Earth, Energy & Environment
Received: 11 Oct 2019 , Published: 17 October 2019
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|1||David Oladimeji Oluwole|
|2||Fadiya Suyi Lawrence|
This study identified and correlated hydrocarbon bearing reservoirs, interpreted geological structures and petrophysical parameters and described facies and environment of deposition using seismic and well log data. These were with a view to assessing the impact of reservoir heterogeneity on petrophysical parameters and to determine the hydrocarbon potential of “Devo” Field, Niger Delta. Porosity, permeability, water saturation, net-to-gross, and hydrocarbon saturation with values
ranging between 25.0 and 26.2%, 735.0 mD and 9019.4 mD, 15.3 and 67.5%, 49.6 and 57.3%, and 32.1 and 84.7% respectively. The Thomas-Steiber shaly-sand model analysis revealed that laminated shale was widely distributed all through the “DEVO” Field reservoirs. Despite the dominance of laminated shale, the reservoir quality from porosities (26.0%, 26.2%, and 25.4%), permeability (5264 mD, 4419.8 mD, and 3658.8 mD) values revealed very good to excellent qualities according to classifications made by Levorsen. Structural framework interpretation showed that sealing fault closure which includes the growth faults F12, F13, and F17 with antithetic faults F18 and F22 constitute the structural heterogeneity influencing oil trapping. Utilizing Amaefule's technique, the crossplots of Reservoir Quality Index and Normalized Porosity indicated
increasing reservoir quality in relation to the normalized porosity. Facies description demonstrated that five different facies (channel, tidal channel, mouth bar, shoreface, and tidal flat) were associated with the reservoirs and their environments of deposition were categorized as fluvial and shallow marine environments. The volumetric estimations showed that Reservoir 1 closures have Prospects 1 (241.6 Million of Stock Tank Barrels, MMSTB) and 2 (78.1 MMSTB) in terms of calculated Stock Tank Original Oil-In-Place (STOOIP). Reservoir 2 closures have Prospects 1 (250.6 MMSTB) and 2 of (127.7 MMSTB), while Reservoir 3 closures have Prospects 1 (48.8 MMSTB) and 2 (63.2 MMSTB) in terms of the calculated STOOIP.
1. Allen, J. R. L. (1965): Late Quaternary Niger Delta and Adjacent Areas: Sedimentary Environments and Lithofacies. American Association Petroleum Geologists Bulletin,Vol. 49, p. 547-600.
2. Alpay, O. A. (1972): A Practical Approach to Defining Reservoir Heterogeneity. Journal of Petroleum Technology, Vol. 24, p. 841-848.
3. Amaefule, J. O., Altunbay, M., Kersey, D. G. and Keelan, D. K. (1993): Enhanced Reservoir Description: Using Core and Log Data to Identify Hydraulic (Flow) Units and Predict Permeability in Uncored Intervals/Wells. Society of Petroleum Engineers Bulletin, 26436-MS, 16 pp.
4. Bonnell, B. and Hurich C. (2008): Characterization of Reservoir Heterogeneity: An Investigation of the Role of Cross-Well
Reflection Data. Journal of Canadian Society of Exploration Geophysicists. Vol. 33, No. 2, p.31-37.
5. Burke, K. (1972): Longshore Drift, Submarine Canyons, and Submarine Fans in the Development of Niger Delta. American
Association of Petroleum Geologists Bulletin, Vol. 56, p. 1975-1983.
6. Cant, D. J. (1992): Subsurface Facies Analysis. In: Walker, R. G. and James, N. P. (eds). Facies Models, Response to Sea Level Changes. Geological Association of Canada, p.409.
7. Doust, H. and Omatsola, E. (1990): Niger Delta. In: Edwards, J. D. and Santogrossi, P. A. (eds), Divergent/Passive Margin Basins. American Association of Petroleum Geologist Memoir 48, p. 239-248.
8. Fitch, P., Davies, S., Lovell, M. and Pritchard, T. (2010): The Petrophysical Link Between Reservoir Quality and Heterogeneity: Application of Lorenz coefficient. Paper presented at 2013 SPWLA 54th Annual Logging Symposium, New Orleans, June 22-26.
9. Hospers, J. (1965): Gravity Field and Structure of the Niger Delta, Nigeria.Geological Society of American Bulletin, Vol.
76, p. 407-422.
10. Kulke, H. (1995): Regional Petroleum Geology of the World. Part II: Africa, America, Australia and Antarctica: Berlin, Gebrüder Borntraeger, p. 143-172.
11. Larionov, V. V. (1969): Radiometry of Boreholes. Open Journal of Geology, Vol. 7, No.10, 66 pp.
12. Maloney, D., Davies, R., Imber, J., Higgins, S. and King, S. (2010): New Insights into Deformation Mechanisms in the
Gravitationally Driven Niger Delta Deep- Water Fold and Thrust Belt. American Association of Petroleum Geologist Bulletin,
Vol. 94, No. 9, p. 1401- 1424.
13. Mode, A. W., Adepehin, E. J. and Anyiam, O. A. (2013): Petrophysical Effects of Clay Heterogeneity on Reservoirs’
Properties: Case Study of “Brown” Field, Niger Delta, Nigeria. Nigerian Association Petroleum Exploration Bulletin, Vol. 25, No.1, p. 61–69.
14. Nanaghan, K. O. (2016): Capturing Complex Reservoir Heterogeneity in a Field Under Water Injection – a Case Study of a Niger Delta Field. Society of Petroleum Engineers Journals, SPE-184489-STU. Volume 1 of 8, p. 556 - 557.
15. Nwachukwu, J. I. and Chukwurah, P. T. (1986): Organic Matter of Agbada Formation, Niger Delta, Nigeria. American Association of Petroleum Geologists Bulletin, Vol. 70, p. 48-55.
16. Sahota, J. T. S. (2006): Deepwater Exploration in the NW Niger Delta: Are there Parallels for Indian Exploration. 6th
International Conference and Exposition on Petroleum Geophysics”Kolkata 2006”, p. 11 – 14.
17. Schlumberger, (1972): Log Interpretation Volume 1: Principles. Schlumberger Limited, New York, 113 pp.
18. Selley, R. C. (1978): Concepts and Methods of Subsurface Facies Analysis. American Association of Petroleum
Geologists Education Course Notes Series 9, 82 pp.
19. Siddiqui, N. A., Hadi, A. A., Chow, W. S. and Mohammad, S. I. (2017): Shallow- marine Sandstone Reservoirs,Depositional Environments,Stratigraphic Characteristics and Facies Model. A Review of the Journal of Applied
Sciences, Vol. 17, No. 5, p. 212-237.
20. Slatt, R. M. and Galloway, W. E. (1993): Geological Heterogeneities. In: Morton-Thompson, D. and Woods, A. M.
(eds), Development Geology Reference Manual. AAPG methods in exploration, Series No. 10, p. 278-281.
21. Tausif, A. ( 2013): Investigating the Relationship Between Reservoir Quality and Heterogeneity in Carbonate
Reservoirs. M.Sc. Unpublished Thesis. Department of Earth Science and Engineering Centre for Petroleum Studies,
Imperial College London, p. 1- 40.33
22. Tyagi, A. K., Guha, R., Voleti, D. and Saxena, K. (2009): Challenges in the Reservoir Characterization of a
Laminated Sand-Shale Sequence. In: Proc. 2nd Society of Petrophysicists and Well Log Analyst, India Regional
Symposium., 19-20 November 2009,Mumbai, India.
23. Weber, K. J. (1986): How Heterogeneity Affects Oil Recovery. In: Lake, L. W. and Carroll, H. B. J. (eds),
Reservoir Characterization. Orlando, FL, Academy Press, p. 487–544.