Integrated 2D joint inversion models of gravity, magnetic, and MT for geothermal potentials: a case study from Gujarat, India

Abstract

Joint Inversion of different geophysical potentials promises to reduce chances of uncertainties which are more probable in case of independent inversions. In this paper, cross-gradient Joint Inversion was applied for gravity, magnetic, and MT data to understand the subsurface geothermal potential in Dholera and Unai, Gujarat, India. This paper narrates the understanding of individual inversion for gravity, magnetic, and MT data followed by joint inversion to delineate more clear understanding of geological and geothermal bodies in the subsurface. To formulate data space, a generalized cross-gradient inversion for data set and model set parameters are discussed. On the basis of the algorithm proposed, an integrated subsurface model for Dholera and Unai was prepared which depicts geological as well as lithological characteristics of the area. For the structural coupling, a Lagrange data multiplier was applied in an iterative manner to reach a global minima. Fluid flow models of Dholera and Unai were prepared where “J” type drilling is suggested up to a depth of 800 m and 700 m, respectively.