Abstract: The disclosure relates to a flapper type safety valve incorporating a pressure equalizing feature in the body of the flapper valve. A bypass aperture in the flapper valve communicates with a downwardly facing conical sealing surface. A conically shaped sealing plug is insertable in the bypass aperture and has a post portion projecting upwardly through such aperture. A diametral slot is provided in the top surface of the flapper valve body to mount a leaf spring which is secured to the upstanding post. An abutment element is also secured to the top end of the upstanding post and projects diametrically into the path of the actuating sleeve normally utilized to effect the opening of the flapper valve.

Abstract: A subterranean well valve assembly includes a valve mounted within an annular housing which is actuated by an annular plunger co-axially mounted within the housing. The plunger is longitudinally shiftable to open the valve, in response to a fluid pressure signal. Within the housing, releasable latches are provided for engaging an annular groove, thereby temporarily locking the plunger in its lower position. The valve assembly also includes a permanent lock open mechanism comprising an annular locking mandrel, including a latch element. Longitudinal movement of the mandrel locks the mandrel in place, thereby interfering with subsequent retraction of the plunger from locked position.

Abstract: A method and an apparatus for setting the temporary lock-open mechanism incorporated in a safety valve employed in the subterranean well, the apparatus including an annular mandrel having an external, axially movable, radially expandable collet operated by an axially movable prong concentrically arranged within the mandrel housing.The temporary lock-open mechanism of the valve includes latch fingers which are adapted to engage the end of a plunger which opens the valve, a spring biased lock-open sleeve and release keys for holding the sleeve in a passive position.The valve is temporarily locked in an open position by introducing control line pressure into the valve for opening it and moving its lock-open mechanism to a position where the expandable collet of the apparatus can release keys that restrain the lock-open sleeve.

Abstract: A locking device and a method and apparatus are provided for emplacing the locking device within a selected one of a plurality of landing nipples positioned along a well conduit. Each nipple typically includes a seal bore portion having a bore diameter less than the conduit bore diameter and a recessed portion located above the seal bore having a diameter greater than the conduit bore diameter. The locking device includes a housing for retaining a plurality of circumferentially spaced expandable locking dogs. A camming sleeve is axially slidably within the housing and is utilized to support the dogs in one of three selected positions: a retracted position, a partially expanded no-go position, or a fully expanded locked position. The locking device is lowered down the well conduit on a running tool with the dogs in the retracted position until the running tool has passed through the seal bore of the nipple located directly above the selected landing nipple.

Abstract: An electronic key comprises a first binary counter and a first multiplexer or pulse code modulating a uniform clock pulse train to produce a first coded pulse train modulated with a given code. The key is connected to an electronic lock comprising: a second binary counter and a second multiplexer for pulse code modulating the same clock pulse train to produce a second coded pulse train modulated with the same code; an EXCLUSIVE-OR gate to which said first and second multiplexers are connected; a first NAND gate having one input connected to the output of the EXCLUSIVE-OR gate; a flip-flop or a binary counter having its clock input connected to the output of the NAND gate and an inital logical ONE output connected to a second input of the NAND gate; a second NAND gate having one input connected to the output of the flip-flop or counter and another input connected to the output of the second multiplexer; and a binary output counter having its clock input connected to the output of the second NAND gate.