Application of Airborne, Ground, and Borehole Geophysical Surveys to Characterize Shallow Hydrogeology in from Area Designed for Sub-Surface Drip Irrigation of Coal Bed Natural Gas Produced Water in the Powder River Basin, Wyoming
Development of coalbed natural gas (CBNG) in the Powder River Basin (PRB) of Wyoming has rapidly increased since 1997, focusing national attention on produced water management. The U.S. Department of Energy’s National Energy Technology Laboratory has utilized multi-frequency airborne, ground electromagnetic, ground resistivity, and borehole methods to characterize the near-surface hydrogeology of several areas within the PRB from 2004 through 2008. Results from the geophysical surveys demonstrate the heterogeneity of the near-surface geology and hydrology of the basin. A current study in progress is characterizing hydrologic properties at a site along the Powder River designed for produced water disposal through sub-surface drip irrigation (SDI). The study integrates hydrologic and geophysical methods to characterize changes in the near-surface produced by the SDI. The geophysical data is consistent between surveys utilizing different geophysical techniques and between surveys carried out at different times. Findings suggest that the geophysical methods applied as part of this research are suitable to address a number of issues of produced water management issues for CBNG production. Among these issues are the salinity of near surface waters both in the ground water and vadose zone and the nature and distribution of clay minerals. Geophysical surveys along with surface-water and ground-water characterization and monitoring are being used to map the nature of subsurface soil and water at the SDI site. The site study began in the spring of 2007 and will continue over the proposed 5 years that the SDI system will be used for CBNG produced water disposal. Results of the study have applications in assessing impacts of CBNG-produced water utilization and disposal within the basin.
AAPG Search and Discovery Article #90090©2009 AAPG Annual Convention and Exhibition, Denver, Colorado, June 7-10, 2009