Seismic Attributes Analysis as a Precursor to Hydrocarbon Indicators: A Case Study of “Ok” Field, Niger Delta

Abstract

Seismic data volume was employed to gain more insights into the complexities of the hydrocarbon hosting units within and outside the vicinity of well control in the OK-field Niger Delta to overcome wrong deductions from complexly faulted subsurface configuration for the oilfield exploration programme. The methodology involved integration of well log with seismic data, seismic structural analysis and seismic attributes analysis. Horizons and fault interpretations were carried out to produce subsurface attribute maps. Lithologic panels derived from well log data showed that the study area is characterized by sand-shale interbedding. Two hydrocarbon bearing reservoirs were delineated within the study interval, namely: R1 and R2. Well to seismic tie revealed that these horizons tied direct hydrocarbon indicators (bright spots) on the vertical sections. Structural interpretation revealed that “OK” field is characterized by a rollover anticline, with a closed trapping mechanism for the D series and fault/dip trapping mechanism in the E series. The conclusion of the study was that the highly prospective areas are where bright spots were observed, while areas with dim spots are less prospective. The study has shown the ability of instantaneous amplitude as a requisite in prospect identification and reservoir prediction.

Keywords: reservoirs; fault; hydrocarbon; seismic; amplitudes; structures