3-D gravity modeling of basement reliefs an offshore case study in the Persian gulf, Iran
In this paper we have proposed a three-dimensional approach to determine depth of basement in which the density contrast varies parabolically with depth. This program based on Newton’s forward difference formula that with optimization of gravity anomalies calculate depths of basement reliefs indeed are anticlinal and synclinal structures has been buried under sediments. This structures are the causes of the positive and negative gravity anomalies. We assume the measured gravity fields have been distributed on a horizontal plane and also sedimentary basin is combined of juxtaposition 3-D cubic prisms. The measurement stations of the gravity field (grid nodes) coincide with center blocks. The initial depth is computed using gravity data and the estimated depths are adjusted with iteration. The advantage of the method is utilization of positive and negative gravity anomalies together as two inputs for written algorithm as well as application of a coded non-linear filter. The efficiency of the code is illustrated with a set of synthetic gravity anomalies. Further, the code is exemplified with the gravity anomalies of an offshore case study in the Persian Gulf, Iran. The purpose of exploratory project in this area will include the development of Hydrocarbon Fields.
Keywords: Basement, Gravity Anomalies, Newton’s Forward Difference Formula, Non-Linear Filter, Persian Gulf.
Athy, L.F., Density, porosity, andcompact ion of sedimentary rocks. Bulletin of the American Association of Petroleum Geologists 14(1930) 1–24.
Hedberg, H.D., The effect of gravitational compaction on the structure of sedimentary rocks. American Association of Petroleum Geologists Bulletin 10(1936) 1035–1072.
Weller, J.M., Compaction of sediments. Bulletin of the American Association of Petroleum Geologists 43(1959) 241–287.
Ham, H.H., New charts help estimate formation pressure. Oil Gas Journal 65(1966) 58–63.
Foster, J.B., Whalen, H.E.,Estimation of formation pressures from electrical surveys—offshore Louisiana. Journal of Petroleum Technology 18(1966) 165–171. http://dx.doi.org/10.2118/1200-PA.
Chakravarthi, V., Sundararajan, N., Automatic 3-D gravity modeling of sedimentary basins with density contrast varying parabolically with depth. Computers & Geosciences 30 (2004) 601–607. http://dx.doi.org/10.1016/j.cageo.2004.03.014.
Chakravarthi, V., Singh, S.B., Ashok Babu, G., INVER2DBASE-A program to compute basement depths of density interfaces above which the density contrast varies with depth. Computers & Geosciences 27 (2001) 1129–1133. http://dx.doi.org/10.1016/S0098-3004 (01)00035-8.
Naudy, H., Dreyer, Essai de filtrage non-linéaire appliqué aux profils aéromagnétiques.Geophysical Prospecting 16(1968) 171–178. http://dx.doi.org/10.1111/j.1365-2478.1968.tb01969.x.
Chakravarthi, V., Raghuram, H.M., Singh, S.B., 3-D forward gravity modeling of density interfaces above which the density contrast varies continuously with depth. Computers & Geosciences 28 (2002), 53–57. http://dx.doi.org/10.1016/S0098-3004 (01)00080-2.
Konyuhov, A. I., Maleki B., The Persian Gulf Basin: Geological history, sedimentary formations, and petroleum potential. Lithology and Mineral Resources, Volume 41(2006) 344-361. http://dx.doi.org/10.1134/S0024490206040055.