Equivalency and Replaceability between Different Permeability Models of Hydrate-Bearing Porous Media When Applied to Numerical Modeling of Hydrate Dissociation: Implications for Model Selection and Parameter Assignment

As a key input parameter in laboratory-scale numerical simulations of the hydrate dissociation process, effective and intrinsic permeability is among the most important factors controlling the hydrate dissociation dynamics and the productivity of hydrate-bearing porous media. A wide variety of permeability models have been developed to capture the effective permeability variations due to hydrate dissociation. The choice of the appropriate application-orientated permeability model is predominantly empirically based without reliable criteria. In this paper, we summarize the classical and popular permeability models associated with hydrate dissociation. Based on systematic numerical sensitivity analysis of modeling outputs (e.g., gas production rate, cumulative gas production volume, hydrate dissociation front characteristics, temperature, and pressure evolution) to alternative permeability model types and permeability model parameters, we demonstrate that there exists an equivalency and replaceability relationship between different permeability models in producing consistent modeling outputs. According to their equivalency and replaceability, various permeability models can be correlated to the frequently used Masuda model, which accordingly largely simplifies the selection of permeability models. This study also suggests the most representative parameter values for the Masuda model at low, medium, and high intrinsic permeabilities, which offers an efficient way to reduce uncertainties in modeling input.