Surface and Subsurface Characterization of a Carbon Sequestration Pilot Site: San Juan Basin, NM

Henthorn, Brian¹, Tom Wilson¹, Art Wells² (1) West Virginia University, Morgantown, WV (2) National Energy Technology Laboratory, Pittsburgh, PA

Successful sequestration of CO2 requires that the majority of injected CO2 remain underground for hundreds to thousands of years. Evaluation of site integrity is important in the design and implementation stages of the sequestration effort. This study presents some of the background evaluation undertaken of a Fruitland coal pilot sequestration site located in the San Juan basin. The study includes comparison of fracture traces measured in the field and in high resolution QuickBird satellite imagery, along with multi-frequency terrain conductivity surveys and subsurface maps of the surrounding area.

Prominent fracture systems are exposed along the edges of mesas formed in the nearly flat-lying Eocene age San Jose Formation. Fracture trend varies considerably, however, rose diagrams reveal two prominent fracture sets: one trending ~N30E and the other ~N45W. Analysis of the QuickBird image reveals similar variability along with two prominent sets: one trending N35E and another smaller set trending N50W. Previous studies in the area suggest that the face cleat orientation and direction of preferential flow during CO2 injection will follow this NE trend. The site lies in the "High Rate Fairway" near a structural low in the Fruitland Formation. Subsurface maps will help determine whether smaller scale folds and faults similar to those observed to the northwest in the Cedar Hill area exist. If present, they may exert additional control on CO2 flow patterns and serve as potential avenues for CO2 escape. The study will help National Energy Technology Laboratory scientists position tracer and soil monitors at the site.