Characterization of Accidental Spills and Releases Affecting Groundwater in the Greater Wattenberg Area of the Denver-Julesburg Basin in Northeastern Colorado

摘要

Public concern about the potential effects of unconventional oil and gas development on water quality has grown in recent years. In this study, we considered accidental spills and releases that occurred from 2007 to 2014 in the Greater Wattenberg Area (GWA), an area of intensive oil and gas extraction located within the Denver-Julesburg Basin in northeastern Colorado. Our objective was to quantify the occurrence rates of (1) all spills and (2) spills determined by the operator to have caused groundwater impacts. Additionally, for spills affecting groundwater, we analyzed characteristics including facilities and equipment involved, causes, and resolution times in order to identify recommendations for improved regulatory or operational practices. Spills and releases were identified from publicly-available reports collected by the Colorado Oil and Gas Conservation Commission (COGCC). Spills were identified as having potentially impacted groundwater based on an operator-reported field present on the reports. Groundwater impacts were verified for this subset of spills by reviewing the narrative description of the incident and the supporting documents (e.g., consultant reports, laboratory data) available in the COGCC database. Additional information collected included the causes of the spills, the facility types, and the time required for resolution of spills. To determine spill occurrence rates, the number of annual spills was compared to several annual indicators of oil and gas development, including the volumes of oil and water produced and the number of active producing wells in the GWA.