Downhole cutting tool positioning assemblies and methods to cut a tubular are presented. The assembly includes a drive screw, a drive nut coupled to the drive screw and configured to shift from a first position to a second position as the drive screw rotates in a first drive screw direction, a pressure piston configured to shift from a first position to a second position in response to force applied to the pressure piston, a chamber having a pressure fluid that is pressurized by the pressure piston as the pressure piston shifts from the first position towards the second position, a sleeve configured to slide from a first position towards a second position in response to pressure from the pressure fluid, and a latch key having a profile configured to shift radially to engage a tubular groove as the sleeve shifts from the first position towards the second position.

A guide assembly comprises a grooved mandrel having a first end adapted for coupling or connecting, a second end, and having a spiral groove and a set of ring grooves on an external surface of the grooved mandrel. The guide assembly comprises a guide shoe concentric to at least the second end of the grooved mandrel and an annular fastener that fastens the guide shoe to the grooved mandrel.

A guide assembly comprises a grooved mandrel having a first end adapted for coupling or connecting, a second end, and having a spiral groove and a set of ring grooves on an external surface of the grooved mandrel. The guide assembly comprises a guide shoe concentric to at least the second end of the grooved mandrel and an annular fastener that fastens the guide shoe to the grooved mandrel.

A shear coupling includes a first half, a second half, and a shear pin connected therebetween. The connections between the shear pin and the first half and the second half substantially isolate the shear pin from torsional, bending, and compression forces experienced by the first half or the second half. The connections between the shear pin and the first half and the second half transfer tension forces experienced by the first half and the second half to the shear pin from. A tension force above a predetermined threshold causes the shear pin to separate into two pieces that remain connected to the first and second halves.

A shear coupling includes a first half, a second half, and a shear pin connected therebetween. The connections between the shear pin and the first half and the second half substantially isolate the shear pin from torsional, bending, and compression forces experienced by the first half or the second half. The connections between the shear pin and the first half and the second half transfer tension forces experienced by the first half and the second half to the shear pin from. A tension force above a predetermined threshold causes the shear pin to separate into two pieces that remain connected to the first and second halves.

Provided, in one aspect, is a downhole torque limiter, comprising a tubular housing; a pipe positioned within the tubular housing; one or more clutch mechanisms positioned between the pipe and the tubular housing, the one or more clutch mechanisms configured to move between a engaged state to fix the tubular housing relative to the pipe and a disengaged state to allow with the tubular housing to rotate relative to the pipe; and a fluid control system coupled with an exterior of the one or more clutch mechanisms, the fluid control system configured to allow the one or more clutch mechanisms to move from the engaged state to the disengaged state based upon sensing movement of the pipe relative to the tubular housing.

Provided, in one aspect, is a downhole torque limiter, comprising a tubular housing; a pipe positioned within the tubular housing; one or more clutch mechanisms positioned between the pipe and the tubular housing, the one or more clutch mechanisms configured to move between a engaged state to fix the tubular housing relative to the pipe and a disengaged state to allow with the tubular housing to rotate relative to the pipe; and a fluid control system coupled with an exterior of the one or more clutch mechanisms, the fluid control system configured to allow the one or more clutch mechanisms to move from the engaged state to the disengaged state based upon sensing movement of the pipe relative to the tubular housing.

The present invention relates to a downhole drilling method for drilling a well in a formation having a formation pressure. The downhole drilling method comprises providing a drill string having a first part and a second part, the second part being arranged closer to a top of the well than the first part, and the first part having a drilling head in a first end and an annular barrier arranged closer to the top of the well than the drilling head. The annular barrier comprises a tubular metal part for mounting as part of the first part of the drill string, the tubular metal part having an outer face; an expandable metal sleeve surrounding the tubular metal part and having an inner face facing the tubular metal part and an outer face facing an inner face of a borehole of the well, each end of the expandable metal sleeve being connected with the tubular metal part; and an annular space between the inner face of the expandable metal sleeve and the tubular metal part, the expandable metal sleeve being configured to expand. The downhole drilling method furthermore comprises drilling the borehole by means of the drilling head; detecting the formation pressure to determine any loss of formation pressure; stopping the drilling; dropping a ball into the drill string; pressurising the drill string until the ball reaches a ball seat arranged opposite or below the annular barrier; expanding the expandable metal sleeve by further pressurising the drill string until the expandable metal sleeve abuts the inner face of the borehole; separating the second part of the drill string from the first part; pulling the second part out of the borehole; and injecting cement into the borehole above the first part to provide a cement plug above the first part. The present invention furthermore relates to a downhole drilling system for performing the downhole drilling method according to the present invention and to a downhole completion system.

A shear coupler provides a breakable connection between adjacent members of a pump rod string. The coupler features an elongated shear stud, a hollow member in which the shear stud is axially received, a first set of rotational locking features externally defined on the shear member for engagement with a first set of matable rotational locking features internally defined on the hollow member; and a second set of rotational locking features externally defined on the shear member for engagement thereof with a second set of matable rotational locking features internally defined on the hollow member. The first and second sets of rotational locking features of the shear member are disposed on opposite sides of a weakened area thereof, and tensile and torsional loads on the coupler are substantially isolated from one another. Methods and equipment for applying torsional and tensile pre-loads to the coupler are also provided.

A shear coupler provides a breakable connection between adjacent members of a pump rod string. The coupler features an elongated shear stud, a hollow member in which the shear stud is axially received, a first set of rotational locking features externally defined on the shear member for engagement with a first set of matable rotational locking features internally defined on the hollow member; and a second set of rotational locking features externally defined on the shear member for engagement thereof with a second set of matable rotational locking features internally defined on the hollow member. The first and second sets of rotational locking features of the shear member are disposed on opposite sides of a weakened area thereof, and tensile and torsional loads on the coupler are substantially isolated from one another. Methods and equipment for applying torsional and tensile pre-loads to the coupler are also provided.