Analyzing Shale Gas Well Casing Deformation in Pittsburgh Seam Longwall Chain Pillars: A Case Study Integrating Numerical Methods and Field Monitoring

Details

• Personal Author:
  Khademian Z ; Kim BH ; Su D ; Tulu IB ; Zhang P
• Description:
  In the Northern Appalachian region of the U.S., the coexistence of longwall coal mining and shale gas operations is a prominent feature. The gas wells in the vicinity of the longwall operations entail the potential for casing deformations arising from mining-induced subsidence and abutment stresses. Researchers at the Pittsburgh Mining Research Division (PMRD) of the National Institute for Occupational Safety and Health (NIOSH) have been employing a combination of field monitoring and calibrated numerical modeling methods to formulate engineering strategies for assessing the effects of longwall mining operations on gas well casing integrity and implementing measures to mitigate potential damage. This paper introduces the numerical modeling approach developed by PMRD researchers and verifies it by comparing the model's predictions of longwall-induced casing deformations with measurements from shale gas wells located in the gate road chain pillar of the Pittsburgh coal seam longwall operation. The longwall panels adjacent to gas well chain pillars operate at a depth of approximately 313 meters, with a mining height of 2.1 meters and panel widths ranges between 450 to 480 meters. The gas well is constructed with fully cemented surface and intermediate casings, with the production casing left uncemented from the surface down to below the Pittsburgh coal seam. The model predicted that, following the first panel mining, the production casing would remain deformation-free, as the maximum predicted intermediate casing deformation falls below the annular space between the intermediate and production casing. This model prediction was subsequently confirmed through casing deformations monitored using a multi-finger caliper survey following the mining of the first panel. [Description provided by NIOSH]
• Subjects:
  Coal Coal Mining Mining Occupational Health Safety
• Keywords:
  Coal Mining Longwall Mining Monitoring Systems Rock Mechanics Stress Subsidence
• Series:
  Mining Publications
• ISBN:
  9780979497599
• Publisher:
  American Rock Mechanics Association (ARMA)
• Document Type:
  Text
• Genre:
  Proceedings
• Place as Subject:
  OSHA Region 10 ; OSHA Region 3 ; Pennsylvania ; Washington
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Division:
  PMRD - Pittsburgh Mining Research Division ; SMRD - Spokane Mining Research Division
• Topic:
  Workplace Safety & Health
• Location:
  North America
• NIOSHTIC Number:
  nn:20070426
• Citation:
  58th US Rock Mechanics/Geomechanics Symposium, June 23-26, 2024, Golden, Colorado. Alexandria, VA: American Rock Mechanics Association (ARMA), 2024 Jun; :ARMA-24-0608
• Federal Fiscal Year:
  2024
• Peer Reviewed:
  False
• Source Full Name:
  58th US Rock Mechanics/Geomechanics Symposium, June 23-26, 2024, Golden, Colorado
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:c49dbb66d8489aeb8f582deb9c71e7b761242a21406320a9cb795de399adabb1fe7471648e138268aecc4281122f3015ffa0c3682b97537021d3621a22258c37
• Download URL:
  https://stacks.cdc.gov/view/cdc/215707/cdc_215707_DS1.pdf
• File Type:
  [PDF - 1.92 MB ]