ASSESSING THE FEASIBILITY OF CARBON STORAGE IN THE VIRGINIA VALLEY AND RIDGE: RESULTS FROM RECENT DRILLING IN SOUTHWEST VIRGINIA

Recent technological advances and legislative incentives have spurred an unprecedented level of interest in carbon capture and storage (CCS) in the United States with much of that interest centered around petroleum bearing basins. The Appalachian basin is one such area, with a history of coal and petroleum extraction as well as major CO₂ emitting non-petroleum industrial facilities such as cement and steel production, which could benefit from CCS adoption. Virginia Tech has partnered with industrial partners in Southwest Virginia to explore the feasibility of a commercial scale CCS facility in the footwall of the Catawba Syncline – Pulaski Thrust system. The fold-and-thrust Appalachians are a difficult environment to characterize due to the complex structural geology and the paucity of seismic reflection and drilling data. To advance CCS in the Appalachian Region and investigate the Catawba Syncline – Pulaski Thrust system for CCS potential, the project team has performed exploratory drilling, geologic modelling, and numerical simulations at our study site.

Three kinematically feasible geologic models were developed for the study site based on surface mapping and geologic principles. The Siluro-Devonian Oriskany Sandstone, a common petroleum reservoir in the region, was identified as a potential CO₂ storage reservoir with the overlying Millboro shale acting as the primary seal. Numerical simulations were performed that suggested these structures could store over fifty million metric tons of CO₂.

Following the simulation study, a 2,500 ft exploratory borehole was drilled in the up-dip section of the Catawba Syncline to access the potential reservoir unit and assess its storage potential. Core characterization and density logging were used to interpret the penetrated geologic units and a detailed stratigraphic column will be presented. This works shows that the borehole successfully penetrated the Millboro shale, the entire Siluro-Devonian interval, and the upper Martinsburg formation. Porosity and density logging identified several high porosity (10-20%) intervals in the Oriskany and Martinsburg formation that could potentially store large volumes of injected CO₂. Future work will involve deeper drilling and 2D seismic acquisition to further characterize the study site for future CCS development.