A Seismic Analysis of Structural History of Makad Field, Onshore Niger Delta and Its Implications for Petroleum Occurrence

This study builds structural frame work for Makad field of deltaic Agbada formation under the Niger Delta by relating strata discontinuities observed in a 3D seismic volume to vertical changes observed in well logs of the field. In order to examine how structural deformation above mobile shale influences patterns of deposition, trap geometry, and their implications for petroleum accumulation, a comprehensive interpretation of a suite of 3D seismic data acquired over Makad field was carried out manually. Three sand tops namely AA-1, AA-7 and AA-L in the field were selected for interpretation based on good petrophysical parameters. The wells penetrated into the downthrown side of the major structural-building fault in the study area. The mapped horizon surfaces and fault were exported to base map and contoured, to generate fault plane maps and structure maps for the interpreted horizon. The trapping mechanism is fault assisted. The results of this study show that field conceptual development plan and economic model ought to be based on detailed 3D seismic interpretation, which must include seismic analysis of the structural geometry to reduce the geologic risk of prospect.