Evaluating outlet working fluid’s temperature by implementing closed-loop geothermal systems in decommissioned hydrocarbon wells: the case studies of San Benigno and Cinzano wells

Abandoned hydrocarbon wells offer significant potential for extracting geothermal energy from the subsurface if effectively repurposed. Among the discussed geothermal systems, closed-loop wellbore heat exchangers (WBHEs) represent one of the most promising technologies. Simplified methods to assess the exploitable temperature potential of decommissioned wells, using coaxial and U-tube WBHEs and integrating geological and technical considerations, have been developed and are available in the literature. Such solutions are useful tools for evaluating the suitability of a selected well for geothermal repurposing during the preliminary analysis phase. This study focuses on the application of simplified approaches for the preliminary assessment of the extracted temperature following the implementation of coaxial and U-tube WBHEs in the San Benigno and Cinzano wells, leveraging on-site temperature data. These assessments allowed the identification of these wells as economically unsuitable for repurposing, unlike others studied and located within the Italian territory.