Feasibility of Repurposing Oil and Gas Wells for Geothermal Energy Production in Wyoming, USA

ABSTRACT: Wyoming possesses a substantial infrastructure of existing oil and gas wells. This study investigates the potential of repurposing abandoned and inactive oil and gas wells for geothermal energy production. While Wyoming's subsurface geology does not offer significant geothermal resources overall, utilizing existing wells could provide easy access to the existing resources, or provide access to previously unprofitable resources while significantly reducing the cost. Our analysis examines wells and geological data to identify suitable candidates for repurposing. Factors considered include well depth, bottom-hole temperature, temperature gradient, casing design, and proximity to potential energy demand centers. We conclude the study with a numerical simulation for geothermal energy production from a selected candidate well under Huff-n-Puff production strategy. Our findings outline the potential geothermal capacity that could be exploited through well repurposing. This offers an actionable path toward energy diversification and a reduced environmental footprint for the state of Wyoming. 1. INTRODUCTION Geothermal energy, derived from the Earth's internal heat, offers a unique and compelling solution to the world's growing energy demands and the trend towards decarbonization of the planet (Sharmin et al., 2023). This heat is generated by the radioactive decay of elements deep within the Earth's core and by residual heat from planetary formation. Geothermal energy can be harnessed for a wide range of applications, including electricity generation, urban heating, and agricultural and industrial processes. One of the primary advantages of geothermal energy over other renewable sources, such as solar and wind, is its inherent consistency, as it is not intermittent or dependent on weather conditions, providing a reliable and baseload source of power (Kulasekara & Seynulabdeen, 2019). Amid escalating environmental concerns surrounding fossil fuels, geothermal offers a clean and sustainable energy source with a significantly smaller carbon footprint. The transition to geothermal energy represents not only an environmental imperative but also a strategic move to reduce dependence on volatile fossil fuel markets (Orujov et al., 2023). While significant hurdles exist in harnessing this vast and practically infinite resource, its potential is worthy of tackling the associated challenges. With continued investment and technological innovation, geothermal energy could ultimately revolutionize the global energy landscape. Several types of geothermal energy systems exist, each tailored to harness this thermal energy in a different way. Open-loop systems utilize existing groundwater sources, pumping hot water for direct use or to power heat exchangers. Closed-loop systems circulate fluid through underground pipes, absorbing heat from the surrounding earth. Enhanced geothermal systems (EGS) increase the permeability of rock formations using hydraulic fracturing, facilitating greater heat extraction, and enabling geothermal development in areas once considered unsuitable such as geological formations with low permeabilities (Chellal et al., 2022).