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Probability of encountering coalbed discontinuities during vertical and horizontal borehole drilling

Public Domain
File Language:
English


Details

  • Personal Author:
    Houseknecht, David W.
  • Corporate Authors:
    United States. Bureau of Mines
  • Description:
    "Probabilities of encountering coalbed discontinuities during vertical or horizontal drilling in a specific coalbed can be estimated based on analysis of mined-out areas of the coalbed where the size, shape, orientation, and distribution of discontinuities are known. The resultant probability estimates can be applied to cost-risk evaluations of drilling programs proposed for exploratory, developmental, or methane drainage purposes in undeveloped areas of that coalbed. Data compiled from mine maive hypothetical drilling programs--one for drilling vertical boreholes. Analysis based on a mined-out area of the Beckley coalbed indicated that vertical methane drainage boreholes spaced 1,000 feet apart in a square grid pattern would each have a 29-percent probability of encountering a discontinuity in a geologically unexplored area of the coalbed. It was also determined that exploratory vertical drilling could locate most of the discontinuities if a borehole spacing of 2,500 feet were used. For horizontal drainage boreholes in the Beckley coalbed, the analysis indicated a linear relationship between hole length and the probability of encountering a discontinuity." - NIOSHTIC-2

    NIOSHTIC no. 10002361

  • Subjects:
  • Series:
    Mining Publications
  • Subseries:
    Report of Investigations
  • Document Type:
    Text
  • Genre:
    Report
  • CIO:
    National Institute for Occupational Safety and Health (NIOSH)
  • Topic:
    Workplace Safety & Health
  • Location:
    North America
  • Pages in Document:
    ii, 21 numbered pages
  • NIOSHTIC Number:
    nn:10002361
  • Collection(s):
  • Main Document Checksum:
    urn:sha-512:599a99c00cfe0dcf9ec98e94a25ed94f2f9cbbb2d450735986abd5fdb3f8b4f2052219a593ff771c97f3e41cde62cd24d56d20561df92d66ab8a7d25ad3ed852
  • Download URL:
  • File Type:
    Filetype[PDF - 1.13 MB ]
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