A single-use pressure-controlled actuator for downhole well tools or mechanisms is provided. The actuator is configured for control of activation/deactivation by agency of wellbore fluid pressure (e.g., pressure levels of drilling fluid or drilling mud in the wellbore). The actuator is further configured for hydraulic actuation by agency of the wellbore fluid. The actuator comprises a plunger displaceably mounted on a sealed cylinder body, with a non-reclosable frangible device closing off wellbore fluid access to an interior of the cylinder body. The frangible device is configured for automatic in response to exposure of wellbore fluid pressures exceeding a predetermined activation threshold. Failure of the frangible device causes exposure of the plunger to the wellbore fluid, resulting in actuated movement of the plunger by hydraulic action of the wellbore fluid.

A downhole cutting tool (13) for perforating a tubular (14) in an oil or gas well comprises a body (4); radially moveable cutting members (3) mounted on the body (4); a helical profiled member (1) rotatable relative to the body (4); and activation members (2) axially movable relative to the body (4). Rotation of the helical profiled member (1) generates axial movement of the activation members (2), and the activation members (2) configured to actuate the cutting members (3) from a retracted configuration to an extended configuration.

A plug assembly includes an expandable assembly, a locking ring and a cup. The expandable assembly is adapted to be deformed radially over the locking ring and the cup. The locking ring has a stopping inner surface. The plug assembly is used with one or more untethered objects, the untethered objects having an outer surface adapted to couple with the cup, and the cup having an outer surface adapted to couple with the stopping inner surface of the locking ring. The combination of cup and untethered objects is also adapted to contact an inner surface of the plug assembly and, using well fluid pressure, to apply forces to the plug assembly. The forces cause the longitudinal movement of the cup and untethered objects while contacting the inner surface of the plug assembly until the cup contacts the stopping inner surface of the locking ring.

Provided, in one aspect, is an anchor for use with a downhole tool in a wellbore. The anchor, according to this aspect, may include a base pipe; and one or more expandable chambers positioned radially about the base pipe. The one or more expandable chambers may, in some aspects, be configured to move from a first collapsed state to a second activated state; and the one or more expandable chambers may be operable to handle at least 20.7 Bar of internal pressure in the second activated state to engage a wall of a wellbore.

A system and method set a liner hanger in a borehole by actuating a hydraulic setting mechanism on the hanger to engage slips in the borehole. A setting tool runs the hanger into position. A reserve volume of the tool holds a clean fluid separate from the borehole. A piston of the tool has a tool volume for the fluid. During run in, pressure in the tool volume is balanced to hydrostatic pressure by drawing actuation fluid from the reserve volume to the tool volume through a check valve. To set the hanger, a plug is engaged on a seat in the tool, tubing pressure is applied behind the engaged plug, and the seat is unlocked. With more applied pressure, the piston moves, reduces the tool volume, and intensifies pressure of the clean fluid communicated to the hanger's setting mechanism. Over-pressure can be handled by a venting valve.

A braking and setting device is configured to slow down a movement of a tool in a well and to fix the tool relative to the well. The braking and setting device includes two or more arms configured to extend from the tool, toward the well, to brake the movement of the tool along a longitudinal axis X; a movable piston configured to be hosted fully within the tool and to move only when a well fluid acts on a base portion of the movable piston, while a tip portion of the movable piston pushes away the two or more arms; and an actuation mechanism configured to establish a fluid communication between the well fluid and the base portion of the movable piston. The movable piston moves exclusively due to a force exerted by the well fluid on the movable piston.

A thru-tubing recover string (10) and method of moving a stuck object (14) in tubing in a well (16). A bottom hole assembly (22) is connected to a work string and includes a first (32) and a second tool (34), each tool configured to apply a force to the object in order to move the object (14), the first force being an impulse force, the second force being a static force, and the tools being operable independently so that an operator can apply either force in the event that application of one type of force on the object fails to move the object. Embodiments are described for the first tool (32) being a hammer tool or a jar and the second tool being a pulling tool such as a jack. The invention finds application in removing stuck objects such as plugs or actuating elements on tools such as sliding sleeves in production tubing.

A method and apparatus for casing recovery for well abandonment. A string is run-in, the string including a hydraulic jack (18), an anchor (28), a casing spear (20), a downhole flow pulsing device (22) and a pressure drop sub (24). The casing spear grips an upper end of the length of casing to be pulled. The anchor is set in casing of a greater diameter above the length of cut casing. Fluid pumped through the string and through the pressure drop sub will increase fluid pressure at the hydraulic jack to a first fluid pressure (78). Fluid pumped through the downhole flow pulsing device will vary the fluid flow superimposing a cyclic pressure (82) on the first pressure (78), causing oscillation of an inner mandrel (30) of the hydraulic jack. The jack moves the oscillating inner mandrel upwards relative to the anchor to pull the length of casing.

An anchor for securing a well tool can include a longitudinally extending central axis, an outwardly extendable grip member, and a mechanical linkage including multiple pivotably connected links. The links pivot relative to each other in a plane laterally offset from the central axis. A method of anchoring a well tool can include flowing a fluid through an anchor connected to the well tool, thereby outwardly extending a grip member into contact with a well surface, and applying a tensile force to the anchor, thereby increasingly biasing the grip member against the well surface and securing the well tool relative to the well surface. A method of anchoring a tubing cutter in a tubular string can include applying a tensile force from an anchor to the tubular string, and cutting the tubular string while the tensile force is applied from the anchor to the tubular string.

A downhole tool that has a plurality of arm assemblies. Each of the arm assemblies has an arm configured to expand and retract and an actuator. A hydraulic bus in fluid communication with the plurality of arm assemblies. A plurality of flow control devices. The flow control devices are configured to selectively isolate one or more arm assemblies of the plurality of arm assemblies from the hydraulic bus while maintaining the other arm assemblies of the plurality of arm assemblies in communication with the hydraulic bus.