Simulation for the Effects of Well Pressure and Initial Temperature on Methane Hydrate Dissociation

Abstract

Methane hydrate dissociation is a process of heat and mass transfer, and pressure and temperature are the most important parameters. The influence of pressure and temperature on the hydrate dissociate relationship between the two parameters is the determinant for gas hydrate dissociation; meanwhile, the gradients of these parameters are the sources of flow and gas production. In this study, a 1D simulator was developed for investigating the effects of well pressures (3 MPa, 5 MPa, and 8 MPa) and initial temperatures (274 K, 279 K, and 284 K) in the process of methane hydrate dissociation by depressurization. The simulation results showed that the well pressure and initial temperature have significant effects on pressure distribution, temperature distribution, and gas production. A lower well pressure and higher initial temperature can promote methane hydrate dissociation. The combined effect of hydrate dissociation and fluid flow can cause more substantial changes in pressure distribution, temperature distribution, and gas production, especially in the initial stage of the methane hydrate dissociation process. However, the changes of the parameters tend to disappear as mining time goes on. There is a difference in the influences of exploitation well pressure and initial temperature on the stability time of gas production.

Keywords

• methane hydrate
• well pressure
• initial temperature
• numerical simulation