Abstract: A double acting hydraulic drilling mechanism, i.e. drilling jar, is disclosed for use in a tubular drilling string for applying upward or downward jarring forces for dislodging a "fish" from a well. The jar is adapted to be run into a well on a drill string and connected to a fishing tool in the well bore. This jar comprises outer and inner housing members positioned in telescoping relation for longitudinal movement of one relative to the other and having a hammer member on one and an anvil member on the other. The housing members enclose a chamber adapted to contain a fluid for controlling application of jarring forces. A pair of pistons are positioned in spaced relation for movement of each relative to the other in the hydraulic fluid chamber. The pistons are arranged so that movement of one housing relative to the other in one direction will move the first piston toward the second and movement in the opposite direction will move the second piston toward the first.

Abstract: A threaded connection is subject in use after assembly to a load of specified magnitude in a selected direction along the thread axis. As so loaded, the basically constant pitch threads are uniformly stressed. The load faces of the threads on at least one of the members are defined, in the unstressed condition, to have a lead which varies from a constant lead by an amount which, at any given location along the threads, is equal to the amount of net relative deflection of the threaded members along the axis at such location in response to the application to the members of the load of specified magnitude.The design considerations pertinent to such a connection are set forth in the context of the presently preferred embodiment of the connection.

Abstract: A hydraulic well jar of the type having a longitudinally slidable inner mandrel within an outer case, the inner mandrel having a hammer element threon which impacts on an anvil element in the case. Hydraulic fluid is disposed between the case and mandrel. Initial movement of the mandrel with respect to the case is impeded by a hydraulic fluid metering jet mechanism, which is bypassed as the mandrel reaches a predetermined point in its travel, allowing a sudden, more rapid movement of the mandrel, thereby generating a greater impact force. The present invention comprises an improved fluid bypass design, as well as an improved mounting system for the hydraulic fluid screen and jet of the metering mechanism. An improved seal arrangement between the metering mechanism, which is attached to the mandrel and the interior of the outer case provides greater seal life and better performance for the jar.

Abstract: The present invention accordingly relates to hydraulic jars which include elongated telescopically arranged mandrel and housing members relatively movable between contracted and extended positions such members respectively having a hammer and an anvil with the anvil being spaced from the hammer when the members are in the contracted position and arranged for contract when the members are in the extended position. The jar includes hydraulic means for retarding movement of the mandrel relative to the housing member for a given time during a jarring stroke when the jar is tensioned. The hydraulic means includes a fluid-filled chamber having adjoining first and second bores, the first bore being of lesser diameter than the second bore and a piston on the mandrel member being receivable in the first bore with the piston having a slightly smaller diameter than the first bore to restrict the flow of fluid past the piston as it moves relative to the first bore during the jarring stroke.

Abstract: A hydraulic jar apparatus to be disposed in a drilling string embodying inner and outer telescopically arranged elements. Overlapping portions of the elements provide an annual chamber confining an operating liquid by an annular seal fixed to the outer element at the lower end of the chamber and an annular Polly Pack seal fixed to the outer element at the upper end of the chamber. A piston is extended radially from the inner element into the chamber and the chamber is divided by a cylinder on the outer element into low and high pressure sections. Impact shoulders are provided on the elements in axially opposed relation to produce a jarring blow and the elements are telescopically coupled by a hexagonal spline sub assembly.

Abstract: A bumping and jarring tool for a well drill string is provided having a telescoping housing and mandrel with an annular hydraulic chamber therebetween divided into two portions. The lower portion is exposed to the ambient hydrostatic well pressure and the upper portion varies in volume as the tool opens and closes. When the tool is opened a jar is produced by a valve between the chamber portions which restricts hydraulic fluid flow between the chamber portions resulting in a pressure drop in the upper portion and by a pressure increasing element in the lower portion which increases the pressure therein while the pressure drops in the upper portion. When the valve permits unrestricted flow again, the sudden return to pressure equilibrium produces the jar stroke.

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 hydraulic jarring tool includes a system for externally adjusting the orifice size of the sleeve valve flow passage. The jarring tool includes an outer member and an inner member telescopically arranged. Spline means between said outer member and said inner member transmit torque. A hammer and anvil system provides a jarring effect upon actuation of the tool. An upper seal and lower seal provide a fluid seal between said outer member and said inner member. A working fluid is maintained in a working fluid chamber between the upper and lower seals. A detent means provides a tripping action to produce the jarring effect. The detent means includes an orifice plate that is rotatable to change the fluid restriction. An exterior port allows a wrench or tool to be inserted to rotate the orifice plate to provide selectable orifice passages that produce the detent action by the slow metering of hydraulic working fluid.

Abstract: A hydraulic jarring tool is provided that vents pressure slowly from the tool's internal operating fluid chamber to allow maximum filling of the tool prior to the tool's entering a well and to provide for operating fluid expansion with temperature increases. The jarring tool includes an outer member and an inner member telescopically arranged. Spline means between said outer member and said inner member transmit torque. A hammer and anvil system provide a jarring effect upon actuation of the tool. An operating fluid is maintained in an operating fluid chamber between the outer and inner members. Seal means between the outer and inner members provides a fluid seal to contain the operating fluid. The seal means includes a seal and thermal relief valve assembly mounted for axial travel between said inner member and said outer member with a passage extending therethrough. A thermal relief valve means in the passage provides pressure equalization.

Abstract: A hydraulic drilling jar apparatus having axially elongated outer housing and inner mandrel members that telescope relative to each other when tripped by a predetermined axial force applied to the mandrel to deliver an impact blow to an object stuck in a well bore. A negative pressure is developed within the apparatus during initial retarded telescoping movement to effect acceleration of the mandrel member upon release at a rate exceeding the acceleration rate otherwise imposed by the axial force.

Abstract: A hydraulic jarring tool includes a temperature compensated hydraulic detent actuation means. The jarring tool includes an outer member and an inner member telescopically arranged. Spline means between said outer member and said inner member transmit torque. A hammer and anvil system provide a jarring effect upon actuation of the tool. An upper seal and lower seal provide a fluid seal between said outer member and said inner member. A working fluid is maintained in a working fluid chamber between the upper and lower seals. The hydraulic detent actuation means provides a tripping action to produce the jarring effect. The hydraulic detent actuation includes a sliding sleeve member with an orifice passage that produces a detent action by the slow metering of the hydraulic working fluid. A valve means is positioned in the orifice passage for providing a consistent flow through the sleeve valve to produce the hydraulic detent irrespective of the temperature of the working fluid.

Abstract: A hydraulic jarring tool includes a reliable and closely repeating hydraulic detent actuation means. The jarring tool includes an outer member and an inner member telescopically arranged. Spline means between said outer member and said inner member transmit torque. A hammer and anvil system provide a jarring effect upon actuation of the tool. An upper seal and lower seal provide a fluid seal between said outer member and said inner member. A working fluid is maintained in a working fluid chamber between the upper and lower seals. The detent actuation means provides a tripping action to produce the jarring effect. Annular grooves in a lower stop member cooperate with a sliding sleeve element to provide orifice passages that produce the detent action by the slow metering of the hydraulic working fluid. Large bypass holes through the sleeve element allow the working fluid to flow rapidly in the opposite direction to recock the jar tool.

Abstract: A hydraulic jarring tool includes a system for externally adjusting the sleeve valve flow rate mechanically. The jarring tool includes an outer member and an inner member telescopically arranged. Spline means between said outer member and said inner member transmit torque. A hammer and anvil system provides a jarring effect upon actuation of the tool. An upper seal and lower seal provide fluid seals between said outer member and said inner member. A working fluid is maintained in a working fluid chamber between the upper and lower seals. A detent means provides a tripping action to produce the jarring effect. The detent means includes a sleeve valve with an internal needle valve that is adjustable to change the fluid restriction. An exterior port allows a wrench or tool to be inserted to adjust the needle valve and provide a selectable size passage that produces the detent action by the slow metering of hydraulic working fluid.

Abstract: Disclosed is an apparatus for controlling sliding movement between two telescoping members of a jar or like apparatus for use in an oil well. The telescopic sliding movement between the two members is controlled by a hydraulic impedance device which is bypassed by a hydraulic fluid dump valve after a predetermined amount of telescopic movement between the two members. A dump valve opening means is releasably attached to the walls of one of the members and, after opening the dump valve mechanism, releases from the member wall to move with the telescoping member holding the dump valve mechanism in the open condition. Means is also disclosed for recocking the apparatus and for returning the opening means to its initial position such that the opening means is reattached to the wall of said one member.

Abstract: There is disclosed a hydraulic jarring device in which an impediment mechanism for controlling the movement of a mandrel with respect to a barrel is exposed to a fluid pressure which is significantly reduced from that pressure generated by the tensional load applied to the jarring device by the hoisting apparatus used to recover an object lodged within a well bore. The impediment mechanism, in one embodiment, is actuated by one or more hydraulically operated plungers slidably mounted within the housing of the jarring device. The plungers cooperate with a control sleeve whose movement is in turn controlled by a metering valve operating at a pressure significantly less than that above the plungers, and having an effect on movement of the sleeve inverse to the tension generated by the hoisting apparatus. The metering valve, in one embodiment, comprises a movable helical plug having a needle nose which associates with a valve seat to control fluid flow.

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: Well bore pressure is utilized to develop an activating pressure during telescoping movement between an outer drill string and an inner mandrel for momentarily locking the mandrel to the drill string. Locking is effected through laterally displaceable mechanical elements carried by the mandrel and held engaged for a predetermined period of time during which an axial tension is applied to the mandrel. A control circuit independent of the amount of axial tension load provides for sudden release of the locking elements at the end of said predetermined period which results in free travel of the mandrel to an impact position to deliver a jarring blow to the drill string for dislodging stuck elements or junk in the well bore.

Abstract: Hydraulic jar apparatus to be disposed in a drilling string used in drilling a well bore or other bore hole, embodying inner and outer telescopically arranged bodies, with a hammer on the inner body adapted to strike an anvil on the outer body, the bodies being initially releasably locked or interconnected in fully telescoped or contracted relation by a locking device which can be released while the apparatus is in the bore hole before the apparatus can function as a jarring device or a bumper sub.

Abstract: A fishing jar is provided for removing stuck objects from a well bore wherein an upward strain on the running string compresses hydraulic fluid in a compression chamber to the amount of the upward jar or impact load desired to be applied to the fish stuck in the well. A pressure relief mechanism is provided to transfer compressed hydraulic fluid within the compression chamber to automatically activate the jarring mechanism when the load on the jar exceeds the recommended operating load. In a preferred form, the relief mechanism is provided in a piston means which has a normally activated flow regulator bypass means therein together with the pressure relief mechanism.

Abstract: The present invention relates to a hydraulic fishing jar adapted to be run into a well on a fishing string and connected to a fishing tool in the well bore. The jar comprises inner and outer telescopically interengaged bodies. A plurality of diametrically defined pressure areas, each of said pressure areas having upper and lower sealed ends, are contained within the jar. Tandem piston means are immediate one of said upper and lower sealed ends of each of the pressure areas. Seal means are carried by one of the inner and outer interengagable bodies and are engagable by the other of the inner and outer interengagable bodies and define one of the upper and lower sealed ends of the pressure areas. Seal means are provided between the piston means and one of the inner and outer telescopically interengaged bodies and define one of the upper and lower sealed ends of the pressure areas. The pressure areas are in fluid communication with one another and define a chamber for receipt of lubricant therewithin.

Abstract: A well jar has telescoping inner and outer elements having a torque transmitting connection therebetween. An intermediate member is rotatably mounted relative to the telescoping elements and is affixed in a longitudinal direction to one of the telescoping elements. A releasable latch is connected between the intermediate member and one of the telescoping elements. The intermediate member is rotatable relative to the telescoping elements upon a predetermined minimum longitudinal force applied between the telescoping elements. The rotation causes a release of the latch and movement of the telescoping elements to an impact of coacting impact faces on the telescoping elements. An improvement involves a time delay section connected between the intermediate member and at least one of the telescoping elements for restraining such relative rotation for a preselected time interval of application of at least such minimum longitudinal force.

Abstract: Hydraulic jar comprising a housing, a piston axially movable within the housing, an anvil disposed within the housing, a hammer associated with the housing and means for maintaining the housing in a position with the hammer spaced from the anvil and then releasing the housing when the piston moves to a select, extended position.

Abstract: An improved hydromechanical drilling jar for applying upward and downward jarring blows to an object stuck in a well wherein the jar comprises a mechanically operated jar section which is connected with a hydraulically operated jar section by flexible tubular connector means for providing flexibility therebetween for relieving bending moments on the jar sections during use. The jar sections are separable for ease in storage and transportation and may be relatively positioned in a drill string as desired.

Abstract: A hydraulic jar for applying a jarring blow to an object stuck in a well wherein two separate annular fluid chambers are provided in the jar, with one of the chambers confining a body of operating hydraulic fluid and means for restraining relative longitudinal movement of the jar for developing tension and stretch in the drill string so as to produce the jarring blow, and with the second annular fluid chamber confining a body of heavy lubricating fluid and splined portions and jarring surfaces to isolate foreign particles from the operating fluid chamber to prevent or inhibit internal jamming or sticking during actuation. Because the means disposed in the operating fluid chamber are subjected only to forces developed during the pulling stroke, the operating fluid chamber may have a greater area for the development of greater pull loads at lower hydraulic pressures than prior hydraulic jar.

Abstract: A jarring and bumping tool for a drill string is described. The tool includes an inner mandrel and an outer housing telescopically coupled together and defining therebetween an annular chamber for hydraulic fluid. A floating piston assembly is located in said chamber and is moved along in the chamber by a piston displacing device carried by the mandrel. A vertical strain applied to the mandrel when the tool is in use causes the said device to lift the piston assembly. The pressure of hydraulic fluid in the said chamber cushions movement of the mandrel until the piston assembly enters an enlarged portion of the hydraulic cylinder, whereupon the hydraulic pressure is released, allowing abutment faces on the mandrel and housing to slam together and apply an upward jar to the drill string. When the mandrel is returned downwardly, the piston displacing device draws the piston assembly down in the cylinder until movement of the assembly is arrested.

Abstract: A single tool, having a bumper free-stroke chamber and jar free-stroke chamber spaced apart by the usual reduced-diameter barrel section, is provided. The tool carries impact faces and is adapted to selectively jar upwardly or bump downwardly.