Exploration of a geothermal reservoir using geoelectrical resistivity inversion: case study at Hammam Mousa, Sinai, Egypt

Abstract

Geoelectrical resistivity is a pioneer geophysical technique used in geothermal exploration. With the advent of computing technology, it has become convenient to apply sophisticated data analysis and inversion to geoelectrical resistivity field data. In this work, a geoelectrical resistivity survey was conducted in the Hammam Mousa area to explore the geothermal resources and groundwater aquifer. The survey comprises 19 vertical electrical soundings (VES) using the well-known Schlumberger array with AB/2 up to 1000 m. Interpretation of one-dimensional (1D) inversion gave a layered-earth resistivity model using a nonlinear least-squares method. However, some resistivity sections of the 1D inversion were not fully resolved for the complicated geologic structure. Therefore, we carried out a two-dimensional (2D) inversion based on the ABIC least-squares method for the same data set. The general distribution of resistivity shows a very low value near Hammam Mousa Hot Spring. The 2D resistivity cross section clearly elaborates the subsurface structure in the spring area and it elucidates and gives an explanation for the hot water source in the area. It is concluded that the hydrothermal system in the Hammam Mousa area is adequately delineated from the 1D and 2D inversions of vertical electric sounding data using a Schlumberger electrode array. Accordingly, a proposal for geothermal drilling in the study area is recommended.