Characterization of Reservoir Sands Using 3-D Seismic Attributes in FUBA Field, Onshore Niger Delta, Nigeria

Characterization of reservoir sands using 3D seismic attributes in Fuba Field, onshore Niger Delta, Nigeria are here presented. Well-log and 3D Seismic data were obtained from Shell Petroleum Development Company. Seismic interpretation was carried out using Petrel software. The structural interpretation of seismic data reveal highly synthetic and antithetic faults which are in line with faults trends identified in the Niger Delta. Two distinct horizons were mapped. Reservoir M is found at a shallower depth from 10937 to 10997 ft while reservoir N is found at a depth ranging from 11213 to 11241 ft respectively. Petrophysical summary of the sand units revealed that the area is characterized by high sand/shale ratio, effective porosity ranged from 16 to 37% and hydrocarbon saturation between 55 and 82%. By extracting attribute maps of variance, dip magnitude, average instantaneous frequency, average positive amplitude and RMS amplitude, characterization of the sand units in terms of reservoir geomorphological features, facies distribution and hydrocarbon potential was achieved. The variance values ranges from 0.0 to 1.0. The dip magnitude values ranges from 0 to 90 degrees. The Variance edge analysis and dip magnitude were used to delineate the prominent and subtle faults in the area. The average instantaneous frequency results indicate lower frequency range of 7 to 15 Hz at the center of the field indicating that this part comprises of substantially thick facies compared to its surroundings. The RMS amplitude values range from 0 to 13,000 in the reservoirs. The average positive amplitude and RMS attributes analysis indicate the presence of hydrocarbon in the seismic data. Results from this study have enhanced the delineation of drillable locations which are not recognized on conventional seismic interpretations, which could be further evaluated for hydrocarbon production.