THE INDIAN CREEK FIELD, KANAWHA COUNTY, WV: A POTENTIAL ANALOG FOR CO2 STORAGE

Geologic storage of CO₂ in depleted natural gas fields is one mitigation option for reducing the amount of CO₂ emitted to the atmosphere. Analog studies of high-CO₂ gas fields, which are classified as containing greater than 10 wt.% CO₂, are useful to better understand the potential long-term mineralogical and geochemical effects inherent in geologic storage of CO₂. One such analog exists in the Kanawha County, WV, Indian Creek natural gas field. This field has exceptionally high CO₂ concentrations ranging between 20-83 wt.% with a mean of 65 wt.%. The gas is trapped within the lower Silurian Tuscarora sandstone, which is a medium to coarse-grained, well-rounded, pure orthoquartzite that is dominated by secondary fracture porosity. Over 40 samples obtained from a continuous well core of the Tuscarora will be compared to similar lithologies from outside of the high CO₂ field to determine differences in texture, composition, and mineralogy. This comparison, using multiple petrographic and isotopic analytical techniques, is expected to show the effect of high CO₂ concentrations on a subsurface reservoir body. Possible changes in the Tuscarora due to the high of CO₂ concentrations might include modifications of cementation, porosity, and mineralogy. Although the Tuscarora is typically tightly cemented, previous studies have interpreted areas of relatively high porosity to be the paleo-locations of trapped gas pockets or areas where clay minerals impeded quartz overgrowth formation. Therefore, this study will focus on locations within thin sections that contain high porosity, clay minerals, or fractures. Because no other analog studies within the Appalachian basin have been done, this analog study will provide first order information that can be applied to local reservoirs within the Tuscarora and similar lithologies for the purpose of geologic storage of CO₂ in the subsurface.