3D SEISMIC INTERPRETATION OF THE KB FIELD, OFFSHORE, NIGER DELTA BASIN, SOUTHERN NIGERIA.

Abstract

Niger Delta Basin is one of the most prolific oil producing basins in the world made up of complex structural features which if not well understood may hinder maximum exploitation of hydrocarbon. Therefore, understanding the detailed structural relationships between fault networks and stratigraphic stacking patterns of the area for future field development is very necessary. 2D and 3D seismic data associated with drilling data are the unique tools that facilitate study and interpretation of geologic structural subsurface features. 3D seismic, well log and structural interpretation was carried out to evaluate hydrocarbon potentials of the reservoirs using the Petrel 2017 Software. The seismic dataset which covers an area of about 55,000 is used majorly in the interpretation of faults and horizons. Well data which includes 6 well datasets is used in the identification of reservoirs and for petrophysical evaluation. Prediction of Depositional environment is carried out using the well data. The depositional environment is interpreted to be a coastal environment and prograding marine shelf environment. Faults are interpreted to be normal faults which include growth faults, synthetic faults and antithetic faults. Mapping of six horizons that corresponded to selected well tops after well to seismic tie is carried out. Time and depth structural maps are generated from the mapped horizons which are used for the identification of tested area and prospect area. Isopach maps are also generated. Petrophysical analysis is conducted on three hydrocarbon bearing reservoirs within the depth range of 9,567.23ft – 11,209.60ft obtaining values of parameters which include an average Porosity value of 0.24, an average water saturation of 0.52 and an average Net to Gross of 0.6. Volumetric estimations are carried out on three hydrocarbon bearing reservoirs. For sand F, the STOIIP for the tested area, prospect 1 and prospect 2 is 21.5mmBBL, 1.6MMbbl and 7.9MMbbl respectively. For sand G, the OGIP for the tested area and prospect is 102.5MMscf and 36.8MMscf while the OOIP for the tested area and prospect is 17.3mmBBL and 4.7MMbbl. For sand H, the STOIIP for the tested area, prospect 1 and prospect 2 is 40.4mmBBL, 4.9MMbbl and 19.4MMbbl respectively. Seismic attributes analysis of the horizon maps are carried out. Amplitude maps are used as direct hydrocarbon indicator for the targeted formations. As a result, bright spots are indicated and used to identify potential reservoirs. The use of structural and attribute maps has aided the identification of prospects in the KB Field. It is recommended that xv wells be drilled to target the new prospects which will improve the hydrocarbon recovery in KB Field.