Horizontal trajectories of rotary-drilled holes
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Filetype[PDF-554.81 KB]


  • English
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    Details:

    • Personal Author:
    • Corporate Authors:
      United States. Bureau of Mines.
    • Description:
      "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)." - NIOSHTIC-2

      NIOSH no. 10006100

    • Subject:
    • Series:
      Report of investigations (United States. Bureau of Mines) ; 9177
    • Document Type:
      Report
    • Collection(s):
      National Institute for Occupational Safety and Health
    • Main Document Checksum:
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