Gas hydrate equilibrium dissociation conditions in the porous media were predicted using two thermodynamic approaches, based on equal fugacities and equal activities, respectively. For non-hydrate phase, the Trebble-Bishnoi (TB) equation was employed in the fugacity approach, while the Soave-Redlich- Kwong (SRK) equation was applied in the activity approach. For the hydrate phase, the van der Waals- Platteeuw model in conjunction with the capillary model of Llamedo et al. was used in both the two approaches. The predictions by the two approaches were all in good agreement with the experimental data. The prediction accuracy of the fugacity approach is better than that of the activity approach.

Key words: hydrate, porous media, equilibrium dissociation condition, fugacity, activity