Numerical study of natural gas hydrate dissociation in a laboratory sandstone sample under a depression regime

The present work covers mathematical modeling of the process of dissociation(decomposition) of natural gas hydrate of the Sredneviluysky gas condensate field in a laboratory sample of natural sandstone. Initially, the porous medium, filled with natural gas, water, and hydrate, is in thermobaric conditions meeting the stable state of the gas hydrate. Then, the pressure is released from one side of the cylindrical hydrate sample, which causes its decomposition. The mathematical model of the decomposition process takes into account the two-phase filtration of gas and water, the throttling effect, convective heat exchange, heat absorption during hydrate dissociation, and the kinetics of this process. The developed model and its implementation algorithm are tested against the results of a known experimental work. As a result of the computational experiment, distributions of gas pressure and temperature, hydrate and water saturation are obtained. Furthermore, the duration of the hydrate dissociation process is estimated with varying some initial parameters.