A new theoretical model incorporating geomechanical effects for hydrate dissociation in sediments under thermal stimulation

Abstract

Previous analytical models for hydrate dissociation under thermal stimulation usually focused on heat and mass transfer while ignoring geomechanical effects. However, it is accepted that hydrate dissociation under thermal stimulation involves multifield coupling problems, and the effect of a stress field on hydrate dissociation cannot be ignored. Thus, in this paper, based on a classic analytical model for predicting hydrate dissociation under thermal stimulation derived by Selim and Sloan, we propose a novel model that takes the geomechanical behavior into account to simulate hydrate dissociation. Specifically, we applied an incremental solution scheme to solve this coupled system. Afterwards, we validated our derived model and compared the influence of different porosity strategies (i.e., Lagrange's porosity and true porosity) on the coupled system. The result shows that, at small strains, porosity strategies have little influence on the coupled system. Moreover, parametric analysis was conducted to study the effects of relative parameters on hydrate dissociation. Compared with previous studies, our model not only is more efficient but also reveals more mechanisms of hydrate dissociation under thermal stimulation.