Abstract: Piston bore distortions in a sub-surface safety valve are reduced or eliminated when valve body is subjected to high working pressures. In one embodiment, a piston is disposed in a sleeve that is disposed in a piston bore. The bore can distort but the sleeve within will not distort to the point of losing sealing pressure around the piston. In another approach additional bore or bores are provided adjacent the piston bore to make the pin end of the connection for the valve housing more uniform in the region of the piston bore so that pressure loading does not result in sufficient distortion of the piston bore to lose the piston sealing relation in its bore.

Abstract: A system is provided for switching between redundant control systems for a subsurface safety valve (SSV) while being able to isolate the closure spring from hydrostatic pressure in the control line of the system that is not being used. There are two control lines that connect to discrete operating pistons that are both coupled to the flow tube. Each operating piston is connected to a control rod with the control rods terminating near opposed ends of a pivoting member. Pushing down on one rod pushes up on the other rod so that the other rod is held supported and the hydrostatic pressure in its associated control line doesn't affect the force needed by the closure spring to close the SSV. Releasing control line pressure puts the system in neutral to allow either of the systems to be reselected.

Abstract: A shape memory material is used for a power spring in a subsurface safety valve. The spring is sized for the force it will deliver when it goes past its transition temperature and reverts to an original shape. The force released by having the spring pass its transition temperature holds the valve closed against hydrostatic pressure. Since the force exerted by the spring does not increase as the valve opens less force is required to hold the valve in the open position, thus lowering opening pressure. The trigger to cross the transition temperature comes from the expected temperature of well fluids at the mounting position of the subsurface safety valve. Other downhole applications are anticipated.

Abstract: A control system for a subsurface safety valve features a control line from the surface leading to one side of an operating piston. The operating piston is exposed to tubing pressure and is in pressure balance from tubing pressure. The opposite end of the operating piston is exposed to a chamber in the housing of the subsurface safety valve and that chamber is open through a port to the surrounding annulus. The operating piston is coupled to the flow tube and a power spring so that pressure in the control line shifts the operating piston and the flow tube against the power spring to rotate the flapper open. Provisions for fail closed mode if certain seals fail are also made though a passage extending from between seals near the upper end of the operating piston to the chamber open to the annulus.

Abstract: Disclosed herein is a biased actuator. The actuator includes, a reservoir, at least one piston in operable communication with the reservoir, at least one metal seal disposed about the at least one piston and in substantial sealing communication therewith, the at least one metal seal further being in substantial sealing communication with the reservoir and a biasing system in operable communication with both the reservoir and the at least one piston.

Abstract: A sensor and transmitter is employed with a pressurized chamber of a downhole tool to be able to tell at a glance when the tool is delivered for service that it is properly charged. The sensor and transmitter can be integrated within the tool so as to be protected from damage during run in. While in service the sensor and transmitter can monitor pressure in real time and include a capability to send surface signals for real time monitoring of chamber pressures corrected for the service depth, temperature and density of the hydraulic fluid, for example. The signal can be acoustic through the control line or the annulus or delivered through a fiber optic cable or signal wire run in the hydraulic control line, an auxiliary line or through the annulus.

Abstract: A control system for a downhole tool, such as a subsurface safety valve, features an operating piston that is insensitive to tubing pressure in the valve. The hydrostatic forces from the single control line from the surface are significantly reduced with a branch line to a piston bottom that is slightly smaller than the piston top. A variable volume between piston seals is connected to a low pressure compressible fluid reservoir to permit piston movement. The piston can be modular to facilitate assembly or bore offsets in the valve body. Failsafe closure upon seal failures is contemplated.

Abstract: A control system can be used with a single control line to a subsurface safety valve. The operating piston is exposed to the flow tube between two blocks with near identical seals to make the piston insensitive to tubing pressure. A control system seal is carried by the piston in the upper block and a passage between the control system seal and the tubing pressure seal in the upper block communicates to a compressible fluid reservoir in the lower block that is also isolated from tubing pressure by a tubing pressure seal. Movement of the piston compresses the fluid in the reservoir. The reservoir can also include a spring to return the piston and the flow tube to a position to close the valve. A redundant system can be actuated if the primary system fails.

Abstract: Piston bore distortions in a sub-surface safety valve are reduced or eliminated when valve body is subjected to high working pressures. In one embodiment, a piston is disposed in a sleeve that is disposed in a piston bore. The bore can distort but the sleeve within will not distort to the point of losing sealing pressure around the piston. In another approach additional bore or bores are provided adjacent the piston bore to make the pin end of the connection for the valve housing more uniform in the region of the piston bore so that pressure loading does not result in sufficient distortion of the piston bore to lose the piston sealing relation in its bore.

Abstract: A control system for a subsurface safety valve addresses normal open and closed operation and a failsafe operation if key system components fail. It features a single control line from the surface that splits at the subsurface safety valve and goes to one end of two discrete piston chambers that are aligned and isolated from tubing pressure. The piston in one chamber is larger than in the other and the pistons are connected for tandem movement. Each side of the unbalanced system's piston has a seal mounted to it and another for the rod attached to it that exits the chamber. A jumper line connects the chambers at a point between the seals in each chamber and features a large reservoir. The jumper line is filled with a compressible fluid. Fail safe closure of the valve occurs if any of the four seals fail.