Abstract

Author:
Ede Tiekuro, Emujakporue, GO, Nwankwo, CN

Doi: 10.26480/gsrj.02.2024.84.95

This is an open access article distributed under the Creative Commons Attribution License CC BY 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited

The ETI field, located offshore Niger Delta, is characterized by complicated faulting and structural deformation, resulting in considerable reservoir property ambiguity. These discrepancies have a significant impact on field exploration and development plans, necessitating the appraisal of hydrocarbon plays. The interpretation of 3-D seismic and well log data from seven wells was used to determine the hydrocarbon entrapment pattern and petrophysical parameters of hydrocarbon reservoirs in the ETI field. Three reservoirs (R-ETI-1000, R-ETI-2000, and R-ETI-3000) were identified from seven wells (ED-001, ED-002, ED-003, ED-004, ED-005, ED-006, and ED-007) utilizing gamma ray and resistivity log responses. The structural interpretation of Inline 6895 revealed three horizons (H1, H2, and H3) and four (4) faults that were labeled. The structural interpretation and trend of underlying geological formations within the examined horizons revealed that the hydrocarbon containing features in the field are fault-assisted closures. Attribute maps i:e variance edge and root mean square (RMS) obtained was consistent with the structural highs found on the time-depth structural maps, confirming that the structural controls in the field are normal faults and depicting a typical tectonic setting in the Niger Delta basin. Results of petrophysical properties revealed that in reservoir R-ETI 1000, gross thickness of 142.7871Ft, net to gross of 73.19%, effective porosity of 26.44%, water saturation of 59.39% and hydrocarbon saturation of 40.61% was obtained across the wells. For reservoir R-ETI 2000, gross thickness of 123.2288Ft, net to gross of 84.37%, effective porosity of 25.85%, water saturation of 62.34% and hydrocarbon saturation of 37.66% was obtained across the wells, and for reservoir R-ETI 3000, gross thickness of 494.01Ft, net to gross of 55.032%, effective porosity of 22.21%, water saturation of 42.29% and hydrocarbon saturation of 57.71% was obtained across the wells. Bulk volume of water (BVW) obtained was averaged at 15.68%, 16.02% and 9.02% for reservoirs R-1000, R-2000 and R-3000 respectively, while irreducible water saturation was 7.51%, 7.58% and 8.97% in reservoirs R-1000, R-2000 and R-3000 respectively. The values of bulk volume of water (BVW) obtained for the reservoirs were not consistent and implies that the reservoirs are not close to their irreducible water saturation and therefore, some water production is expected for the reservoirs as observed from their petrophysical properties. Effective porosity of the reservoirs (R-1000 to R-3000) have an average range of 22.21 to 26.44%, and is rated very good. Permeability indices of the order (K > 100mD and k > 1000mD) was obtained in most reservoirs across the seven wells and is rated good, very good to excellent. Volumetric estimation showed that reservoir R-1000 contains 132 × 106 STB of hydrocarbon in place and 1290 × 106 SCF of gas in place while reservoir R-2000 contains 327 × 106 STB of hydrocarbon in place and 245 × 106 SCF of gas in place and reservoir R-3000 contains 1510 × 106 STB of hydrocarbon in place and 3470 × 106 SCF of gas in place. These findings have a positive impact on hydrocarbon production in the field and confirm that the reservoirs are very promising.