in which no rotation occurs. Including a rest period between changes in rotation direction may advantageously help protect the motor and extend its operating life.

[0091] Alternatively, if the cutting wheel remains stuck after completing the first predetermined cycle, a second predetermined cycle of reverse rotation may be performed. Optionally, the second predetermined cycle has the same length of time as the first predetermined cycle. Optionally, the drive shaft may be optionally set to rotate in the opposite direction for a second time period, which may optionally be equal to enough rotation to pass the second pawl (e.g., in a three-pawl configuration, a further 120 degrees of rotation).

[0092] This process can be repeated as often as necessary to release the cutting wheel and restart the cutting operation, or alternatively, to recycle the tool.

[0093] According to the present invention, there is provided a method for cutting a pipe in an oil well or a gas well, the method comprising:

[0094] Deploy a cutting tool into the wellbore to the depth of the tubular to be cut, wherein the cutting tool comprises:

[0095] a battery powered power assembly, wherein operation of the power assembly causes the drive shaft to rotate and change the fluid pressure within the cutting tool; and

[0096] a cutting wheel assembly including a cutting wheel;

[0097] The method further includes:

[0098] rotating the drive shaft, thereby rotating the cutting wheel assembly;

[0099] rotating the cutting wheel about an axis; and

[0100] In response to changes in fluid pressure, the cutting wheel is actuated to radially move the cutting wheel.

[0101] Optionally, the cutting wheel is disposed within the housing. Optionally, the housing is configured to move radially in response to a change in fluid pressure. Optionally, radial movement of the housing thereby radially moves the cutting wheel.

[0102] Optionally, the method comprises: in a first configuration, rotationally engaging the drive shaft and the cutting wheel assembly such that rotation of the drive shaft rotates the cutting wheel assembly. Optionally, the method comprises: in a second configuration, disengaging the drive shaft and the cutting wheel assembly such that rotation of the drive shaft does not rotate the cutting wheel assembly.

[0103] Optionally, the drive shaft forms part of a rotating assembly, the rotating assembly further comprising a linear actuator, and wherein the drive shaft comprises at least one clutch, and further optionally, the method comprises rotating the drive shaft and the linear actuator together until a predetermined threshold torque is reached. Optionally, the method comprises configuring the clutch to slip when the predetermined threshold level of torque is reached, thereby allowing relative movement between the drive shaft and the linear actuator.

[0104] Optionally, the rotary assembly further comprises a piston configured to move axially with the linear actuator, and the method further comprises converting the rotary motion into fluid pressure via the axial motion of the piston.

[0105] Optionally, the method includes providing a piston chamber between the piston and the cutting wheel assembly, the cutting wheel assembly being in fluid communication with the piston chamber. Optionally, the method includes increasing fluid pressure in the cutting wheel assembly by compressing fluid in the piston chamber. Optionally, the method includes radially extending the cutting wheel assembly when the fluid pressure in the cutting wheel assembly reaches a predetermined threshold.

[0106] Optionally, the drive shaft and the cutting wheel assembly are rotationally engaged when the drive shaft is rotated in a first direction, and the drive shaft and the cutting wheel assembly are rotationally disengaged when the drive shaft is rotated in a second direction.

[0107] Optionally, the method includes at least partially retracting the cutting wheel by: rotating the drive shaft in a second direction, thereby reversing axial movement of the linear actuator; retracting the piston; and reducing fluid pressure within the cutting wheel assembly.

[0108] Optionally, the method comprises at least partially cutting the wall of the tubular by rotating the cutting wheel assembly as the cutting wheel assembly extends radially within the tubular.

[0109] Optionally, the method comprises radially extending the cutting wheel in predetermined increments.

[0110] Optionally, the method includes anchoring the cutting tool within the tubular to restrict relative movement of the cutting tool.

[0111] The drawings illustrate current exemplary embodiments of the present disclosure and, together with the general description given above and the detailed description of the embodiments given below, serve to explain the principles of the present disclosure by way of example.

[0112] In the following description, throughout the specification and the accompanying drawings, the same parts are represented by the same figure numerals, respectively. The accompanying drawings are not necessarily drawn to scale. Certain features of the invention may be shown in an enlarged scale or in a slightly schematic form, and for the sake of clarity and brevity, certain details of conventional elements may not be shown. The present invention relates to different forms of implementation. Specific embodiments of the invention are shown in the accompanying drawings and will be described in detail herein, it should be understood that the present disclosure is considered to be an example of the principles of the present invention, rather than to limit the invention to what is shown and described herein. It should be fully recognized that the different teachings of the embodiments discussed below can be used alone or in any suitable combination to produce the desired results.

[0113] The following definitions will be followed in the specification. As used herein, the term "wellbore" refers to a wellbore or a borehole provided or drilled in a manner known to those skilled in the art. The wellbore may be an "open hole" or a "cased hole" lined with a tubing string. For the purpose of description, reference will be made to above or below, the term "above", "up", "upward", "upper" or "upstream" refers to the longitudinal axis of the working string away from the bottom of the wellbore toward the surface, "below", "down", "downward", "lower" or "downstream" refers to the longitudinal axis of the working string toward the bottom of the wellbore and away from the surface and deeper into the well, whether the well referred to is a conventional vertical well or a deviated well, and therefore includes the following typical situations: when the drilling rig is above the wellhead and the well extends downward from the wellhead into the formation; it can also be a horizontal well, in which the formation may not necessarily be below the wellhead. Similarly, "working string" refers to any tubular configuration used to transport fluids and / or tools from the surface into a wellbore. In the present invention, a slickline, a slickline, a wireline or an electric cable are preferred working strings.

[0114] Various aspects of the present invention can be implemented separately or in combination with one or more other aspects, as will be understood by those skilled in the relevant art. Various aspects of the present invention can optionally be provided in combination with one or more optional features of other aspects of the present invention. In addition, in different embodiments of the present invention, the optional features described about an embodiment can usually be combined separately or combined with other features. In addition, any feature disclosed in the specification can be combined separately or with other features in the specification to form the present invention.

[0115] Various embodiments and aspects of the present invention will now be described in detail with reference to the accompanying drawings. Other aspects, features and advantages of the present invention are apparent from the entire description thereof, including the accompanying drawings illustrating a number of exemplary embodiments and aspects and implementations. The present invention is also capable of other and different embodiments and aspects, and several details thereof may be modified in various respects, all without departing from the scope of the present invention as defined by the claims.

[0116] Any discussion of documents, acts, materials, devices, articles or the like is included in this specification solely for the purpose of providing a context for the present invention. It is not suggested or represented that any or all of these matters form part of the prior art base or are common general knowledge in the field relevant to the present invention.

[0117] Therefore, the drawings and descriptions are considered to be illustrative rather than restrictive in nature. In addition, the terms and expressions used herein are only for descriptive purposes and should not be interpreted as limiting the scope. Language such as "including", "comprising", "having", "containing" or "involving" and variations thereof are intended to be broad and cover the subject matter, equivalents and unlisted additional subject matter listed thereafter, and are not intended to exclude other additives, components, wholes or steps. In the present disclosure, whenever there is a transitional phrase "comprising" before a composition, element or element group, it should be understood that we also envision that the same composition, element or element group has a transitional phrase "consisting essentially of", "consisting of", "selected from the group of consisting of", "including" or "is" before the narration of a composition, element or element group, and vice versa. In this disclosure, the words “typically” or “optionally” should be understood as intended to indicate optional or non-essential features of the invention, which are present in some embodiments but may be omitted in other embodiments without departing from the scope of the invention as defined in the claims.

[0118] All numerical values ​​in this disclosure should be understood to be modified by “about.” All elements in the singular or any other components described herein (including but not limited to components of a downhole tool) should be understood to include the plural form thereof and vice versa. BRIEF DESCRIPTION OF THE DRAWINGS

[0119] In the attached picture:

[0120] Figure 1 shows a schematic end view of an example of a PCM forming part of a cutting tool according to the present invention;

[0121] Figure 2 Shows Figure 2 A schematic cross-sectional view of a PCM;

[0122] Figure 3 Shows Figure 1 and Figure 2 A schematic three-dimensional partial exploded view of a PCM;

[0123] Figure 4 shows a schematic end view of an example of an electric motor forming part of a cutting tool according to the invention;

[0124] Figure 5 Shows Figure 4 A schematic cross-sectional view of a motor;

[0125] Figure 6 Shows Figure 4 and Figure 5 A schematic perspective view of an electric motor;

[0126] Figure 7 shows a schematic end view of an example of a gearbox forming part of a cutting tool according to the invention;

[0127] Figure 8 Shows Figure 7 A schematic cross-sectional view of a gearbox;

[0128] Fig. 9 shows a schematic cross-sectional view of a first example of a cutting tool according to the present invention, wherein the cutting wheel assembly is in an extended configuration, the cutting tool comprising a power control module (PCM), a motor, a gearbox, a rotation assembly (shown in this example as a ball screw assembly), an anchor module, and a cutting wheel assembly;

[0129] Fig.10 A schematic cross-sectional view of an example of a rotating assembly forming part of a cutting tool according to the present invention is shown, the rotating assembly comprising a ball screw assembly, an anchor module and a cutting wheel assembly, wherein the anchor has been energized and is in an extended configuration, and the cutting wheel assembly is also in an extended configuration;

[0130] Fig.11 Shows Fig.10 A schematic diagram of a rotating assembly, an anchoring module and a cutting wheel assembly;

[0131] Fig.12 Shows Fig.10 and Fig.11A schematic perspective view of a rotating assembly, an anchoring module and a cutting wheel assembly;

[0132] Fig.13 shows a schematic diagram of a rotating assembly including a slip clutch in the form of a tolerance ring;

[0133] Fig.14 Shows Fig.13 A schematic cross-sectional view of a rotating assembly;

[0134] Fig.15 Shows Fig.13 and Fig.14 Another schematic cross-sectional view of a rotating assembly of;

[0135] Fig.16 Shows Figure 13-Figure 15 A schematic cross-sectional view of a rotating assembly;

[0136] Fig.17 Shows the formation Figure 13-16 A schematic perspective view of a drive shaft and a tolerance ring of a portion of a rotating assembly;

[0137] Fig.18 shows a schematic end view of an anchor module in an unextended "run-in hole" configuration, wherein the anchor is in the form of a ridged or grooved anchor button;

[0138] Fig.19 Shows Fig.18 A schematic cross-sectional view of an anchoring module;

[0139] Fig. 20 Shows Fig.18 and Fig.19 A schematic end view of an anchor module of FIG. 1 with the anchor button extended in an “anchor deployed” configuration;

[0140] Fig.21 Shows Fig. 20 Schematic diagram of the anchor module;

[0141] Fig. 22 Shows Fig. 20 and Fig.21 A schematic cross-sectional view of an anchoring module;

[0142] Fig.23 Shows Figure 20-22 A schematic perspective view of an anchoring module;

[0143] Fig.24 a schematic perspective view showing an alternative example of an anchor module including an anchor pad in an extended "anchor deployed" configuration;

[0144] Fig.25 Shows Fig.24 Schematic diagram of the anchor module;

[0145] Fig.26 Shows Fig.24 and Fig.25 A schematic cross-sectional view of an anchoring module;

[0146] Fig. 27 A schematic diagram of a cutting wheel assembly is shown, wherein the cutting wheel assembly includes a pressure relief valve and a check valve;

[0147] Fig.28 Shows Fig. 27 A schematic cross-sectional view of a cutting wheel assembly of , wherein the cutting wheel is in a retracted "drill down" configuration;

[0148] Fig.29 Shows Fig. 27 and Fig.28 A schematic cross-sectional view of a cutting wheel assembly;

[0149] Fig.30 Shows Figure 27-Figure 29 A schematic cross-sectional view of a cutting wheel assembly of , wherein the cutting wheel is in an extended “deployed” configuration;

[0150] Fig.31 Shows Fig.30 A schematic cross-sectional view of a cutting wheel assembly;

[0151] Fig.32 Shows Figure 27-Figure 31 Schematic diagram of the configuration of a pressure relief valve and a check valve in a cutting wheel assembly;

[0152] Fig.33 shows a schematic perspective view of a second example of a cutting tool according to the present invention, the cutting tool comprising a torque limiting clutch as part of a rotating assembly, which in this example is illustrated as a ball screw assembly;

[0153] Fig.34 Shows Fig.33 A schematic cross-sectional view of a cutting tool;

[0154] Fig.35 Shows Fig.33 and Fig.34 Schematic diagram of a cutting tool;

[0155] Fig.36 Shows Figure 33-Figure 35 A schematic cross-sectional view of a rotating assembly, an anchoring module and a cutting wheel assembly of a cutting tool;

[0156] Fig.37 Shows Figure 33-Figure 36 A schematic cross-sectional view of a rotating assembly;

[0157] Fig.38 Shows Fig.37 A schematic diagram of a rotating assembly;

[0158] Fig.39 Shows Fig.37 Another schematic cross-sectional view of ;

[0159] Fig.40 Shows Figure 37-Figure 39 A schematic diagram of a cross section of a rotating assembly;

[0160] Fig.41 Shows Fig.37 a close-up schematic cross-sectional view of a portion of, in particular an end portion of a rotating assembly, showing a portion of a drive shaft, a clutch, an adapter, and a portion of a ball screw;

[0161] Fig.42 Shows Figure 33-Figure 41 A schematic perspective view of a linear actuator, a piston and a clutch of a cutting tool;

[0162] Fig.43 Shows Fig.42 Partial exploded view of

[0163] Fig.44 shows a schematic diagram of a cutting wheel assembly;

[0164] Fig.45 Shows Fig.44 A schematic cross-sectional view of a cutting wheel assembly of , wherein the cutting wheel is in a retracted "drill down" configuration;

[0165] Fig.46 Shows Fig.44 and Fig.45 A schematic cross-sectional view of a cutting wheel assembly;

[0166] Fig.47 Shows Figure 44-Figure 46 A schematic cross-sectional view of a cutting wheel assembly of , wherein the cutting wheel is in an extended “deployed” configuration;

[0167] Fig.48 Shows Fig.47 A schematic cross-sectional view of a cutting wheel assembly;

[0168] Fig.49 shows a schematic diagram of a third example of a cutting tool according to the present invention, the cutting tool including a piston pressure relief valve (PRV);

[0169] Fig.50 Shows Fig.49 A schematic cross-sectional view of a cutting tool;

[0170] Fig.51 Shows Fig.49 and Fig.50 A schematic diagram of a rotating assembly of a cutting tool;

[0171] Fig.52 Shows Fig.51 A schematic cross-sectional view of a rotating assembly;

[0172] Fig.53 Shows Fig.51 Another schematic cross-sectional view of a rotating assembly of;

[0173] Fig.54 Shows Figure 51-Figure 53 A schematic cross-sectional view of a rotating assembly;

[0174] Fig.55 is a detailed view of the piston PRV;

[0175] Fig.56 Shows Figure 24-26 a schematic cross-sectional view of an anchor module connected to a cutting wheel assembly including a ratchet and pawl arrangement and an optional arrangement of rollers and a cutting wheel, the cutting wheel including a resilient device;

[0176] Fig.57 Shows Fig.56 A schematic cross-sectional view of a ratchet and pawl configuration;

[0177] Fig.58 Show Fig.56 A schematic cross-sectional view of a cutting wheel;

[0178] Fig.59 Shows Fig.56 A schematic cross-sectional view of a roller;

[0179] Fig.60 shows a schematic cross-sectional view of a shear release configuration prior to vibration;

[0180] Fig.61 Show Fig.60 A schematic cross-sectional view of a shear release configuration after vibration;

[0181] Fig.62 shows a schematic perspective view of an alternative linear actuator including a lead screw and lead screw nut, a piston and a clutch;

[0182] Fig.63 Show Fig.62 Partial exploded view of

[0183] Fig.64 Shows Fig.63 a perspective cutaway view of

[0184] Fig.65 Show Fig.63 Another cross-sectional view of . DETAILED DESCRIPTION

[0185] Figure 1-Figure 8 An example of a power control module (PCM) is shown, which includes a housing 2 and a battery pack 3, a motor 4, and a gear assembly 5 (in this example, a planetary gear assembly), which is configured to work with a linear actuator according to the present invention and is therefore suitable for use with a cutting tool. Examples of these modular components are disclosed in PCT patent application number WO2019 / 180642, the entire contents of which are incorporated herein by reference, and which is patented by Aberdeen, UK Made and available for purchase from.

[0186] Use of these components in the cutting tools described below allows the tool to be run into the well on a wireline rather than an electric cable, or a slickline, or a slickline, because power is provided to the tool through the PCM rather than being transmitted down the line from the surface. However, if the cutting tool is run on a slickline, for example, the slickline can be used as a means of transmitting commands and / or data between the tool and the surface of the wellbore into which the tool is run.

[0187] Fig. 9 An example of a cutting tool 100 is shown which can be used to cut casing or other pipes / tubulars in a downhole environment (e.g., an oil well). For simplicity, "tubulars" will be used as a general term in this specification, but it will be understood by those skilled in the art that this extends to any form of pipe, tubing, casing, etc. that can be used downhole. The cutting tool 100 includes a PCM 1, a motor 4, and a planetary gear assembly 5 that form a drive assembly 10 in a modular configuration. The drive assembly 10 is connected to a rotation assembly 110 that includes a linear actuator in the form of a ball screw assembly 120 configuration, wherein the rotation assembly 110 has a central drive shaft 112 that extends from the end of the drive assembly 10 through the tool to the end of the cutting wheel assembly 160. The rotation assembly 110 is connected to an anchoring module 140 that includes an anchor 142 to stabilize the cutting tool 100 on the wall of the casing, etc. being cut. The anchor module 140 is then connected to a cutting wheel assembly 160, which includes a cutting wheel 162 that performs the cutting. Each of these modules and assemblies is described in more detail below.

[0188] The gear assembly 5 is connected to the drive shaft 112 of the cutting tool 100 via a drive coupling 105 received in a sub 111, as shown in FIG. Fig.10As shown. An annular race of a thrust bearing 107 extends around the circumference of the drive coupling 105, with the race of the bearing 107 disposed between an upper support thrust washer 106 and a lower support thrust washer 108. The upper and lower washers 106, 108 and the race of the thrust bearing 107 are held in place by a split ring 104, which is located in a recess formed on the outer surface of the drive coupling 105. The split ring 104 is adjacent to the upper support thrust washer 106. The lower support thrust washer 108 abuts against a shoulder 111s formed as a step in the inner diameter of the joint 111, and also against a corresponding shoulder 105s formed on the outer diameter of the drive coupling 105. The combination of the shoulder and the split ring 104 serves to prevent axial movement of the washers 106, 108, and the race of the thrust bearing 107.

[0189] The drive shaft 112 is connected to the drive coupling 105 at its upper end, and a portion of the drive shaft 112 is surrounded by the race of the spherical bearing 103, which portion of the drive shaft is configured to facilitate rotation of the drive shaft 112. In addition to the step of the shoulder 111s, a further step and narrowing of the inner diameter of the joint 111 provides an annular recess in which the race of the spherical bearing 103 is retained.

[0190] The inner diameter of the joint 111 is narrowed again to form an axially aligned bore through which the drive shaft 112 extends. An annular wedge seal 102 is slightly spaced from the race of the spherical bearing 103, which is disposed within a recess in the bore formed in the joint 111. The annular wedge seal 102 seals against the outer diameter of the drive shaft 112 to prevent fluid from entering the upper components of the drive coupling 105 (i.e., the spherical bearing 103, the thrust bearing 107, etc.). The inner diameter of the joint 111 then widens to form a chamber 114c.

[0191] The opening 109 extends through the wall of the joint 111 and is configured to allow well fluid to enter the chamber 114c. There may be three openings 109 spaced 120° apart around the circumference of the joint 111. Each opening 109 includes a filter to prevent debris from entering the tool 100. Within the chamber 114c is an annular balance piston 114 having a central hole through which the drive shaft 112 extends. The balance piston 114 has an annular inner seal, in this case a wedge seal 114a, which is disposed in a recess extending around the inner diameter of the bore of the balance piston 114 and seals against the outer surface of the drive shaft 112. The balance piston 114 also includes an annular outer seal, in this case an O-ring 114b, which seals against the inner surface of the joint 111. The seals together serve to prevent fluid communication between the upper end of the rotating assembly 120 and the well.

[0192] The joint 111 is connected to the ball screw assembly housing 119 by a threaded connection. The joint 111 is also locked to the ball screw assembly housing 119 by threaded fixings, in this case, by screws 111a spaced around the circumference of the joint 111. The ball screw assembly 120 includes another race of a thrust bearing 121 at its upper end, which is a spherical bearing in this case. A circlip 117 and a bearing washer 118 hold the bearing 121 at the upper end of the rotating assembly 120. On the opposite side of the bearing race 121, another bearing washer 123 is provided, which abuts against a first shoulder 119s formed in the inner diameter of the ball screw assembly housing 119 and a second shoulder 122s formed in the outer surface of the ball screw 122.

[0193] The drive shaft 112 passes through a central bore in the ball screw assembly 120 formed by the ball screw 122 (and subsequently an opening in the hydraulic piston 126, described in more detail below). A portion of the drive shaft 112 includes a shallow annular recess around which the ball screw 122 is disposed, and into which one or more tolerance rings 113 fit. In this example, five tolerance rings 113 are illustrated on the drive shaft 112, as shown in FIG. Fig.17 It is best seen, but this is not limiting. Suitable tolerance rings are manufactured, for example, by Saint-Gobain Performance Plastics Tolerance Ring. The tolerance ring 113 is ridged or otherwise textured and forms a frictional engagement with the inner surface of the surrounding ball screw 122.

[0194] The ball screw 122 is threaded with a spiral ball groove on its outer surface, and the ball bearing 125 of the ball nut 124 is located in the spiral ball groove. When the drive shaft 112 begins to rotate, the ball screw 122 rotates together with the drive shaft 112 due to the frictional engagement with the tolerance ring 113. As the ball bearing follows the thread of the ball screw 122, the rotation of the ball screw 122 is converted into axial movement of the ball nut 124. The ball nut 124 is fixedly connected to a piston at one end, which is a hydraulic piston 126 in this case. The axial movement of the ball nut 124 in turn causes the piston 126 to move axially, while the fixing member prevents relative movement between the piston 126 and the ball nut 124.

[0195] The piston 126 is disposed within a fluid-filled piston chamber 130, to which one end of the anchor module 140 is connected. The inner diameter of the piston 126 remains substantially constant along its length, with the piston end opposite the ball nut 124 forming a narrower diameter that provides an opening through which the drive shaft 112 passes. This forms an inner cavity 126b within the body of the piston 126, which is smaller in volume than the volume of the piston chamber 130 on the opposite side of the piston end.

[0196] The ball screw assembly housing 119 also includes a retraction hole 129 formed by a first annular groove 129a and a second annular groove 129b formed in the inner surface of the housing 119. At the beginning of operation, before the ball screw assembly 120 begins to move, the end of the piston 126 is initially aligned with the second groove 129b. Fig.14 and Fig.15 , it can be seen that as the piston 126 moves axially through the ball nut 124 (from left to right in these figures), it penetrates from the second groove 129b into the narrower section of the housing 119, which includes the piston chamber 130. The end of the piston 126 is then sealed against the inner surface of the ball screw assembly housing 119 by an annular seal 128 (e.g., an O-ring), thereby preventing fluid from entering the retraction bore 129 from the piston chamber 130. As the piston 126 continues to move from left to right along this narrower section, the fluid pressure within the piston chamber 130 increases.

[0197] The piston 126 also seals against the outer surface of the drive shaft 112 via the annular wedge seal 127, thereby preventing fluid communication along these surfaces between the piston chamber 130 and the ball screw assembly 120. As the ball nut 124 moves downwardly along the ball screw 122 (i.e., in a direction toward the anchor module 140), the piston 126 moves in the same direction within the piston chamber 130, increasing the fluid pressure between the end of the anchor module 140 and the piston 126.

[0198] The piston 126 includes a piston pressure relief valve (PRV) 131 (at Fig.15 126b) to control the fluid pressure within the piston chamber 130. The piston PRV is configured to allow fluid communication between the piston chamber 130 and the inner cavity 126b, as well as with the retraction hole 129.

[0199] The fluid within the piston chamber 130 is in fluid communication with the anchor module 140. When the pressure of the fluid within the piston chamber 130 increases, the pressure in the anchor module 140 increases accordingly, as described further below.

[0200] A first example of anchor module 140 is Figure 18-Figure 23. The anchor module 140 includes a bearing race 135 located in a recess formed in the end of the anchor module 140 and arranged to facilitate rotation of the drive shaft 112 at the entry point of the anchor module 140. The anchor module 140 includes a through hole 140b through which the drive shaft 112 extends. The bearing 135 is also held in place by a circlip in a groove adjacent to the bearing 135 at the upper end, thereby preventing the race of the bearing 135 from moving toward the piston chamber 130.

[0201] The anchoring module 140 includes a plurality of circular anchoring buttons 142 extending radially to anchor the cutting tool 100 on the inner wall of the pipe being cut. Fig.18 and Fig.19 The anchor buttons 142 are shown in their retracted configuration. In this example, two circumferential and equally spaced rows of anchor buttons 142 extend around the anchor module 140, with the buttons of the first and second rows staggered relative to each other. Fig.19 As shown, the anchor buttons 142 are retained in a movable housing forming an anchor piston 143, and the anchor piston 143 and the anchor button 142 are located in an orifice formed in the body of the anchor module 140. The anchor buttons 142 are each connected to an anchor spring 146, which is disposed in an orifice in each anchor piston 143 and is resiliently biased to resist the movement of the anchor piston 143, thereby retaining the anchor piston 143 and, therefore, the anchor button 142 in their retracted configuration. The anchor spring 146 helps the anchor button 142 to retract in shallow working conditions and / or conditions with low hydrostatic pressure.

[0202] The anchor button 142 is restrained from falling out of the anchor module 140 by the retaining plate 141. Each retaining button 142 has an axially aligned groove on its outer surface into which the restraining plate 141 can fit. The width of the plate 141 and the depth of the groove on the anchor button 142 are selected so that when the anchor button 142 extends radially outward from the anchor module 140, the button 142 can travel a sufficient distance to contact the inner wall of the pipe to anchor the cutting tool 100. The surface of the anchor button 142 further has ridges or similar textures to enhance frictional contact with the surface of the object being cut and reduce the chance of unwanted movement (rotational or axial) of the cutting tool 100 during operation.

[0203] The anchor spring 146 serves to retain the anchor button 142 within the body of the anchor module 140 when the fluid pressure within the piston chamber 130 is relatively low. As fluid pressure builds within the piston chamber 130, due to the fluid communication between the chamber 130 and the anchor module 140, the pressurized fluid builds up within the fluid conduit 148, which directs the fluid toward the anchor piston 143. Each anchor piston 143 has an annular seal 147 disposed within an annular recess in the outer surface of the anchor piston 143 that seals against the opening in which the anchor piston 143 is located and prevents fluid from entering or exiting between the wellbore and the fluid conduit 148. The fluid is initially restricted from further travel through the anchor module 140 into the cutting wheel assembly 160 by a pressure relief valve 150 located within the end of the cutting wheel assembly 160 that is connected to the anchor module 140 (see, e.g., Fig.10 and Fig.28 ). The pressure relief valve 150 is located near an optional check valve 155, which adds redundancy in limiting fluid communication from the anchoring module 140. When the pressure relief valve 150 prevents fluid from escaping from the anchoring module 140, the fluid pressure behind the anchoring piston 143 continues to increase as the piston 126 moves downward. Eventually, the fluid pressure in the conduit 148 reaches a level high enough to overcome the biasing force of the anchoring spring 146 (e.g., 10-500 psi, where the higher end of the pressure range (e.g., 300 psi) can be used in examples of the present invention that include a pressure relief valve 150 located between the anchoring module and the cutting wheel assembly, and the anchor is deployed before the cutting wheel begins to retract; and in the case where the anchor is deployed simultaneously with the cutting wheel, a lower pressure within this range (e.g., 50 psi) can be used and the anchoring piston 143 is pushed, causing the anchor buttons 142 to extend radially until they contact the inner surface of the tubular and anchor the cutting tool 100. Figure 20-23 The anchor module 140 is shown in a “deployed” configuration, wherein the anchor piston 143 moves outward in response to fluid pressure, causing the anchor button 142 to extend radially from the body of the anchor module 140 .

[0204] In this example, the anchors are first deployed before any movement of the cutting wheel 162 occurs, but the anchors may also be deployed simultaneously with the extension of the cutting wheel, as will be discussed below in the context of alternative examples of the invention.

[0205] exist Figure 24-26 The middle figure shows an alternative anchor module 240 (in an extended, deployed configuration) wherein reference numerals are increased by 100 from those used in connection with the anchor module 140. Components that remain the same between the two forms of the anchor module will not be described again herein.

[0206] In this example, the anchor module 240 includes a plurality of anchor pads 242 arranged in a single row around the circumference of the anchor module 240. In contrast to the anchor button 142, the anchor pads 242 of this example extend in the longitudinal direction. The surface of the anchor pad 242 that contacts the wall of the cut tubular is grooved, ridged, or otherwise textured to increase the frictional contact between the two surfaces. Similar to the fixing button 142, the anchor pad 242 has a groove extending longitudinally downward along the center of the anchor pad 242, aligned with the retaining plate 241. As previously described, the retaining plate 241 limits the movement of the anchor pad 242 to prevent the anchor pad 242 (and the anchor piston 243) from potentially becoming detached from the anchor module 240 and falling into the well.

[0207] When the anchor pads 242 extend longitudinally, they have two anchor springs 264 at each end of each pad 242 to resist the movement of the anchor piston 243 under fluid pressure. The pressurized fluid enters the fluid conduit 248 and acts on the biasing force of the anchor springs 246 and the anchor piston 243 to cause the anchor pads 242 to extend radially outward and against the inner surface of the object being cut (e.g., at a pressure in the range of 10-500 psi, the higher end of the pressure range (e.g., 300 psi) can be used in the example of the present invention including a pressure relief valve 150 between the anchor module and the cutting wheel assembly, and the anchor is deployed before the cutting wheel begins to retract; and in the case where the anchor is deployed simultaneously with the cutting wheel, a lower pressure within the range (e.g., 50 psi) can be used. The anchor springs 264 assist in the retraction of the anchor pads 242 in shallow working conditions and / or conditions with low fluid static pressure.

[0208] As shown above and Figure 27-Figure 31 As shown, the cutting wheel assembly 160 is connected at one end to the anchor module 140, 240 by a coupling 154. Within the coupling 154 are two annular thrust bearing races 159a, 159b which relieve axial loads between the anchor module 140, 240 and the cutting wheel assembly 160 as the drive shaft 112 (and therefore the cutting wheel assembly 160) rotates.

[0209] At the same end of the cutting wheel assembly 160, there is a splined opening 152. The drive shaft 112 has a corresponding splined end 115, which is inserted into the splined opening 152 for mutual engagement of the drive shaft 112 and the cutting wheel assembly 160. Due to the spline connection, the rotation of the drive shaft 112 drives the rotation of the cutting wheel assembly 160. Another type of connection is also suitable, which can rotatably fix the drive shaft 112 and the cutting wheel assembly 160 so that they rotate together.

[0210] The spline opening 152 leads to a fluid conduit through which fluid can flow to or from the anchor module 140. Fig.28 , Fig.31 and Fig.32 As best seen, a pressure relief valve (PRV) 150 and a check valve 155 are housed within the conduit adjacent to the splined opening 152. As described above, the pressure relief valve 150 (and optional check valve 155) are used to prevent fluid flow when the pressure is below a certain threshold (e.g., 100-500 psi). Once the fluid exceeds the threshold pressure, the pressure relief valve 150 opens and the fluid flows into the cutting wheel assembly 160.

[0211] exist Figure 27-Figure 29 The downhole configuration of the cutting wheel assembly 160 is shown in FIG. The fluid passing through the PRV enters the fluid conduit 153, which directs the fluid into the cutting wheel assembly 160. There are two rollers 170 in the cutting wheel assembly 160, each of which is disposed on an axle 171 and received in a recess in a roller piston 173. Fig.30 and Fig.31 As shown, the fluid entering the cutting wheel assembly 160 is intensified behind the roller piston 173, which results in the roller piston 173 extending radially outward from the cutting wheel assembly 160. As the cutting wheel assembly 160 rotates, the roller 170 rotates about the axis 171 while the roller 170 contacts the inner wall of the pipe. This also balances the action of the cutting wheel 162 as it cuts into the pipe, helping to keep the cutting wheel assembly 160 centered. This in turn means that the cut made in the pipe stays in the same plane through the pipe, reducing the time required to make the cut and reducing the risk of damaging the cutting wheel 162.

[0212] The cutting wheel assembly 160 also includes a cutting wheel 162 including a circular blade having an opening through which an axis 164 passes. In the example shown in the figure, the cutting wheel 162 is perpendicular to the longitudinal axis of the cutting wheel assembly 160 (and the cutting tool 100); however, this is not limiting and optional angles of the cutting wheel may be more suitable for a particular cutting operation. The cutting wheel 162 is configured to rotate about the axis 164 as it cuts the tubular. The cutting wheel 162 is located within a recess formed in the cutting wheel piston 166. Similar to the roller piston 173, fluid is directed through the fluid conduit 153 and increases in the chamber 168 behind the cutting wheel piston 166, and the volume increases as the cutting wheel piston 166 moves radially outward. When the fluid pressure increases, the cutting wheel piston 166 is pushed out of the cutting wheel assembly 160 and extends radially outward (such as Figure 9-10 , Figure 30-Figure 31 As shown), the cutting tool contacts the inner wall of the pipe to perform cutting.

[0213] When the load is applied to the cutting wheel 162, it cuts around the inner diameter of the tubular. With each rotation of the cutting wheel assembly 160, the cutting around the tubular is completed, and the load applied to the cutting wheel remains substantially constant, thereby allowing the cutting wheel to further cut into the tubular with each rotation. The cutting wheel assembly 160 continues to rotate, and the process is repeated until the tubular is cut off. As an example, the cutting tool 100 can be preset to rotate for 10 minutes under a fluid pressure of 1200psi applied to the cutting wheel 162, which will provide 30 turns of the cutting wheel assembly 160. As an alternative, in order to provide redundancy of power that can be applied to the cutting tool 100 by the drive assembly 10 and fully ensure the complete cutting of the tubular, the tool 100 can be configured to allow additional rotations of the cutting wheel assembly 162, for example, the tool 100 can be rotated 80-100 times downhole. The construction of the tool 100 can be adjusted as needed to consider the weight and grade of different tubulars.

[0214] The load is applied to the cutting wheel 162 by the increase in fluid pressure within the piston chamber 130, and this increase is transmitted to the cutting wheel assembly 160 through the anchoring modules 140, 240. If the fluid pressure exceeds a predetermined threshold (e.g., 200-1500 psi, more preferably 800-1200 psi, but this may vary depending on the cutting requirements and downhole environment), the tolerance ring 113 disengages its frictional engagement with the ball screw 122, and the drive shaft 112 rotates without the ball screw 122 rotating. Thus, the hydraulic piston 126 remains in place and the fluid pressure is reduced below the threshold. Maintaining the fluid pressure within the piston chamber 130 at a substantially constant level mitigates the risk of damaging the cutting wheel 162 due to the application of excessive load during the cutting process, while maintaining a constant force on the cutting wheel 162 to cut the tubular.

[0215] The running time of the cutting tool 100 can be preset to a time length sufficient to ensure that the cutting is completed. When the cutting is completed, the rotation of the drive shaft 112 is reversed. This pulls the ball screw 122 and the hydraulic piston 126 back to the original configuration. In order to ensure that the cutting wheel 162 is fully retracted, the hydraulic piston 126 is retracted to a position exceeding the initial starting point of the hydraulic piston 126 in the rotating assembly 110 until the hydraulic piston is aligned with the first groove 129a in the ball screw assembly housing 119. This creates a pressure difference and pulls the well fluid from the wellbore into the system to balance the tool 100 with the well pressure fluid. Once the cutting wheel 162 is retracted, the cutting tool 100 can be retrieved from the wellbore.

[0216] Alternatively, the cutting wheel piston 126 (and / or the roller piston 173) may be connected to a spring return mechanism (an example of which is shown in FIG. Fig.56 and Fig.58), the spring return mechanism can alternatively or additionally retract the cutting wheel piston 126. This is particularly useful, for example, in shallow cutting operations, where there is little hydrostatic pressure to assist the return of the cutting wheel piston 126 and / or the roller piston 173.

[0217] A second example of a cutting tool 200 is Figure 33-Figure 43 Shown in.

[0218] Figure 33-Figure 35 The entire tool 200 is shown, including the drive assembly 10 as described above, which will not be described again for the sake of brevity. The tool 200 also includes an example of an anchor module 240. All other features that are the same as the first embodiment will be identified by the same reference numerals increased by 100.

[0219] In this example of the cutting tool 200, instead of a tolerance ring for maintaining a constant fluid pressure within the anchor module 240, and more specifically within the cutting wheel assembly 260, an alternative clutch configuration is shown, in this example a synchronous torque limiting clutch, but this is not limiting. A suitable clutch that can be used for the cutting tool 200 is available from Mauerstetten, Germany. Obtained A clutch, although this is not limiting, is not the only form of clutch that will provide the desired torque limiting function in tool 200.

[0220] The top joint 211 includes two connected smaller joints, namely the upper joint 211a and the lower joint 211b. The upper joint 211a accommodates the connection between the gear assembly 5 and the drive shaft 212, including the thrust bearing 207. The lower joint 211b accommodates the balance piston 214, the clutch 280 and the adapter 281. The upper and lower joint configuration makes it easier to manufacture the cutting tool 200 and, if necessary, also facilitate the maintenance of the clutch 280. The clutch 280 is set to slip at a specific predetermined value (e.g., 20-50Nm) to achieve an appropriate level of hydraulic pressure in the cutting wheel assembly 260 (e.g., 200-1500psi, or more preferably 800-1200psi, but this can vary according to the cutting requirements and the downhole environment).

[0221] The drive shaft 212 passes through the central opening in the clutch 280. The clutch 280 is on the left hand side of the clutch 280 (the position of this side is in reference to the direction of the illustration in the figure, for example Fig.41 ) is clamped to the drive shaft 212. The right hand side of the clutch drives the ball screw assembly 220. Figure 41-43As shown, the clutch 280 is fixedly connected to the adapter 281, which also includes a central opening through which the drive shaft 212 also passes. The adapter 281 includes a rib 282 around one side and is connected to the clutch 280 on its opposite side by at least one threaded fastener. The rib 282 is arranged around the drive shaft 212 and engages with a castellated piece formed on one end of the ball screw 222. The mutual engagement of the adapter 281 and the ball screw 222 transmits the rotational motion from the drive assembly 10 to the ball screw assembly 220 via the drive shaft 212.

[0222] As in the first example, the ball screw assembly 220 is used to increase the fluid pressure within the piston chamber 230, which is then transmitted to the anchor module 240 and the cutting wheel assembly 260. Figure 44-Figure 48 As shown, there is no pressure relief valve or check valve between the anchor module 240 and the cutting wheel assembly 260. Therefore, an increase in fluid pressure in the chamber 230 is reflected by a corresponding increase in fluid pressure in the anchor module 240 and the cutting wheel assembly 260. The anchor pad 242 is thus deployed simultaneously with the cutting wheel 262 and the roller 270, and each of them contacts the inner surface of the pipe at substantially the same time. Therefore, the cutting tool 200 is anchored at the same time as the cutting wheel 262 begins to cut the pipe. The cutting operation can then be performed as described above to sever the pipe.

[0223] Once the tubular is severed, the cutting wheel piston 264 (and therefore the cutting wheel 262), rollers 270 and anchor pads 242 are retracted by reversing the direction of rotation of the drive shaft 212 and retracting the hydraulic piston 230 as previously described. As the retraction of the piston 230 proceeds, the pressure behind the piston 230 decreases to zero and a pressure differential is then created to further assist (along with the anchor spring 246) the retraction of the radially extending components. Once the extended components, particularly the cutting wheel 262, have been fully retracted, the cutting tool 200 can be retrieved from the well.

[0224] A third example of a cutting tool 300 is shown in FIG. Figure 49-Figure 55 Shown in.

[0225] Fig.49 and Fig.50 The entire tool 300 is shown, including the drive assembly 10 as described above, which will not be described again for the sake of brevity. The tool 300 also includes an example of an anchor module 240. All other features that are the same as the first embodiment will be identified by the same reference numerals plus 200.

[0226] In this example of cutting tool 300, the fluid pressure within piston chamber 330 is controlled solely by a piston pressure relief valve (PRV) 331 disposed within the wall of hydraulic piston 326, as shown in FIG. Fig.55The piston PRV is set to open at a threshold fluid pressure value (eg, 200-1500 psi, or more preferably 800-1200 psi, although the threshold may vary depending on cutting requirements and downhole environment).

[0227] The ball screw 322 is fixedly attached to the drive shaft 312 by a threaded fastener (although any form of hard mounting the ball screw 322 to the drive shaft 312 is suitable). This configuration means that each full rotation of the drive shaft 312 advances the hydraulic piston 326 a distance equal to the pitch of the ball screw 322.

[0228] As fluid pressure builds up in piston chamber 330, increasing pressurized fluid is delivered to anchor module 240 and cutting wheel assembly 360 to actuate anchor pad 242, cutting wheel piston 366 and cutting wheel 362, and roller piston 373 and roller 370. If the pressure in piston chamber 330 exceeds the threshold of piston PRV 331, the valve will open and the pressure will be released by the fluid flowing from piston chamber 330, through piston PRV 331 and into chamber 333 on the opposite side of piston 326.

[0229] Once the cut is complete and the tubular has been severed, the hydraulic piston 326 can be retracted by reversing the direction of rotation of the drive shaft 312, which retracts the ball screw assembly 320. The retraction of the piston 326 occurs by the hydrostatic pressure pushing against the piston 326. The effect of the retraction is to reduce the fluid pressure experienced by the cutting wheel piston 366, the roller piston 373, and the anchor pad 242. The pressure behind the hydraulic piston 326 gradually decreases to zero and then a vacuum is drawn, causing these components to return to their original configuration and allowing the tool 300 to be retrieved from the well.

[0230] Fig.56 An optional cutting wheel assembly 460 is shown. Figure 57-Figure 59 Cross sections of the cutting wheel assembly 460 are shown taken at different locations to illustrate the different components.

[0231] like Fig.57 As shown, the cutting wheel assembly 460 includes a ratchet and pawl arrangement 490 located in the end of the cutting wheel assembly 460. In this example, there are three pawls 491 arranged circumferentially around the drive shaft 412. The pawl is blade-shaped with a narrow end and a thick end, wherein the pawl 491 is connected to a hinged fixture (or any other suitable fixture that allows the pawl 491 to rotate about the axis of the thick end) at its thick end.

[0232] The pawls 491 are positioned adjacent to the cavities 494 formed in the cutting wheel assembly. A spring 492 is located in each cavity 494 and contacts the narrow end of the corresponding pawl 491. The spring 492 is used to resiliently bias each pawl 491 toward the drive shaft 412.

[0233] The drive shaft 412 has teeth 493 formed around its outer circumference at the end of the drive shaft 412. In this example, there are three teeth 493 formed around the drive shaft 412 and spaced apart so that each tooth 493 can engage with a pawl 491. The teeth 493 allow this end of the drive shaft 412 to function as a ratchet.

[0234] When the drive shaft 412 rotates in one direction— Fig.57 In the example shown, rotation in the counterclockwise direction causes the tooth 493 to engage the pawl 491, resulting in a rotational lock of the drive shaft 412 and the cutting wheel assembly 460. Thus, rotation of the drive shaft 412 in this direction causes a corresponding rotation of the cutting wheel assembly 460.

[0235] Rotation of the drive shaft 412 in the opposite direction (i.e., in this example, in a clockwise direction) causes the drive shaft 412 to slide past each pawl 491. In this rotational direction, as the drive shaft 412 passes each pawl 491, the teeth 493 on the drive shaft 412 push each pawl 491 against each spring 492. As the drive shaft 412 moves past the or each pawl, the free (narrow) end of each pawl moves in an arc within the cavity 494. This allows the drive shaft 412 to rotate without correspondingly rotating the cutting wheel assembly 460.

[0236] In the event that the cutting wheel 462 / cutting wheel assembly 460 is stuck or stuck in the wellbore, the drive shaft 412 can be rotated in a clockwise direction to retract the piston and reduce the fluid pressure in the tool. Once the fluid pressure is released, in the event that the cutting wheel 462 is stuck, the cutting wheel 462 can be vibrated to release the tool from the tubular and allow the tool to return to the surface.

[0237] Fig.58An example of a cutting wheel assembly 460 is shown, wherein a cutting wheel piston 466 includes a fastener (e.g., a bolt or screw) 469 disposed within an opening in the cutting wheel piston 466. The fastener 469 is at least partially surrounded by a spring 467, which extends downwardly at least a portion of each fastener 469 and is coaxial with each fastener 469. The opening of the cutting wheel piston 466 includes a first inner diameter, in which the spring 467 is retained, and a second inner diameter, which is smaller than the first inner diameter, through which the corresponding fastener 469 passes. The second inner diameter forms a step or shoulder against which one end of each spring 467 abuts. The opposite end of each spring 467 abuts against a shoulder formed in the fastener 469 through the wider diameter portion of the fastener 469. Thus, the spring 467 acts on the cutting wheel piston 466 at one end and on the fastener 469 at the other end of the spring 467.

[0238] The cutting wheel piston 466 moves relative to the fastener 469, which is connected to the housing of the cutting wheel assembly 460 and remains in place when the cutting wheel piston 466 moves radially. When the fluid pressure behind the cutting wheel piston 466 increases, the piston 466 moves radially outward, thereby forming a piston chamber 468 and compressing the spring 467. Therefore, the spring 467 is used to resist the radial extension of the cutting wheel piston 466 and biases the cutting wheel piston 466 (and the cutting wheel 462) towards radial retraction. Therefore, when the fluid pressure is low enough, the spring 467 retracts the cutting wheel piston 466 into the body of the cutting wheel assembly 460.

[0239] Similarly, Fig.59 The connection to two fasteners 474 (eg Fig.56 As shown; Fig.59 474). Each fastener 474 is disposed in an opening in the cutting wheel assembly 460 and is fixed to the roller piston 473 at one end. Similar to the cutting wheel piston 466, the opening in the cutting wheel assembly 460 includes a shoulder at one end, and each fastener 474 also includes a shoulder spaced apart from the shoulder of the opening. A spring 475 coaxially surrounds the fastener 474 between the two shoulders. When the fluid pressure in the cutting wheel assembly 460 increases, the roller piston 473 moves radially outward to form a piston chamber 478. The radial extension of the roller piston 473 compresses each spring 475. The spring 475 is used to resist the radial extension of the roller piston 473 and bias the roller piston 473 (and the roller 470) toward radial retraction. Therefore, when the fluid pressure is low enough, the spring 475 retracts the roller piston 473 into the body of the cutting wheel assembly 460.

[0240] Fig.58 and Fig.59Also best shown are bearing races 464b, 471b disposed about the circumference of shafts 464, 471 about which the cutting wheel 462 and roller 470 rotate, respectively. This configuration facilitates rotation of the cutting wheel 462 and roller 470 and is suitable for each example of the invention described herein.

[0241] like Fig.60 and Fig.61 As best shown, the tool includes a shear release configuration that allows for emergency venting in the event of tool failure.

[0242] At the end of the ball screw assembly housing 219 connected to the anchor module 240, the ball screw assembly housing 219 includes shear screws 219a (e.g., 8 shear screws 219a) positioned around the circumference of the ball screw assembly housing 219 and extending into openings in the outer wall of the anchor module 240.

[0243] The rotating bushing 245 is located in a recess formed in the end of the ball screw assembly housing 219, and when the connection between the two components is formed, the rotating bushing 245 extends vertically into the space formed between the anchor module 240 and the ball screw assembly housing 219. The rotating bushing 245 surrounds the end of the ball screw assembly housing 219. The shear release configuration also includes a snap ring 247 located in a recess formed between the inner surface of the end of the ball screw assembly housing 219 and the outer surface of the anchor module 240. The snap ring 247 is positioned to partially abut against one end of the recess formed in the anchor module 240 and one end of the rotating bushing 245.

[0244] The end of the anchor module 240 also includes an O-ring seal 249 disposed in a groove around the periphery of the anchor module 240. The O-ring 249 is located adjacent the shear screw 219a, on the side of the shear screw 219a opposite the rotating bushing 245 and the snap ring 247.

[0245] In the event of a tool failure—for example, it becomes stuck, or it becomes trapped or stuck in a pipe—the tool can be vibrated upward. The tool is vibrated to shear the shear screw 219a, thereby allowing the ball screw assembly housing 219 to move axially relative to the anchor module 240. The shear release arrangement including the snap ring 247 and the rotating bushing 245 moves axially with the ball screw assembly housing 219.

[0246] This movement of the ball screw assembly housing 219 aligns the opening through the ball screw assembly housing 219, wherein each shear screw 219a is arranged to at least partially align with the O-ring 249 around the end of the anchor module 240, thereby disengaging the O-ring 249 from its groove. This allows the fluid within the tool to be discharged into the wellbore for emergency retraction of the anchor, cutting wheel and roller (if possible), and recovery of the tool to the surface.

[0247] Figure 62-Figure 65 An alternative linear actuator assembly is shown. In the example shown, a lead screw assembly 520 is used instead of the ball screw assembly 120, 220. The lead screw assembly 520 can directly replace the ball screw assembly 120, 220 in the cutting tools 100, 200, 300 described above.

[0248] like Figure 62-Figure 65 As shown, the drive shaft 512 passes through the central opening in the clutch 580. The clutch 580 can be a synchronous torque limiting clutch. The clutch 580 is on the left hand side of the clutch 580 (the position of this side is in reference to the direction of the illustration in the figure, for example Fig.65 ) is clamped to the drive shaft 512. The right hand side of the clutch drives the screw assembly 520. Fig.65 As best shown, the clutch 580 is fixedly connected to an adapter 581, which in turn includes a central opening through which the drive shaft 512 also passes. The adapter 581 includes a rib 582 around one side (at Fig.63 512) and connected to the clutch 580 on its opposite side by at least one threaded fastener. Ribs 582 are disposed around the drive shaft 512 and engage with a castellation formed on one end of the lead screw 522. The mutual engagement of the adapter 581 and the lead screw 522 transfers rotational motion from the drive assembly 10 to the lead screw assembly 520 via the drive shaft 512.

[0249] The outer surface of the lead screw 522 is at least partially threaded. The lead screw nut 524 includes complementary threads on its inner surface and also includes a central opening through which the lead screw 522 and the drive shaft 512 pass. The opening of the lead screw 522 (through which the drive shaft 512 extends) is coaxial with the opening of the lead screw nut 526.

[0250] Piston 526 is connected to one end of the lead screw nut 524. As previously described, the movement of piston 526 increases and decreases the fluid pressure in the lower section of the tool. Figure 62-Figure 65512 is not shown. When the drive shaft 512 rotates, the lead screw 522 also rotates. According to the direction of rotation, the lead screw nut 524 moves the lead screw 522 axially backward and forward, upward and downward. This in turn causes the piston 526 to move axially in the piston chamber (e.g., piston chamber 130, 230), increasing and decreasing the fluid pressure as the fluid is compressed or decompressed in the piston chamber. As described above, the fluid pressure in the cutting wheel assembly 160, 260, 360, 460 increases and decreases accordingly.

[0251] Modifications and improvements may be made to the examples and implementations described above without departing from the scope of the present invention.

Claims

1. A cutting tool for use in an oil well or a gas well, the cutting tool comprising: a battery powered power assembly, wherein operation of the power assembly causes the drive shaft to rotate and change the fluid pressure within the cutting tool; wherein the drive shaft is configured to rotate a cutting wheel assembly; wherein the cutting wheel assembly includes a cutting wheel configured to rotate about an axis; and Wherein the cutting wheel is actuated to move radially in response to changes in the fluid pressure.

2. The cutting tool of claim 1, wherein the drive shaft forms part of a rotational assembly, wherein the rotational assembly further comprises a linear actuator.

3. The cutting tool according to claim 2, wherein: The rotational assembly is configured to convert rotational motion into fluid pressure.

4. The cutting tool according to claim 2 or 3, wherein: When fluid pressure within the cutting wheel assembly reaches a predetermined threshold, the drive shaft is disengaged from the linear actuator such that the drive shaft rotates independently of the linear actuator.

5. The cutting tool according to claim 4, wherein: The cutting wheel is configured to radially extend when fluid pressure within the cutting wheel assembly reaches the predetermined threshold.

6. The cutting tool according to claims 2-5, wherein: The linear actuator includes a through hole through which the drive shaft extends.

7. The cutting tool according to claims 1 to 6, wherein: In a first configuration, the drive shaft and the cutting wheel assembly are in rotational engagement, and rotation of the drive shaft causes the cutting wheel assembly to rotate; and Wherein, in a second configuration, the drive shaft and the cutting wheel assembly are rotationally disengaged and rotation of the drive shaft does not rotate the cutting wheel assembly.

8. The cutting tool according to claims 2-7, wherein: The drive shaft includes at least one clutch.

9. The cutting tool according to claim 8, wherein: The clutch is configured to rotate the drive shaft and the linear actuator together until a predetermined threshold level of torque is reached; Wherein, the clutch is further configured to slip when the predetermined threshold level of torque is reached, thereby allowing relative movement between the drive shaft and the linear actuator.

10. The cutting tool according to claims 2-9, wherein: The rotating assembly also includes a piston.

11. The cutting tool according to claim 10, wherein: The piston includes an opening through which the drive shaft extends.

12. The cutting tool according to claim 10 or 11, wherein: The cutting tool includes a piston chamber within the rotating assembly; wherein the piston chamber is disposed between the piston and the cutting wheel assembly.

13. The cutting tool according to claim 12, wherein: The cutting wheel assembly is in fluid communication with the piston chamber.

14. A cutting tool as claimed in claim 12 or claim 13, wherein: Compression of the fluid within the piston chamber increases fluid pressure within the cutting wheel assembly.

15. The cutting tool according to claims 10-14, wherein: The linear actuator is configured to reversibly move axially under rotation; Wherein the piston is configured to move axially with the linear actuator.

16. The cutting tool of claim 15, wherein: The drive shaft and the cutting wheel assembly are configured to engage one another when the drive shaft rotates in a first direction; and Wherein the drive shaft and the cutting wheel assembly are configured to disengage from each other when the drive shaft rotates in the second direction.

17. The cutting tool of claim 16, wherein: Rotation of the drive shaft in the second direction reverses the axial motion of the linear actuator, thereby retracting the piston.

18. The cutting tool of claim 17, wherein retraction of the piston reduces fluid pressure within the cutting wheel assembly; A reduction in fluid pressure allows the cutting wheel to at least partially retract.

19. The cutting tool according to claims 1 to 18, wherein: The cutting tool also includes an anchor module including a reversibly actuatable anchor configured to engage an inner surface of a tubular and rotatably fix the cutting tool relative to the tubular.

20. The cutting tool according to claims 1-19, wherein: The cutting wheel is mounted on a cutting wheel axle within a cutting wheel housing, and the cutting wheel is configured to rotate about the cutting wheel axle.

21. The cutting tool according to claims 1-20, wherein: The cutting wheel is configured to at least partially cut a 360 degree section of the wall of the tubular.

22. The cutting tool of claims 1-21, wherein: The cutting wheel is configured to extend radially in predetermined increments.

23. The cutting tool of claims 1-22, wherein: The cutting tool comprises at least one roller, wherein the at least one roller comprises a roller wheel and a roller shaft which are arranged in a roller shell capable of radial movement.

24. The cutting tool of claims 1-23, wherein: The power assembly includes an electric motor; Wherein, the electric motor is connected to the gearbox via a first end of an input shaft; wherein rotation of the motor rotates the input shaft, thereby rotating the gearbox; and The input shaft is coupled to the drive shaft at a second end of the input shaft.

25. According to the present invention, there is provided a method for cutting a tubular in an oil or gas well, the method comprising: deploying a cutting tool into the wellbore to the depth of the tubular to be cut, wherein the cutting tool comprises: a battery powered power assembly, wherein operation of the power assembly causes the drive shaft to rotate and change the fluid pressure within the cutting tool; and a cutting wheel assembly including a cutting wheel; The method further includes: rotating the drive shaft, thereby rotating the cutting wheel assembly; rotating the cutting wheel about an axis; and In response to the change in fluid pressure, the cutting wheel is actuated to radially move the cutting wheel.

26. The method of claim 25, comprising, in a first configuration, rotationally engaging the drive shaft and the cutting wheel assembly such that rotation of the drive shaft rotates the cutting wheel assembly; In a second configuration, the drive shaft and the cutting wheel assembly are disengaged such that rotation of the drive shaft does not rotate the cutting wheel assembly.

27. The method of claim 25 or 26, wherein the drive shaft forms part of a rotating assembly, the rotating assembly further comprising a linear actuator, and wherein the drive shaft includes at least one clutch; and The method comprises: rotating the drive shaft and the linear actuator until a predetermined threshold level of torque is reached; and The clutch is configured to slip when the predetermined threshold level of torque is reached, allowing relative movement between the drive shaft and the linear actuator.

28. The method of claim 27, wherein: The rotation assembly also includes a piston configured to move axially with the linear actuator; and The method further comprises converting the rotational motion into fluid pressure by axial movement of the piston.

29. The method of claim 28, comprising providing a piston chamber between the piston and the cutting wheel assembly, wherein the cutting wheel assembly is in fluid communication with the piston chamber; increasing fluid pressure within the cutting wheel assembly by compressing fluid within the piston chamber; and When the fluid pressure within the cutting wheel assembly reaches a predetermined threshold, the cutting wheel assembly is radially extended.

30. The method of claim 29, wherein: The drive shaft and the cutting wheel assembly are rotationally engaged when the drive shaft rotates in a first direction and are rotationally disengaged when the drive shaft rotates in a second direction.

31. The method of claim 30, wherein: The method comprises at least partially retracting the cutting wheel by: rotating the drive shaft in the second direction to reverse the axial movement of the linear actuator; retracting the piston; and Fluid pressure within the cutting wheel assembly is reduced.

32. The method of claims 25-31, comprising: The wall of the tubular is at least partially cut by rotating the cutting wheel assembly as the cutting wheel assembly extends radially within the tubular.

33. The method of claims 25-32, comprising radially extending the cutting wheel in predetermined increments.

34. The method of claims 25-33, comprising anchoring the cutting tool within the tubular to restrict relative rotational movement of the cutting tool.

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