The analysis for the theoretical model about the gas production from gas hydrate by depressurization

By doing research on the fields of pressure and temperature in the process of gas hydrates decomposition, we can predict the output of gas, and can provide feasible ways to increase the efficiency of gas production. The axisymmetric mathematical model is improved about the gas productions from hydrate by depressurization, the energy balance equation is employed considering the effect of the latent heat of gas hydrate at the decomposition front, the analytical solution is introduced by the method of Boltzmann transformation. The exact location of the gas hydrate decomposition front is obtained by solving initial value problems of ordinary differential equations through numerical method. Finally, the distribution of pressure and temperature fields and natural gas production with time are given according to numeric calculation example, the impact of the well bore pressure on the speed of the decomposition front is analyzed. The results show that the latent heat of gas hydrate has effect on the field of temperature, the temperature near the decomposition front is lower, the rate of gas production can be raised by reducing the pressure of well.