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Longwall-Induced Shale Gas Well Casing Deformations and Stresses-Critical Effects of Geologic and Geometric Parameters

Public Domain


Details

  • Personal Author:
  • Description:
    This paper summarizes geo-mechanical findings from the ongoing Gas Well Stability research at the National Institute for Occupational Safety and Health (NIOSH)-in particular, the critical effects of geologic and geometric parameters on longwall-induced gas well casing deformations and stresses. Overburden geology is one of the most important factors affecting the longwall-induced casing deformations and stresses. The large contrast of bending stiffness at the soft-to-hard rock interfaces has been found to induce large casing deformations and stresses. Overburden depth to the mining seam is also an influential factor. Shallow overburden depth induces large horizontal displacement and resulting casing deformation and stress, due to smaller longwall-induced vertical pressure. Deep overburden depth induces large longwall-induced vertical pressure, which tends to limit longwall-induced horizontal movement. Strata dip would magnify longwall-induced deformations by 20% for each degree of strata dip with down dip longwall excavation. The gas well setback distance is a critical geometric parameter. The effect of longwall-induced deformation decreases exponentially as the setback distance increases. Longwall-induced casing deformation and stress will be mitigated or totally uncoupled if the production casing is uncemented. Longwall-induced fracture zone height is linearly propositional to the panel width. [Description provided by NIOSH]
  • Subjects:
  • Keywords:
  • Series:
    Mining Publications
  • ISBN:
    9780979497599
  • Publisher:
    American Rock Mechanics Association (ARMA)
  • Document Type:
    Text
  • Genre:
    Proceedings
  • Place as Subject:
  • CIO:
    National Institute for Occupational Safety and Health (NIOSH)
  • Division:
    PMRD - Pittsburgh Mining Research Division
  • Topic:
    Workplace Safety & Health
  • Location:
    North America
  • NIOSHTIC Number:
    nn:20070430
  • Citation:
    58th US Rock Mechanics/Geomechanics Symposium, June 23-26, 2024, Golden, Colorado. Alexandria, VA: American Rock Mechanics Association (ARMA), 2024 Jun; :ARMA-24-0789
  • Federal Fiscal Year:
    2024
  • Peer Reviewed:
    False
  • Source Full Name:
    58th US Rock Mechanics/Geomechanics Symposium, June 23-26, 2024, Golden, Colorado
  • Collection(s):
  • Main Document Checksum:
    urn:sha-512:262fe38cf92556423b1f585fcba06ebb1ae79892ff2e37b4d1e273b73ce35fa843a030e872bd0d35f9ff40ea791aa26a8e831fb2f11a36d47141e8cc434465f3
  • Download URL:
  • File Type:
    Filetype[PDF - 540.22 KB ]
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