Regimes of Dissociation of Gas Hydrates Coexisting with a Gas in Natural Strata

Abstract

A mathematical model of decomposition of gas hydrates that coexist with a gas in natural strata is proposed; the model takes into account the mobility of the liquid phase. Conditions at the unknown boundary of dissociation are derived. In the self-similar approximation, the solution is represented in the form of probability integrals. The obtained system of transcendental equations at the moving boundary has been investigated numerically in a wide range of parameters. It is shown that different regimes of dissociation in collectors with a positive initial temperature exist; these regimes correspond to the decomposition of a hydrate into gas and water and gas and ice and have both a sharp phase-transition front and are accompanied by the formation of an extended region of dissociation. On the plane of the main parameters of the process, the critical diagram is constructed and the existence domains of the solution of each form are singled out.