Abstract: A release mechanism for a jarring tool is formed by a plurality of segmented release lugs. Each lug includes a plurality of axial spaced projections on an inner surface and a plurality of grooves on an outer surface. The projections may have either different widths or may be separated by varying distances and releasably engage corresponding grooves in a mandrel located within a housing of the tool. The release lugs are positioned between a trigger sleeve and the mandrel. In one embodiment, the release lugs are positioned within a support collar. In a second embodiment, the lugs are provided with stabilizing posts and cavities that serve to maintain the lugs in a proper alignment.

Abstract: A release device for a jarring tool includes a collet positioned between the mandrel of the jarring tool and a trigger sleeve. At least one end of the collet is in contact with a precompressed spring via a bushing. In order for the jarring tool to operate, a force greater than the precompressed force of the spring must be applied to the mandrel so that the collet can move in axial direction against the spring thereby releasing the mandrel.

Abstract: A release mechanism for a jarring tool is formed by a plurality of segmented release lugs. Each lug includes a plurality of axial spaced projections on an inner surface and a plurality of grooves on an outer surface. The projections have either different widths or are separated by varying distances and releaseably engage corresponding grooves in a mandrel located within a housing of the tool. The release lugs are positioned between a trigger sleeve and the mandrel. The release lugs may be supported by an annular ring member.

Abstract: An apparatus has an elongate body defining an interior chamber and a gas passage in communication with the interior chamber. The elongate body further includes a base defining a liquid opening and a cap defining an outlet opening. The liquid opening is adapted to receive a liquid disposed in a wellbore. The gas passage is adapted to receive a gas. An outlet of the gas passage is disposed a first distance from the base and an inner conduit is disposed in the interior chamber. The inner conduit includes a first open end in communication with the liquid opening and a second open end in communication with the interior chamber. The second open end is disposed a second distance from the base.

Abstract: A release mechanism for a jarring tool is formed by a plurality of segmented release lugs. Each lug includes a plurality of axial spaced projections on an inner surface and a plurality of grooves on an outer surface. The projections have either different widths or are separated by varying distances and releaseably engage corresponding grooves in a mandrel located within a housing of the tool. The release lugs are positioned between a trigger sleeve and the mandrel.

Abstract: A method for jarring allowing the operator to selectively control the jarring force while the tool is downhole and a powered bidirectional mechanical jar therefor, is disclosed. The jar includes a housing, an anvil fixed within the interior the housing, first and second hammers movably disposed within the housing at obverse sides of the anvil, first and second springs disposed to urge the hammers towards the anvil, and a rod with a radial catch that selectively engages and disengages the hammers so as move the hammers to compress the springs and thereafter release the hammers to be accelerated against the anvil. A actuator operates the catch. By controlling the movement of the rod, the spring compression and resultant jarring intensity can be controlled. A stroker tool may be provided to move the rod.

Abstract: Apparatus and method for adjusting spring preloading in a downhole tool. In an apparatus, a mechanism includes a nut and a piston. The nut is configured to axially compress a spring in the downhole tool. The piston is coupled to the nut. Extension of the piston causes the nut to rotate and compress the spring. The nut is configured to maintain compression of the spring after the piston retracts.

Abstract: An underground drilling method where drilling fluid pulsing down hole tool is combined with a multiple in series pistons down hole tool to provide vigorous vibrations in the drill string and deliver vibrating energy to the drill bit to increase penetration rates and reduce friction between the drill string and the hole. One example method and apparatus shown can operate a simple percussive down hole mud hammer.

Abstract: Method and apparatus for decreasing drag force in a mechanism for releasing a mandrel is provided. The mandrel is released by a collet, which is controlled by a trigger sleeve. Most of the axial force on the collet is relieved, thereby decreasing the frictional force exerted by the collet on the mandrel after it is released.

Abstract: A jar provided with an adjustable preload has a housing defining an anvil surface and a mandrel, movable relative to the housing under an applied load, defining a hammer surface to impact the anvil surface. A trigger mechanism for releasing the mandrel to cause the hammer surface to impact the anvil surface includes a trigger sleeve axially positioned with the housing and a collet that engages the mandrel during application of a load to the mandrel. The collet releases the mandrel to cause the hammer surface to impact the anvil surface upon being moved into registration with the trigger sleeve against the resistance of a biasing spring disposed within the housing. The preload is adjusted by an adjustment mechanism carried by the housing and coupled to the biasing spring. The adjustment mechanism includes an adjustment mandrel disposed between an end of the upper housing section and an end of the lower housing section. The adjustment mandrel is axially movable relative to the upper and lower housing sections.

Abstract: A jar mechanism comprises a housing having a fluid chamber therein, a piston encircled by an annular metering sleeve and movably mounted in the fluid chamber for movement between a first position and a second position, and a jar member moveably mounted in the housing such that a pull or push force exerted on the jar member moves the piston from the first position to the second position within the fluid chamber against the resistance of the fluid, and the action of the pull or push force exerted on the jar member actuates a release device. The jar member is releasably coupled to the piston by the release device such that, when the piston is in the first position in the fluid chamber, the jar member is coupled to the piston by the release device for movement therewith. Actuation of the release device enables the jar member to be uncoupled from the piston.

Abstract: A hydraulic jarring tool may be suspended in a well from a wireline, tubular string or drill string, and may be activated to release a tool stuck in the well, or to release the drill string. Each of an upper and lower jarring section include a housing, a piston, a piston biasing member, a fluid metering device and a release mechanism for holding an hammer in a downward position and releasing the hammer to strike an anvil in response to movement of the piston. A timing mechanism results in a timed delay between the impact of one hammer striking the anvil and the other hammer striking the anvil.

Abstract: A downhole tool is provided that creates balancing forces that allow a tool such as ajar to continue to function when intrusion of gas into the fluid chamber of the jar occurs to cause gas pressure in the jar to exceed hydrostatic pressure. The excess pressure is balanced by forming an area acted on by the gas pressure equal to the cross-sectional area of the mandrel, such that the forces on the mandrel are equal and opposite.

Abstract: An internal, positive engagement lock that locks a tool, such as a hydraulic drilling jar, in the fully open position when the tool is racked back and when tripping in and out of the hole close to the surface. The lock mechanism is spring biased into a locked position that provides a positive engagement between two axially translatable components, thus preventing any actuation of the tool. As the tool is run in the hole, increasing hydrostatic pressure within the tool will cause the locking mechanism to shift to a disengaged position and the tool will operate normally. The spring-biased locking mechanism will return to the locked position as hydrostatic pressure decreases as the tool is retrieved to the surface.

Abstract: A jar (10), for use in a downhole toolstring comprising: a hollow housing (11); a jar mandrel (13); a latch sub (14); one or more latch keys (16); a cam surface (17); a chamber (23); a compression spring; and an adjuster (24). The hollow housing (11) supports, moveably retained therein, the jar mandrel (13). The jar mandrel (13) and the latch sub (14) are releasably securable together by means of the one or more latch keys (16), and each latch key (16) is moveable between a latching position, in which the latching sub (14) and the jar mandrel (13) are connected together, and a release position permitting separation thereof. The cam surface (17) engages each latch key (16) to move it from its latching position to its release position when the jar mandrel (13) occupies a preselected position in the housing (11).

Abstract: An internal, positive engagement lock that locks a tool, such as a hydraulic drilling jar, in the fully open position when the tool is racked back and when tripping in and out of the hole close to the surface. The lock mechanism is spring biased into a locked position that provides a positive engagement between two axially translatable components, thus preventing any actuation of the tool. As the tool is run in the hole, increasing hydrostatic pressure within the tool will cause the locking mechanism to shift to a disengaged position and the tool will operate normally. The spring-biased locking mechanism will return to the locked position as hydrostatic pressure decreases as the tool is retrieved to the surface.

Abstract: According to the present invention, the e-line downhole jarring tool is an electrical line downhole tool for manipulating a work string which is easily configured to deliver a specific amount of force to the work string in a small and simple apparatus.

Abstract: In a directional drilling apparatus in which a sensor/transmitter or sonde is located in one section of a drill string and an element of an adjacent section is configured to “steer” the bore drilled in a predetermined lateral direction, a device is provided for automatically ensuring correct registry or alignment of the sensor/transmitter and the steerable element, this device comprising an azimuth member on the section carrying the sensor/transmitter engageable with a reference member of the adjoining section to present, after such engagement, relative rotation of the azimuth member, which is rotatable in the section carrying it, with the sensor/transmitter, but non-rotatably connected with the sonde. The reference member or the azimuth member is resiliently displaceable axially to allow the two sections to be screwed up together.

Abstract: An apparatus for jarring a portion of drill string lodged within a borehole, by jarring downhole using tension only, including a first member for attaching a first lower end of the apparatus to the upper end of the lodged tool or pipe through a threadable attachment; a second member for attaching a second end of the apparatus to a drill string on its upper end portion; a third anvil or hammer member which is triggered by spring having stored compressional force transferred by tension from the drill string to the apparatus when the drill string is pulled upward. There is also provided an actuator for rapidly releasing the tension force provided by the spring downward onto the stuck pipe in order to provide an impacting, downward force onto the pipe in an effort to dislodge the pipe. There is further provided a slow release mechanism for slowly releasing the tension force stored by the spring in the event the tool is not fired downhole.

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 rotary jar is described that is part of a drill string and includes a mandrel and an anvil that move longitudinally in opposite directions to deliver a sharp upward or downward blow that is transmitted to a fish, which may be a separate tool or a portion of the drill string that is stuck in the well bore in an effort to free the fish or the stuck portion of the drill pipe. The mandrel carries rollers that move through longitudinally extending grooves when the jars are tripped. In the jars of this invention, the grooves follow a serpentine path to cause the mandrel to transmit a torsional force on the fish to try to rotate the fish as well as providing an upward or downward blow.

Abstract: In a drill string jar apparatus having an elongated tool body positionable within a drill string, which would also include a latch mandrel movable within a bore of the tool body between a first neutral position and fired up or fired down positions; a substantially continuous channel formed in the interior wall of the tool body, a shoulder portion on the exterior wall of the latch mandrel body for latching into the channel of the tool body when the mandrel is in the neutral position and slots in the wall of the latch mandrel for allowing the mandrel body to flex inwardly sufficiently to disengage the shoulder portion from the channel in the tool body and allow the latch mandrel to move upward or downward within the bore of the tool body depending upon the direction of the force imparted on the mandrel and make contact with the upper or lower end of the tool in order to dislodge a tool below the jar apparatus.

Abstract: A new and improved mechanical jar apparatus for delivering downhole blows in a wellbore in either of opposite directions in response to the controlled application of a longitudinal force. A plurality of mechanically released collets are employed to releasably secure the concentric telescoping members of the jar apparatus in the ready condition until the longitudinal actuation force is applied to move the telescoping members to the longitudinally extended or compressed jarring positions. The plurality of collets may be arranged for controlling the magnitude and direction of the jarring force without inadvertently triggering a jarring force in the undesired direction.

Abstract: A jar tool for inclusion into a well fishing operating string which provides resilient tensional stretch to operate the tool. The tool is adapted to compress an upper release spring to store energy corresponding to tensional force in the operating string force. A release latching lug array connects the spring to a central mandrel having an impact hammer. The tool housing forms an impact anvil. The spring is compressed to a designated compressional force by the distance that the latch lug array is moved in an adjustable latch release sleeve before suddenly releasing the spring from the mandrel. The tension in the operating string then pulls the mandrel hammer into jarring impact with the housing anvil. Provision is made for designating this pre-release movement of the latching lug array and also provides apparatus for adjusting the distance of the pre-release movement and thereby the compressional force imparted into the spring.

Abstract: A latch for a telescoping drill string jar is confined in an opening in the jar housing and engages the arbor of the jar to prevent telescoping action for normal drilling. The latch has a number of spring bars, each with a latch lug extending into a latch groove in the arbor. The lugs and the groove have beveled engagement surfaces that urge the spring bars radially outward, into clearance provided, when axial forces on the arbor relative to the housing exceed a preselected amount. The end of the spring bars are restrained in a cup with tubular sides extending along the spring bars to limit the length of spring bar allowed to flex radially outward. The length free to flex determines the average axial force required to release the latch. The ratio of the extending sides of the opposed cups determines the ratio of tension or compresive axial forces required to release the latch. The jar fitted with the latch is free to telescope, to cause jarring, when the lugs clear the groove.

Abstract: A jarring device for use in drilling comprises first and second members longitudinally relatively movable between a locked position and a released position said device comprising control means including a pair of locking devices each arranged to prevent relative movement between said members until a predetermined force is applied to one of said movable members in either of two longitudinal directions. The control means includes two locking devices each of which locks in one of the two directions.The locking devices may comprise pivotable bolts pivoted on a sliding member so that the free ends of the bolts contact an abutment on one of the movable members to effect locking, the bolts being retracted from engagement with the abutment by movement of the sliding member.

Abstract: A mechanical jar used primarily on drill strings, in earth boreholes, to aid in freeing drill strings stuck in a well bore. A telescoping drill string component is constrained in a selected telescoped condition by a biased lock until enough axial stress is applied to the telescoped jar to release the lock. Energy stored in the stressed length of drill string then moves rapidly to strike a solid limit to the telescoping travel. The inertia of the moving part of the drill string applies a shock to the stationary, downwardly continuing part of the drill string. The shock is to aid in releasing the stuck string situation. The tension required to release the lock is adjustable, as a design alternative, by applying torque to the drill string. The jar can, by design alternative, be used to strike in either or both axial directions.

Abstract: A mechanical well jar is disclosed having inner and outer tubular members movable longitudinally relative to each other a limited distance for connecting in a pipe string. Annular shoulders on the members engage to limit the relative longitudinal movement of the members. A plurality of laterally spaced, arcuate cam plates are attached to the inner surface of the outer member. Each plate has a laterally extending U-shaped notch opening into the space between the plates and formed with curved outwardly flaring sidewalls. Rollers are mounted on the outer surface of the inner member to extend into the spaces between the cam plates for movement into the U-shaped notches to hold the members from longitudinal movement relative to each other.

Abstract: A mechanical jar having a variable diameter tension ring which can be reciprocated from a large into a small diameter chamber and vice versa. When a fishing tool is connected to the jar, the jar is run downhole and set down, and a mandrel retracts into a barrel, causing a collet to move the ring into the large diameter chamber whereupon the ring expands to a large diameter and telescopingly receives the collet fingers therewithin. As the jar is picked up, the mandrel moves the ring from the large to the small diameter chamber, thereby reducing the diameter of the ring. This action releasably latches the ring and the collet fingers together. Accordingly, a very large axial force must be applied to the mandrel in order to cause the collet to be released from the ring; and, a very small reverse axial force is required for the collet to latch onto the ring.

Abstract: Method and apparatus for firing perforating apparatus in a borehole. A mechanically operated firing assembly is run into the borehole on the end of a cable and latched onto a perforating apparatus. Tension is pulled on the cable. At a predetermined tension force a firing rod is automatically released and as a result of force exerted by a compression spring driven into impactment with a percussion firing head to thereby detonate the perforating apparatus. Additionally, the firing assembly can be reset by application of downward force thereto.

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 well jar having an elongated body with an axial passageway and threaded connections for assembly into a string of well pipe. The body has a tubular mandrel slideably mounted within a tubular barrel with the annulus therebetween exposed to well fluid. Fluid seals in the annulus provide an isolated chamber containing a latch whereby the mandrel and barrel are selectively released for delivering an impact to the wellpipe. The improvement to the jar comprises a plurality of elongated, resilient vibration snubbers integrally carried by the mandrel and aligned longitudinally in the annulus between the mandrel and the barrel. The snubbers slideably engage the barrel throughout its telescopic movement along the mandrel. The snubbers are circumferentially spaced apart about the mandrel with the intervening spaces forming flow channels in the annulus to accommodate well fluid flows when the jar is mounted in the string of well pipe being rotated in the well bore.

Abstract: A drilling jar to be installed in a set of drill collars in a drill string is disclosed. In the illustrated embodiment, first and second tubular members telescope relative to one another. At the upper end of the lower tubular member, a set of protruding lugs match shoulders having undercuts which permit relative rotation of the two tubular members through part of a turn, thereby permitting the two members to axially telescope whereby locking or unlocking the telescoping movement is controlled. The lower tubular member has an upwardly facing shoulder which is abutted against the lower end of the upper tubular member. This permits the two to be reciprocated and banged together to create a jar for the drill string. A dual jarring activity is developed by a cam actuated radially yieldable collet-type release mechanism that allows relative linear movement of the tubular members and permits selected jarring activity independently of or in conjunction with the lugged locking and releasing portions thereof.

Abstract: An improvement on the tool shown in U.S. Pat. No. 3,853,187, this tool also embodies in a single structure inner and outer telescopically related tubular elements confining a body of operating liquid and comprising a hydraulically retarded up-blow jar, actuated by placing a lifting strain on the drill string, and a simple mechanically retarded down-blow jar actuated optionally by a controlled downward pressure of the drill string on the jar. This jar differs from the patented jar by inverting said structure and actuating said two jar mechanisms respectively by upward and downward movements of said inner element. It also embraces improved specific control devices for said up-blow and down-blow jar mechanisms.

Abstract: A jar for use in facilitating the removal of stuck objects from wells. The jar has a telescoping assembly held in a collapsed position by a latching means urged into latching position by a resilient means so that the hammer of the jar is spaced from the anvil thereof. The release of the latching means is actuated by a predetermined longitudinal force applied to the upper end of the jar which overcomes the resilient means to cause the hammer to strike the anvil with a sudden impact translated by a connecting means from the jar to the stuck object.

Abstract: A remotely operated connector for electrically and mechanically coupling a wireline to a connector located at the bottom of a drill string. The connector includes a spring-actuated jar that facilitates the release of the connector.

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: A well jar is characterized by inner and outer telescoped members held from relative displacement by a latching member having an extending portion thereon. Imposition of an axially directed triggering force exceeding a predetermined magnitude is transmitted against the biasing force of a resilient member through a force transmitting arrangement to a latch release member provided with an opening therein sized to receive the extending portion of the latching member. The release member rotates in a predetermined angular direction to come into registry with the opening therein to receive the extending portion of the latching member as the latching member displaces radially outwardly to release the inner member. Upon release, the inner member responds to the axially directed force to drive impact surfaces disposed on the inner and outer members into an impact-producing engagement.

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: 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.