Optimizing Geothermal Energy Extraction from Decommissioned Oil Wells: the Case Study of the Villafortuna-Trecate Oil Field

Currently, there are 20-30 million decommissioned hydrocarbon wells worldwide, presenting an excellent opportunity for geothermal energy production. The debate over disused hydrocarbon wells revolves around whether to seal them to avoid potential issues or to reuse them to transition to sustainable energy. Shutting down these wells involves significant costs and challenges, including financial challenges, environmental risks such as pollution and methane leakage. One viable solution is to repurpose these wells to extract geothermal energy from existing deep hydrocarbon reservoirs, minimizing initial costs by 40 to 60% and resulting in revenue generation, reduction of leaking emissions, and maintenance of workforce involvement. Reusing of these wells must adapt to local energy demand, potential markets, existing infrastructure and technical obstacles. Until now, most studies have either been scattered or focused on determining if converting a particular wells is possible. The aim of this study is to assess the geothermal potential within the depleted Villafortuna-Trecate oil field in Italy. This will be achieved by utilizing information from the Ministry of Economic Development, published data on hydrocarbon fields, and estimated depth temperatures from the Italian National Geothermal Database. We will employ simplified closed-loop system models developed and applied to specific wells using Python to facilitate this assessment. The present study examines the feasibility of implementing a Coaxial Wellbore Heat eXchanger CWHX on four promising wells in one of the Europe's largest and deepest oilfields, the Villafortuna-Trecate oilfield, with a focus on optimizing the WHX for maximum heat extraction. The study concludes that while challenges exist, such as high initial costs and technical complexities, repurposing these wells can generate sustainable energy and reduce environmental impact, particularly through district heating applications and industrial processes.