Research on Dynamic Movement of Temperature and Pressure During Hydrate Depressurization Mining

It is of great significance to study the dynamic movement of temperature and pressure during depressurization mining process of hydrate reservoir. This paper first obtains the formula for calculating the temperature and pressure of hydrate decomposition based on the law of conservation of mass, conservation of energy, and phase equilibrium, Hydrateressim (HRS) is used to carry out the numerical simulation of the front edge of the one-dimensional model. The results show the pressure and the hydrate saturation front are correlated with the temperature front edge and compared with the Computer Modelling Group Ltd. (CMG) simulation results. It is found that the pressure front edge is an area in the balance model and an interface in the dynamic model. Then the movement of the front edge of the three-dimensional model was simulated. By simulating the movement regulation of pressure, temperature, and hydrate saturation front of each layer at different times, the longitudinal decrease of each layer is compared and analyzed. The conclusion drawn is that the bottom-hole pressure of the production well is an important factor for production, and the endothermic reaction of hydrate will cause the dynamic movement of temperature to lag slightly behind the pressure and hydrate saturation. By determining the relationship between the pressure and the temperature front, the position of the front edge of the hydrate saturation can be inferred that it is the position of the decomposition front and it overcomes the limitation of the experimental method that the hydrate saturation cannot be measured.