Comprehensive Assessment of Technological and Economic Advantages of Oil and Gas Wells Re-Profiling for Geothermal Projects

The relevance of the research topic is due to the need for optimal use of existing infra-structure, reducing costs for the construction of new wells, as well as providing environmentally friendly energy for the region and the state.Analysis of the technological and economic advantages of reprofiling wells: determining the geological conditions of the Dnieper-Donets Basin, which contribute to the production of geothermal energy, assessing reservoir temperatures, depth and flow rates of wells to con-firm the project's prospects, modeling heat flows, using FEFLOW software to calculate heat energy flows in a system with a doublet of wells, determining the optimal parameters of the system's operation, assessing heat losses and risks of cold breakthrough between wells, predicting the project's investment payback over an acceptable period of time, taking into ac-count the annual production of heat energy and the use of existing infrastructure.The purpose of this work is to analyze the opportunities, advantages and challenges of reprofiling oil and gas wells in the DDZ, taking into account technical, economic and environmental aspects using modeling in the Feflow program.The study outlined the technological and economic advantages and confirmed the high relevance of re-profiling previously constructed oil and gas wells for the development of geo-thermal energy at the DZ facilities in Ukraine. In particular, wells H-1 and L-4 for geothermal energy production. The geological conditions of the Dnipro-Donetsk Basin, reservoir temperatures of 120–130 °C, a depth of more than 5000 m and a high flow rate of up to 2592 m³/day ensure the prospects for project implementation. The modeling performed in the FEFLOW software allowed us to calculate the heat energy flows for an open system with a duplicate well, determine the optimal system parameters, and assess heat losses and risks of cold break-through between wells. The calculations confirmed the economic benefits of re-profiling wells compared to building new ones. The investment payback period of the project was also predicted to be about 4 years, taking into account the annual heat production and the use of existing infrastructure.