Document Type : Review Paper

Authors

• Alireza Behinrad ¹
• Seyyed Shahab Tabatabaee Moradi ²
• Ehsan Jafarbeigi ³

¹ Faculty of Petroleum and Natural Gas Engineering, Sahand University of Technology, Tabriz, Iran

² Faculty of Petroleum and Natural Gas Engineering, Sahand University of Technology, Sahand New Town, Iran

³ Department of Chemical and Petroleum Engineering, Ilam University, Ilam, Iran

Abstract

This research investigates the factors influencing the mechanical behavior of rock in geothermal reservoirs, also examining the role of working fluid in extracting heat from geothermal systems. Geothermal reservoirs involve several processes: thermal, hydraulic, mechanical and chemical. Thermal, hydraulic, and mechanical processes can lead to the generation of stresses and related changes in the structural properties of the rock, which will impact the heat extraction performance and the overall stability of the geothermal reservoir. Choice of working fluid, such as water or carbon dioxide, would affect the performance of heat extraction - but, more importantly, alter the mechanical and structural behavior of the rock. Some studies have shown that supercritical carbon dioxide can enhance heat extraction efficiency due to its combination of thermal and chemical properties, thereby minimizing environmental impacts. This working fluid alters rock mechanical properties through chemical reactions, including dissolution and precipitation, which can also impact rock integrity and permeability. Through examinations of laboratory data and existing models from previous studies, this research will conclude the central importance of managing the factors that affect the mechanical and structural behavior of the rock and ensuring optimal operational conditions for the sustainable performance of geothermal systems. This research demonstrated that effectively managing factors affecting rock properties and changes in their condition can optimize stability in geothermal reservoirs and improve energy output. Finally, this study provides suggestions for improving the performance of geothermal systems under different operating conditions.

Keywords

• Geothermal reservoirs
• Mechanical behavior
• Working fluid
• Carbon dioxide
• Heat transfer