HR: 0800h
AN: H21E-1070    [Abstracts]
TI: Using Airborne and Ground Electromagnetic Surveys and DC Resistivity Surveys to Delineate a Plume of Conductive Water at an In-Channel Coalbed Methane Produced Water Impoundment Near the Powder River, Wyoming
AU: * Lipinski, B A
EM: BAL17@pitt.edu
AF: University of Pittsburgh Department of Geology and Planetary Science, 200 SRCC Building 4107 O'Hara Street, Pittsburgh, PA 15260 United States
AU: Harbert, W
EM: harbert@pitt.edu
AF: University of Pittsburgh Department of Geology and Planetary Science, 200 SRCC Building 4107 O'Hara Street, Pittsburgh, PA 15260 United States
AU: Hammack, R
EM: richard.hammack@netl.doe.gov
AF: Department of Energy National Energy Technology Laboratory, 626 Cochrans Mill Road, Pittsburgh, PA 15236 United States
AU: Sams, J
EM: jsams@netl.doe.gov
AF: Department of Energy National Energy Technology Laboratory, 626 Cochrans Mill Road, Pittsburgh, PA 15236 United States
AU: Veloski, G
EM: garret.veloski@netl.doe.gov
AF: Department of Energy National Energy Technology Laboratory, 626 Cochrans Mill Road, Pittsburgh, PA 15236 United States
AU: Smith, B D
EM: bsmith@usgs.gov
AF: United States Geological Survey Crustal Imaging and Characterization Team, PO Box 25046 Denver Federal Center, Denver, CO 80225 United States
AB: Development of coal bed methane (CBM) in the Powder River Basin of Wyoming and Montana has significantly increased since 1997. Production of CBM involves withdrawing groundwater from the coal bed to lower the hydrostatic pressure thereby allowing methane to desorb from the coal. The water co-produced with CBM is managed by storing it in impoundments until it can infiltrate to the groundwater, be used for beneficial purposes, or be discharged to surface streams. Skewed Reservoir was constructed as a research site to evaluate disposal of CBM water through infiltration ponds constructed by damming ephemeral streams. Geochemical data collected from monitoring wells placed downgradient of the reservoir detected a plume of water with total dissolved solids concentrations an order of magnitude higher than the CBM water stored in the impoundment. Infiltrating CBM water is suspected to have dissolved salts that were present in the unconsolidated materials beneath the reservoir. A geophysical investigation of the Skewed Reservoir area was conducted in July of 2004 to map the horizontal and vertical extent of the plume and to possibly identify the source of solutes to the infiltrating water. The Department of Energy's National Energy Technology Laboratory contracted Fugro Airborne Surveys to fly their RESOLVE frequency domain airborne electromagnetic (AEM) system with 50-m line spacing at the site. A ground investigation was completed at the same time as the airborne survey. Five 2-D dipole-dipole resistivity surveys and one 3-D pole-dipole survey were conducted using the AGI SuperSting R8/IP multi-channel resistivity imaging system. Additionally, ground conductivity measurements were recorded along each resistivity line using a Geophex GEM-2 multi-frequency ground conductivity meter. All geoelectrical measurements were inverted to obtain the subsurface conductivity distribution. Inversions were constrained using results of downhole borehole induction logs. Results were compared to geological and geochemical data collected from on-site monitoring wells. The geophysical methods accurately delineated the CBM water plume. Differences in the inversion results were observed and are discussed. The AEM data may also prove useful in identifying potential problem areas for locating future in-channel storage impoundments.
DE: 1829 Groundwater hydrology
DE: 1831 Groundwater quality
DE: 1878 Water/energy interactions
SC: Hydrology [H]
MN: 2004 AGU Fall Meeting