Integrating Old and New Data-Evaluation Techniques for Effective Reservoir Characterization of Southeastern Niger Delta Reservoirs

Adeosho, S. A. (MacBenuz Enviros Limited and Technovate Nigeria) | Babalola, O. P. (Afren Energy Nigeria) | Adepelumi, A. A. (Obafemi Awolowo University)



The value of data integration has been proved in assessing the thin-bedded H4 reservoir and the stratigraphically natured H5 reservoir in UKU Field, southeastern Niger Delta, toward planning effective development strategies for depletion. Reservoirs of these definitions pose problems during mapping from seismic for well planning and drilling activities, as well as at the production stage. Data for this work consist of a recently acquired full-stack, 3D ocean-bottom-cable (OBC), prestack-time-migrated (PSTM) seismic data; well logs from five vertical wells; core information; and modular-dynamic-test (MDT) data.
Seismic-attribute maps and extracted geobodies revealed the reservoir extent within the limit of seismic resolution (approximately 27 ft), while petrophysical analysis indicates the reservoirs to be of excellent flow-and-storage quality. MDT data reveal the hydrocarbon fill to be of medium-to-heavy grade. While water production was decided not to be probable for H4 reservoir depletion, it is of certainty in H5 reservoir production. Mapping showed that the field is separated into two fault blocks (FB1 and FB2) on the basis of the difference in water-contact levels, with calculated oil volume of 4 million BO (FB1) and 12 million BO (FB2) in H4 reservoir and 12 million BO (FB1) and 2 million BO (FB2) in H5 reservoir. Gas reserves in H4 sand were calculated to be 480 MMcF in FB2.