High-temperature treated oil-rich bedded rock layer and deterioration mechanism of heat transfer performance

The study of the changes in heat transfer properties of oil-rich bedded rock layer at high temperatures is important for the development of projects such as underground coal gasification, geothermal mining and nuclear plant construction. In this paper, the change characteristics of heat transfer performance of oil-rich bedded rock layer after high-temperature treatment were studied from macro-meso-microscopic perspective by systematic testing means such as thermal parameter test, NMR, XRD and SEM, and the influence law of temperature and heating time on heat transfer performance was grasped, and the deterioration mechanism of heat transfer performance was revealed. The results show that the heat transfer performance of baseboard rock layer undergoes significant deterioration after high-temperature treatment, with the greatest deterioration rate in the temperature interval of 400 ℃-600 ℃ and 500 ℃ as the temperature threshold for rapid deterioration. The content of the main mineral components such as quartz and kaolinite, which affect the density of the geotechnical structure within the specimens, changed significantly, with the percentage of quartz in the mudstone specimens decreasing from 93 to 83% and kaolinite from 5 to 2%. The percentage of quartz in the siltstone decreased from 91 to 82%, and kaolinite decreased from 6 to 1%. This led to a rapid deterioration of the heat transfer properties of baseboard rock layer, with a reduction in thermal conductivity of 47.2% for mudstone and 58.9% for siltstone.