Mining Publication: Horizontal Trajectories of Rotary-Drilled Holes

Original creation date: January 1988

Authors: TW Goodman, J Cervik

Report of Investigations - January 1988

NIOSHTIC2 Number: 10006100

U.S. Department of the Interior, Bureau of Mines. Report of Investigations 9177, NTIS No. PB89-104087, 1988; :1-11

This Bureau of Mines report investigates the horizontal trajectory of boreholes drilled in coalbeds using the rotary drilling technique. Test holes drilled in coalbeds showed that the path of a borehole in the horizontal plane depends on drilling assembly configuration, drill bit rotation, and coalbed geologic features. An assembly that contained an 18-ft (5.5-M) long drill collar and two centralizers had the best horizontal stability evidenced by trajectories that deviated less than 16 ft (4.9 m) from a target at 1,000 ft (305 m). Removal of one of the centralizers resulted in a loss of control of hole trajectory in the horizontal plane. Generally, holes tended to turn to the right, presumably because of right-hand rotation of the bit. Deviations from the original bearing line were as much as 200 ft (61 m) or more at a depth of 1,000 ft (305 m).

Image of publication Horizontal Trajectories of Rotary-Drilled Holes
Report of Investigations - January 1988

NIOSHTIC2 Number: 10006100

U.S. Department of the Interior, Bureau of Mines. Report of Investigations 9177, NTIS No. PB89-104087, 1988; :1-11


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