Integration of Seismic and Well Log Data Using Acoustic Impedance for Lithology and Hydrocarbon Evaluation of “Ovi” Field, Niger Delta

This research work is aimed at using acoustic impedance as means of predicting lithology and hydrocarbon away from well control of "Ovi" Field hence providing a detailed evaluation of the hydrocarbon potential of the area.The methodology used involves identification of hydrocarbon bearing reservoirs from well logs using Gamma ray and resistivity logs, wells correlation, petrophysical analysis, well to seismic tie, horizon and fault mapping, generation of structural maps, acoustic impedance crossplot analysis and seismic inversion using model based approach.Three reservoir sand were mapped within the Agbada Formation.From the crossplot of acoustic impedance against gamma ray, porosity and water saturation, the acoustic impedance ranges from 24500-27500 (ft/s)*(g/cc) for shale and 17500-24500 (ft/s)*(g/cc) for sand based on the saturating fluids, the results also shows that acoustic impedance have a linear relationship with water saturation, while porosity have an inverse relationship with acoustic impedance for the study area.Average acoustic impedance maps for reservoir tops generated from the inverted seismic data indicated areas of low acoustic impedance corresponding to hydrocarbon bearing zones that were not detected on the time maps.The result provided detailed information about the subsurface lithology and hydrocarbon saturation away from well control of the study area.