A jarring device 100 and method for applying an impact to a casing 10 of a wellbore in a subterranean or subsea formation. The jarring device 100 comprises: a hammer 120 and a driving means 110 for driving the hammer 120 between a first position in which the hammer is spaced from the casing 10 and a second position in which the hammer 120 contacts the casing 10, such that the driving means 110 is operable during use to drive the hammer 120 from the first position to the second position so as to impact the casing 10; wherein the hammer 120 is reciprocated by the driving means 110.

A method comprising determining a property of a first section of drill pipe that is to connect a first agitator to a second agitator in a bottom hole assembly of a drill string, determining a distance between the first agitator and the second agitator based, at least in part, on the property of the lirst section of drill pipe, positioning the first agitator in the bottom hole assembly of the drill string, and positioning the second agitator in the bottom hole assembly of the drill string relative to the lirst agitator based, at least in part, on the distance.

A system for generating pressure pulses in drilling fluid includes a concentric drive power section. The power section includes a stator and a rotor rotatably disposed in the stator. The rotor is coaxially aligned with the stator. The system also includes a valve. The valve includes a first valve member coupled to the stator and a second valve member coupled to the rotor. The second valve member is configured to rotate with the rotor relative to the first valve member and the stator. The rotation of the second valve member relative to the first valve member is configured to generate pressure pulses in drilling fluid flowing through the concentric drive power section.

A hydraulic oscillation tool with variable stage, small pressure drop and strong impact based on radio frequency identification is provided. It includes a conversion connector, a disc spring upper bracket, a disc spring housing, a disc spring group, a multi-stage piston shaft, an upper piston sleeve, a first radial sealing ring, a double-female-buckle piston sleeve, a double-male-buckle piston sleeve, a second radial sealing ring, a double-female-buckle lower piston sleeve, an end piston, an impacting connector, a power housing, a power shaft end cap, a high torque turbine, a power shaft, a lower connector, a rotating valve, a bearing supporting ring, and a turbine special bearing. The hydraulic oscillation tool realizes the low pressure drop and strong impact, and thus the problems that with the continuous increase of horizontal length, excessive pressure drop will make the annular pressure drop sharply, and drilling fluid circulation is difficult are solved.

Systems and methods for moving a tubular string within a subterranean well include a downhole assembly. The downhole assembly includes a torque disconnecting member and a shock generating member. During normal drilling activities, both components are inactive. When a stuck pipe event occurs, first the torque disconnecting member is activated while the shock generating member is still inactive. Once the torque disconnecting member is activated, then the shock generating member is activated. A laterally-protruding shock pad of the activated shock generating member produces shocks against the proximate side of a wellbore wall while the shock generating member is rotating. Systems and methods for moving a tubular string within a subterranean well include a fishing assembly. The fishing assembly includes a fishing member, a swivel member, and an imbalanced member. The imbalanced member has a cross-sectional center of gravity off-centered relative to the longitudinal axis to produce shocks against the proximate side of the wellbore wall while the imbalanced member is rotating.

A downhole apparatus has a casing string and a degradable plug positioned in the casing string to block flow therethrough. An upper membrane covers an upper end of the degradable plug. The upper membrane is made up of a plurality of separable membranes. A lower membrane covers a lower end of the degradable plug and is comprised of a plurality of separable membranes.

An embodiment relates to a composition comprising an amorphous alloy having a low coefficient of friction (COF) of 0.15 or less, wherein the amorphous alloy is substantially free of phosphor (P) and substantially free of boron (B). An embodiment relates to a method comprising solidifying a molten layer of an amorphous feedstock on a preexisting layer by controlling a heating source and a cooling rate so as to avoid formation of crystals in the molten layer and not affect a crystalline structure of the preexisting layer, and forming a specimen; wherein, the at least a portion specimen has the low COF. Another embodiment relates to a system comprising a drill string, wherein the drill string comprises a drilling bit and a drill pipe connected thereto, wherein at least a portion of the drill pipe comprises a coating having the low COF.

A shock and agitator tool assembly vibrates a drill string to overcome stick slip and other friction-based problems that may occur during directional drilling. The agitator tool portion of the assembly, which can be used without the shock tool, allows for controlled activation and deactivation of the agitator tool by the use of one or more darts pumped downhole. The darts can be retrieved with a wireline tool. When activated, the agitator portion creates alternating pressure pulses. These pulses cause axial movement of the drill string above the agitator. A shock tool is described which utilizes a telescoping mandrel to amplify the axial movement created by the agitator tool.

A tubing string, such as a coiled tubing or jointed tubing string, has an agitator mounted within an interior of the tubing string at an intermediate position between an uphole end and a downhole end of the tubing string. A tubing agitator is structured to be installed within a tubing string. A method includes: forming or installing a seat within an interior of a tubing string at an intermediate position between an uphole end and a downhole end of the tubing string; and conveying an agitator through the interior of the tubing string until the agitator contacts the seat. A hammer drift tool is also described.

An impression tool for providing an impression of an object in a borehole includes a block held by a gripper. The block has a plurality of discrete elements that can deform or move so as to create an impression of an impacted object. The bock can be formed of knitted wire mesh. The tool is impacted on an object such that an impression is formed in the block.