APPLICATION OF SEQUENCE STRATIGRAPHY IN RESERVOIR CHARACTERIZATION: A CASE STUDY OF EMI FIELD, COASTAL SWAMP DEPOBELT IN THE NIGER DELTA, NIGERIA

Sequence stratigraphic concept in defining sediments accumulation and preservation trends within the basin-fills have become a successful exploration technique in the search for hydrocarbons. This concept has been employed in this present study. The study area has two recognised depositional sequences, bounded above and below by maximum flooding surfaces (MFS). The maximum flooding surfaces are Uvigerina 8, (9.5ma) and Dodo shale (11.5ma), and the two sequence boundaries are 10.35ma and 10.6ma. Nonion 4, MFS(10.4ma) was missing in the section, which could have been as a result of 10.6ma erosion as evidenced from the seismic section. Based on the above, system tracts were interpreted; Highstand system tract (HST), Lowstand system tract (LST) and Transgressive system tract (TST). The hydrocarbon bearing sand units were analysed based on systems tracts. The LST had more hydrocarbon bearing sand units, followed by HST, while none was observed for the LST. The average porosity and permeability values for the system tracts are; for the HST, ϕ = 38%, K = 1202mD, second HST, ϕ = 36%, K = 152mD, LST ϕ = 35%, K =37mD and the last HST ϕ =33%, K = 34mD. The reservoirs are more of gas bearing than oil. This is attributed to the source rock type, temperature effect and low permeability values (reduced pore throat).