Numerical Simulation On Methane Hydrate Dissociation By Depressurization

Gas hydrate is probably the most potential one of energy in the Future. Nowadays there is a lot of pollution coming from burning of fossil fuels; however, because of a huge reserve and clean tail gas, gas hydrate owns a good reputation. But the industry of gas hydrate is not very mature, how to get it efficiently and safely is an important problem to solve. Now exploiting gas hydrate by depressurize method is consider as an economical way by scientists. Meanwhile, the gas hydrate simulation is also developing fast, doing research about simulation is very important for the gas hydrate study work.In this paper, we used black-oil-type simulation model to describe the course of dissociation. The sensitivity analysis such as pressure, temperature and different phase saturation in different time are showed in the simulation. Besides, we also focused on the water phase change in the dissociation; we discussed the water and methane gas transfer; compare heat conduction and convection of heat transfer in the hydrate dissociation. In addition, we suggested used Darcy-Forchheimer law instead of classical Darcy law in the simulation to prove the accuracy of model result.In order to analyze the character of gas hydrate dissociation course, to study the water transfer by observing the change of water saturation in the core, to compare different result coming from different initial water saturation, we used simulation to reveal the relationship between the front dissociation area and water saturation distribution. On the other hand, our simulation result also showed the methane gas driving water course as the time passed. Then, we attempted to describe the gas and liquid two phase flow regulation among this experiment.Trough the simulator, we have mainly done three part work related to hydrate. They are water sensitivity analysis in the methane hydrate dissociation, water transfer character in the un-saturated media when hydrate decompose, and used Darcy-Forchheimer law instead of classical Darcy law to fit the special low temperature and high pressure environment.