Assessment of Hydrocarbon Seepage on Fort Peck Reservation, Northeast Montana: A Comparison of Surface Exploration Techniques

Surface exploration techniques have been employed in separate study areas on the Fort Peck Reservation in northeastern Montana. Anomalies associated with hydrocarbon seepage are documented in all three areas and a variety of surface exploration techniques can be compared. In a small area with established production, head gas and thermal desorption methods best match production; other methods also mapped depletion. In a moderate-size area that has prospects defined by 3D seismic data, head gas along with microbial, iodine, and Eh soil anomalies are all associated with the best hydrocarbon prospect. In a large area that contains many curvilinear patterns observed on Landsat images, results are preliminary. Reconnaissance mapping of magnetic susceptibility has identified a potential prospect; subsequent soil gas and head gas surveys suggest hydrocarbon potential