Structures and petroleum prospects of the Saramaguacán basin, Cuba, from 3D inversion of gravimetric data

Abstract

New structural details of the Saramaguacán basin in central Cuba are presented, based on 3D inversion of gravimetric data constrained by wells and surface geology information. The basin shows complex tectonics of the overthrust process. A probable structural analysis of the basin suggests structures of ramp and shelf, as well as the location and geometry of the basin and several sub-basins. Known location and behavior of fault depth suggests some possible new or unknown faults. Geometry variation, depth and thickness were determined for different rock formations. This has great importance for the sedimentary (oil-bearing) and paleomargin (oil-source) rocks, because it is the basis for future research to select the best sites for drilling, as well as a broad estimate calculation of hydrocarbon volume that can be stored in the oil-collector rocks. Both groups of rocks are potential targets for oil prospecting. The oil-source rocks of the Cuban system were found to be around 4 km depth. They are associated with carbonated rocks of the Paleomargin. The oil-bearing rocks reache a depth of 10 km. The 3D model obtained supports the hypothesis that the ophiolites and the Cretaceous volcanic arc rocks were tectonically emplaced from south to north, on top of carbonate-terrigenous sequences from the Bahamas paleomargin. The model shows elements of the compressive tectonics that originated the Saramaguacán basin in the Mesozoic-Tertiary. It also suggests that the Saramaguacán basin presents favorable geologic conditions for oil deposits.