A method for drilling a subterranean wellbore includes rotating a drill string in the subterranean wellbore to drill the wellbore. The drill string includes a rotary steerable tool or a steerable drill bit including at least first and second axially spaced pads configured to extend radially outward from a tool body and engage a wall of the wellbore. Radial displacements of each of the first and second axially spaced pads are measured while drilling. The measured radial displacements are processed to compute a rate of penetration of drilling.

Spherical projectiles may be used to form one or more holes in geologic or other material. These holes may be used for drilling, tunnel boring, excavation, and so forth.

A cutting tool includes a body configured to rotate about a longitudinal axis, a blade connected to the body, and a pre-formed segment. The blade extends away from the body and includes a recess formed in a leading face of the blade. The pre-formed segment is disposed in the recess adjacent to the leading face of the blade. The pre-formed segment is connected to the blade. The pre-formed segment includes a cutter pocket therein, the cutter pocket having a sidewall and a base.

A mill including a housing having a fluid bypass pathway, a milling feature at a longitudinal end of the housing, a chamber defined by the housing, and a piston disposed in communication with the chamber, the piston defining a fluid passageway initially aligned with the fluid bypass pathway, the piston responsive to pump pressure to move toward the milling feature, the movement misaligning the fluid passageway with the fluid bypass pathway.

A downhole tool includes a blade coupled to a body. The body and blade rotate about a longitudinal axis. A pre-formed faceplate is connected to the blade and partially defines a cutter pocket therein. Another portion of the cutter pocket is defined by the blade. The cutter pocket includes a sidewall and a base, with the sidewall formed by the blade and the pre-formed faceplate, and the base formed by the blade. The pre-formed faceplate includes a pre-formed hardfacing element. A downhole tool includes a blade coupled to a body. The body and blade rotate about a longitudinal axis. A pre-formed segment is connected to the blade and has a cutter pocket therein. The cutter pocket includes a sidewall and a base, and a cutting element is coupled to the pre-formed segment and within the cutter pocket. The pre-formed segment is optionally made of a different material than the blade and has increased wear and/or erosion resistance compared to the blade.

Control valves can allow a well operator to steer a drill string. An exemplary control valve can include a valve body with an axial bore and a radial orifice in fluid communication with the axial bore, wherein flow passing through the axial bore passes through the radial orifice and into a piston flow channel to be in fluid communication with a piston bore to exert pressure against a piston movable within the piston bore, the piston being coupled a steering pad for applying force against the wellbore wall. A rotary valve element is disposed within the axial bore and including an actuation flow channel, wherein the rotary valve element is rotatable with respect to the axial bore to change flow through the actuation channel and the radial orifice to modify fluid pressure within the piston flow channel that is exerted against the piston.

A mill including a housing having a fluid bypass pathway, a milling feature at a longitudinal end of the housing, a chamber defined by the housing, and a piston disposed in communication with the chamber, the piston defining a fluid passageway initially aligned with the fluid bypass pathway, the piston responsive to pump pressure to move toward the milling feature, the movement misaligning the fluid passageway with the fluid bypass pathway.

A retrievable whipstock assembly for a wellbore includes a whipstock including a longitudinal body and an anchor connection, a deflection surface provided on the longitudinal body with a first engagement element, and a drilling assembly including a drill housing and a second engagement element. The second engagement element is selectively extendible between a recessed position and an extended position. In the extended position the second engagement element is engageable with the first engagement element.

A drill assembly (10) for use in trenchless subterranean boring, comprising: a drill shoe (20) having a body with a posterior portion (30) and an anterior portion (22), the latter defining a recess while the former comprises drill bits (32) disposed on a front end (34), opposing lateral sides, and flanks to assist the shoe (20) in acting as both pilot bore drilling tool and as reaming tool; a drill head (50) demount ably mounted to tire drill shoe (20) via tire recess and in communication with directional guidance means; a string of connectable drill rods (80), having a bailing end (82) and a leading end (84) when connected, and through which a drilling solution can be pumped towards tire drill shoe (20); a coupling (86) for linking tire leading end (84) to said drill head (50); and a connector (88) for connecting the trailing end (82) to a vehicle. The invention extends to a drill shoe (20) and a method of use and manufacture thereof.

In an embodiment, the present system can primarily determine the pilot bore profile of a horizontal directional drill (HDD) based on the number of rod sections added and the pitch reading from the underground transmitter at the front of the drill string (as communicated to the HDD drill rig via the walk-over locator), with such calculations being able to be made at the HDD drill rig and/or related remote display on the HDD drill rig. That is, since the length of a given rod section is known and the pitch readout is provided by the underground transmitter, the change in the overall depth of the drill string can be calculated, for example, on drill rod to drill rod basis based on rise over run geometry. The walk-over locator can then be used for a secondary confirmation of the actual depth, if conditions permit (e.g., in range of a direct walk-over).