Disclosed combination impact tool generates optimized linear hammering and vibrational impacts. Flow of pressurized fluid through an upper section of the tool generates linear hammering impacts, and flow of pressurized fluid through a lower section of the tool generates vibrational impacts. Flow of pressurized fluid through the lower section induces an eccentric arm to rotate and cause vibrational impacts. While frequency of hammering impacts can be controlled by varying pressure of the fluid flowing through the upper section, the frequency and amplitude of vibrational impacts can be controlled by varying weight of the eccentric arm and by varying pressure of the fluid flowing through lower section. Disclosed tool is particularly useful in drilling in shale and in fishing operations in a well-bore.

A jarring tool includes a spring and a hydraulic piston cylinder arrangement for controlling the release of a mandrel to initiate a jarring force. The tool includes an adjustment mechanism for adjusting the minimum amount of an upward pulling force required to release the mandrel. The adjustment mechanism includes an axially adjustable trigger sleeve that cooperates with a dog clutch surrounding the mandrel.

A jarring tool includes a spring and a hydraulic piston cylinder arrangement for controlling the release of a mandrel to initiate a jarring force. The tool includes an adjustment mechanism for adjusting the minimum amount of an upward pulling force required to release the mandrel. The adjustment mechanism includes an axially adjustable trigger sleeve that cooperates with a dog clutch surrounding the mandrel.

A jarring tool used to dislodge a stuck tubular string or bottom hole assembly within an underground wellbore. Tubular strings with which the tool may be used may be formed from drill pipe, jointed pipe, or coiled tubing. A funnel element is placed underground either within, or as part of, a tubular string. A deformable ball may be seated within the funnel element to block fluid from passing within the tubular string. Hydraulic pressure may build within the tubular string until it exceeds the pressure the ball can withstand. This will cause the ball to deform and be expelled through the funnel element. With no ball to block its flow, fluid will be rapidly released through the funnel element. The rapid release of fluid will cause a powerful jarring or jolting to the tubular string or bottom hole assembly.

A jarring tool used to dislodge a stuck tubular string or bottom hole assembly within an underground wellbore. Tubular strings with which the tool may be used may be formed from drill pipe, jointed pipe, or coiled tubing. A funnel element is placed underground either within, or as part of, a tubular string. A deformable ball may be seated within the funnel element to block fluid from passing within the tubular string. Hydraulic pressure may build within the tubular string until it exceeds the pressure the ball can withstand. This will cause the ball to deform and be expelled through the funnel element. With no ball to block its flow, fluid will be rapidly released through the funnel element. The rapid release of fluid will cause a powerful jarring or jolting to the tubular string or bottom hole assembly.

A jar device is provided with a releasable locking mechanism which secures the telescopic portions of the jar device from relative movement until released. The locking mechanism is released by a tensional force which ruptures one or more frangible members.

A jar device is provided with a releasable locking mechanism which secures the telescopic portions of the jar device from relative movement until released. The locking mechanism is released by a tensional force which ruptures one or more frangible members.

An apparatus for coupling between opposing first and second portions of a downhole tool string. The apparatus includes a housing having a port therein, a shaft extending within at least a portion of the housing, and a flow restrictor reducing a flow area of the port. The housing and the shaft move axially relative to each other. The port fluidly connects a space external to the housing with an annulus defined between the housing and the shaft.

The invention is directed to a novel and useful fluid-tight, metal-to-metal, annular seal which can be repeatedly cycled in a high temperature, high pressure environment. More specifically, the invention provides a metal-to-metal, annular, seal on a radially expandable sliding sleeve which moves longitudinally from a reduced ID section of a bore to an enlarged section of the bore. The seal is disengaged at the enlarged bore section resulting in rapid fluid flow and pressure equalization which would destroy many traditional elastomer seals.

A system used to dislodge and, if necessary, sever a tubular string that is stuck within a cased wellbore. The system utilizes a jar, a plurality of plugs, and a tubular severance device. Components of the system are carried to their respective desired downhole positions by downward fluid flow within the wellbore. The jar is configured to jar the string in an effort to dislodge the string from its stuck point. The plugs are configured to fill open perforations formed in the casing in order to direct the fluid toward the stuck point and away from the perforations. If the string cannot be freed by the jar, the tubular severance device is deployed within the string above the stuck point. Detonation of the device severs the string above the stuck point.