Contribution of aerogravity data interpretation to the study of the deep structure of Agadem petroleum block (Niger)
Abstract
The main information provided by gravity maps is the geographical distribution of density heterogeneities in the subsurface. It is an important tool widely used for the mapping of geological structures, especially in the oil industry. Thus, this study based on the interpretation of aerogravity data has for objective, the qualitative description of the characteristics of the gravity anomalies of the study area, interpretation and mapping of the gravity lineaments as well as their depths, knowing that the lineaments constitute potential structural traps favorable to the accumulation of the hydrocarbons. Methods such as horizontal derivative, upward continuation and Euler deconvolution are used to give a geological signifiance to the different anomalies and to highlight deep structures. Thus, the analysis of the residual anomaly map revealed elongated negative and positive anomaly zones, oriented globally NW-SE, considered respectively as horst and graben zones. Gravity lineaments, considered as normal faults, are mapped using the horizontal gradient method. Finally, the depths of the density contrasts are estimated by the Euler deconvolution calculation using the value “1” as structural index. The depths thus determined are highly variable. The shallowest depths vary between 3000 m and 6000 m, while the deepest depths reach 18000 m.
Keyword : gravity, structural, interpretation, anomalies, lineaments, Agadem Block
How to Cite
Halidou Amadou, A., El Azzab, D., & Chaouni, A. A. (2023). Contribution of aerogravity data interpretation to the study of the deep structure of Agadem petroleum block (Niger). Geodesy and Cartography, 49(3), 157–165. https://doi.org/10.3846/gac.2023.17299
This work is licensed under a Creative Commons Attribution 4.0 International License.
References
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Guiraud, R., & William, B. (1997). Implications to plate-scale tectonics Senonian basin inversion and rejuvenation of rifting in Africa and Arabia: Synthesis and implications to plate-scale. Tectonics, 282, 39–82. https://doi.org/10.1016/S0040-1951(97)00212-6
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Hildebrand, A. R., Pilkington, M., Connors, M., Ortiz-Aleman, C., & Chavez, R. E. (1995). Size and structure of the Chicxulub crater revealed by horizontal gravity gradients and cenotes. Letters to Nature, 376, 415–417. https://doi.org/10.1038/376415a0
Hood, P., & Ward, S. H. (1969). Airborne geophysical methods. Advances in Geophysics, 13, 2–3. https://doi.org/10.1016/S0065-2687(08)60508-7
Jacobsen, B. H. (1987). Case for upward continuation as a standard separation filter for potential-field maps. Geophysics, 52(8), 1138–1148. https://doi.org/10.1190/1.1442378
Maurin, J. C., & Guiraud, R. (1993). Basement control in the development of the Early Cretaceous West and Central African rift system. Tectonophysics, 228, 81–95. https://doi.org/10.1016/0040-1951(93)90215-6
Nabighian, M. N., Grauch, V. J. S., Hansen, R. O., LaFehr, T. R., Li, Y., Peirce, J. W., Phillips, J. D., & Ruder, M. E. (2005). The historical development of the magnetic method in exploration. Geophysics, 70(6), 63–89. https://doi.org/10.1190/1.2133784
Reid, A. B., Allsop, J. M., Granser, H., Millet, A. J., & Somerton, I. W. (1990). Magnetic interpretation in three dimensions using Euler deconvolution. Geophysics, 55(4), 80–91. https://doi.org/10.1190/1.1442861
Wilson, M. (1992). Magmatism and rifting in Western and Central Africa from Late Jurassic to recent times. Tectonophysics, 213, 203–225. https://doi.org/10.1016/0040-1951(92)90259-9
Zeng, H., Xu, D., & Tan, H. (2007). A model study for estimating optimum upward-continuation height for gravity separation with application to a Bouguer gravity anomaly over a mineral deposit, Jilin province, northeast China. Geophysics, 72(4), 145–150. https://doi.org/10.1190/1.2719497
ARKeX Ltd Company. (2015). ARKeX data processing report. Agadem Block.
Armstrong, M., & Rodeghiero, A. (2006). Airborne geophysical techniques in Aziz. In Coal Operators’ Conference (pp. 113–131), University of Wollongong and the Australasian Institute Mining and Metallurgy.
Basseka, C. A., Nijiteu, T. C. D., Eyike, Y. A., Shandini, Y., & Kenfack, J. V. (2016). Apport des données magnétiques de surface et satellitaires à l’étude des structures profondes du Sud-Cameroun. Sciences, Technologies et Développement, 18, 15–30.
Beiki, M. (2010). Analytic signals of gravity gradient tensor and their application to estimate source location. Geophysics, 75(6), 159–174. https://doi.org/10.1190/1.3493639
Blakely, R. J., & Simpson, R. W. (1986). Approximating edges of source bodies from magnetic or gravity anomalies. Geophysics, 51(7), 1494–1498. https://doi.org/10.1190/1.1442197
Cordell, L. (1979). Gravimetric expression of graben faulting in santa fe country and the espanola basin, New Mexico. In New Mexico Geological Society 30th Annual Fall Field Conference Guidebook, Santa Fe Country (pp. 59–64). https://nmgs.nmt.edu/publications/guidebooks/downloads/30/30_p0059_p0064.pdf
Cordell, L., & Grauch, V. J. S. (1985). Mapping basement magnetization zones from aeromagnetic data in the San Juan basin, New Mexico. https://doi.org/10.1190/1.0931830346.ch16
Dampney, C. N. G. (2018). Gravity interpretation for hydrocarbon exploration? A workshop manual or learning to see geology in a gravity profile. Exploration Geophysics, 8(4), 161–180. https://doi.org/10.1071/EG977161
Dubois, J., Diament, M., & Cogné, J. (2011). La gravimétrie en mer (4e ed). Institut océanographique.
El Azzab, D., Younès, G., & Christian, H. (2001). Contribution du géomagnétisme à l’etude géologique de la région d’aguelmous (Est du massif hercynien central marocain). Communications, PANGEA, (35/36), 59–66.
Fairhead, J. D. (1980). The structure of the cross-cutting volcanic chain of Northern Tanzania and its relation to the East African rift system. Tectonophysics, 65, 193–208. https://doi.org/10.1016/0040-1951(80)90074-8
Fairhead, J. D. (1988a). Late Mesozoic rifting in Africa. Developments in Geotectonics, 22, 821–831. https://doi.org/10.1016/B978-0-444-42903-2.50038-5
Fairhead, J. D. (1988b). Mesozoic plate tectonic reconstructions of the central South Atlantic Ocean: The role of the West and Central African rift system. Tectonophysics, 155, 181–191. https://doi.org/10.1016/0040-1951(88)90265-X
Fairhead, J. D., & Green, C. M. (1989). Controls of rifting in Africa and the regional tectonic model for the Nigeria and East Niger rift basins. Journal of African Earth Sciences, 8(2–4), 231–249. https://doi.org/10.1016/S0899-5362(89)80027-2
Genik, G. J. (1992). Regional framework, structural and petroleum aspects of rift basins in Niger, Chad and the Central African Republic (C.A.R). Tectonophysics, 213, 169–185. https://doi.org/10.1016/0040-1951(92)90257-7
Genik, G. J. (1993). Petroleum geology of Cretaceous-Tertiary rift basins in Niger, Chad and Central African Republic. The American Association of Petroleum Geologists Bulletin, 77(8), 1405–1434. https://doi.org/10.1306/BDFF8EAC-1718-11D7-8645000102C1865D
Grauch, V. J. S., & Cordell, L. (1987). Short note limitations of determining density or magnetic boundaries from the horizontal gradient of gravity or pseudogravity data. Geophysics, 52(1), 118–121. https://doi.org/10.1190/1.1442236
Grieve, R. A., Thomas, M. D., & Halpenny, J. F. (1987). Horizontal gravity gradient: An aid to the definition of crustal structure in North America. Geophysical Research Letters, 14(8), 808–811. https://doi.org/10.1029/GL014i008p00808
Guiraud, R., Bellion, Y., Benkhelil, J., & Moreau, C. (1987). Post-Hercynian tectonics in Northern and Western Africa. Geological Journal, 22, 433–466. https://doi.org/10.1002/gj.3350220628
Guiraud, M. (1990). Tectono-sedimentary framework of the early Cretaceous continental Bima formation (upper Benue Trough, NE Nigeria). Journal of African Earth Sciences, 10(1–2), 341–353. https://doi.org/10.1016/0899-5362(90)90065-M
Guiraud, R., & Maurin, J. C. (1992). Early Cretaceous rifts of Western and Central Africa: An overview. Tectonophysics, 213(1–2), 153–168. https://doi.org/10.1016/0040-1951(92)90256-6
Guiraud, R., & William, B. (1997). Implications to plate-scale tectonics Senonian basin inversion and rejuvenation of rifting in Africa and Arabia: Synthesis and implications to plate-scale. Tectonics, 282, 39–82. https://doi.org/10.1016/S0040-1951(97)00212-6
Hammer, S. (1982). Airborne gravity is here! Geophysics, 48(3), 213–233. https://doi.org/10.1190/1.1436758
Hildebrand, A. R., Pilkington, M., Connors, M., Ortiz-Aleman, C., & Chavez, R. E. (1995). Size and structure of the Chicxulub crater revealed by horizontal gravity gradients and cenotes. Letters to Nature, 376, 415–417. https://doi.org/10.1038/376415a0
Hood, P., & Ward, S. H. (1969). Airborne geophysical methods. Advances in Geophysics, 13, 2–3. https://doi.org/10.1016/S0065-2687(08)60508-7
Jacobsen, B. H. (1987). Case for upward continuation as a standard separation filter for potential-field maps. Geophysics, 52(8), 1138–1148. https://doi.org/10.1190/1.1442378
Maurin, J. C., & Guiraud, R. (1993). Basement control in the development of the Early Cretaceous West and Central African rift system. Tectonophysics, 228, 81–95. https://doi.org/10.1016/0040-1951(93)90215-6
Nabighian, M. N., Grauch, V. J. S., Hansen, R. O., LaFehr, T. R., Li, Y., Peirce, J. W., Phillips, J. D., & Ruder, M. E. (2005). The historical development of the magnetic method in exploration. Geophysics, 70(6), 63–89. https://doi.org/10.1190/1.2133784
Reid, A. B., Allsop, J. M., Granser, H., Millet, A. J., & Somerton, I. W. (1990). Magnetic interpretation in three dimensions using Euler deconvolution. Geophysics, 55(4), 80–91. https://doi.org/10.1190/1.1442861
Wilson, M. (1992). Magmatism and rifting in Western and Central Africa from Late Jurassic to recent times. Tectonophysics, 213, 203–225. https://doi.org/10.1016/0040-1951(92)90259-9
Zeng, H., Xu, D., & Tan, H. (2007). A model study for estimating optimum upward-continuation height for gravity separation with application to a Bouguer gravity anomaly over a mineral deposit, Jilin province, northeast China. Geophysics, 72(4), 145–150. https://doi.org/10.1190/1.2719497