Utilization of existing hydrocarbon wells for geothermal system development: A review.

• Repurposing abandoned wells for geothermal utilization increases its deployment. • Bottomhole temperature is a detrimental factor to assess the viability of a geothermal system. • An operating full well conversion project to be implemented. • Repurposing abandoned wells holds significant economic and environmental advantages. • Assessment on a per-well basis needs to be performed. This review focuses on repurposing abandoned hydrocarbon (oil and gas) wells for the geothermal system development. There are approximately three million abandoned wells in the United States alone, and these wells emit alarming amounts of greenhouse gases and pose serious health hazards. These issues can be addressed by repurposing abandoned wells for the utilization of geothermal energy systems, leading to an increase in the number of geothermal systems deployments. Despite this potential, there are only a few numbers of installations of a geothermal system converted from hydrocarbon wells. Therefore, this study presents a comprehensive review on the current status of abandoned wells, potential risks to environment and human health they pose, and available feasibility and pilot studies on repurposing oil and gas wells for geothermal system development. The challenges, opportunities, and pathways to improve the current understanding of repurposing wells are presented in detail. Utilization of existing wells for an advanced geothermal energy storage system development for flexible energy generation is proposed. [ABSTRACT FROM AUTHOR]