The Effects of Structural Control on Reservoir Properties of the Akani-Field, Coastal
Swamp, Eastern, Niger Delta, Nigeria
Tochukwu C Iheaturu, B.Sc Geology
Richmond Uwanemesor Ideozu, Ph.D. & Lecturer
University of Port Harcourt, Nigeria
This study focuses on the effects of structural control on the reservoir properties of the Akani Field, Coastal Swamp, Eastern Niger Delta. 3D Seismic data has been used to generate the interpreted grid horizons and fault polygons. These horizons were juxtaposed across the reservoirs and used for the fault-seal analysis x-ray its control on cross fault flow and reservoir properties. Petrophysical data generated fault linkages, architecture and property modeling (net to gross, porosity, permeability and volume of shale distribution) using the Sequential Gaussian Simulation on petrel work flow software. The field has a high level of complexity of fault / seals (a major regional fault and 23 faults picked showing soft and minor hard linkages) which controlled the distribution of fault, facies architecture and petrophysical properties across Akani Field. Shale Gouge ratio values and its distribution on the juxtaposition plane determined the control on cross fault flow and the sealing potential of the faults. A hydrocarbon column of 266.6ft identified in Akani 6C sand is controlled by structural and smear spill points prior to capillary failure, and as such suggests strong sealing and ability to withstand formation pressure differentials. Furthermore, hydrocarbon column of 269.5ft and 333.54ft identified in Akani 13C sand with an average thickness of about 301.5ft, is however, believed to be fault independent. Petrophysical results of sand 6C and 13C reservoirs stand out as very good reservoirs with average porosity of 28.5%, average permeability of 2200mD, with good average net to gross (value) and volume of shale distribution (average value). This suggests that the mapped horizons indicate very good hydrocarbon prospect based on RMS amplitude map. This study has demonstrated the effectiveness of 3-D static modeling technique as a tool for better understanding of fault sealing potential under static conditions.