Abstract:
This research work is an integrated structural, stratigraphic and seismic facies study of the Goza field, offshore Niger delta, with the aim of improving the present understanding of the structural development, sequence stratigraphic history, paleo-depositional environments and hydrocarbon reservoir potential of the field. Three well logs data (resistivity and gamma ray logs), checkshot data, 3D seismic sections (637in-lines and 595cross-lines) and base map of the study area were utilized and analyzed in this study. Eight faults labelled F1, F2, F3, F4, F5, F6, F7 and F8 and four horizons located at a time window of 2076 to 2376 ms were delineated and mapped. Time and depth structural maps constructed to study the subsurface geology reveal two prominent closures both at the central and south-eastern part of the study area which could possibly harbour hydrocarbon.Log sequence stratigraphic interpretation of the study area revealed two major depositional sequences characterized by type 1 sequenceboundary and composed of lowstand, transgressive and highstand system tracts. Seismic sequence analysis from reflection geometries within the sequence were conducted. The internal reflection geometry of the sequences varies laterally and are characterized by high discontinuous amplitude to medium-low discontinuous amplitude reflection configurations. This reflection patterns indicate lateral facies changes typical of sand-shale interbeddings deposited in a high to low energy environments. Seismic facies such as parallel and wavy, divergent and chaotic were also delineated. The facies gave insight into basinal stratification as well as energy regimes prevailing during sediment deposition. Structurally some prospective fault blocks and closures have been identified that could possibly harbour hydrocarbon in the study area. Stratigraphically the lowstand systems tracts constitute the main reservoirs while the transgressive systems tracts however serve as seals/caprocks.
