The decarbonisation of the energy sector is probably one of the main worldwide challenges of the future. Global changes urge a radical transformation and improvement of the energy-producing systems to meet the decarbonisation targets and a reduction of greenhouse gas emissions. The hydrocarbon industry also contributes to this transition path. In a mature stage of oil and gas fields, the production of hydrocarbons is associated with formation waters. The volume of produced water increases with the maturity of the assets and the conversion into geothermal wells could be an alternative to the mining closure. In the described transition scenario, the geothermal energy seems very promising because of its wide range of applications depending onthe temperature of extracted fluids. This flexibility enables to propose projects inspired to a circular economy vision with the integration in the territory and social acceptance. In Italy, since 1985, 7246 well has been drilled for hydrocarbonof which 898 are located on-shorewith a productive or potentially productive operational status. The paper presents a preliminary investigation on oil and gas fields located on shore in Italian territory based on the available informationon temperature distribution at different depth. Then, taking into account the local energy demand, existing infrastructure, and land use of the territory, a conversion strategy for the producing wells has been proposed for three case studies.