DEMONSTRATION OF SAFETY PLUGGING OF OIL WELLS PENETRATING APPALACHIAN COAL MINES.

Abstract

An oil well penetrating the Pittsburgh bituminous coalbed in northern West Virginia was plugged and safely mined through 3 mo later. A sensitive chemical tracer, introduced into the oil reservoir before the test, was not detected in the mine air following the plugging and during mining of the pillar and penetration of the well. Effectiveness of the plugging in preventing reservoir gas from entering the mine through the well hole was verified by continuous monitoring of the mine air for indications of sulfur hexafluoride, an inert gas detectable in amounts as minute as one-half part per billion. Expandable cement and fly ash-gel slurry were utilized to seal the well above and below the coal seam.