There is provided a gap sub-assembly for electrically isolating an upstream portion of a drill string from a downstream portion of the drill string. The gap sub-assembly includes a first sub; a second sub; and a non-conductive isolation between the first sub and the second sub, the non-conductive isolation being interposed between respective shoulders of the first sub and the second sub and being interposed between respective threads of a male end of the first sub and a female end of the second sub, the non-conductive isolation comprising an insulative wrapping between at least the respective threads of the first and second subs, wherein connecting the female end of the second sub to the male end of the first sub over the insulative wrapping electrically isolates the respective threads of the first and second subs. A method for assembling such a gap sub-assembly is also provided.

A method and apparatus that includes positioning a completion string that has an internal passageway and that has an external surface that at least partially defines an external region within a wellbore; isolating a zone of the external region from a wellbore hydrostatic pressure; measuring a pressure within the external region of the isolated zone; determining whether the pressure within the external region of the isolated zone is within a predetermined pressure range; and operating a valve that controls a flow of a fluid through a flow path from the internal region to the external region of the isolated zone when the pressure within the external region is outside of the predetermined pressure range.

A control valve assembly for a downhole wellbore including a body formed partially from a magnetic material. A plunger is moveably mounted in the body. A portion of the plunger is formed from a magnetic material. A magnetic circuit having a gap is arranged within the control valve assembly. The portion of the body formed from a magnetic material defines a first portion of the magnetic circuit and the portion of the plunger formed from magnetic material forms another portion of the magnetic circuit. A solenoid is mounted at the body and is selectively activated to create a magnetic field across the gap in the magnetic circuit causing the plunger to move thereby narrowing the gap to produce a pressure pulse in the wellbore.

A fluid pressure pulse generator for a telemetry tool comprising a stator and a rotor. The stator comprising a stator body and a plurality of radially extending stator projections spaced around the stator body, whereby adjacently spaced stator projections define stator flow channels extending therebetween. The rotor comprising a rotor body and a plurality of radially extending rotor projections spaced around the rotor body. The rotor projections are axially adjacent the stator projections and the rotor is rotatable relative to the stator such that the rotor projections move in and out of fluid communication with the stator flow channels to generate fluid pressure pulses in fluid flowing through the stator flow channels. At least one of the rotor projections has an angled rotor bypass channel which moves in and out of fluid communication with the stator flow channels as the rotor rotates relative to the stator, the angled rotor bypass channel extending through or along a surface of the at least one rotor projection and having a fluid inlet and a fluid outlet downhole and lateral relative to the fluid inlet. The angled rotor bypass channel providing a self-correction mechanism causing the rotor to rotate to an open flow position when there is failure of the telemetry tool.

A motorized release device for a downhole device includes one or more dogs disposed within a guide of the downhole device. The one or more dogs may move radially within the guide relative to a central axis of the motorized release device, such that the one or more dogs may move between an engaged position and a disengaged position. The motorized release device also includes a cam that is rotatable about the central axis, such that the cam may move between a locked position and an unlocked position. The cam may block the one or more dogs from moving to the disengaged position while the cam is in the locked position. The motorized release device may also include an electronics board. The electronics board may attach to a motor that rotates the cam between the locked position and the unlocked position.

In one aspect, an apparatus for use in a drilling assembly is disclosed that in one embodiment includes a flow control device that further includes: a fluid flow path having an inlet and an outlet; an electromagnetic circuit that includes a closing member made from a soft magnetic or magnetic material as a part of the electromagnetic circuit, wherein the closing member moves from a first open position to a second closed position to close the fluid flow path to produce a pressure pulse in a fluid flowing through the fluid flow path when the electromagnetic circuit is formed.

A control valve assembly includes a body including a mud flow passage having a mud flow inlet and a mud flow outlet, a magnetic plunger slidingly mounted within the body, and a solenoid mounted at the body about the magnetic plunger. The solenoid is selectively activated to shift the magnetic plunger between a first position covering the mud flow outlet and a second position exposing the mud flow outlet allowing a pulse of mud to flow through the mud flow passage.

A control valve assembly for a downhole wellbore including a body formed partially from a magnetic material. A plunger is moveably mounted in the body. A portion of the plunger is formed from a magnetic material. A magnetic circuit having a gap is arranged within the control valve assembly. The portion of the body formed from a magnetic material defines a first portion of the magnetic circuit and the portion of the plunger formed from magnetic material forms another portion of the magnetic circuit. A solenoid is mounted at the body and is selectively activated to create a magnetic field across the gap in the magnetic circuit causing the plunger to move thereby narrowing the gap to produce a pressure pulse in the wellbore.

Well systems comprise communicating devices for use in subterranean formations. An example well system comprises a mud valve system having a stator and a rotor to modulate drilling mud flow to provide increased pulse amplitude signals up-hole for improved and faster signaling from down-hole tools while also providing for better detection capability up-hole. The improved signaling technique permits for deeper well applications.

A flow restriction tool can include a closure device having positions in which flow is permitted through the tool, in one position a flow passage is open to the flow and the closure device blocks flow through another flow passage, and in another position both passages are open to the flow, and a biasing device which displaces the closure device to the former position in response to a flow rate being less than a predetermined level. A well tool string can include an orientation tool that intermittently permits flow through a wall of the tool string to transmit orientation data via pressure pulses in a flow passage through the string, and a flow restriction tool that permits flow through one flow area when a flow rate of the flow is less than a predetermined level, and permits flow through a larger flow area when the flow rate is increased.