Uncontrolled produced water releases result in elevated soil electrical conductivity (EC) which can be costly to characterize. This study sought to determine the best methods for field evaluation of EC using four methods at three legacy sites. Soil EC data were collected utilizing a Profiler EMP-400 surface electromagnetic (EM) survey, a Geoprobe HPT-EC meter for depth sampling, and continuous core sampling subjected to 1:1 soil/water extracts measured with field EC meters and 1:1 soil/water laboratory extracts measured with laboratory-precision EC instruments. These methods were compared with regression equation predictive models to determine which field measurement method best predicted laboratory-determined EC.
The models were also evaluated to determine if they were transferable between sites and thus transferable to future project sites. The models developed from two of the sites resulted in relatively good predictions of laboratory results and were transferable between these two sites. The field screening data resulted in the best predicted data set; however, the Geoprobe data were also good. These results did not hold true for the third site where the data collection methods varied slightly. The EM surveys provided relative levels of EC, but did not result in a strong enough model for use as a stand-alone tool.

Primary Author/Conference Presenter:
Robin Bay
Habitat Management, Inc.
Englewood, Colorado

Kenneth E. Carlson, Habitat Management, Inc., Englewood, CO
Kerry L. Sublette, University of Tulsa, Tulsa, OK
Brad Stevens, Energy & Environmental Research Center, Grand Forks, ND