CONDUCTIVITY DEPTH IMAGING OF AREAS OF SHALLOW BRINE
PLUMES AT THE USGS OSPER SITE, OSAGE CO. OKLAHOMA
Bruce D Smith*
James K. Otton
Robert A. Zielinski
U.S. Geological Survey
PO Box 25046, MS973
Denver Federal Center
Denver, CO 80225
Voice: 303-236-1399
Fax: 303-236-3200
E-mail: bsmith@usgs.gov
Marvin M. Abbott
U.S. Geological Survey
Okalahoma City, OK
Hoaping Huang
Geophex
Raleigh, NC
Alan J. Witten
University of Oklahoma
Norman OK
Ground based electrical conductivity and resistivity geophysical surveys and borehole geophysical logging were done at the two OSPER (Osage-Skiatook Petroleum Environmental Research) sites from October 2000 through August 2004. The geophysical surveys map areas of very high subsurface electrical conductivity caused by high concentration of subsurface chloride-rich water. The apparent conductivity maps were used to guide drilling and sampling of the site. Borehole natural total gamma ray and electrical induction conductivity logs of shallow project drill holes help constrain the interpretation of the ground geophysical surveys. Borehole conductivity logs and laboratory measurements of extractable chloride in core samples were used to derive a correlation function between chloride content and electrical conductivity. In addition, borehole conductivity logs were used to calibrate ground conductivity survey measurements as a function of frequency. Images of subsurface conductivity can be used to map the subsurface extent of plumes and to estimate the possible volume of chloride.