Abstract: A downhole welding tool includes a tool body and a welding device coupled to the tool body. The welding device includes a carrier arm reversibly pivotable between a collapsed configuration of the welding device in which the carrier arm is oriented parallel to the tool body and an extended configuration of the welding device in which the carrier arm projects outward from the tool body at an acute angle relative to the tool body, as well as a consumable welding tip secured to the carrier arm. The downhole welding tool also includes a rotatable actuator coupled to the tool body adjacent the welding device and configured to adjust the carrier arm between the collapsed configuration and the extended configuration.

Abstract: A system for drilling a well includes a gripping unit provided at a rig above a surface of the well for holding a top end of a drill string in the well, a liner releasably connected to the drill string, and a downhole motor installed on the drill string in an axial position between the surface of the well and the liner, where the downhole motor has a stator connected to the drill string and a rotor operatively connected to an axial end of the liner closest to the surface of the well.

Abstract: A pipe segment includes an outer pipe including a shaft wall, a first connector disposed at a first end of the shaft wall, and a second connector disposed at a second end of the shaft wall opposite the first end. The pipe segment further includes an electrical cable extending through the shaft wall along a length of the outer pipe between the first and second connectors and an inner pipe positioned within the outer pipe and surrounding the electrical cable, the inner pipe being movable axially with respect to the outer pipe, and the outer pipe being movable rotationally with respect to the inner pipe.

Abstract: A method of performing a logging operation at a wellbore includes providing first and second pipe segments respectively including a first internal electrical cable and a second internal electrical cable, connecting a first end of the first internal electrical cable to a wireline cable of a logging tool to form a drill pipe string, lowering the drill pipe string, including the logging tool and the first pipe segment, into the wellbore, connecting a first end of the second internal electrical cable to a second end of the first internal electrical cable to add the second pipe segment to the drill pipe string, lowering the drill pipe string, including the logging tool, the first pipe segment, and the second pipe segment, into the wellbore, and connecting a second end of the second internal electrical cable to a surface logging unit to couple the surface logging unit to the drill pipe string.

Abstract: A swivel includes a male segment, a female segment, and a lock pin. The male segment can mate with the female segment, and the lock pin can pass through the female segment and engage with the male segment to prevent relative axial movement of the male segment and the female segment while allowing relative rotational movement of the male segment and the female segment. The male segment includes a first conductive ring configured to couple to a first wire. The female segment includes a second conductive ring configured to couple to a second wire. Contact between the first and second conductive rings establishes an electrical connection between the first and second wires.

Abstract: A downhole welding tool includes a tool body and a welding device coupled to the tool body. The welding device includes a carrier arm reversibly pivotable between a collapsed configuration of the welding device in which the carrier arm is oriented parallel to the tool body and an extended configuration of the welding device in which the carrier arm projects outward from the tool body at an acute angle relative to the tool body, as well as a consumable welding tip secured to the carrier arm. The downhole welding tool also includes a rotatable actuator coupled to the tool body adjacent the welding device and configured to adjust the carrier arm between the collapsed configuration and the extended configuration.

Abstract: A system for drilling a well includes a gripping unit provided at a rig above a surface of the well for holding a top end of a drill string in the well, a liner releasably connected to the drill string, and a downhole motor installed on the drill string in an axial position between the surface of the well and the liner, where the downhole motor has a stator connected to the drill string and a rotor operatively connected to an axial end of the liner closest to the surface of the well.

Abstract: A packer assembly includes a tubing string disposed in a wellbore and a packer releasably coupled to the tubing string. The packer includes a housing releasably coupled to the tubing string, a packer slip, a flexible sealing element, a piston coupled to the housing, a locking member, and a mandrel disposed inside the housing. The piston moves to activate the packer slip and the flexible sealing element to set the packer on a wall of the wellbore. The locking member engages the piston to constrain movement of the piston to keep the packer set on the wall of the wellbore. The mandrel connects to the tubing string when the tubing string is released from the housing. The locking member is collapsible to disengage the piston to unset the packer slip and the flexible sealing element responsive to shear force applied by the mandrel to the locking member.

Abstract: A downhole tool includes a streamlined housing sized to freely move through a wellbore formed from a terranean surface to a subterranean formation; an explosive material enclosed within an interior volume of the housing, the explosive material sufficient to cut at least a portion of a tubular positioned in the wellbore upon detonation; a detonator coupled to the explosive material; and a detonator control system communicably coupled to the detonator and configured to activate the detonator with a detonation signal to detonate the explosive material.

Abstract: Wellbore tool assembly to open collapsed tubing includes a chisel head having a first end configured to be positioned within an end of a collapsed tubing portion of a tubular member. The chisel head has a second end opposite the first end. The second end has an outer diameter smaller than an outer diameter of an uncollapsed tubing portion of the tubular member. The chisel head is configured to expand a diameter of the collapsed tubing portion responsive to a movement of the chisel head toward the collapsed tubing portion. The assembly includes a packer attached to the chisel head. The packer is configured to expand responsive to fluidic pressure and to further expand the diameter of the collapsed tubing portion.

Abstract: A method of performing a logging operation at a wellbore includes providing first and second pipe segments respectively including a first internal electrical cable and a second internal electrical cable, connecting a first end of the first internal electrical cable to a wireline cable of a logging tool to form a drill pipe string, lowering the drill pipe string, including the logging tool and the first pipe segment, into the wellbore, connecting a first end of the second internal electrical cable to a second end of the first internal electrical cable to add the second pipe segment to the drill pipe string, lowering the drill pipe string, including the logging tool, the first pipe segment, and the second pipe segment, into the wellbore, and connecting a second end of the second internal electrical cable to a surface logging unit to couple the surface logging unit to the drill pipe string.

Abstract: A pipe segment includes an outer pipe including a shaft wall, a first connector disposed at a first end of the shaft wall, and a second connector disposed at a second end of the shaft wall opposite the first end. The pipe segment further includes an electrical cable extending through the shaft wall along a length of the outer pipe between the first and second connectors and an inner pipe positioned within the outer pipe and surrounding the electrical cable, the inner pipe being movable axially with respect to the outer pipe, and the outer pipe being movable rotationally with respect to the inner pipe.

Abstract: A swivel includes a male segment, a female segment, and a lock pin. The male segment can mate with the female segment, and the lock pin can pass through the female segment and engage with the male segment to prevent relative axial movement of the male segment and the female segment while allowing relative rotational movement of the male segment and the female segment. The male segment includes a first conductive ring configured to couple to a first wire. The female segment includes a second conductive ring configured to couple to a second wire. Contact between the first and second conductive rings establishes an electrical connection between the first and second wires.

Abstract: Wellbore tool assembly to open collapsed tubing includes a chisel head having a first end configured to be positioned within an end of a collapsed tubing portion of a tubular member. The chisel head has a second end opposite the first end. The second end has an outer diameter smaller than an outer diameter of an uncollapsed tubing portion of the tubular member. The chisel head is configured to expand a diameter of the collapsed tubing portion responsive to a movement of the chisel head toward the collapsed tubing portion. The assembly includes a packer attached to the chisel head. The packer is configured to expand responsive to fluidic pressure and to further expand the diameter of the collapsed tubing portion.

Abstract: A packer assembly includes a tubing string disposed in a wellbore and a packer releasably coupled to the tubing string. The packer includes a housing releasably coupled to the tubing string, a packer slip, a flexible sealing element, a piston coupled to the housing, a locking member, and a mandrel disposed inside the housing. The piston moves to activate the packer slip and the flexible sealing element to set the packer on a wall of the wellbore. The locking member engages the piston to constrain movement of the piston to keep the packer set on the wall of the wellbore. The mandrel connects to the tubing string when the tubing string is released from the housing. The locking member is collapsible to disengage the piston to unset the packer slip and the flexible sealing element responsive to shear force applied by the mandrel to the locking member.

Abstract: A downhole tool includes a streamlined housing sized to freely move through a wellbore formed from a terranean surface to a subterranean formation; an explosive material enclosed within an interior volume of the housing, the explosive material sufficient to cut at least a portion of a tubular positioned in the wellbore upon detonation; a detonator coupled to the explosive material; and a detonator control system communicably coupled to the detonator and configured to activate the detonator with a detonation signal to detonate the explosive material.