ABANDONED OIL AND GAS WELLS IN PENNSYLVANIA: WELL ATTRIBUTES AND EFFECTIVE PERMEABILITY

Abstract

More than three million abandoned oil and gas wells exist in the U.S., and information on many of these wells is lost. Recent measurements of 88 abandoned wells in Pennsylvania show that they can act as leakage pathways and may be a significant source of methane emissions to the atmosphere. Methane is a short-lived climate forcer with a high global warming potential, making it an important greenhouse gas to address in near-term climate change mitigation. Geospatial proximity analysis that combines available public databases from the Pennsylvania Department of Environmental Protection and the Pennsylvania Department of Conservation and Natural Resources with historical documents is used to determine the likely depth, producing formation, well type, and coal seam intersections of each measured well. Effective permeability values are calculated for each measured abandoned well to quantify the combined effect of all leakage pathways within and around the wellbores. A multiple linear regression of the well depth, well type, producing formation, and coal seam intersection, featuring corresponding attribute certainty scores, indicates that, collectively, these conditional variables cannot explain the variability observed in effective permeability values.