Numerical study of the process of gas hydrate decomposition under the thermal impact on the hydrate-containing region of a porous formation

Abstract

A mathematical model that describes, in a two-dimensional approximation, the thermal impact (a temperature increase at the upper boundary of the reservoir) on the region of the porous medium containing methane and its hydrate in the initial state is proposed. The boundaries of the region are impermeable to decomposition products of the gas hydrate (gas and water). The gas reality and the non-isothermal effects during the movement of gas and water in the porous medium are considered. The methane hydrate decomposition is assumed to be in equilibrium. A numerical study of non-isothermal filtration flow is performed considering the dissociation of methane gas hydrate in the porous medium. The obtained results show that a frontal mode of phase transitions is observed under the thermal impact. The region containing the products of gas hydrate decomposition grows along with the increase in the values of temperature at the upper boundary of the formation and its initial permeability, as well as with the decrease in the hydrate saturation.

Keywords

• gas hydrate
• porous medium
• non-isothermal filtration
• hydrate decomposition
• numerical study