Abstract: A flow tube is axially moveable within an actuator body between a first axial position and a second axial position for actuating a downhole tool, such as for closing a subsurface safety valve. The flow tube includes an interior flow bore for conveying fluids from the tubing string through the actuator body. An external flow tube profile defined on the flow tube includes an upper shoulder for engagement with a wiper in the first axial position, a lower shoulder for engagement with the wiper in the second axial position, and a clearance path between the upper and lower shoulders for allowing viscous flow past the wiper when the flow tube is moved between the first and second axial positions.

Abstract: A flow tube is axially moveable within an actuator body between a first axial position and a second axial position for actuating a downhole tool, such as for closing a subsurface safety valve. The flow tube includes an interior flow bore for conveying fluids from the tubing string through the actuator body. An external flow tube profile defined on the flow tube includes an upper shoulder for engagement with a wiper in the first axial position, a lower shoulder for engagement with the wiper in the second axial position, and a clearance path between the upper and lower shoulders for allowing viscous flow past the wiper when the flow tube is moved between the first and second axial positions.

Abstract: Methods of operating a downhole tool comprise thermally-controlling the tool by sensing a temperature and controlling the tool in response to the sensed temperature. Thermally-controlled downhole tools comprise a control element responsive to a change in temperature that control flow into, out of, or through a wellbore. Methods and systems for servicing a wellbore comprise using a thermally-controlled tool comprising a thermally-controlled valve (TCV) in a wellbore. The TCV includes a valve body comprising an injection port for allowing material to flow into or out of the wellbore and an opening/closing mechanism for regulating flow of the material through the injection port in response to a change in temperature. The valve body may be coupled to a downhole conduit. A plurality of TCV's may be arranged in the wellbore to control the injection of steam into the wellbore or the recovery of oil from the wellbore.

Abstract: A hydraulic control assembly (80) for actuating a hydraulically controllable downhole device (100) comprises a hydraulic fluid source (82) located on a surface installation that supplies a low pressure hydraulic fluid, an umbilical assembly (88) coupled to the hydraulic fluid source (82) that provides a supply fluid passageway for the low pressure hydraulic fluid and a subsea intensifier (90) operably associated with a subsea wellhead. The subsea intensifier (90) is operable to convert the low pressure hydraulic fluid from the hydraulic fluid source (82) into a high pressure hydraulic fluid for actuating the hydraulically controllable downhole device (100).

Abstract: A hydraulic control assembly (80) for actuating a hydraulically controllable downhole device (100) comprises a hydraulic fluid source (82) located on a surface installation that supplies a low pressure hydraulic fluid, an umbilical assembly (88) coupled to the hydraulic fluid source (82) that provides a supply fluid passageway for the low pressure hydraulic fluid and a subsea intensifier (90) operably associated with a subsea wellhead. The subsea intensifier (90) is operable to convert the low pressure hydraulic fluid from the hydraulic fluid source (82) into a high pressure hydraulic fluid for actuating the hydraulically controllable downhole device (100).

Abstract: A subsurface safety valve has a tubular valve housing, a valve closure member movable between an open and a closed position, an axially shiftable flow tube for opening the valve closure member. Hydraulic pressure from the control line is used to move a piston, which in turn moves an axially shiftable opening prong through the closure member. A balance line, or second hydraulic line is also used to make the valve well insensitive. An isolation valve is placed in the flow path of the second hydraulic line. The isolation valve prevents gas migration into the balance line. It also provides volume control for the fluid displaced when the piston is moved by pressure from the control line. Further, the valve can be closed by the application of sufficient pressure through the second hydraulic line.