Jiamin Wang , Yun Wu , Pengyu Mu , Chongyuan Zhang , Xiangshang Li
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引用次数: 0
Abstract
In order to exploit deep geothermal resources, it is critical to comprehensively understand the meso‑damage mechanism and physico-mechanical properties of high-temperature rocks after water-cooling treatment. In this paper, water-cooling experiments were carried out on granite at varying temperatures (20 °C, 150 °C, 300 °C, 450 °C, 600 °C and 750 °C), and the corresponding damage degree of microstructure was quantitatively assessed by computed tomography, optical electron microscopy, and nuclear magnetic resonance The effects of thermal shock on physical and mechanical parameters such as elastic wave velocity, permeability, uniaxial compressive strength (UCS) and elastic modulus of granite were analyzed. The results showed that the number and size of cracks in granite increase gradually with the increase in heating temperature; in particular, when the temperature rises to 600 °C and 750 °C, the proportion of macropores significantly increase, indicating the development and penetration of pores and cracks, which leads to the aggravation of the meso‑damage degree of granite. The fractal dimension of pores decreases with the increase in temperature, which shows that high temperature refines the pore structure. However, the fractal dimension of mesopores and macropores is insensitive to temperature variations. The meso‑damage of granite directly affects its physical and mechanical properties. The P-wave velocity, uniaxial compressive strength and elastic modulus of granite gradually decrease with temperature increase, whereas the peak strain gradually increases. The permeability of granite also exhibits a trend of slow increase first and then rapid rise, similar to the porosity variation trend. The results provide valuable theoretical support for evaluating the thermal energy utilization efficiency of hot dry rock and the stability analysis of reservoir reconstruction projects.
期刊介绍:
Geothermics is an international journal devoted to the research and development of geothermal energy. The International Board of Editors of Geothermics, which comprises specialists in the various aspects of geothermal resources, exploration and development, guarantees the balanced, comprehensive view of scientific and technological developments in this promising energy field.
It promulgates the state of the art and science of geothermal energy, its exploration and exploitation through a regular exchange of information from all parts of the world. The journal publishes articles dealing with the theory, exploration techniques and all aspects of the utilization of geothermal resources. Geothermics serves as the scientific house, or exchange medium, through which the growing community of geothermal specialists can provide and receive information.