Stratigraphic Control of Pore-Scale Hydrodynamics and Localized Hydraulic Resistance in Marine Sediments

Stratigraphic heterogeneity in marine sediments creates localized pore-scale hydraulic bottlenecks that influence fluid flow and drainage behavior; however, the pore-scale mechanisms by which sediment architecture organizes hydraulic resistance remain insufficiently quantified. In this study, we use high-resolution Computational Fluid Dynamics (CFD) simulations with OpenFOAM to investigate pore-scale flow behavior in three idealized sediment configurations representative of common marine stratigraphic architectures: homogeneous, fining-upward, and coarse–fine–coarse (CFC). Analysis of velocity fields, effective flow path length, hydraulic-gradient magnitudes, and strain-rate magnitudes reveals pronounced architecture-dependent differences in the spatial organization of hydraulic resistance despite comparable bulk porosities (~ 0.34) and bulk permeabilities within the same order of magnitude, ranging from 2.08 × 10 −11 to 7.89 × 10 −12 m 2 . At comparable mean velocities, the stratigraphically heterogeneous configurations exhibit higher hydraulic-gradient and strain-rate magnitudes than the homogeneous configuration. The homogeneous configuration shows comparatively uniform profiles, whereas the fining-upward configuration develops an upward increase in hydraulic-gradient magnitude. CFC concentrates elevated resistance indicators near abrupt interfaces and shows weak coupling between the mean-velocity and hydraulic-gradient profiles. These findings demonstrate that mean flow velocity and bulk permeability do not fully describe internal hydraulic resistance in stratified sediments. Instead, stratigraphic architecture controls where pore-scale hydraulic resistance is concentrated, identifying potential hydraulic bottlenecks with implications for fluid redistribution in layered marine sediments.