Assessment of Geothermal Resources and Hydrogeological Conditions in the Pre-Caspian–Guba Zone

The utilization of thermal waters as a renewable energy source is one of the most significant priorities of modern energy policy. Unlike fossil fuels, clean energy sources contribute to long-term improvements in human health and mitigate short-term mortality associated with air pollution. At the same time, the progressive depletion of conventional oil and gas reserves, which have been exploited for decades, further strengthens the urgency of identifying alternative solutions. As the hydrocarbon industry is a leading contributor to global climate change, the gradual abandonment of such fuels is inevitable. Consequently, adopting renewable and sustainable resources such as solar, wind, hydropower and geothermal energy is imperative. These sources have low carbon footprints and negligible emissions, making them vital in reducing greenhouse gas concentrations and tackling climate change. Therefore, the global transition to renewable energy is not only environmentally necessary, but also critical for securing a sustainable future.Systematic geological and exploratory investigations have been conducted in the Caspian–Guba region to assess geothermal potential. Drilling activities have revealed thermal waters with discharge rates ranging from 300 to 2000 mÑ/day and temperatures between 50°C and 90°C within the Jurassic and productive strata. For example, well no. 3 in the Khudat area had a yield of 4,500 mÑ per hour and a recorded surface temperature of 81 °C. Since 1983, systematic geothermal monitoring has been carried out in wells drilled across Nabran, Khudat, Khachmaz and the surrounding area. The estimated reserves of thermal waters in the Jurassic, Cretaceous, Maikop and Absheron deposits in the Caspian–Guba zone are approximately 81.4 thousand mÑ/day. Furthermore, hydrogeological assessments suggest that renewed exploration efforts, particularly the rehabilitation of wells that were previously drilled but did not penetrate hydrocarbon-bearing layers, could increase the exploitable reserves of thermal waters by two to three times.