Study Of Thermal Properties Of Carbonate Rocks And Minerals Based On The First Principles

Carbonate minerals are widely distributed and are one of the common mineral types on earth.The research on carbonate minerals formation and thermophysical parameters are of great significance for the utilization of carbonate reservoir geothermal resources.The crystal simulation software(MS)is used to simulate and analyze the crystal structure changes during the calcite-dolomite-magnesite substitution process.By establishing different carbonate minerals crystal models,the thermophysical parameters of common carbonate minerals and their variation patterns are calculated,obtaining the quantitative relationship between the thermophysical parameters of carbonate minerals and the average atomic weight.Besides,the thermal properties of ferrous dolomite are predicted.The thermal conductivity and specific heat of typical dolomite samples in North China are tested and simulated.Based on traditional methods,new technical means are used to study thermophysical parameters of carbonate minerals to provide theoretical basis for development and utilization of carbonate minerals.The main content is as follows:The variations of the crystal structure during the formation of calcite-dolomite-magnesite are simulated and analyzed based on the crystal simulation software(MS).The results show that the angles of the 104 and 116 diffraction peaks of the crystals increase gradually and the relative intensity of the 116 diffraction peak increase gradually during the substitution.There is a linear relationship between the content of calcium carbonate in the crystal and the mesh spacing and diffraction angle of the 104 and116 diffraction peaks.Besides,a linear relationship is also found between the content of iron carbonate in ferrous dolomite and the mesh spacing and diffraction angle of the 104 and 116 diffraction peaks.Based on established carbonate mineral crystal models,the thermophysical parameters of common carbonate minerals and their variations with temperature are calculated.The relationship between the thermophysical parameters of carbonate minerals at different temperatures and the average atomic weight is obtained,and the thermophysical parameters of ferrous dolomite are predicted as well.The results show that the specific heat capacity and entropy values constantly increase with increase temperature.In contrast,the thermal conductivity and thermal diffusivity of the crystal are decreasing with the increasing temperature.The thermal properties of carbonate minerals are significantly related to their average atomic weight at different temperatures.Besides,The thermal conductivity and specific heat capacity of ferrous dolomite at different temperatures are obtained.The specific heat capacity and thermal conductivity of some typical dolomite samples in North China are tested and simulated,and the thermal conductivity and specific heat capacity of the actual samples at different temperatures were obtained.The results show that the purity of the tested samples are higher overall and the porosity of the tested samples are smaller.The samples are mainly developed in the evaporative tidal flat sedimentary environment.The distribution range of thermal conductivity and specific heat capacity of the actual dolomite samples at different temperatures is obtained according to the simulation results.