04953638 is referenced by 47 patents and cites 16 patents.

A method of boring a hole in the earth such as for passing under obstacles, not limited, but including roadways, rivers, dikes, canals or other inexcessible areas where it is impossible to trench a ditch including the steps of advancing a rotating drill string in a direction inclined to the earth's surface to establish a borehole, stopping the rotation and advancement of the drill string, aligning the drill pipe so that the drill bit is inclined at an angle relative to the axis of the drill string towards a new direction desired for the borehole, advancing the drill string and drill bit a short distance without rotation, resuming rotation advancement of the drill string for a short distance, sequentially repeating the steps of advancing the rotationally aligned drill string without rotation to move the drill bit in the newly desired direction, followed by rotation with simultaneous advancement until the new direction of drilling is achieved, after which, until a still different direction is desired, drilling is continued by simultaneously rotating and advancing the drill string.

Title
Method of and apparatus for drilling a horizontal controlled borehole in the earth
Application Number
7/211889
Publication Number
4953638
Application Date
June 27, 1988
Publication Date
September 4, 1990
Inventor
Richard P Dunn
Wichita Falls
TX, US
Agent
Banner Birch McKie & Beckett
Assignee
The Charles Machine Works
OK, US
IPC
E21B 10/00
E21B 7/06
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