Electrical Property Investigation of Potential Carbon Sequestration Formations

In a carbon conscious world steps are being taken to decrease the amount of CO₂ being released into the atmosphere. Geological sequestration has been proposed as a viable option for mitigating the vast amount of CO₂ being produced daily. Test sites for CO₂ injection have been appearing across the world to ascertain the feasibility of capturing and sequestering carbon dioxide. Ohio’s deep saline reservoirs are currently being investigated for their injection potential. The Mountaineer power plant, located on the Ohio River, was a pilot site for a capture and injection.

Geophysical methods, seismic and electromagnetic, play a crucial role in monitoring the subsurface pre- and post-injection. Seismic techniques have been the most popular but electromagnetic methods are gaining interest. The goal of our research is to study the effectiveness of electromagnetic methods as a monitoring tool in Ohio. We gathered core samples from numerous wells around Ohio. Specific interest was placed on reservoir targets (Mt. Simon, Middle Run, and Eau Claire) and cap rocks (Point Pleasant and Utica). The employed methods involve making resistivity and permittivity measurements on the samples in the laboratory.

We designed our own experimental core holders to make electrical measurements on brine saturated samples at ambient pressure. We collected resistivity measurements with a 4-electrode array utilizing frequencies from DC through 100 kHz. The permittivity measurements were made using a coaxial probe with frequencies ranging from 300 kHz to 3 GHz. Our research outlines the range of resistivity and permittivity values for rocks found throughout Ohio’s subsurface. This data gave us the ability to illustrate the limits of using electromagnetic methods to monitor CO₂ injection projects in Ohio.

AAPG Search and Discovery Article #90142 © 2012 AAPG Annual Convention and Exhibition, April 22-25, 2012, Long Beach, California