Abstract: The proposed invention relates to wellbore technologies and is intended to produce action on productive rock. Device for hydrodynamic action on wall of a well comprising a casing jointed with the pipe conduit directly or via a roller support and inside of which the mechanism for cavitating of flow of a liquid, mechanism for directing and splitting of the flow and mechanism for interrupting of the discharge jets are sequentially placed. The mechanism for cavitating of flow of a liquid is made in form of an auto-oscillating system. And specifically it can be made in a form of a ball with its diameter ratio to inner diameter of the casing of 0.9–0.98 and a limiter of axial motion; or a ball with its diameter ratio to inner diameter of the casing less than 0.

Abstract: A hydraulic accumulator for use in a drill string having a fluid passage for supply of fluid to a hydraulic drill string tool is provided. The accumulator comprises a body provided with connecting means for connecting the accumulator to the drill string and an expansion chamber in fluid communication the fluid passage when the accumulator is connected to the drill string by the connecting means. The expansion chamber is expandable between a first volume and a second volume which is larger than the first volume. Further, the expansion chamber is provided with means for moving the expansion chamber from the first to the second volume upon a fluid pressure increase in the fluid passage and for moving the expansion chamber from the second to the first volume upon a pressure decrease in the fluid passage.

Abstract: An apparatus for use in a wellbore comprises a housing having a longitudinal axis and a mechanism having one or more impact elements adapted to move along the longitudinal axis in an oscillating manner to impart a back and forth force on the housing to vibrate the housing. In another arrangement, an apparatus for use in a wellbore comprises a housing and at least one impact element rotatably mounted in the housing. The at least one impact element is rotatable to oscillate back and forth to impart a vibration force to the housing.

Abstract: A drilling jar comprising a mandrel with a shoulder extending radially outward. The shoulder defines at least one openable and closeable orifice therethrough. An outer housing is slidably disposed about the mandrel to define an upper chamber above the shoulder and a lower chamber below the shoulder. The jar also comprises a magnetorestriction material that responds to a predetermined pressure in the upper chamber to open at least one orifice in the shoulder to allow rapid pressure communication between the upper and lower chambers.

Abstract: The down hole jar tool is a tool used to apply jarring forces to objects that may be obstructing the path of a down hole, or above-ground operation that requires a repetitive jarring action to dislodge or remove such objects. The tool is used by providing a linear input to a mandrel portion that draws back against a compressible unit of predetermined resistance until a releasing means abruptly releases the mandrel portion. The mandrel portion then rapidly moves in the direction of the linear input until it encounters a stationary anvil, which produces the desired jarring action. This tool may also be combined with accelerators and/or valves, as well as other tools, to create a more substantial jarring impact.

Abstract: The present invention generally provides a downhole tool with an improved means of transmitting data to and from the tool through the use of wired pipe capable of transmitting a signal and/or power between the surface of the well and any components in a drill string. In one aspect, a downhole tool includes a body, and a mandrel disposed in the body and movable in relation to the body. A conducive wire runs the length of the body and permits signals and/or power to be transmitted though the body as the tool changes its length.

Abstract: An apparatus for use in a wellbore comprises a housing having a longitudinal axis and a mechanism having one or more impact elements adapted to move along the longitudinal axis in an oscillating manner to impart a back and forth force on the housing to vibrate the housing. In another arrangement, an apparatus for use in a wellbore comprises a housing and at least one impact element rotatably mounted in the housing. The at least one impact element is rotatable to oscillate back and forth to impart a vibration force to the housing.

Abstract: A fishing jar is placed in a work string for delivering blows to a stuck object in a well. This fishing jar utilizes energy stored in the work string for delivering the blow, rather than having a main spring of its own. The fishing jar uses hydraulic pressure to move a piston member. The piston member engages a firing member when it reaches one end of its stroke. The directional valve then directs fluid to the other side of the piston to cause the piston to move in the opposite direction. When it starts to move in the opposite direction, the firing member will provide a restrictive load against that movement. Once the pressure builds to a high enough level, it will move the housing relative to the piston, which is restricted from movement by the firing member. When the housing moves, it elastically deforms the work string, storing energy in the work string. The firing member will release the housing once the housing reaches the end of its stroke.

Abstract: A fishing jar is placed in a work string for delivering blows to a stuck object in a well. This fishing jar utilizes energy stored in the work string for delivering the blow, rather than having a main spring of its own. The fishing jar uses hydraulic pressure to move a piston member. The piston member engages a firing member when it reaches one end of its stroke. The directional valve then directs fluid to the other side of the piston to cause the piston to move in the opposite direction. When it starts to move in the opposite direction, the firing member will provide a restrictive load against that movement. Once the pressure builds to a high enough level, it will move the housing relative to the piston, which is restricted from movement by the firing member. When the housing moves, it elastically deforms the work string, storing energy in the work string. The firing member will release the housing once the housing reaches the end of its stroke.

Abstract: An apparatus for dislodging stuck tools downhole, which includes a tool body; a mandrel moveable within the tool body; a spring member for allowing the mandrel to move with jarring force within the tool body when actuated; actuating fluid allowing the mandrel to travel a portion of the distance in a controlled manner, and at a predetermined point, accelerate its travel to provide a jarring force against the tool body; wherein the actuating fluid includes a first and second volumes of fluid through which a portion of the mandrel travels; the first volume providing controlled travel, and the second volume allowing accelerated travel of the mandrel.

Abstract: A hydraulic drilling jar for use in association with downhole drilling and adaptable for connection between components of a drill string or the like. The hydraulic drilling jar generally comprises an outer generally hollow hydraulic housing, an inner mandrel assembly, an anvil portion, a hammer portion, and a hydraulic valve. The hydraulic housing has an enclosed first end and an open second end with the first end releasably securable to a first component of the drill string. The mandrel has a first end releasably securable to a second component of the drill string and a second end slidably receivable within the open second end of the hydraulic housing to forming an internal fluid chamber between the mandrel and the housing. The mandrel is also slidable within the outer housing from a contracted position to an extended position. The hydraulic housing and the mandrel operatively connect the first and second components of the drill string.

Abstract: A jar mechanism comprises an outer body member an, inner body member which is movably mounted on the outer body member, and a fluid chamber which is defined by the inner and outer body members. A resistance mechanism is in fluid communication with the fluid chamber. The inner and outer body members are moveable relative to each other between a first configuration in which the resistance mechanism resists relative movement therebetween, and a second configuration in which the resistance mechanism substantially does not resist relative movement therebetween. The resistance mechanism comprises two valve devices, where each valve device resists movement of fluid within the fluid chamber in one direction and the valve devices are arranged to resist the movement of fluid in opposite directions. A releasable locking mechanism locks the inner body member with respect to the outer body member, where a piston section permits a load to be applied between the body members after the locking mechanism has released.

Abstract: A jar up, bump down hydraulic drilling jar is described. A hydraulic tripping valve arrangement permits the storage of large amounts of static force before releasing a hammer to strike an anvil surface with substantial force. The hammer is positioned on the mandrel and interacts with the anvil surface in the housing to deliver upward jarring forces, to the drill string. During a downward jarring movement, the tripping valve is opened to prevent pressure buildup and accidental downward jarring; thus, a single-acting drilling jar is formed.

Abstract: A jar up, bump down hydraulic drilling jar is described. A hydraulic tripping valve arrangement permits the storage of large amounts of static force before releasing a hammer to strike an anvil surface with substantial force. The hammer is positioned on the mandrel and interacts with the anvil surface in the housing to deliver upward jarring forces, to the drill string. During a downward jarring movement, the tripping valve is opened to prevent pressure buildup and accidental downward jarring; thus, a single-acting drilling jar is formed.

Abstract: A ram-boring machine with forward and reverse motion control which comprises a percussion piston that can be axially displaced in a tubular housing, a control tube that is arranged in the housing and controls the forward and reverse motion of the percussion piston by passing over radial control openings in the percussion piston, control edges on the control tube which are guided in the percussion piston in sealed fashion, a compressed air bore that runs into the front end of the control tube, a compressed air bore or compressed air line that runs into an annular chamber between a first control edge and a second control edge, an outlet bore or outlet line that originates in the region between the second control edge and a third control edge and leads to the rear end of the control tube, and control means for selectively charging the compressed air bore or compressed air line or ventilating the outlet bore or outlet line.

Abstract: A tool for enhancing the impact of either an upward or downward blow delivered by a single-acting jar to an object stuck in a well bore includes first and second tubular members telescopically arranged and vertically reciprocable with respect to one another to form an annular space between them, upper, lower and intermediate seal rings between equal diameter portions of the tubular members, and a ring carried by the second tubular member within the annular space between the intermediate seal ring and each of the upper and lower seal rings to form upper and lower pressure and charging chambers on the opposite side of each ring, the rings being of such construction that, with each charging chamber filled with a compressible fluid, movement of the second tubular member in one vertical direction will compress the fluid in the upper and lower pressure chambers and thus enhance the impact of a jar in the same vertical direction, and permit flow therepast, in response to movement of the second tubular member in the

Abstract: A dual acting hydraulic jarring tool which includes dual acting metering devices and is particularly well suited for coiled tubing application. A common annular chamber is formed between reciprocating cylindrical assemblies and dual engaging and metering devices are used to engage and meter hydraulic fluid at a predetermined rate flowing from one chamber to another chamber defined within the annular space. An improved retarding and metering mechanism is also disclosed which serves to retard relative telescoping movement of one cylindrical assembly relative to the other cylindrical assembly and meter the hydraulic fluid at the predetermined rate. The present invention is particularly well suited for coiled tubing application due to its low load requirements, minimal overall length and enlarged interior bore for the passage of downhole tools; however, the present invention is well suited for use with conventional drilling strings as well.

Abstract: A valve for a two way hydraulic drilling jar which includes a hollow cylindrical member having an exterior surface, an interior surface, a first end and a second end. At least one spiral-form fluid bypass passage is positioned in each of the first end and the second end of the cylindrical member. The at least one spiral-form bypass passages has a first end communicating with the exterior surface and a second end communicating with the interior surface.

Abstract: An in-hole rock drilling machine has a hydraulic impact motor within a housing. The hydraulic impact motor has a spool valve contained within a valve housing. The spool valve has two operating positions to alternately pressurize and depressurize a drive chamber to reciprocate a hammer. The spool valve has a continuously pressurized third control surface that biases the spool valve towards a second operating position, a first control surface that acts opposite the third control surface to move the spool valve to a first operating position, and a second control surface that acts with the third control surface to return the spool valve to the second operating position. The valve housing guides the rear portion of the hammer, and a guide bushing guides the front portion of the hammer. The guide bushing, valve housing, and a distance sleeve are clamped against a shoulder of the housing.

Abstract: A two way hydraulic drilling jar which includes a tubular housing having an interior surface defining an interior bore. A mandrel is provided having an exterior surface. The mandrel is telescopically received within the interior bore of the tubular housing. The exterior surface of the mandrel has an enlarged diameter portion. An annular valve member is provided having a first end, a second end, and an interior surface defining an interior bore. The mandrel extends through the interior bore of the valve member. The valve member is confined with capability of limited axial movement between two shoulders projecting from the interior surface of the housing. The interior bore of the annular valve member receives the enlarged diameter portion of the mandrel in close fitting relation. At least one fluid bypass channel is disposed in one of the valve member and the enlarged diameter portion of the exterior surface of the mandrel.

Abstract: There is disclosed a double acting hydraulic jar of such construction as to permit it to be "short cocked" during either an up or down jar, and further in which flow past a detent in metered in such a way as to permit lesser flow therepast during an upward jar than during a downward jar, whereby the rate of movement of the detent ring through a restriction, and thus the "delay", may be essentially the same during both up and down jars.

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 jar apparatus (jar) 10 includes a plurality of pistons 16 that are secured together to form a piston assembly 23. Piston assembly 23 is movable axially in response to an actuating pressure differential between the jar bore 17 and the portion of borehole 19 that surrounds jar 10. Biasing spring 28 biases piston assembly 23 to return to a closed position when the actuating pressure differential is reduced by a predetermined amount. Piston assembly 23 forces a hammer member 32 and a movable anvil portion 30A axially to cock the jar in response to the applied actuating pressure differential. When the pressure differential is reduced, biasing spring 28 moves movable anvil portion 30A against anvil support portion 30B. Detent assembly 47 temporarily limits the velocity of hammer member 32 towards movable anvil portion 30A after the pressure differential is reduced. Compressed nitrogen 64 in nitrogen chamber 31 biases hammer member towards movable anvil portion 30A to deliver a jar impact.

Abstract: A hydraulic jar device for use in connection to coil tubing which consists of an elongate tube having an upper hammer sub, a kelly cylinder and a hydraulic cylinder with central restrictor. A lower sub connects to the bottom end of the hydraulic cylinder. The sliding interior components are an upper mandrel secured to an anvil sub which, in turn, is fastened to an axial plunger, all of which are slidable down within the elongate tube. A guide means prevents relative rotation between the mandrel and the elongate tube consisting of hammer sub, kelly cylinder, hydraulic cylinder and lower sub. A metering ring retained on the plunger interacts with the central restrictor of the hydraulic cylinder to control force effected up and down jars that occur when the mandrel strikes the hammer sub on the down stroke, and when the anvil sub strikes the hammer sub bottom on the up stroke.

Abstract: A hydraulic jar device for use in through-tubing drilling and fishing operations which consists of an elongate tube having an upper hammer sub, a kelly cylinder and a hydraulic cylinder with central restrictor secured therebelow. A lower sub connects to the bottom end of the hydraulic cylinder. The sliding interior components are an upper mandrel secured to an anvil sub which, in turn, is fastened to an axial plunger, all of which are slidable down within the elongate tube. A metering ring retained on the plunger interacts with the central restrictor of the hydraulic cylinder to control force effected up and down jars that occur when the mandrel strikes the hammer sub on the down stroke, and when the anvil sub strikes the hammer sub bottom on the up stroke.

Abstract: A reduce waiting time drilling jar 1 includes a mandrel 2, a housing 3 telescopingly positioned about the mandrel 2, and first and second pistons 89, 111 positioned axially between the mandrel 2 and the housing 3. The pistons 89, 111 are spaced longitudinally apart, forming a substantially sealed chamber 88 therebetween. The first piston 89 has a first and second substantially parallel flow passage 94, 200 formed therein and extending longitudinally therethrough to provide first and second flow characteristics. A valve 204 is hydraulically connected to the second flow passage 200. The valve 204 is translatable between first and second operating positions, wherein fluid flows relatively freely through the second flow passage 200 in the first operating position, but is restricted in the second operating position.

Abstract: A double acting accelerator 1 includes a mandrel 2 arranged in a housing 3 for sliding longitudinal movement. A pair of pistons 89, 111 are positioned radially between the housing 3 and mandrel 2 to form a substantially sealed chamber 88 longitudinally therebetween. Movement of the mandrel 2 in a first direction urges the first piston 89 toward the second piston 111, thereby greatly increasing the pressure of fluid in the chamber 88. Movement of the mandrel 2 in a second, opposite direction urges the second piston 111 toward the first piston 89 to, likewise, greatly increase the pressure of fluid in the chamber 88. Thus, a large amount of energy is stored in the accelerator 1 independent of the relative direction of movement of the mandrel 2 and housing 3.

Abstract: A reciprocating full flow tester valve is provided with a shock absorber and tolerance adjustment device for absorbing an impact between a power mandrel of the tool and an operating assembly of the tool. An improved hydraulic impedance system is also provided for providing a time delay in telescopingly collapsing movement of the tool when weight is set down on the tool to open the tester valve.

Abstract: A firing apparatus for use with a tubing-conveyed perforating apparatus is disclosed. Wellbore pressure applies an upward force to a first piston connected by a shearable coupling to a firing piston. At a predetermined pressure the coupling shears, allowing the first piston to move upward. The first piston moves upward until the firing piston is in fluid communication with the pressure. The firing piston is forced downward by the pressure, firing the perforating apparatus.

Abstract: This invention relates to flow pulsing methods and apparatus for various applications including downhole drilling equipment and in particular to an improved flow pulsing method and apparatus of this type to be connected in a drill string above a drill bit with a view to securing improvements in the drilling process.

Abstract: There are disclosed alternate embodiments of a double acting hydraulic jar having a single detent chamber having a restriction on the inner diameter of its outer tubular member through which detent means carried about the outer diameter of the inner tubular member may be moved in order to impart either an up or down jar.

Abstract: An improvement in a valve used in a hydraulic drilling jar. A fluid chamber is divided into a first chamber and a second chamber by a restrictive bore. An annular valve is mounted on the exterior surface of the mandrel between a first shoulder and a second shoulder. The valve has a first end, a second end and an exterior surface. The valve substantially obstructs the flow of fluid within the fluid chamber when the valve is positioned in the restrictive bore. The valve has a first bypass passage whereby fluid passes from the first chamber to the second chamber creating a time delay as the valve slowly moves out of the restrictive bore whereupon the telescopic movement of the mandrel in a first direction is unrestricted. The valve has a second bypass passage whereby fluid passes from the second chamber to the first chamber creating a time delay as the valve slowly moves out of the restrictive bore whereupon the telescopic movement of the mandrel in a second direction is unrestricted.

Abstract: A double acting hydraulic drilling jar 1 includes a mandrel 2 arranged in a housing 3 for sliding longitudinal movement. A hammer 69 is positioned on the mandrel 2 and interacts with anvil surfaces 64, 66 in the housing 3 to deliver both upward and downward jarring forces to a drill string. A hydraulic valve arrangement permits the storage of large amounts of static force before releasing the hammer 69 to strike the anvil surfaces with great force. The hydraulic valve arrangement includes a tripping valve 95 positioned to be actuated by a first pair of engaging surfaces in response to downward movement of the mandrel 2 in the housing 3 and a second pair of engaging surfaces in response to upward movement of the mandrel 2 in the housing 3. Thus, independent control over the upward and downward jarring action is achieved.

Abstract: In a self-propelled reversible boring ram, selection of forward/reverse boring modes is determined by the position of a control piston. A concentric supply pipe to a source of working fluid pressure connected to coaxial fluid inputs on the ram. Working fluid pressure for an impacting piston (hammer) is supplied through the input. For forward mode operation, pressure from a coil spring and reactive force on the piston is overcome by working fluid pressure on servo pistons. Restricting fluid pressure on the pistons allows the piston to move to reverse mode operating position.

Abstract: A jar mechanism is described, which comprises a piston (5) movably mounted in a fluid chamber (9). A jar member (2) is releasably coupled to the piston (5) by a release device (3, 4; 3, 38, 39, 40, 54, 64) so that when the piston (5) is in a first position in the fluid chamber (9), the jar member (2) is coupled to the piston (5) by the release device (3, 4; 3, 38, 39, 40, 54, 64). A first force exerted on the jar member (2) moves the piston (5) to a second position within the fluid chamber (9) against the resistance of the fluid (11). When the piston (5) is in the second position, the action of the first force applied to the jar member (2) actuates the release device (3, 4; 3, 38, 39, 40, 54, 64) to enable the jar member (2) to be uncoupled from the piston (5).

Abstract: In accordance with an illustrative embodiment of the present invention, a hydraulic drilling jar includes a mandrel and a housing movable between extended and retracted relative positions to deliver jarring blows to a struck object, a piston on the mandrel that slides in a cylinder in the housing, and a restriction assembly on the housing having an internal seal that engages an enlarged section of the mandrel to enclose a high pressure, oil-filled chamber between the piston and the restriction assembly, the restriction assembly including a pin check valve that provides a very slow leakage of oil from the high pressure chamber while the enlarged section of the mandrel is engaged with the seal. An oil-filled compensating chamber on the opposite side of the restriction means from the high pressure chamber has its pressure equalized with the pressure inside the mandrel by ports through the wall of the mandrel.

Abstract: This invention relates to flow pulsing methods and apparatus for various applications including downhole drilling equipment and in particular to an improved flow pulsing method and apparatus of this type to be connected in a drill string above a drill bit with a view to securing improvements in the drilling process.

Abstract: A hydraulic jar for use in a well and a method of operating same in which an outer housing assembly extends around an inner mandrel assembly in a coaxial relation thereto to define two fluid chambers separated by a piston. The housing assembly is movable relative to the mandrel assembly to force the fluid from one of the chambers to the other. The fluid flow rate is varied between a relative low flow rate and a relative high flow rate in response to the relative position of the housing assembly causing corresponding movement at the latter assembly. A high impact load is transferred to a member connected to the jar in response to a movement at the relatively high flow rate. The jar can be used to create a high impact load in both an upward direction and a downward direction.

Abstract: A pneumatic percussive device has a casing (1) accomodating a movable hammer piston dividing the interior space of the casing (1) into two chambers. One of these chambers (7) alternately communicates, by means of an air distribution arrangement (3) having a movable actuator member (8), with a compressed air source and with the environment. In addition, said chamber (7) communicates, via a throttling passage (27), with a cavity (10) of the air distribution arrangement (3) the pressure in which ensures movement of the actuator member to one of its limit positions.

Abstract: A hydraulic well jar mechanism capable of developing jarring force in an upwardly or downwardly direction or in both upward and downward directions for imparting jarring forces to stuck well pipe. Inner and outer tubular members cooperate to define an annulus therebetween, which annulus contains a volume of metering liquid such as oil. One or more metering valves are disposed within the annulus and establish metering of the metering liquid during a portion of the stroke of the well jar to thus retard movement thereof. After a certain metering movement has occurred, the operative metering valve will be clear of the metering surface and the jar mechanism will then have relatively free movment from the retarded position to the jarring position. Closing movement of the jar mechanism may be induced by a compression spring closure.

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 jar tool having a mandrel and a housing substantially surrounding said housing. The mandrel and housing are splined such that they may move longitudinally relative to each other. First and second pairs of abutment faces for the jar and bump strokes respectively, are provided between the mandrel and the housing. Both sets of abutment faces are enclosed within the jar tool.

Abstract: This invention relates to a double-acting drilling jar characterized by a constantly recharged hydraulic system operating in concert with a mechanical brake to actuate the latter and temporarily inhibit extension of the relatively moving parts utilizing a modest fluid pressure multiplied many-fold so as to exert a holding force far in excess of that which the hydraulic system could impose alone without destroying the seals. The invention also encompasses the virtual elimination of heat build-up through the use of drilling mud as the working fluid in a hydraulic system where once-used fluid is discharged downhole before it gets too hot while, at the same time, being replaced by a fresh supply of cool fluid from the surface. By calling upon the hydraulic system to only exert enough force to actuate the mechanical system, none of the fluid seals need be loaded to anywhere near their capacity.

Abstract: A single acting hydraulic fishing jar, for use in a tubular drilling string for applying upward jarring forces for dislodging a "fish" from a well, may be run into a well on a drill string to operate a fishing tool in the well bore. The jar has housing members in telescoping relation for longitudinal movement of one relative to the other with a hammer member on one and an anvil member on the other. The housing members enclose a chamber containing an incompressible hydraulic fluid for controlling application of jarring forces. A sliding seal closes one end of the chamber and supports the inner housing member, i.e. mandrel, for sliding movement in the outer housing member. A piston is spaced from the sliding seal so that movement of one relative to the other. Movement of one housing relative to the other in one direction moves the piston toward the sliding seal. The chamber between the piston and the sliding seal has an outlet controlled by a valve member slidably supported for movement on the mandrel.

Abstract: A hydraulic jarring tool for imparting up-jarring impacts to release a stuck earth boring drill string component is shown. The tool defines upper and lower closed fluid chambers between telescopically moveable concentric cylinders. A fluid metering valve in one fluid passage between the chambers provides limited flow from one chamber to the other and permits telescopic movement at a rate which establishes tension on the drill string and causes the tool to jar. A normally open valve is provided in a by-pass passage between the chambers and is responsive to the fluid velocity therethrough to move to a closed position, restricting fluid flow to pass through the metering valve. However, the tool can be telescopically extended at a somewhat lesser rate insufficient to cause the velocity responsive valve to close thereby permitting the tool to be extended smoothly without a jarring impact.

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: A jar for use in imparting jarring blows to an object lodged in the bore of a well. The jar includes a mandrel member and outer telescopically related tubular member, the mandrel member and said tubular member being telescopically movable between an extended and a collapsed position of the jar. One of the members is connected to a drill string while the other of the members is connected to the object to be jarred. Telescopically overlapping portions of the members provide an annular chamber for confining an operating fluid. A sleeve and a cylinder extend into the chamber and into an essentially fluid tight fit with each other for a selected portion of the telescopic travel between the extended and collapsed positions. An operating fluid bypass is provided in the first one of the members, the bypass being in fluid communication with the operating fluid above and below the sleeve, the bypass including a channel. An orifice is disposed in the channel.

Abstract: A locking device for a tool with telescopically displaceable parts such as the various tools including a drilling jar used in the deep-well drilling art comprises thickened spindle portion (1) and a sleeve portion (2) with a displaceable sleeve (11) displaceable therein to and away from an axial abutment (17). The thickening of the spindle portion provided by a rigid tapered sleeve (3) with tapered end surfaces (5 and 6) and the sleeve (11) within the sleeve portion with an internal tapered surface (12) are coupled via locking balls (19) disposed for radial movement in an annular cage 20 between the rigid and displaceable sleeves 3 and 11. The sleeve (11) is held by an axial spring (16) in such a position that the balls come to lie axially between the axial abutment (17) and a region of the tapered sleeve (3) having a larger diameter and thereby form a constriction to the passage of the sleeve (3) of the spindle portion ( 11).

Abstract: A bidirectional hydraulic drilling jar includes an elongated mandrel telescopingly disposed within a body and defining spaced apart fluid chambers separated by a restricted bore portion of the body. The mandrel is provided with spaced apart positive mechanical seal assemblies engageable with the restricted bore portion to form a hydraulic dashpot to retard movement of the mandrel in each direction over a limited stroke length so that the spring tension or weight of the drill stem may become effective to deliver an impact blow when the seal assemblies move out of sealing engagement with the restriction. Back-to-back check valves are arranged to bridge the respective seal assemblies to reduce the length of stroke required to cock and trip the jar in each direction. A separate orifice or flow restricting passage is provided across the seal assemblies so that the retarding effect is independent of coacting seal surfaces between the mandrel and the jar body.

Abstract: A drill string splined resilient tubular telescopic joint for balanced load deep weel drilling comprises a double acting damper having a very low spring rate upon both extension and contraction from the zero deflection condition. Stacks of spring rings are employed for the spring means, the rings being either shaped elastomer-metal sandwiches or, preferably, roller Belleville springs. The spline and spring means are disposed in an annular chamber formed by mandrel and barrel members constituting the telescopic joint. The chamber containing the spring means, and also containing the spline means, is filled with lubricant, the chamber being sealed with a pressure seal at its lower end and an inverted floating seal at its upper end.A prototype includes of this a bellows seal instead of the floating seal at the upper end of the tool, and a bellows in the side of the lubricant chamber provides volume compensation.