Abstract: A plunger tool is provided having a nose assembly to slow the descent of the tool into the well, a valve assembly, and a piston cylinder assembly. When the tool is dropped into the well, the gas and liquids in the well flow through restrictions in the nose assembly, thereby braking the fall. The fluid flows along a fingered collet which retains an angled valve. The fluid flows around the opened valve and out of the upper end of the plunger lift tool. The valve is connected to the piston which is exposed to ambient pressure on one side and a predetermined pressure on the other. Thus, the piston is set to close the valve at a predetermined pressure. As the pressure builds up, the piston moves the valve so that a lower portion of the valve is gripped by a detent mechanism, in this case collet fingers. When adequate pressure is built up to unsnap the valve, the piston forces the valve out of the detenting collet fingers and into its seat. Formation pressure from below the seal increases the sealing force.

Abstract: A system for securing a measurement-while-drilling (MWD) instrument in a generally centralized position within a protective drill collar. The system includes a pressure responsive slidable contact pad member in combination with a plurality of fixed contact pad members. As the instrument is subjected to an increase in pressure, above atmospheric, a slidable contact pad member moves longitudinally along an inclined angle face of a base member into contact with the inner wall of the drill collar to thereby centralize and secure the instrument within the drill collar.

Abstract: A flapper valve has integral, oppositely projecting hinge pins mounted in a recess provided between two abutting tubular housing members. The flapper valve is of cylindrical segment configuration so as to maximize the opening within a conduit in which it is mounted when the flapper valve is pivoted to its open position. The spring bias urging the flapper valve to the closed position is provided by helical springs mounted in surrounding relationship to the axis of the conduit and in an annular recess provided between two abutting tubular housing members. The bottom surface of the actuating sleeve for the flapper is contoured so as to exert a minimum unbalanced torque on the flapper valve during opening with the mechanical opening force being balanced by an opposing force exerted by fluid pressure.

Abstract: The subterranean well safety valve useful in oil and gas wells employs a rotatable flapper to close a fluid production flow path. A through-the-flapper equalizing valve means is employed to equalize pressure across the closed valve in response to movement of an axially shiftable flow tube actuator. A spring-loaded poppet valve extends through the flapper on the periphery of the flapper in alignment with the end of the flow tube. The equalizing valve is opened upon initial movement of the flow tube followed by full opening of the flapper.

Abstract: An apparatus, such as a shear-out safety joint, which is incorporated in a subterranean well tubing string for separating or severing the tubing string when subjected to excessive loads is disclosed. The shear-out safety joint is used with a safety valve and by providing a prescribed failure point will ensure that the safety valve remains intact. The apparatus includes inner and outer telescoping members which can separate when the tubing above and below the joint moves in opposite directions. A shear ring connecting the two telescoping members will shear when a predetermined load is applied. The joint also has a second releasable connecting member extending through the inner telescoping member and engaging the outer telescoping member which will support a load greater than that which can be carried by the shear ring. A longitudinally shiftable member, movable within a recess, holds the second connecting member in engagement but disengages the second connecting member when moved to a second position.