Numerical simulations for analyzing deformation characteristics of hydrate-bearing sediments during depressurization

Abstract

Natural gas hydrates have been treated as a potential energy resource for decades. Understanding geomechanical properties of hydrate-bearing porous media is an essential to protect the safety of individuals and devices during hydrate production. In this work, a numerical simulator named GrapeFloater is developed to study the deformation behavior of hydrate-bearing porous media during depressurization, and the numerical simulator couples multiple processes such as conductive-convective heat transfer, two-phase fluid flow, intrinsic kinetics of hydrate dissociation, and deformation of solid skeleton. Then, a depressurization experiment is carried out to validate the numerical simulator. A parameter sensitivity analysis is performed to discuss the deformation behavior of hydrate-bearing porous media as well as its effect on production responses. Conclusions are drawn as follows: the numerical simulator named GrapeFloater predicts the experimental results well; the modulus of hydrate-bearing porous media has an obvious effect on production responses; final deformation increases with decreasing outlet pressure; both the depressurization and the modulus decrease during hydrate dissociation contribute to the deformation of hydrate-bearing porous media.Cited as: Liu, L., Lu, X., Zhang, X., et al. Numerical simulations for analyzing deformation characteristics of hydrate-bearing sediments during depressurization. Advances in Geo-Energy Research, 2017, 1(3): 135-147, doi: 10.26804/ager.2017.03.0

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