This invention relates to an apparatus and method for controlling a part of a downhole assembly, and to the downhole assembly. The downhole assembly may include a steering mechanism adapted to steer a drill bit in a chosen direction, and the steering mechanism may be the part of the downhole assembly which is controlled by the apparatus. The downhole assembly includes a drill bit and a motor, the motor having a stator and a rotor, the rotor being driven to rotate relative to the stator by the passage of a drilling fluid along a drilling fluid path between the rotor and the stator. The motor has a conduit through which the drilling fluid can pass, the conduit being separate from the drilling fluid path, and the apparatus has a valve to control the flow of drilling fluid through the conduit. The invention provides a robust and reliable means of delivering high pressure drilling fluid downstream of the motor.

A centralizer assembly replaces an existing centralizer of a wireline tool so the tool can be used with smaller casing, such as casing smaller than 6-in. The assembly includes first and second centralizer units that replace the existing centralizer on a mandrel. Each unit has a sleeve that fits in a recess of the mandrel, and each unit has slider blocks disposed together in the recess on opposing sides of a divider on the sleeve. Arms hingedly connected to the blocks on each unit connect together at a joint having a roller for engaging in the casing. On each unit, a common pin is disposed through the slider blocks, and biasing elements on the common pin bias the blocks toward one another with different amounts of bias.

A stabilizer design for improving the likelihood of recovery of a drill string when obstructions are encountered in a wellbore is disclosed herein. The stabilizer includes a tubular body, a track, and a stabilizer blade. The track is disposed along the tubular body. The stabilizer blade is operatively coupled to the track and is configured to slide along the track from a first position to a second position.

A method of drilling a wellbore includes running a drilling assembly into the wellbore through a casing string, the drilling assembly having a tubular string, a stabilizer, and a drill bit; applying a force to an arm of the stabilizer, thereby causing the arm to retract; and removing the stabilizer and the drill bit from the wellbore.

A rotary steering tool includes a steering member configured to move between a retracted configuration and an extended configuration. The rotary steering tool also includes a pump configured to pump a fluid, a power source independent of the downhole motor, the power source configured to power the pump, and a piston in fluid communication with the pump. The piston is configured to apply a force to the steering member to move the steering member from the retracted configuration to the extended configuration when the pump pumps the fluid at an operating system pressure. The rotary steering tool includes a controller to operate the pump at a range of operating system pressures, and a variable pressure control valve. The variable pressure control valve adjusts the operating system pressure between the range of operating system pressures to adjust the force applied to the steering member.

The present invention relates to a stabilizing system (100, 200, 300) adapted to be used in a drilling system, wherein the transversal diameter of the stabilizing system (100, 200, 300) increases when drilling forces are applied onto the stabilizing system (100, 200, 300). The invention further comprises a corresponding method for drilling a hole.

A centralizer system and a method for centralizing a casing in a well bore before cementing of the casing in the well bore is disclosed, where the centralizer system comprises at least one centralizer which is adapted for mounting on the casing where the at least one centralizer comprises a receiving unit capable of receiving a wireless signal in form of a pressure wave and a wireless signal generator for generation and transmission of a wireless signal in form of a pressure wave which the receiving unit of the at least one centralizer is capable of receiving. The at least one centralizer is further configured such that the centralizer is activated for centralizing of the casing when the receiving unit receives a wireless signal transmitted by the signal generator.

An apparatus for use downhole is disclosed that, in one configuration includes a downhole tool configured to operate in an active position and an inactive position and an actuation device, which may include a control unit. The apparatus includes a telemetry unit that sends a first pattern recognition signal to the control unit to move the tool into the active position and a second pattern recognition signal to move the tool into the inactive position. The apparatus may be used for drilling a subterranean formation and include a tubular body and one or more extendable features, each positionally coupled to a track of the tubular body, and a drilling fluid flow path extending through a bore of the tubular body for conducting drilling fluid therethrough. A push sleeve is disposed within the tubular body and coupled to the one or more features. A valve assembly is disposed within the tubular body and configured to control the flow of the drilling fluid into an annular chamber in communication with the push sleeve; the valve assembly comprising a mechanically operated valve and/or an electronically operated valve. Other embodiments, including methods of operation, are provided.

A centraliser comprises longitudinally spaced collars connected by a plurality of springs, each of the springs comprising two or more bow sections.

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.