Bound Water In Shaly Sands - Its Relation To Q And Other Formation Properties

Abstract

A portion of the water contained in the pores of a shaly sand is closely associated with the clay mineral as hydration or bound water. Anions are assumed to be substantially excluded from this water, and a method of measuring the resulting salinity change in the supernatant solution has been adapted to determine experimentally the amount of bound water. A relation is presented between the amount of bound water, the cation exchange capacity of the clay minerals, and the concentration of the equilibrating electrolyte solution. Assuming that the bound water is essentially immobile and utilizing certain other simplifying assumptions, we have been able to develop and test relations which are useful in estimating brine permeability and oil-water capillary pressure curves from routine core analysis data.