Influence of the sedimentation regime and compaction of sediments under subaqueous conditions on the accumulation of gas hydrates in the zone of their stability

Abstract

Formation of gas hydrate that form in a porous medium of sediments from gas dissolved in a gassaturated fluid is analyzed for different regimes of fluid movement determined by the permeability of sediments, their physical properties, and their accumulation rate. In the framework of the presented general mathematical model of viscoelastic compaction of accumulated sediments, characteristic porosity decrease patterns, fluid movement, and gas hydrate accumulation are described by a nonlinear system of eight partial differential equations. The regime of compaction and fluid movement is determined by the values of dimensionaless similarity numbers defined as nonlinear combinations of physical and dynamic parameters of the process studied. The results of model calculations with the use of representative physical and hydrodynamic parameters of the system provided constraints on the dependence of the hydrate formation rate on the similarity numbers of the problem. It is shown that the rate and volume of hydrate accumulation are determined by the similarity numbers and dimensionless time.