Dissociation kinetics of methane hydrate in frozen rocks at decreasing external pressure: mathematical and laboratory modeling

Dissociation of pore methane hydrate in ice- and gas-bearing sediments at external pressure below the equilibrium has been simulated in mathematical and physical (laboratory) models. The mathematical model, along with the experiment, provides constraints on dissociation kinetics. The suggested theoretical model confirms the trend of decreasing hydrate saturation of frozen soil Sh~Aτ(-n). observed previously in experiments. The physical model makes basis for calculating the coefficients A and n, while the mathematical modeling shows how the coefficients depend on the problem parameters. The theoretical estimates agree with the experimental results, both qualitatively and quantitatively. The results of mathematical and physical modeling have implications for key factors that control self-preservation of pore methane hydrates in frozen sediments.