Structural framework and fault analysis in the east-central Gulf of Mexico shelf: Implications for offshore CO2 storage

Abstract

A vast CO2 storage resource exists offshore in Cretaceous through Neogene sandstone in the DeSoto Canyon Salt Basin in the east-central Gulf of Mexico continental shelf. Understanding the structural styles, the likelihood of reactivation, and seal properties of the faults in this area is essential for selecting safe carbon storage sites and minimizing the risk of injected CO2 migrating beyond the confines of the storage complex. The DeSoto Canyon Salt Basin has variable structural styles in the basin with different insights for CO2 storage. The Mobile-Viosca Knoll shelf contains stable shelf and a large four-way structural closure, where provide favorable storage opportunities. The Destin Dome region contains three groups of peripheral faults of the Destin Fault System. Faults that strike along SHmax dip at 60°, and steeply dipping faults are predicted to have elevated risk of slip and dilation. The W-E striking fault group has an overall higher slip and dilation tendency than the other two groups under the same injection conditions. Fault seal analysis shows that elevated risk along faults occurs at sandstone-sandstone juxtaposition zones and zones with high fault throw and low SGR values. Storage plans should avoid the faults with elevated risk to ensure that the injectate will not flow into or pressurize the fault zones. Ideal injection sites within the Destin Fault System in the Destin Dome region are in hanging wall rollovers that contain low fault throw and shale-sandstone juxtapositions. Future research should focus on geomechanical, pressure, and flow simulation of the potential reservoirs and associated seals in the area of the peripheral faults.