GEOLOGY, SEDIMENTOLOGICAL AND HYDRAULIC CONDUCTIVITY OF AJALI POTENTIAL RESERVOIR SANDSTONE EXPOSED AROUND GRA IN IDAH, NORTHERN ANAMBRA BASIN
Abstract
The Ajali sandstone is a possible reservoir rock in the Lower Benue Trough (LBT)/Anambra Basin (AB), and understanding its geological, sedimentological distribution is essential for accurate prediction of fluid flow dynamic. Geological, granulometric analysis and laboratory hydraulic conductivity test are integrated for this investigation. Results from geological studies reveals three sandstone lithofacies; namely; AJALI L2A a sandstone intermixed with siltstone, lamination, bioturbated, and crossed bedded, AJALI L2B sandstone mixed with silty clay, crossed bedded and bioturbated and AJALI L2C an excessive weathered sandstone with visible ripple and ridges with all sedimentary features supporting the earlier proposed fluvio-deltaic depositional environments. The granulometric analysis reveals medium to coarse grain, poorly sorted sandstone lithofacies. Hydraulic conductivity test for AJALI L2A crossed bedded and lamination sandstone contributes smaller pore spaces between grains, which reduce overall interconnectivity of the pore network primarily decreasing the fluid hydraulic flow conductivity and thus lowers the permeability value to 75mD. While in the AJALI L2B intermixed with siltstone and clay sandstone, lowers porosity; but cross-bedding may have contributed positively to increase in permeability value to 1850 mD in this lithofacies. The weathered AJALI L2C sandstone with visible ripples and ridges significantly affect the physical properties and pore spaces obliteration by iron oxide, by contributing to reduction in the permeability value to 60 mD. In overall it is concluded that the Ajali sandstones generally will exhibits an average moderate permeability of 662 mD.
References
Abdlmutalib, A. J., Ayranci, K., Yassin, M. A., Hussaini, S. R., Abdullatif, O. A., & Humphrey, J. D. (2022). Impact of sedimentary fabrics on small-scale permeability variations within fine-grained sediments: Early Silurian Qusaiba Member, Northern Saudi Arabia. Marine and Petroleum Geology, 139, 105607. DOI: https://doi.org/10.1016/j.marpetgeo.2022.105607
Abubakar, M. (2014). Petroleum potentials of the Nigerian Benue Trough and Anambra Basin: a regional synthesis. Natural Resources, 2014. DOI: https://doi.org/10.4236/nr.2014.51005
Azidane, H., Michel, B., Bouhaddioui, M. E., Haddout, S., Magrane, B., & Benmohammadi, A. (2021). Grain size analysis and characterization of sedimentary environment along the Atlantic Coast, Kenitra (Morocco). Marine Georesources & Geotechnology, 39(5), 569-576. DOI: https://doi.org/10.1080/1064119X.2020.1726536
Boggs Jr, S., & Boggs, S. (2009). Petrology of sedimentary rocks: Cambridge university press. DOI: https://doi.org/10.1017/CBO9780511626487
Folk, R. L., & Ward, W. C. (1957). Brazos River bar [Texas]; a study in the significance of grain size parameters. Journal of Sedimentary Research, 27(1), 3-26. DOI: https://doi.org/10.1306/74D70646-2B21-11D7-8648000102C1865D
Ilevbare, M., & Imasuen, O. (2020). Sedimentology and maturity of Ajali formation, Benin flank Anambra basin, Nigeria. Ife Journal of Science, 22(1), 123-136. DOI: https://doi.org/10.4314/ijs.v22i1.13
Ladipo, K. O. (1986). Tidal shelf depositional model for the Ajali Sandstone, Anambra Basin, southern Nigeria. Journal of African Earth Sciences (1983), 5(2), 177-185. DOI: https://doi.org/10.1016/0899-5362(86)90008-4
Mehmood, M., Naseem, A. A., Saleem, M., Rehman, J. u., Kontakiotis, G., Janjuhah, H. T., . . . Rehman, A. u. (2023). Sedimentary Facies, Architectural Elements, and Depositional Environments of the Maastrichtian Pab Formation in the Rakhi Gorge, Eastern Sulaiman Ranges, Pakistan. Journal of Marine Science and Engineering, 11(4), 726. DOI: https://doi.org/10.3390/jmse11040726
Nwajide, C. (2005). Anambra Basin of Nigeria: synoptic basin analysis as a basis for evaluating its hydrocarbon prospectivity. Hydrocarbon potentials of the Anambra Basin, PTDF Chair, 2-46.
Obaje. (1999). Biostratigraphic and geochemical controls of hydrocarbon prospects in the Benue Trough and Anambra Basin, Nigeria. Nigerian Association of Petroleum Explorationists (NAPE) Bulletin, 14, 18-54.
Obaje, N. G. (2019). Updates on the Geology and Mineral Resources of Nigeria (Revised edition ed. Vol. V). Nigeria: Ajiboye Printers & Publisher Nig. LTD.
Onuoha, K. M., & Dim, C. I. (2016). Prospects and challenges of developing unconventional petroleum resources in the Anambra Inland Basin of Nigeria. Paper presented at the SPE/AAPG Africa Energy and Technology Conference. DOI: https://doi.org/10.2118/AFRC-2571791-MS
Onyekuru, S. O., Achukwu-Ononye, O. U., Ukpong, A. J., Ofoh, I. J., Ibeneme, S. I., Ibe, K. K., & Anyanwu, T. C. (2023). Stratigraphy and Paleoenvironment (s) of the Late Cretaceous deposits in Ohafia area, Afikpo Basin, Southeastern Nigeria. Journal of African Earth Sciences, 197, 104713. DOI: https://doi.org/10.1016/j.jafrearsci.2022.104713
Petters, S. W. (1982). Central west African Cretaceous-Tertiary benthic foraminifera and stratigraphy. Palaeontographica Abt. A, 179, 1-104.
Pliakas, F., & Petalas, C. (2011). Determination of hydraulic conductivity of unconsolidated river alluvium from permeameter tests, empirical formulas and statistical parameters effect analysis. Water Resources Management, 25, 2877-2899. DOI: https://doi.org/10.1007/s11269-011-9844-8
Rajganapathi, V., Jitheshkumar, N., Sundararajan, M., Bhat, K., & Velusamy, S. (2013). Grain size analysis and characterization of sedimentary environment along Thiruchendur coast, Tamilnadu, India. Arabian Journal of Geosciences, 6, 4717-4728. DOI: https://doi.org/10.1007/s12517-012-0709-0
Xu, K., Wei, W., Chen, Y., Tian, H., Xu, S., & Cai, J. (2022). A pore network approach to study throat size effect on the permeability of reconstructed porous media. Water, 14(1), 77. DOI: https://doi.org/10.3390/w14010077
Yusuf, I. (2018). Impact of Small - Scale Heterogeneity on Potential Recovery in Selecetd Reservor
Sandstone from West Baram Delta, Offshore,Sarawak, Malaysia. Petroleum and Coal, 60(3), 13.
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