A Green solution for depleted oil wells integrating it in the territory

The ongoing acceleration of the transition from traditional fossil fuels to renewable energy sources will entail the progressive phase-out of hydrocarbon production. This process will possibly also involve the gradual shut-in of hydrocarbon producing wells, which will eventually be plugged and abandoned. In this context, the objective of this paper is to demonstrate the existence of valid alternatives to avoid such an irreversible process. Indeed, the availability of existing deep wells corresponds to an avoided cost for geothermal applications and it is an opportunity for the community to develop new green businesses. The case study considered is the Irminio field located in Southern Italy. In this field several wells are currently producing oil and gas and the co-produced gas is used in a cogeneration plant. This solution has been adopted to integrate a cogenerator into the production process to make the best use of the tail gas of the plant, which currently cannot be released into the atmosphere or flared. The basic idea is to integrate the present plant into a circular economy. The proposed solution is based on an Anaerobic Digestion plant for the production of Biogas that will be exhausted and biogas will replace it in the cogenerator. This study analyses two different scenarios to provide a complete view of the potential of this solution. The first scenario is “as it is” and the second one requires the improvement of the production from well. Improving the thermodynamic conditions of the well requires the installation of a pump. This will enable to use of the well stream for anaerobic digestion with a thermophilic process increasing the biogas production. The biomass used for the process allows the development of a possible collaboration between the owning company and the province of Ragusa (RG), in compliance with the circular economy principles. A possible improvement of the plant is the use of combustion gases and a part of the thermal stream in algae cultivation to be fed to the nearby plant for biofuel.