Abstract: A subsurface well safety valve having two control lines which run from the well surface to first and second piston and cylinder assemblies for controlling the valve. The first of the assemblies is connected to a flow tube for operating the valve but the second assembly is disconnected from the flow tube. When a failure occurs in the primary control system, the first assembly is disconnected from the flow tube and the second piston and cylinder assembly is connected to the flow tube to operate the safety valve.

Abstract: A subsurface well safety valve having a flow tube telescopically movable in a housing for controlling the movement of a valve closure member. A piston and cylinder assembly actuates the flow tube and is in communication with hydraulic control fluid from the well surface on one side and a gas biasing chamber on the second side and includes a spring acting on the flow tube to close the valve. An equalizing system equalizes fluid pressure on opposite sides of the piston and cylinder assembly in the event of a failure in the seal between the piston and cylinder thereby allowing the spring to close the valve.

Abstract: A well tool, for setting in a nipple having a locking notch, including a body with initially retracted first and second locking dogs with a threaded actuator for moving the first and second dogs axially relative to each other and into engagement with the top and bottom of the locking notch for preventing axial movement of the body in the nipple. A plurality of metal cup sealing rings positioned about the body and expandable into a sealing relationship between the body and the nipple by a piston. A tapered expander extends into each of the sealing cups and at least one of the rings is positioned with the cups directed oppositely to the cup in another ring for holding pressure in both directions. The cup rings are shaped for setting in a sequential order starting with the rings furthest from the piston. A protector sleeve is releasably connected to the body and initially encloses the locking dogs and the sealing rings.

Abstract: A metal seal on a well tool for sealing between an inner tubular member and an outer tubular member including an annular metal ring positioned about the inner member having a pair of spaced lips on the outer periphery with a flowable metal insert positioned between the lips. Metal seals are provided on each side of the metal ring sealing between each side of the ring and the inner member. Fingers between the setting mechanism and the metal ring expand the metal ring outwardly upon movement of the setting mechanism. An expandable metal support is positioned on the outside of the setting mechanism adjacent the outer edge of the metal ring for supporting the ring as the ring is set. The setting mechanism includes a pair of expansion rings having coacting tapered faces for increasing the setting force as the temperature increases.

Abstract: A method and valve for stopping production of an oil and/or gas well by injecting a fluid from the outside of a well conduit into the well bore through a check safety valve. The valve, initially in the open position, is actuated to the closed position by an increase of the pressure outside of the conduit relative to the inside pressure. A communication path from the outside of the conduit to the inside of the conduit above the safety valve is opened by pressure in the conduit below the closed safety valve. Fluid is injected into the open communication path through the safety valve to kill well production while maintaining a safety check on the production fluid below the safety valve. The valve may be relatched to its initial open position and reactuated.