Abstract: A subsurface safety valve has a valve seat and an upwardly closing flapper plate whose sealing surfaces each have a matched spherical radius of curvature. The sealing surface of the valve seat is a concave spherical segment and the sealing surface of the flapper plate is a convex spherical segment. The matching spherical surfaces are lapped together to provide a metal-to-metal seal along the interface between the nested convex and concave sealing surfaces. This permits angular displacement of the flapper plate relative to the valve seat without interrupting positive sealing engagement. The concave spherical seating surface of the safety valve seat will tolerate a limited amount of misalignment of the flapper plate which sometimes occurs during operation of the safety valve under high flow rate, high differential pressure conditions.

Abstract: A safety system including a surface controlled subsurface safety valves for use in a well having annulus fluid flow. One of the safety valves has a valve closure member, and a small diameter offset piston actuator to move the valve closure member in response to control fluid pressure conducted from the well surface to its open position which allows annulus fluid flow. A spring biases the valve closure member to block annulus fluid flow. The annulus safety valve has an enlarged flow area for use in high volume gas injection wells. The annulus safety valve has metal-to-metal sealing systems to improve valve life under harsh downhole well environments.

Abstract: A subsurface safety valve has a valve seat and an upwardly closing flapper plate whose sealing surfaces each have a matched spherical radius of curvature. The sealing surface of the valve seat is a concave spherical segment and the sealing surface of the flapper plate is a convex spherical segment. The matching spherical surfaces are lapped together to provide a metal-to-metal seal along the interface between the nested convex and concave sealing surfaces. This permits angular displacement of the flapper plate relative to the valve seat without interrupting positive sealing engagement. The concave spherical seating surface of the safety valve seat will tolerate a limited amount of misalignment of the flapper plate which sometimes occurs during operation of the safety valve under high flow rate, high differential pressure conditions.

Abstract: A well safety system with two surface controlled subsurface safety valves. The invention allows various alternatives for controlling injection into and production from a gas storage well. For maximum production, gas can flow from the underground storage reservoir to the well surface via a tubing string and the annulus between the tubing and well casing. The invention provides at least two alternative flow paths for injecting kill fluids into the well bore.

Abstract: A surface controlled subsurface safety valve for use in a well tubing string including a valve closure member, an operator tube for opening the valve closure member, an annular piston on the operator tube responsive to control fluid pressure conducted from the well surface, and a spring biasing the operator tube to a position closing the valve. A lockout sleeve mounted in tandem with the operator tube for movement to a position in which the lockout sleeve holds the valve open. The operator tube having multiple flow paths and barriers to prevent accumulation of debris from well fluids within the safety valve. One flow path including a plurality of small ports extending through the upper portion of the operator tube. Another flow path defined in part by a reduced outside diameter portion of the operator tube near its lower end and multiple channels in the valve housing adjacent thereto.