Evaluation of Hydrocarbon Reservoir in the “SIMA” Field of Niger Delta Nigeria from Interpretation of 3D Seismic and Petrophysical Log Data

Abstract

3D seismic and petrophysical log data interpretation of reservoir sands in "SIMA" Field, onshore Niger Delta has been undertaken in this study to ascertain the reservoir characteristics in terms of favourable structural and petrophysical parameters suitable for hydrocarbon accumulation and entrapment in the field. Horizon and fault interpretation were carried out for subsurface structural delineation. In all, seven faults (five normal and two listric faults) were mapped in the seismic section. These faults were major structure building faults corresponding to the growth and antithetic faults in the area within the well control. The antithetic fault trending northwest-southeast and the normal fault trending northeast-southwest on the structural high in the section act as good trapping mechanisms for hydrocarbon accumulations in the reservoir. From the manual and auto-tracking methods applied, several horizons were identified and mapped. The section is characterized by high amplitude with moderate-to-good continuity reflections appearing parallel to sub-parallel, mostly disturbed by some truncations which are more fault related than lithologic heterogeneity. The southwestern part is, however, characterized by low-to-high or variable amplitude reflections with poor-to-low continuity. Normal faults linked to roll-over anticlines were identified. Some fault truncations were observed due to lithologic heterogeneity. The combination of these faults acts as good traps for hydrocarbon accumulations in the reservoir. Reservoir favourable petrophysical qualities, having average NTG, porosity, permeability and water saturation of 5 m, 0.20423, 1128.219 kD and 0.458 respectively.

Evaluation of Hydrocarbon Potential Using AVO Analysis in the FORMAT Field, Niger Delta Basin, Nigeria

“…This work did not predict the fluid properties within the reservoir. Similarly, [4] performed an assessment of the spectral decomposition techniques in the evaluation of hydrocarbon potential of "BOMS" field, coastal swamp Niger Delta. Also, [5] had studied the characteristics of a hydrocarbon field to establish the hydrocarbon prospectivity and risk analysis using seismic and well log data; These methods could identity a hydrocarbon prospect and quantify the hydrocarbon in place based on available data, but fail to predict the fluid properties of the reservoir from a seismic attribute, like the amplitude variation with offset (AVO) analysis.…”

“…However this had sometimes yielded surprising disappointing results especially in areas impregnated by highly cemented sands often calcite cement in thin pinch-out zones, low-porosity heterolithic sands and over-pressured zones. In his study of the hydrocarbon reservoir, [2] had used both seismic and well data to successfully evaluate the hydrocarbon reservoir in the SIMA field of the Niger Delta. Similarly, [4] had also attempted successfully to evaluate the hydrocarbon potential of BOMS field in the Niger Delta using spectral decomposition method.…”

“…In his study of the hydrocarbon reservoir, [2] had used both seismic and well data to successfully evaluate the hydrocarbon reservoir in the SIMA field of the Niger Delta. Similarly, [4] had also attempted successfully to evaluate the hydrocarbon potential of BOMS field in the Niger Delta using spectral decomposition method. It thus becomes necessary to deploy, in this study, the use of AVO analysis to evaluate the reservoir to assess the performance in the characterization and identification of the fluid properties by integrating the AVO attributes.…”