Assessing Possibility of Carbon Dioxide Injection into Formations of Oil and Gas Fields for Geothermal Energy Production: A Case Study

This study investigates the feasibility of utilizing carbon dioxide (CO₂) injection into depleted oil and gas reservoirs for geothermal energy production, aiming to enhance energy efficiency. A novel "wells-reservoir-power unit" system is proposed, where CO₂ serves as a working fluid in a closed-loop petrothermal cycle. The system integrates injection and production wells, a geothermal reservoir, and a power generation unit, modeled using Aspen HYSYS software. Key parameters such as CO₂ flow rates, tubing diameters, and thermodynamic conditions were analyzed to optimize energy output. Simulation results demonstrate that increasing tubing diameter reduces pressure losses and improves thermal power generation, with optimal flow rates identified for maximum efficiency. The system achieved a positive energy balance under specified conditions, scalable by increasing the number of wells. Temperature and pressure profiles confirmed CO₂ transition to a supercritical state within the reservoir, critical for efficient heat extraction. The results of the work can be used to carry out measures to reduce carbon footprint and improve energy efficiency of oil and gas production, transportation, treatment and refining processes in field conditions.