InSAR-IDENTIFIED SURFACE DEFORMATION RESULTING FROM COAL BED METHANE PRODUCTION IN THE POWDER RIVER BASIN, WYOMING

In the past two decades, Interferometric Synthetic Aperture Radar (InSAR) has been used to document surface displacements resulting from a myriad of anthropogenic and non-anthropogenic causes. InSAR allows for the delineation of these features with a spatial resolution that is orders of magnitude greater than traditional leveling techniques and even the most rigorous Global Positioning System (GPS) studies. Areas as large as 100 x 100 kilometers can be evaluated with a vertical resolution (representing deformation) of less than 1 cm. One of the more recent applications of InSAR is the evaluation of subsidence resulting from groundwater withdrawal. InSAR has proven an invaluable tool in assessing aquifer system response to groundwater use in the arid West as well as other locations.

This study documents surface deformation resulting from Coal Bed Methane (CBM) production within the Powder River Basin in Eastern Wyoming. CBM production involves pumping large volumes of water (as much as 68,000,000 barrels or 8,700 acre-feet, per month, basin wide). Research performed at a newly established InSAR processing laboratory at the South Dakota School of Mines and Technology has documented multiple sites within the Powder River Basin where several centimeters of surface subsidence has occurred over areas as large as 200 square kilometers. These results may have implications for potential efficiency improvements in CBM production as well as for improved oversight and water management in the region.