Novel formulation of Slichter’s model for permeability determination in unconsolidated materials: a critical review through field data

Abstract

ABSTRACT Slichter’s model is a theoretical model that can be used for quantifying the permeability of non-cohesive materials. An inaccurate form of the equation has prevailed, undermining this model, which has been considered unreliable. This paper revises Slichter’s work and proposes a corrected formulation of his equation by redefining key parameters such as the referential grain size, the porosity function, and the area of the pores. This approach was tested for poorly graded sands and well-graded sandy gravels in northern Croatia and a literature control group of heterogeneous sediments. The results were compared with permeabilities determined from: (1) pumping and slug tests, and (2) the well-established Hazen’s experimental and Kozeny-Carman theoretical formulae. High correlativity between the different methods and with the field results confirmed the validity of the corrected Slichter’s equation for predicting the permeability of non-cohesive materials, regardless of their gradation and mean geometric grain size.