Abstract: An energy accumulator for use with a well pipe string to enhance the jarring impact delivered to an object stuck in a well bore by an up and/or down jar mechanism includes inner and outer telescopically connected members relatively movable longitudinally to accumulate energy in a mechanical spring arrangement, gas or compressible liquid in the accumulator. Cooperating surfaces on the inner and outer members of the energy accumulator assure that the jarring impact of the jar mechanism members is delivered to the stuck independently of the tensile or compressive load applied to the object jar mechanism and independently of the load rate of accumulating energy in the energy accumulator.

Abstract: A sealing arrangement for the pin and box of a threaded connection between tubular members includes annular piston means for positioning in the box of one of the tubular members. Resilient seal means supported on the piston means seals between the pin end, box and piston means when the pin is threadedly engaged in the box. Additional seal means on the piston means is responsive to fluid pressure in the tubular members whereby the piston means may be urged toward sealing engagement with the pin end and the resilient seal means.

Abstract: An elongated mandrel has enlargements adjacent each end with a reduced diameter mandrel section extending therebetween. A stabilizer member is supported on the mandrel section by bearing surfaces for relative rotation of the mandrel with a well string when the stabilizer member engages a well bore wall. Spaced seals and wipers between the mandrel and stabilizer member form a closed reservoir for receiving lubricant, and a passage that communicates with the reservoir and the well bore has a floating piston therein responsive to well bore pressure to equalize the well bore and reservoir pressure without exposing the lubricant in the chamber to well bore contaminants.

Abstract: A telescopic shock absorber for use in a drill string includes a resilient arrangement to cushion telescopic contraction and extension of the shock absorber in response to shock loads and vibrations imparted during drilling. The shock absorber operates independently of the drilling fluid pressure conducted through the structure during drilling operations. A dampening system assists in cushioning the shock loads and vibrations and the dampening system and resilient arrangement are deactivated when jarring impacts are delivered to the well string by a drilling jar carried therein. The resilient arrangement provides a combination mechanical and hydraulic system for cushioning the impact loads and vibrations encountered.

Abstract: An energizer for use with a jar mechanism incorporated on inner and outer bodies in a well string to assist the jar mechanism in delivering an upward jar to the well string includes longitudinally spaced seal means between the inner and outer bodies forming a chamber for receiving a compressible medium therein. A differential area formed on one of the bodies within the compressible medium chamber compresses a compressible medium in the chamber as the well string is lowered to position the inner and outer bodies so that the jar mechanism is actuated to restrain relative longitudinal movement between the inner and outer bodies to an extended position whereby a pull force may be developed in the well string in one of the bodies.

Abstract: First and second separate one-way acting hydraulic jar sections each include inner and outer telescopically arranged tubular members with means for connecting one end of each the inner and outer tubular members of each jar section in the drill string. Spaced seal means between the inner and outer tubular members form a chamber in each jar section for confining hydraulic operating fluid.Hydraulic jar means are formed by cooperating means on the inner and outer tubular members within each operating fluid chamber. The cooperating means is spaced axially and disengaged in each fluid chamber when the drill string is in tension and compression during rotary drilling operation to inhibit damage and wear thereto. The hydraulic jar means in the first jar section is constructed to deliver an up jar and the jar means in the separate second jar section is constructed to deliver a down jar to the drill string.

Abstract: A double acting jar includes inner and outer telescopically arranged tubular parts movable longitudinally, but nonrotatable relative to each other. Cooperating means on the inner and outer telescopically arranged tubular parts deliver an upward jar to a stuck drill string upon relative longitudinal movement of the inner and outer telescopically arranged tubular parts in one direction and deliver a downward jar to a stuck drill string upon relative longitudinal movement of the inner and outer telescopically arranged tubular parts in the other direction. The cooperating means is constructed and arranged to be disengaged and maintained in an inoperative relationship when the drill string is in tension and compression during rotary drilling operations. When the jar is effected by a hydraulic jarring arrangement, fluid meter means incorporates a temperature responsive, compensating means to maintain substantially uniform flow rates through the metering means at varying temperature conditions.

Abstract: An overshot tool having a cylindrical grapple seated within the bowl of a tubular body, each of the grapple and bowl having longitudinal slots extending from each end thereof, and tangs being carried within the body and extending into the slots to limit rotation of the grapple with respect to the body.

Abstract: A housing with a mandrel therein is adapted to be connected in a rotary drill string. The housing and mandrel are constructed and arranged to support the work load of the rotary drill string as well as dissipate both longitudinal and radial impact or shock loads that the drill string may encounter. The construction also includes means whereby radial impacts applied to the drilling assembly are connected or translated into longitudinal components of force so that various combinations of longitudinal and/or radial impact or shock loading of the drill string may be dissipated in a manner to inhibit damage to the drill string and its components.

Abstract: A double acting mechanical jar includes an outer housing and a mandrel extending longitudinally thereof with means connecting the mandrel and housing for relative longitudinal movement therebetween while inhibiting relative rotation therebetween.

Abstract: A riser assembly in which each of the riser pipe and choke and kill lines includes a telescoping joint in a lower portion thereof which is at least partially pressure balanced so that the upper end of the assembly may be fixed to the drilling vessel.