Conoco Inc.

Emrys H Jones, Jr

Ronald W Umphrey

Pramod C Thakur

Stephen D Lauer

Thomas R Miller

Charles E Mason

A process for controlling the direction of advance of a generally horizontal borehole extended through a subterranean coal-bearing formation by a rotary drilling operation. As the drill string is rotated in the hole, the advance of the drill bit is guided along a designated path by repeatedly deflecting the drill string from its axis in a constant radial direction. The drill string may also be centralized and the deflection operation carried out either within or outside of the drill-pipe segment between the bit and the centralizer. A deflection unit includes a plurality of deflector pads disposed about the periphery of a segment of the drill pipe. The deflector pads are cyclicly actuated to sequentially place each pad in an extended position at a constant rotational position of the drill pipe segment.

Method and apparatus for rotary drill guidance

Rotary process and apparatus for drilling a borehole through a subterranean formation in which the path of a rotary drill bit is varied by deflecting the drill string in response to the pulsating flow of drilling fluid through the drill string. The pulsating drilling-fluid flow is synchronized with the rotation of the drill string by generating a function representative of the rotational position of the drill string and, in response to this function, diverting a portion of the drilling fluid through a secondary line. Flow through the secondary line is controlled by a valve which is opened and closed in synchronization with the rotational position of the drill string. The diverted fluid is supplied to the drilling fluid source for recirculation.

Rotary drill indexing system

A variable diameter drill rod stabilizer including an inner piston having cam surfaces which bear against wall engaging segments. Movement of the piston axially within a drill rod section by differential pressure of a fluid flowing through a passage in the piston moves the wall engaging segments radially and controls the diameter of the stabilizer.

Variable diameter drill rod stabilizer

A device for placement between a rotary drill motor and a drill rod for use in pumping instruments down the drill rod. The device has pressure seals at each end and an opening for an instrument cable which slides through the opening as the instruments are pumped down the drill rod.

Pressure seal for pumping instruments through drill rod

A drilling fluid circulation system for containing drilling cuttings, gas and drilling fluid in a closed loop. The system includes a separator having two sealed compartments, one for settling out drilling cuttings and one for holding clean drilling fluid. A fine solids separator is provided between the two compartments, and a gas exhaust line for conducting gas released from the returning drilling fluid is provided to conduct the produced gas to a safe location away from the working area. A solids discharge device is provided for removing settled drilling cuttings.

Drilling fluid circulation system

A heavy cylinder having an axial flow passage is pumped down a rotary drill string to a position adjacent a drill bit to cause an in-seam horizontal drill to be guided in a downward direction. The cylinder can be removed with a latchable retrieval tool after the path of the borehole is sufficiently altered.

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Westover, WV, United States of America

Emrys H Jones, Jr