Matching Grant: Geochemical Analysis of Surface and Shallow Gas Flux and Composition Over a Proposed Carbon Sequestration Site in Eastern Kentucky

Over the next four years the Kentucky Geological Survey at the University of Kentucky will be involved in field tests that will evaluate the ability to sequester carbon dioxide (C02) in geologic reservoirs. The tests, to be performed nationwide, are part of a nationwide strategy to reduce human input of C02 into the atmosphere. Carbon dioxide is a non-toxic and non-flammable gas derived, in part, from the burning of fossil fuels such as coal, oil, and gas. Volumetrically, however, C02 is the main greenhouse gas responsible for global warming. "Sequester" refers to the process of capturing and storing C02 so that it does not enter into the atmosphere. Geological sequestration is the developing technology of injecting and storing C02 in geologic reservoirs, which act as containers below the earth's surface. The C02 used for injection could be captured, for example, from coal-fired or ethanol plants. Worldwide and in Kentucky, the ability of geologic reservoirs to act as effective containers is demonstrated by the presence of oil and gas trapped in such reservoirs for millions of years. For geologic sequestration to be effective, C02 must also remain in the reservoirs for significant time periods, that is, thousands of years and longer. Geologic reservoirs, however, are not always perfect containers, and injected C02 will tend to migrate upward due to buoyancy forces. Therefore, it will be necessary to monitor sequestration projects to ensure that injected C02 remains in the target reservoir. The monitoring process, called "Monitoring, Mitigation, and Verification," will use a variety of geologic, geochemical, and geophysical technologies to verify where injected C02 resides in the geologic reservoir. The Kentucky Geological Survey has recently been awarded a grant from the U.S. Department of Energy to develop geochemical techniques that could be used to detect injected C02 that has leaked from geologic reservoirs to the surface. Leakage could occur, for example, along abandoned wellbores used to produce oil or gas, or along faults. Leakage would produce a characteristic geochemical signature in the soil zone that would be detectable with field and laboratory techniques. The overall goal of the project is to characterize the geochemical properties (gas flux and composition) of the soil zone in areas overlying possible carbon sequestration sites in Kentucky. Results of the project will aid in the evaluation of possible sequestration sites by identifying possible leak points before injection. Once a sequestration project begins, the pre-injection database will provide a reference for recognizing leakage that might occur as a result of leakage. If geologic carbon sequestration and associated technologies are successful, Kentucky will be in a better position to realize the economic benefits of its energy resources. Moreover, it will be able to do so while minimizing greenhouse gas emissions, which will mitigate resent warming trends thereby preserving the quality of life for Kentuckians.