Strategies to De-Risk Faults in the Subsurface for CO2 Storage: A Case Study from Smeaheia

Abstract

Summary Developing an accurate understanding of fault growth can aid risk management of sites for CO2 storage purposes. Areas of fault interaction lead to differences in the stress field, resulting in an increased strain, which is often accommodated by a high intensity of deformation bands and/or fracturing alter the permeability of the faults. Hence, detecting areas of interaction of pre-existing structures may indicate locations of high risk in terms of the fault’s hydraulic properties. The Vette Fault Zone (VFZ), bounding the Alpha prospect within the potential CO2 Smeaheia storage site developed from a minimum of seven fault segments. Using data from the adjacent Tusse Fault Zone (TFZ), we can identify potential areas of high-risk, where fluids may have the ability to flow across or along the VFZ. The TFZ and VFZ have a high seal potential through gouge and smear mechanisms. Instead of any membrane breaching, areas of high risk have been identified at locations of relict fault-fault intersections where the initial displacement and area of overlap is high, and corresponds with the spill point of Troll East. Using the same assumptions for the VFZ, we can observe one potential high-risk zone, which occurs within the area of potential CO2 accumulation.