2018/08/23 by Zongyu Gu, Martin Z. Bazant, Gu, Zongyu +1
Engineering · Physics and Astronomy · #Chemical Physics (physics.chem-ph) #Enhanced Oil Recovery Techniques #FOS: Physical sciences #Fluid Dynamics (physics.flu-dyn) #Hydrocarbon exploration and reservoir analysis #NMR spectroscopy and applications #Soft Condensed Matter (cond-mat.soft)
paper · pdf · doi:10.48550/arxiv.1808.09804
openalex publication_date 2018/08/23 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Continuum models of porous media use macroscopic parameters and state variables to capture essential features of pore-scale physics. We propose a macroscopic property "accessivity" (α) to characterize the network connectivity of different sized pores in a porous medium, and macroscopic state descriptors "radius-resolved saturations" (ψw(F),ψn(F)) to characterize the distribution of fluid phases within. Small accessivity (α→0) implies serial connections between different sized pores, while large accessivity (α→1) corresponds to more parallel arrangements, as the classical capillary bundle model implicitly assumes. Based on these concepts, we develop a statistical theory for quasistatic immiscible drainage-imbibition in arbitrary cycles, and arrive at simple algebraic formulae for updating ψn(F) that naturally capture capillary pressure hysteresis, with α controlling the amount of hysteresis. These concepts may be used to interpret hysteretic data, upscale pore-scale observations, and formulate new constitutive laws by providing a simple conceptual framework for quantifying connectivity effects, and may have broader utility in continuum modeling of transport, reactions, and phase transformations in porous media.