Abstract:
This study involves the understanding of the stratigraphic distribution of the area by integrating well logs, biostratigraphic data and seismic data to better define hydrocarbon reservoir distributions within the Middle to Late Miocene sediments in ‘’OGBO” Field Coastal swamp Depobelt of Niger Delta Basin. Sequence stratigraphic, geostatistical and structural analytical tool have been incorporated in this study, in order to achieve this. Based on the sequence stratigraphic studies, stratigraphic bounding surface such as Maximum Flooding Surfaces – MFS’s, Sequence Boundaries – SB’s and Transgressive Surface of Erosion – TSEs, were delineated and dated. The surfaces were correlated across various wells and mapped along dip and strikes lines on seismic sections, thus providing a good understanding of the stratigraphic distribution. In addition, genetic system tracts which include Lowstand System Tract – LST, Transgressive System Tract- TST and Highstand System Tract – HST, were recognized with the aid of sediment stacking patterns (progradational, retrogradational and aggradational stacks). This gave insight into reservoir, source, and seal rock distributions across the study area. Geostatistical analysis and petrophysical studies were carried out across reservoir tops of interest to determine variation in parameters such as porosity, permeability, water saturation, net to gross, etc. Structural analysis indicates the occurrence down to basin faults, deep seated rollovers, anticlinal structures, and dip fault closures at deeper intervals. These studies unraveled the existence of by-passed opportunities (B5000AB, C4000, D4100A and D4100AA prospects) which in no small measure led to an upward (about 3, 766, 750 MMBOE and 47, 376,962MMSCF) review of the hydrocarbon reserves in the field. This study led to the generation of a better and more reliable geological model for use in the reservoir studies of “OGBO” field.
