MAPPING BEDDED SALTS OF THE SILURIAN SALINA GROUP IN PENNSYLVANIA FOR ENERGY STORAGE APPLICATIONS

The Salina Group is an extensive Silurian-age bedded evaporite sequence deposited over much of the northeastern United States. Considered a regional geologic seal, these formations have been penetrated by oil and gas wells and geophysical logging efforts for decades. Pennsylvania’s Carbon Sequestration Technical Assessment Project (2009), mapped the structure and thickness of the Salina at the group level, but did not interpret, correlate or map individual evaporite units. Current work focuses on interpretation, correlation and mapping of the structure and thickness of individual Salina formations using geophysical log data from Pennsylvania’s Exploration and Development Well Information Network (EDWIN) with an interest in thick salt beds with minimal anhydrite or dolomite. A recent Salina salts investigation in West Virginia and Ohio identified a thick F4 salt section bisected by a 30 foot thick section of anhydrite. Following this salt deposit into northwestern Pennsylvania shows a major thinning and even elimination of this anhydrite bed.

Due to the amount of CO₂ emitters, deep and complex geology of the region, and significant interest in CO₂ storage within the basin, extensive research has characterized CO₂ reservoirs in southwestern Pennsylvania. Significantly less work has been done to establish the extent, thickness, and properties of seals for these reservoirs. Although solution mining technology is mature, it has more recently been considered for the purpose of constructing caverns in salt for storing various gases and fluids. General industry consensus is that a 100 foot thickness is optimum for insuring cavern wall integrity and a depth greater than 2500 feet is necessary to maintain CO₂ in a supercritical state. This data will be critical for operators interested in CO₂ storage in deep saline formations, as well as for those operators considering developing mined caverns for petroleum hydrocarbon or hydrogen storage. This work will provide maps that have not yet been compiled for the state and will include depth to structure maps, thickness maps, and reservoir characterization maps where data is available. The conclusions of this work will be critical to operators for decision-making regarding local and regional CO₂ storage projects as well as funding decisions regarding CO₂ and hydrogen hubs.