Water sensitivity of sandstones containing swelling and non-swelling clays

Abstract

The study presented here focuses on the phenomenon of water sensitivity of sandstones containing swelling and nons-welling clays. This paper describes results of an ongoing investigation on the mechanisms of permeability reduction in sandstones containing swelling and non-swelling clays. These studies show that the critical salt concentrations of sodium chloride and potassium chloride needed to prevent loss of permeability in sandstones containing swelling clay (Stevens sandstone) are considerably higher than the corresponding values for Berea sandstone. A critical salt concentration of calcium chloride is shown to exist for these sandstones. As opposed to Berea sandstone, pH control may not be sufficient to eliminate loss of permeability in swelling clay sandstones. The results show that crystalline swelling of smectites/mixed layer clays induces significant permeability reduction in the swelling clay sandstones considered in this paper.