KAUST Geothermal Exploration Project (K-GEP) – A Promising Solution for Green, Clean, Sustainable Energy Provision

Abstract In arid countries with a continuously growing population, affected by depleting fossil aquifers and stressed by the impact of climate change, the dependency on fossil fuel consumption for desalination and cooling may be reduced using medium-enthalpy geothermal energy. By harvesting geothermal resources, clean and sustainable energy for desalination, district cooling, and brine mineral extraction may be targeted. In our K-GEP project, we aim to demonstrate a comprehensively integrated approach. We started to explore the Kingdom’s geothermal potential by drilling a shallow pilot hole on KAUST campus, located along the Red Sea shore. The pilot hole reached a depth of ~400m and provided an opportunity during drilling and subsequent logging to acquire a variety of data ranging from fiber optic distributed acoustic and temperature sensing (DAS & DTS), seismic while drilling, and multi-scale ambient-noise seismic monitoring. Drill cuttings reveal a complex heterogeneous lithology varying between sandstones, claystones, gypsum, anhydrite, and dolomite intervals. Some of these are challenging for drilling. A major unconformity from the Plio-/Pleistocene Lisan group to the Mid-Miocene Kial formation is interpreted at a depth of ~75m. Some of the layers described by wellsite geology can also be resolved using DAS in combination with advanced seismic ambient-noise processing methods. Repeated temperature measurements along the hole (both logging and DTS) confirm an average heat gradient of ~31°C/km (once downhole temperatures had recovered from the drilling process). Although the Red Sea Shore is only a lateral distance of ~1.1 km away from the well location, an aquifer system at the bottom of the well shows a distinct chemical signature different from sea water (including elevated lithium concentration). Our preliminary results suggest that the K-GEP project has the potential to prove the feasibility of low to medium-enthalpy geothermal development in KSA based on cascaded energy extraction.