Abstract: A double shoulder drill stem connection for high torque applications includes a thread taper within a range between about 1.0 and 1.2 inch per foot. The thread form is characterized by a stab angle between about 35 and 42 and a load angle between about 25 and 34 degrees and by a short thread height with elliptical roots and with crests having an angle which slopes in an opposite direction with respect to the joint centerline from the thread taper. A drill string includes a tool joint having different inner diameters for a substantial axial length to provide enhanced strength in the threaded portion of the joint.

Abstract: A hydraulic well jar accelerator used in a fishing string in conjunction with a well jar. The well jar accelerator includes inner and outer cylindrical assemblies movable longitudinally relative to each other and having an annular space between the cylindrical assemblies. An annular seal and an expansion sleeve disposed between the cylindrical assemblies are longitudinally spaced relative one another to form an annular liquid chamber in the annular space. The annular liquid chamber confines a hydraulic operating fluid. The volume of the annular liquid chamber can be adjusted by spring-loading the expansion sleeve without relative longitudinal movement of the inner and outer assemblies. The annular liquid chamber is operatively segregated into a main liquid chamber and an expansion liquid chamber. An annular seal body and an annular piston are disposed between the cylindrical assemblies in the annular liquid chamber. The seal body is attached to one of the cylindrical assemblies and has a first end surface.

Abstract: A shock absorber assembly adapted to be used with a drill string dampening intermittent shocks and vibrational forces encountered with a drill string, the shock absorber assembly including a mandrel, a tubular body reciprocally mounted with respect to the mandrel, and a dampening device including an annular chamber adapted to be filled with a compressible fluid and a flexible wall with the mandrel adjacent the annular chamber for permitting flexure of the mandrel as needed for dampening.

Abstract: A shock absorber assembly for absorbing shocks encountered by a drill string wherein the shock absorber assembly is for use with a drill string having a working fluid therein and includes a body member affixed to the drill string, a mandrel mounted for reciprocal longitudinal movement with respect to the body member and a fluid dampening member floated within the central bore of the body member in engagement with the body member and the mandrel for absorbing shocks transmitted between the body member and the mandrel.