Universität zu Köln

Ashadi, Abdul Latif ORCID: 0000-0002-6239-0070 (2025). Optimizing Magnetotelluric Studies for Geothermal Exploration in Western Saudi Arabia: A Comprehensive Study of 3D Forward and Inverse Modeling Approaches. PhD thesis, Universität zu Köln.

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Abstract

With its ambitious vision of 2030, Saudi Arabia has recognized the need to reduce its dependence on fossil-based energy and has taken concrete steps to diversify its energy sources. Among the priorities is the development of renewable energy, including geothermal resources. This thesis focuses on the application of Electromagnetic (EM) methods, specifically Magnetotellurics (MT) and Transient Electromagnetics (TEM), for the exploration of geothermal resources in the Al-Lith’s area, western Saudi Arabia, one of the most promising sites for geothermal development in Saudi Arabia. To comprehensively investigate and explore the prospect of geothermal resources in the area, broadband MT data covering a period range of 0.001–512 seconds were acquired at 50 locations, along with 13 TEM soundings. The phase tensor and its skew calculations revealed a complex subsurface conductivity structure, characterized by predominantly 1D/2D geoelectric behavior for short periods (< 2 sec) and a more complex 3D structure for longer periods. Prior to the inversion of the MT data, 3D MT synthetic modeling and inversion studies were carried out to assess the detectability of geothermal anomalies, optimize survey parameters, and evaluate the sensitivity of various parameter inputs applied in the 3D inversion. In order to ensure the robustness of the inversion results, extensive 3D MT inversion tests were performed. The resistivity model derived from TEM data was incorporated to optimize the 3D MT inversion. The final 3D resistivity model, with an RMS of 1.96, provides a high-resolution image of the geothermal system, delineating the heat source, convection pattern, and groundwater system. The geothermal reservoir is represented by deep elongated conductive bodies (< 20 Ωm) extending from 2.5 to over 8 km in depth. The individual protrusions above the reservoir indicate the pathways for geothermal fluids, forming convection cells from the reservoir to the surface or near the surface, potentially leading to an active geothermal surface manifestation (hot spring). The outcome of this study serves as the key input to understanding the complexity and characterization of the geothermal system of the Al-Lith region, confirming its potential for geothermal exploration and development efforts in Saudi Arabia.

Item Type:	Thesis (PhD thesis)
Creators:	Creators Email ORCID ORCID Put Code Ashadi, Abdul Latif latif.demak@gmail.com orcid.org/0000-0002-6239-0070 UNSPECIFIED
URN:	urn:nbn:de:hbz:38-781797
Date:	2025
Language:	English
Faculty:	Faculty of Mathematics and Natural Sciences
Divisions:	Faculty of Mathematics and Natural Sciences > Department of Geosciences > Institute for Geophysics and Meteorology
Subjects:	Earth sciences
Uncontrolled Keywords:	Keywords Language Geothermal Exploration English Magnetotellurics English Transient Electromagnetics English 3D inversion English Saudi Arabia UNSPECIFIED
Date of oral exam:	28 April 2025
Referee:	Name Academic Title Tezkan, Bülent Prof. Dr. Becken, Michael Prof. Dr.
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/78179