Experimental Research On Thermal Property Of Gas Hydrate In Sediments With Thermo-TDR Technique

Thermal property of gas hydrate is an important basic data in the exploration,development and storage transportation of gas hydrate. We understand it a few for some reasons , such as sample keeping needs a special condition and the sample is complex and behaves anisotropy. Our experiments combine TDR technique and thermal testing technique to design out three sets of thermo-TDR probes. In this paper, we detect several thermal properties of gas hydrate in sediment and variety of moisture, temperature and pressure during the formation and dissociation of gas hydrates.According to the experiments, it shows clearly that thermo-TDR technique can be applied to determine thermal properties, water content and temperature of gas hydrate in sediments. It can avoid the infection of spatial and temporal variability and continues working in situ. The results shows that thermal conductivity of gas hydrate in sediments is approximately 1.0 W/mK, thermal diffusivity is 8.988×10^-7m²/s and heat capacity is 112354.4J/m3K. In addition, that detected results of dry sands, saturated sands and pure water are consistent with the data of literatures .Compared with one-rod thermo-TDR probe, results of two-rod probe has a more ideal regression.In the figure about water content, temperature and pressure, we can see clearly that these parameters vary in accord with one another during the formation and dissociation of gas hydrate. From the figures we can see four stages of the experiment: nucleation, crystallization, congregation and dissociation. According to the experiments of gas hydrate formation under different pressure, it shows that the time of formation are short obviously with increasing the pressure.In the simulation experiment pollution and recovery in soil using TDR technique, we obtained a relationship between water content and electrical conductivity in soils that indicates different degree of pollution. From the experiment about soil pollution and recovery , it shows that soil can be polluted rapidly but it's recovery needs a long period and make a waste of a large number of freshwater.