| The development and utilization of geothermal energy will help to achieve the goals of "carbon peak" and "carbon neutralization".The performance of cementing material is one of the key factors to determine the efficiency of geothermal energy exploitation.In this paper,the microstructure,heat conduction mechanism,and thermodynamic properties of two kinds of high thermal conductivity cementing materials under different curing temperatures,pressure,time,and temperature pressure coupling environment were studied by laboratory test and microscopic test.The results are as follows:(1)It is found that the hydration product content of two kinds of high thermal conductivity cementing materials(A1,B1)is higher than that of the control,and the structure is more optimized.There is a strong negative correlation between strength and harmful porosity.It is found that the heat conduction mechanism of A1 and B1 is consistent with the heat conduction path theory and the compact packing theory.(2)It is found that the thermal conductivity and compressive strength of A1 and B1 increase gradually with the increase of curing time in the range of 20?100 ? and0.1?30 MPa;When curing for 7 days,with the increase of curing temperature and pressure,the vibration trend increases slowly at first and then decreases slowly.It is found that the microstructure of A1 and B1 is the best at 60 ? and 20 MPa.(3)It is found that the thermal conductivity and compressive strength of A1 and B1 increase at first and then decrease slowly with the increase of curing depth in the range of 0?2000 m for 7 days.The relationship between thermal conductivity and depth is obtained by fitting.It is found that at the depth of 1000 m,A1 and B1 have the highest degree of hydration,the highest content of hydration products,smaller pore size and quantity,and the densest structure.The research results of this paper can provide a reference for the efficient development and utilization of medium and deep geothermal energy. |
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