3D Modeling Approach of Fault Seal Integrity Analysis in Sonia Field Onshore Niger Delta

Geologic structures that aids the accumulation of hydrocarbon in reservoirs could be fault assisted or fault dependent, these faults can be described as sealing or leaking in nature. In this study, well logs and 3D seismic data were utilized for the seal integrity analysis in Sonia Field onshore Niger Delta.

The methods employed include reservoir evaluation (i.e. Determining the volume of shale), and the generation of 3D models by computing the fault seal algorithms such as the shale gouge ratio, which was used to access the sealing capacity of the fault planes trending NW-SE in the study area. In order to ascertain the sealing integrity of the identified hydrocarbon bearing sand, the following were done: horizon to fault intersection on the shale gouge ratio model, the 3D models of the fault attributes i.e. Fault-throw. Hydrocarbon column height (HCH and fault flow properties specifically, fault transmissibility and fault permeablillity using ‘Manzocchi’ equation.

The shale gouge ratio ranged from (leaking zones) to sealing Zones) across the fault plane. The hydrocarbon column height at which the faults In the study area can support ranges between 26.6 m to 28.0 m. The predicted permeability model of the faults is less than 1mD in some regions along the fault plane with corresponding transmissibility values between 0 and 0.20. Based on these results, it was observed that none of the hydrocarbon reservoirs in the study area falls within in the leaking category. The fault permeability and transmissibility models which indicate that regions along the faults planes are sealed and might prevent migration of fluid out of these reservoirs.