Assessment of the Geothermal Potential of the Wytch Farm Oil Field, UK

Repurposing oil and gas fields for geothermal energy has gained attention, with several global pilot projects and feasibility studies (Watson et al., 2020). The Wytch Farm oil field in southern England is a promising candidate for this transition. Studies (Singh et al., 2017; Gluyas et al., 2018; Watson et al., 2020) have highlighted its favorable infrastructure and geological characteristics for geothermal energy. With a significant decline in hydrocarbon output (water cut of ~90%), the economic viability of oil extraction has diminished, creating an opportunity for geothermal applications (Gluyas et al., 2018).Wytch Farm’s primary Sherwood Sandstone reservoir, at 1585m depth, is targeted for low-enthalpy geothermal energy production. This transition could extend the field’s operational life and contribute to the UK’s decarbonization goals by providing renewable, low-carbon energy. Potential geothermal district heating markets include Poole, Weymouth, Dorchester, and possibly larger urban centers like Bournemouth, assuming efficient infrastructure minimizes heat loss.Accurately evaluating geothermal potential is crucial for determining energy output, economic feasibility, and the design of heating systems or geothermal plants. This study quantifies potential energy output from Wytch Farm wells, providing a foundation for a detailed feasibility evaluation, while accounting for geological and operational uncertainties.Though Wytch Farm has been identified as a potential geothermal resource, previous studies did not fully address temperature and depth estimates. Recorded temperatures of 65-67°C (Singh et al., 2017; Gluyas et al., 2018; Watson et al., 2020) were cited, but our preliminary analysis of corrected bottom-hole temperature (BHT) data from the Sherwood Sandstone suggests a temperature range of 75-98°C. This indicates that earlier studies may have underestimated the geothermal potential of the site. Elevated reservoir temperatures are also observed in offshore and certain onshore wells.In conclusion, this study highlights the potential of repurposing Wytch Farm for geothermal energy production, providing a more accurate assessment of its geothermal capacity and identifying factors influencing heat retention. The initial findings support the feasibility of transforming the site into a renewable energy resource, aligning with the UK’s decarbonization goals, and demonstrating the role of legacy oil and gas fields in the sustainable energy transition.References:Gluyas, J. G., et al. (2018). Keeping warm: a review of deep geothermal potential of the UK. Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy. Singh, H., et al. (2017). Harnessing Geothermal Energy from Mature Onshore Oil Fields-The Wytch Farm Case Study. Work. Geotherm. Reserv. Eng. Watson, S. M., et al. (2020). Repurposing hydrocarbon wells for geothermal use in the UK: The onshore fields with the greatest potential. Energies.