US 12,312,951 B1
Fracture reactivation index (FRI) for seal integrity analysis in carbon capture and storage (CCS)
Otto Meza Camargo, Dhahran (SA); Waheed Arshad, Dhahran (SA); and Karla Olvera Carranza, Dhahran (SA)
Assigned to Saudi Arabian Oil Company, Dhahran (SA)
Filed by Saudi Arabian Oil Company, Dhahran (SA)
Filed on Apr. 26, 2024, as Appl. No. 18/647,538.
Int. Cl. E21B 49/00 (2006.01); E21B 43/26 (2006.01)
CPC E21B 49/008 (2013.01) [E21B 43/26 (2013.01); E21B 2200/20 (2020.05)] 14 Claims
OG exemplary drawing
 
1. A method for determining caprock integrity in a subsurface reservoir using a fracture reactivation index (FRI), the method comprising:
determining a principal stress associated with subsurface reservoir, the principal stress determined by a micro-fracturing test;
forming, using a mechanical earth model, a fracture network model to identify the presence and extent of natural fractures at locations in the subsurface hydrocarbon reservoir, wherein the mechanical earth model incorporates the principal stress;
determining, using the discrete fracture network, a fracture density index (FDI), wherein determining the fracture density index (FDI) comprises generating a raster map from the discrete fracture network, the raster map representing a fracture density per area;
determining Coulomb Excessive Failure Function (CEFF) values for natural fractures in the discrete fracture network, the CEFF values determined using a shear stress, a normal stress, a friction angle, a vertical stress; and
determining a fracture reactivation index (FRI) using the CEFF values, wherein a subset of CEFF values above a threshold identify a subset of natural fractures having a potential for reactivation due to a failure of caprock integrity;
comprising identifying an area for fluid injection using a map comprising the fracture reactivation index (FRI); and
performing a fluid injection into the subsurface reservoir based on the identified area.