Abstract A fundamental understanding of the transport properties of carbonate rocks is crucial in many geophysical contexts related to natural resources, energy transition, and environment. In this study, we investigated the applicability of the Katz‐Thompson model, based on percolation theory and critical path analysis, to predict the transport properties of dual‐porosity limestones. Laboratory measurements of permeability, formation factor, and specific surface area were conducted on five dual‐porosity limestones, supplemented by Mercury Intrusion Capillary Pressure (MICP) data and published data for three additional limestones. The MICP curves for these rocks exhibit two inflection points, reflecting bimodal pore size distributions. We demonstrated that selecting the first inflection point to estimate the characteristic length scale yields permeability predictions that agreed with experimental measurements within a factor of two. Formation factor predictions based on the second characteristic length defined by Katz & Thompson also from MICP data showed good agreement for most studied rocks, with notable exception in Thala limestone. For this rock, several factors could explain that the model underestimates the formation factor, such as differences between micritic structure or diagenetic process of dolomitization. X‐ray Computed Tomography imaging and Lattice Boltzmann flow simulations on Indiana and Purbeck limestones confirmed that macropores formed interconnected networks dominating fluid transport, justifying the percolation approach. Our findings suggest that despite pore complexity, the Katz‐Thompson critical path model remains robust for allochemical and many dual‐porosity limestones, provided the characteristic length is correctly chosen. However, its applicability to micritic limestones and rocks with narrow or poorly connected pore networks may be limited.
Meng et al. (2026) studied this question.