Lessons Learned from Recent Longwall Mine-By Cases with Uncemented Casings

Details

• Personal Author:
  Kim BH ; Su D ; Tulu B ; Zhang P
• Description:
  Over 2,000 shale gas wells have been drilled in the longwall reserves of the Pittsburgh Coal Seam. When gas wells are in the vicinity of longwall mining, casing deformations are likely to occur due to longwall-induced subsurface movements and abutment stresses. One way to prevent casing deformation is to use a cementing alternative by leaving production casing uncemented. This paper presents three mine-by cases in which shale gas wells were in the chain pillars and the production casings were uncemented. These cases represent mine-by scenarios under shallow, medium, and deep cover. Casing deformations were measured with multi-finger caliper survey and predicted with numerical modeling. These mine-by case studies provide a general demonstration of how uncemented casing can uncouple production casing from longwall-induced stresses and deformations. Based on measurements of casing deformations and numerical modeling, the factors mentioned above are further analyzed to indicate in what conditions a cementing alternative may not eliminate production casing deformations. The knowledge gained from the mine-by case studies would help longwall operators and gas companies to optimize pillar design and casing design, thus minimizing the influence of longwall mining in the stability of shale gas wells in longwall pillars. [Description provided by NIOSH]
• Subjects:
  Geology Mining Occupational Health Safety
• Keywords:
  Coal Mines Longwall Mining Rock Mechanics Underground Mines
• 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:20070431
• Citation:
  58th US Rock Mechanics/Geomechanics Symposium, June 23-26, 2024, Golden, Colorado. Alexandria, VA: American Rock Mechanics Association (ARMA), 2024 Jun; :ARMA-24-0262
• 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-512:489d4b16a27db0735ead7fc1549f3231c0c126a169cd1ec9313cc11053bc4eeb1cdfc664b501f79618deaded17ab1b541a34ba8810eab64e19e4840bcf33db0a
• Download URL:
  https://stacks.cdc.gov/view/cdc/215712/cdc_215712_DS1.pdf
• File Type:
  [PDF - 1.93 MB ]