THE CHARACTERISTIC TIMES OF MULTI-FIELD DURING GAS HYDRATE THERMAL INDUCED DISSOCIATION IN STRATUM

Gas hydrate is a new kind of strategic energy resource. The potential geological hazards and environmental damages due to the commercial production should be predicted and taken effective precautions. The production practice of gas hydrate will lead to evolution of multi-physical processes, i.e. the heat conduction, gas hydrate dissociation and phase transformation around the well, accompanied by multiphase seepage, softening and deformation of the stratum. Soil failures such as large-scale settlement, marine slide and gas outburst could occur because the build-up of excess pore pressure after the dissociation-induced release of gas and water in the porous media. The characteristic time of each physical process is reached in this paper, and it is found that the times differ in two orders of magnitude, hence, the decoupling method is used effectively in the previous investigation.