A valve assembly (100) is disclosed, for controlling fluid communication along a well tubular (10). The valve assembly comprises: a hydraulically operated valve (40, 42) comprising a valve member (41, 43) which is movable between open and closed positions, and a hydraulic actuator (148) associated with the valve member for moving the valve member between these positions; a control system (146) for selectively controlling the flow of hydraulic fluid to and from the actuator, to operate the valve; a vent chamber (84) operatively connectable to the actuator, for selectively receiving hydraulic fluid exhausted from the actuator when the valve member is moved to its closed position; and a vent conduit (172) operatively connectable to the actuator, for selectively receiving hydraulic fluid exhausted from the actuator when the valve member is moved to its closed position, the vent conduit being exposed to fluid external to the valve assembly at the prevailing external pressure. The control system has a first valve closing state in which the vent chamber is isolated from the actuator and fluid exhausted from the actuator during movement of the valve member to its closed position is vented to an exterior of the valve assembly through the vent conduit. The control system has a second valve closing state in which fluid exhausted from the actuator during movement of the valve member to its closed position is vented into the vent chamber. The control system is configurable in a selected one of the first and second valve closing states according to an operating requirement of the valve. A control assembly for a valve, and a method of operating the valve assembly, are also disclosed.

A valve assembly (100) is disclosed, for controlling fluid communication along a well tubular (10). The valve assembly comprises: a hydraulically operated valve (40, 42) comprising a valve member (41, 43) which is movable between open and closed positions, and a hydraulic actuator (148) associated with the valve member for moving the valve member between these positions; a control system (146) for selectively controlling the flow of hydraulic fluid to and from the actuator, to operate the valve; a vent chamber (84) operatively connectable to the actuator, for selectively receiving hydraulic fluid exhausted from the actuator when the valve member is moved to its closed position; and a vent conduit (172) operatively connectable to the actuator, for selectively receiving hydraulic fluid exhausted from the actuator when the valve member is moved to its closed position, the vent conduit being exposed to fluid external to the valve assembly at the prevailing external pressure. The control system has a first valve closing state in which the vent chamber is isolated from the actuator and fluid exhausted from the actuator during movement of the valve member to its closed position is vented to an exterior of the valve assembly through the vent conduit. The control system has a second valve closing state in which fluid exhausted from the actuator during movement of the valve member to its closed position is vented into the vent chamber. The control system is configurable in a selected one of the first and second valve closing states according to an operating requirement of the valve. A control assembly for a valve, and a method of operating the valve assembly, are also disclosed.

The method of providing blowout preventer ram actuator which will move a blowout preventer shear ram into the bore of the blowout preventer and retract the blowout preventer shear ram from the bore of the blowout preventer, comprising providing a first and second piston, pressuring the second cylinder extension area to move the blowout preventer shear ram into contact with the pipe to be sheared while venting the second cylinder, sensing that the blowout preventer shear ram has contacted the pipe to be sheared, pressuring the first and the second cylinder to shear the pipe and pressuring the first cylinder to retract the shear ram.

The method of providing blowout preventer ram actuator which will move a blowout preventer shear ram into the bore of the blowout preventer and retract the blowout preventer shear ram from the bore of the blowout preventer, comprising providing a first and second piston, pressuring the second cylinder extension area to move the blowout preventer shear ram into contact with the pipe to be sheared while venting the second cylinder, sensing that the blowout preventer shear ram has contacted the pipe to be sheared, pressuring the first and the second cylinder to shear the pipe and pressuring the first cylinder to retract the shear ram.

A shaped charge assembly for selectively expanding a wall of a tubular includes a housing comprising an outer surface facing away from the housing and an opposing inner surface facing an interior of the housing. First and second explosive units each includes a predetermined amount of explosive sufficient to expand, without puncturing, at least a portion of the wall of the tubular to form a protrusion extending outward into an annulus adjacent the wall of the tubular.

A shaped charge assembly for selectively expanding a wall of a tubular includes a housing comprising an outer surface facing away from the housing and an opposing inner surface facing an interior of the housing. First and second explosive units each includes a predetermined amount of explosive sufficient to expand, without puncturing, at least a portion of the wall of the tubular to form a protrusion extending outward into an annulus adjacent the wall of the tubular.

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.

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 shaped charge assembly for selectively expanding a wall of a tubular includes a housing comprising an outer surface facing away from the housing and an opposing inner surface facing an interior of the housing. First and second explosive units each includes a predetermined amount of explosive sufficient to expand, without puncturing, at least a portion of the wall of the tubular to form a protrusion extending outward into an annulus adjacent the wall of the tubular.

A shaped charge assembly for selectively expanding a wall of a tubular includes a housing comprising an outer surface facing away from the housing and an opposing inner surface facing an interior of the housing. First and second explosive units each includes a predetermined amount of explosive sufficient to expand, without puncturing, at least a portion of the wall of the tubular to form a protrusion extending outward into an annulus adjacent the wall of the tubular.