Natural Fracture Characterization Through Digital Outcrop Model in Southwestern Saudi Arabia Geothermal Field

Abstract

Geothermal energy is the heat energy stored in the subsurface of the Earth due to the decay of radioactive elements within the mantle and the crust (Schubert et al., 1980). This energy is continuously produced, making it a sustainable and renewable energy source (Owusu and Asumadu-Sarkodie, 2016). One of the key advantages of geothermal energy is its capacity to provide baseload power that can be run constantly to fulfill the energy demands of any society, making it a dependable and persistent source of energy. Unlike other renewable energy sources such as solar and wind, geothermal energy, it is not affected by weather or daylight and can supply a consistent source of electricity day and night. Saudi Arabia possesses significant geothermal resources along of western boundary for both volcanic and non-volcanic geothermal systems (Chandrasekharam et al., 2014; Lashin et al., 2014; Al-Douri et al.,2019; Abu-Mahfouz et al., 2023). One of the potential geothermal areas is in Jizan, Southwestern Saudi Arabia (Hussein et al., 2013; Chandrasekharam et al., 2016; Arrofi and Abu-Mahfouz, 2023). Despite the fact that Jizan has a medium-high enthalpy system, it is largely underutilized. One of the most prevalent challenges encountered during exploitation is a low permeability reservoir to allow fluid circulation. However, it can be addressed by undertaking a detailed study of characterizing natural fractures both in the surface and subsurface. Natural fractures might enhance fluid circulation and permeability, making geothermal extraction a more viable option (Arrofi et al., 2022; Viswanathan et al., 2022; Abu-Mahfouz et al., 2023). It is crucial to investigate the distribution, orientation, and connectivity of fractures in geothermal systems. In the Al-Ardah geothermal field, located in Jizan, hydrothermal fluid is believed to flow from the eastern region, following the dip direction of the regional faults, and discharge on the western side (Arrofi et al., 2023). The reservoir area is indicated to be in the eastern region of Al-Ardah within the granitic rock (Fig. 1). Additionally, the granitic rock in the Al-Ardah area had undergone significant alteration due to intense interaction with the thermal water (Lashin and Al Arifi, 2014). It also suggests that the reservoir is located in the eastern part of the hot springs area. This study aims to characterize fractures and investigate fluid flow in the eastern part of Al-Ardah, Jizan, using an outcrop analogue (see the study location in Fig. 1).