Reconversion of decommissioned hydrocarbon wells for geothermal energy purposes: the influence of the well geometry and the geological context

Renewable energy resources are vital due to their capacity to combat climate change by significantly reducing greenhouse gas emissions, ensuring energy security by diversifying the energy mix and decreasing reliance on finite fossil fuels, while also offering sustainable, long-term solutions. Their importance extends to fostering economic growth through job creation and innovation, mitigating environmental damage by minimizing pollution and habitat destruction, and enhancing the resilience of energy systems in the face of disruptions. Furthermore, the decreasing costs and increasing competitiveness of renewables make them an economically viable choice, marking a pivotal shift towards a cleaner, more sustainable global energy landscape. Renewable energy sources are the superheroes of sustainability, harnessing natural elements like the sun, wind, water, and Earth's heat to power our world. Solar energy, derived from sunlight, is captured through solar panels and converted into electricity or used for heating. Wind energy, harvested by towering turbines, transforms the kinetic energy of wind into electrical power, becoming one of the fastest-growing renewable resources globally. Hydropower, generated from flowing water, propels turbines to produce electricity, often through dams or rivers. Biomass, derived from organic materials, is utilized by burning or conversion into biofuels, offering a renewable alternative to traditional fossil fuels. Geothermal energy taps into the Earth's heat, using steam or hot water to generate electricity or for heating purposes. Tidal energy, stemming from the motion of tides, employs underwater turbines to harness this constant movement for power generation. Together, these renewable resources pave the way for a cleaner, sustainable future, reducing our reliance on finite fossil fuels and combating climate change. Deep wells play a crucial role in harnessing geothermal energy, particularly for power generation and heating purposes. These wells are drilled deep into the Earth's crust, tapping into reservoirs of hot water or steam located beneath the surface. The drilling process involves penetrating through layers of rock to access these geothermal reservoirs, which can range in temperatures from moderately hot to extremely high temperatures. Once drilled, these wells act as conduits to bring the geothermal fluids—hot water or steam—up to the surface or as a heat exchanger in closed loop circuits. The extracted fluids carry immense thermal energy accumulated from the Earth's heat. In geothermal power generation, the hot water or steam is used to drive turbines, generating electricity. In heating systems, this energy is directly utilized for warming buildings or for industrial purposes. The depth of these wells is crucial because the deeper they go, the higher the temperatures of the extracted fluids, resulting in more efficient energy production. However, drilling deeper wells can be more challenging and expensive due to geological complexities and technical requirements. In this study, the possibility of reconversion of decommissioned deep wells such as hydrocarbon wells for geothermal energy purposes considering the influence of the well geometry and the geological context was investigated. In this way, we are able to decrease the drilling costs by reusing the already available deep wells.