Gravity Field Numerical Analysis and Depth Structure of the South-Eastren Caucasus

Abstract

In this paper, the gravity anomalies of the Bouguer of the Absheron, Shamakhi-Gobustan and Pricaspian-Guba oil- and gas-bearing regions are interpreted by the 3D prism method. According to this model, a part of the earth's crust covering the crystalline basement is considered as a set of many prisms located nearby. The depth of the surface of the crystalline basement is calculated taking into account the change in density at the bottom of the low velocity zones of the upper part of the earth's crust and the dependence of the density difference on depth according to a quadratic law. For interpretation of the gravity anomalies in the Absheron, Shamakhy-Gobustan and Pricaspian-Guba regions, a sedimentary basin viewed as, a number of prisms placed in juxtaposition. The decrease of density contrast in sedimentary basins approximated by, a quadratic function. The contour map is sampled at 1160 equispaced points with 5 km interval. The depths to the interface separating sedimentary were calculated using a generalized computer program GR3DSTR for 3-D inversion of gravity data either for a constant density contrast or for a variable density contrast with depth. From 3D gravity model of the sedimentary layer, it was found that the maximum depth is in the areas of Gyuzdek and Meraza (11 km), and the minimum is in the areas of Gonakkend, Gilazi, Garabulag, Dubrar (4 km). The depth of the sedimentary layer around the Agzibirchala well varies within 6 km. The correlation of the distribution of the thickness of the sedimentary layer on the site with the seismic section and well sections was determined. KEYWORDS – gravity anomaly, sedimentary basin, oil and gas fields.