Seismic Amplitudes and Spectral Attributes for Reservoir Characterization and Enhanced Prospect Definition of FUBA Field, Onshore Niger Delta, Nigeria

Seismic amplitudes and spectral attributes analysis for reservoir characterization and enhanced prospect definition of Fuba Field, onshore Niger Delta, Nigeria is here presented. 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. Three distinct horizons were mapped. Reservoir M is found at a shallower depth from 10937 to 10997 ft, reservoir N is found at a depth ranging from 11213 to 11241 ft while reservoir O is found at a deeper depth ranging from 11681 to 11871 ft respectively. By extracting attribute maps of envelope, sweetness, maximum amplitude and RMS (root mean square) amplitude, characterization of the sand units in terms of reservoir geomorphological features, facies distribution and hydrocarbon potential was achieved. The envelope and the sweetness values show similar amplitude characteristics and structure but with varying resolutions. The sweetness value ranges from 0 to 22,500. The high sweetness regions in the seismic data indicate high amplitude which indicates the presence of hydrocarbon-bearing sand units. The maximum amplitude was seen to have bright spot anomalies. These amplitude anomalies served as DHIs (direct hydrocarbon indicators), unravelling the presence and possible hydrocarbon prospective zones. The RMS amplitude values range from 0 to 12,000. The results of spectral decomposition show similar amplitude characteristics and structure with the RMS but with varying resolutions. The spectral attributes indicate areas of low frequency and high amplitude associated with known hydrocarbon zones and meandering channels in the field. At the north-eastern to the south-eastern part and south- western directions, there is high amplitude, an indication of hydrocarbon/gas effect. The results from this study will help in the recovery of more hydrocarbon as by-passed zones and subtle structures are revealed in the area of study.