Prediction of tortuosity, permeability, and pore radius of water-saturated unconsolidated glass beads and sands.

Tortuosity, permeability, and pore radius, which are parameters in the Biot model, are important for analyzing the elastic wave propagation in water-saturated unconsolidated marine sands. In this study, the formation factor and permeability are measured for 34 kinds of water-saturated glass beads and sands with uniformly sized grains and 73 kinds of water-saturated sands with distributed sized grains. Using these measured data, the empirical equations for the formation factor, cementation exponent, and tortuosity are obtained. The pore shape factor, k, in the Kozeny-Carman model and pore shape factor, a, in the Revil-Cathles (RC) model are derived. The Hazen, Kozeny-Carman, and RC models are compared for the measured permeability results. Furthermore, the relationship between the tortuosity and permeability is shown. Finally, the ratio of the effective pore radius to effective mean grain diameter is derived.