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.

A hydraulic jar includes a tubular housing having central bore and an exterior. The housing includes a passage from the central bore to the exterior. A mandrel is axially movable within the housing, forming an annular space between the mandrel and the housing that includes a timing fluid. The mandrel includes an interior axial space that permits the flow of a drilling fluid. A timing device is fixed to the mandrel in the annular space. A trigger is capable of blocking the flow of drilling fluid through the axial space in the mandrel, and the mandrel moves axially in the housing when the trigger engages the mandrel. The timing device causes the mandrel to move at a first speed and at a second speed to create the impulse. The drilling fluid exits the central bore through the opening after the mandrel moves past the opening.

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.

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 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.

A thru-tubing recover string (10) and method of moving a stuck object (14) in tubing in a well (16). A bottom hole assembly (22) is connected to a work string and includes a first (32) and a second tool (34), each tool configured to apply a force to the object in order to move the object (14), the first force being an impulse force, the second force being a static force, and the tools being operable independently so that an operator can apply either force in the event that application of one type of force on the object fails to move the object. Embodiments are described for the first tool (32) being a hammer tool or a jar and the second tool being a pulling tool such as a jack. The invention finds application in removing stuck objects such as plugs or actuating elements on tools such as sliding sleeves in production tubing.

Disclosed is a fluid driven pulsating, hammering tool operational when pressurized fluid is pumped into the tool's upper sub, having a poppet valve which can seal the upper end of a slidable outer valve assembly when closed; an inner valve assembly slidable within the outer valve assembly; wherein the inner and outer valve assemblies remain in selective fluid communication with the poppet valve even when the poppet valve is closed, wherein interruption of said fluid communication occurs from movement of the inner and/or outer valve assemblies to particular positions along their sliding paths; and further including a lower valve which is preferably a Tesla valve having channels which are also in fluid communication with the poppet valve.

A jarring apparatus includes first and second jarring assemblies which are axially moveable relative to each other between first and second axial configurations, and a thrust assembly interposed between the first and second jarring assemblies to limit relative axial movement therebetween at the second axial configuration and permit axial loading in one axial direction to be transferred between the first and second jarring assemblies via the thrust assembly. The apparatus further includes a jarring mass axially moveable within the jarring apparatus in reverse first and second directions upon relative rotation between the first and second jarring assemblies.

Disclosed is a fluid driven pulsating, hammering tool operational when pressurized fluid is pumped into the tool's upper sub, having a poppet valve which can seal the upper end of a slidable outer valve assembly when closed; an inner valve assembly slidable within the outer valve assembly; wherein the inner and outer valve assemblies remain in selective fluid communication with the poppet valve even when the poppet valve is closed, wherein interruption of said fluid communication occurs from movement of the inner and/or outer valve assemblies to particular positions along their sliding paths; and further including a lower valve which is preferably a Tesla valve having channels which are also in fluid communication with the poppet valve.

The disclosed jarring device generates two jarring impacts at the end points of a reciprocating hammer assembly. Initially, flow of pressurized fluid through the jarring device is obstructed by a deformable member. The resulting increase in fluid pressure upstream of the deformable member causes compression of a spring and downstream movement of the hammer assembly to generate a first jarring impact. A further increase in fluid pressure beyond a threshold, causes a release of the obstruction by either deforming the member or by slicing it by pushing it through a slicer. Releasing of the obstruction causes decompression of the spring, and upstream sliding of the hammer assembly to generate a second jarring impact.

A mechanically locking hydraulic jar device includes an outer sleeve, an inner sleeve partially disposed in an inner bore of the outer sleeve, and a mechanical lock engaging the outer sleeve and the inner sleeve in a default position to axially secure the inner sleeve to the outer sleeve. Activation of the hydraulic jar disables the mechanical lock to allow axial movement of the inner sleeve relative to the outer sleeve, which generates an impact force when the inner sleeve reaches an activated position. The hydraulic jar device also includes an upward block and a downward block configured to limit the upward and downward axial movement, respectively, of the inner sleeve relative to the outer sleeve when the mechanical lock is disabled.