Aeromagnetic Data Analysis of Geothermal Energy Potential of a Hot Spring Area in Western Saudi Arabia

Abstract

Western Saudi Arabia is a promising area for geothermal energy exploration. Its geothermal wealth is attributed to the ongoing Red Sea rift evolution and crust thinning. Several hot springs in the region indicate the presence of potential geothermal resources. The present study aimed to characterize the geothermal system of a hot spring in the region, in the area of Wadi Al Lith, where water temperature exceeds 80 °C at the surface. For this, we used aeromagnetic data from the Saudi Geological Survey. We also collected a ground magnetic gradient data profile near the hot spring. To delineate structures of interest and map the distribution of volcanic rocks and tectonic lineaments, data enhancement filters were applied to the aeromagnetic data. These data were also subjected to spectral analysis to determine the depth of the Curie isotherm, which was then used to estimate a 1D geothermal model and predict the heat flow in the study area. According to the results of the spectral analysis of aeromagnetic data, the depth of the Curie temperature isotherm was about 14.8 km. The estimated depth was validated by deep magnetotelluric soundings, which revealed a clear decrease in resistivity at the same depth level. A constrained 1D geothermal model with three different layers (upper crust, lower crust, and mantle) was constructed. The depth of the Curie isotherm and the depth to the lithosphere's base were among the constraints. Furthermore, published data were used to define the radiogenic heat production within the crust and mantle and the corresponding thermal conductivity and thickness of each layer. According to the 1D geothermal modeling results, the average heat flow of the area reaches 109.8 mW/m², indicating potential geothermal resources. The findings of this study can be used to design a drilling program that will provide detailed information on reservoir parameters and put the geothermal resources into production.