A drill pipe assembly includes a first drill pipe and a second drill pipe disposed in a wellbore. The first drill pipe includes a tubular wall and a threaded end at a downhole end of the tubular wall. The second drill pipe is disposed in the wellbore downhole of and fluidically coupled to the first drill pipe. The second drill pipe includes a tubular wall and a threaded end corresponding with and configured to receive the threaded end of the first drill pipe to form a connection. At least one of the first drill pipe or the second drill pipe includes an annular groove residing between a respective tubular wall and a respective threaded end. The drill pipe assembly is collapsible at the annular groove under a torque smaller than a torque required to collapse the connection.

A convertible fishing tool is provided for removing an object (fish) from a wellbore. The fishing tool includes an elongated hollow main housing and a plurality of slip blades that are disposed distal to the main housing and move radially between fully retracted positions and fully extended positions. In the fully retracted positions, the fishing tool is in spear configuration and in the fully extended positions, the fishing tool is in an overshot configuration. The fishing tool also includes an actuation system configured to move the plurality of slip blades in a radial direction between the fully retracted positions and the fully extended positions.

Systems and methods for oscillating a string within a subterranean well include a motor assembly having an output shaft extending along a central axis. A translation coupling is in mechanical communication with the output shaft. An inertia sleeve is in mechanical communication with the translation coupling. The translation coupling is operable to translate a rotation of the output shaft to an oscillating movement of the inertia sleeve. A spring assembly is in mechanical communication with the inertia sleeve. The spring assembly is positioned along the central axis.

A welding tool consisting of a tubular body having a lateral end and a pin end. The pin end has external threads disposed around an external circumferential surface of the pin end. The lateral end comprises an inner wall defining an orifice. Additionally, a heat proof shell is disposed circumferentially around the lateral end. The welding tool further includes a battery housing. The battery housing encloses a plurality of batteries which store energy. The welding tool further includes a welding element disposed on an inner surface of the orifice and an electric line. The electric line is coiled within the tubular body and physically contacts the welding element and is electrically connected to the plurality of batteries. The welding tool further includes a controller. The controller is capable of receiving and parsing mud pulse signals and controlling the release of stored energy from the batteries to the electric line.

A method of recovering casing in a wellbore using a vibratory casing recover), bottom hole assembly. In a vibratory casing recover), bottom hole assembly having a casing spear, a flow modifier and one or more further elements including a shock sub. The flow modifier produces cyclic variations in fluid flow through the assembly at a first frequency and at least one of the elements is configured to have a natural or resonant frequency when vibrated to be near or at the first frequency. By tuning elements of the bottom hole assembly to be close or at the frequency of the output of the flow modifier, the dynamic amplification factor of the system is maximised and longer lengths of casing can be recovered. A method of recovering casing using the vibratory casing recover), bottom hole assembly is also described. Further embodiments include a casing cutter and a hydraulic jack.

A method of treating a subterranean formation by contacting the formation with the following: (a) ammonium compound; (b) an oxidizing agent selected from a perchlorate or a nitrite or combinations thereof; and (c) sulfamic acid.

A vibratory casing recovery bottom hole assembly and a method of recovering casing in a wellbore. The vibratory casing recovery bottom hole assembly includes a casing spear, a flow modifier and a dynamic amplification tool. The flow modifier produces cyclic variations in fluid pressure through the assembly at a first frequency and the bottom hole assembly is configured to have a natural or resonant frequency when vibrated to be near or at the first frequency. The dynamic amplification tool induces vibration in the bottom hole assembly while ensuring the dynamic amplification factor of the system is greater than one so as to transmit maximum vibration to the casing at the casing spear. Embodiments of dynamic amplification tools are described.

An apparatus for controlling tool face and methods of use with a torque generator connected to a drill string for drilling linear and nonlinear subterranean bore segments. In some embodiments, the apparatus and methodologies of use comprise a tool controller having an outer housing independently rotatable from and extension conduit extending therethrough and forming an annulus therebetween. The tool controller may provide for a first fluid pathway for allowing a bypass portion of fluids to flow through the torque generator, and a second fluid pathway through the annulus for allowing a torque generator portion of fluids to flow through the annulus. In some embodiments, at least one fluid flow restrictor may be provided within the annulus to controllable cause a cascading reduction in torque generator fluid pressure as it flows through the annulus, allowing high resolution tool face control over a larger (and tunable) range of drill string speed (rpm) set points.

Apparatus and methods for controlling release of torsional energy from a drill string having a lower portion that is stuck against a subterranean formation and a top end rotated by a top drive. The method may include decreasing a rotational speed set-point of the top drive, decreasing a torque set-point of the top drive, and/or decreasing flow rate of drilling mud being pumped downhole via the drill string, thereby decreasing torque output by a mud motor rotating a drill bit. The method may further include lifting the drill string to free the drill string. Decreasing the torque set-point of the top drive may comprise decreasing the torque set-point of the top drive to a minimum torque level that the top drive can output. Decreasing the rotational speed set-point of the top drive may comprise decreasing the rotational speed set-point of the top drive to zero.

A method of freeing a stuck pipe in a wellbore includes positioning a pipe freeing tool within an annulus of the stuck pipe, the pipe freeing tool including a body and two or more arms coupled to and extending from the body, and activating the two or more arms of the pipe freeing tool to extend outwards from the body to apply a force to the stuck pipe. Another method of freeing a stuck pipe in a wellbore includes determining a stuck point along a drillstring comprising the stuck pipe, and activating a pipe freeing tool coupled to the stuck pipe to apply a force to the stuck pipe, wherein the force moves the stuck pipe away from a surface of the wellbore and towards a center of the wellbore, and the pipe freeing tool includes a plurality of expandable disc elements.