Structural distribution and evaluation of siliciclastic reservoirs of X-onshore field, Niger Delta, Nigeria

This study uses well logs and seismic data sets to map out and evaluate the structural distribution of siliciclastic reservoirs in the field for identification of possible hydrocarbon bearing zones, continuity, and for the creation of appropriate geological models. This is aimed at using the analysis therefore to mitigate the challenges of reservoir facies witnessed during the development and drilling of hydrocarbons from reservoirs found in the field. In order to delineate the hydrocarbon reservoir facies using the structural distribution, the integration of seismic and petrophysics methods were adopted. The result of the petrophysical analysis shows that the identified reservoirs are composed of the intercalation of sand and shale lithofacies. The estimated porosity and permeability values of more than 12% and1000mD respectively indicates that the reservoir are said to be siliciclastic. From the seismic, three different faults-which corresponds to the three correlated reservoirs were mapped. The structural pattern of the investigation indicates that the hydrocarbons are being trapped by growing faults, which a common trapping mechanism is observed in the Niger Delta field. The vertical orientation, position, and connectivity of the reservoirs are shown by the mapped faults. Hydrocarbon saturation increased in the northeastern direction of covered seismic and this was substantiated by the findings of the time surface contour maps. This is as a result of the increase in the hydrocarbon saturation towards the Northeast direction. Therefore, the prospective hydrocarbon region in this study is enclosed by the fault; which is a rollover anticline. This fault growth aligns with the potential hydrocarbon accumulation area.