Seismic Attributes Analysis as a Precursor for Hydrocarbon Indication: A Case Study of Onshore Fuba field, Niger Delta, Nigeria

Abstract

Seismic attributes analysis as a precursor for hydrocarbon indication in onshore Fuba Field, Niger Delta, Nigeria using Well-logs and 3D Seismic data are here presented. Well-to-seismic ties, faults and horizon mapping, time-surface generation, depth conversion and seismic attributes generation were 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. Of the 36 interpreted faults, only synthetic and antithetic faults are regional, running from the top to bottom across the field. These faults play significant roles in trap formation at the upper, middle and lower sections of the field. 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. Analysis of the relevant seismic attributes such as variance edge, root mean square, maximum amplitude and relative acoustic impedance were applied to the seismic data. The variance values ranges from 0.0 to 1.0. The Variance edge analysis was used to delineate the prominent and subtle faults in the area. The RMS amplitude values ranges from 9,000 to 13,000 in the reservoirs. The root mean square amplitude and maximum amplitude analysis reveal bright spot anomaly. These amplitude anomalies served as direct hydrocarbon indicators (DHIs), unravelling the presence and possible hydrocarbon prospective zones. The relative acoustic impedance analysis was used for delineating lithology variation in the seismic sections. Results from this study have shown that away from the currently producing zone of the field, additional leads and prospects exist, which could be further evaluated for hydrocarbon production.