Microscale Seepage Simulation of Two Hydrate-Bearing Sediment Models Based on the Lattice Boltzmann Method

The extraction of natural gas hydrates faces challenges due to unresolved in situ decomposition and permeability mechanisms, with reservoir permeability being a pivotal parameter for extraction safety, efficiency, and economics. This study addresses this by developing a novel competition model and models reconstructed via a multi-point statistical method based on real CT images. Using the lattice Boltzmann method, we examine the influence of key factors, such as porosity and saturation, on permeability. Since single-hydrate-morphology models often fail to match practical observations, we propose a competition model that describes the dynamic transition from grain-coating to pore-filling habits. Simulations show that predictions from the competition model converge more closely with experimental data than single-state models. Furthermore, the MPS-based reconstructions provide a realistic benchmark, validating the representativeness of the modeling approaches. The framework demonstrates promising potential for capturing diverse sedimentary scenarios, indicating wide applicability and avenues for future research.