On the interpretation of hydraulic pulse tests on rock specimens

A widely used procedure for interpreting results of hydraulic pulse tests involves an analysis that is based on the piezo-conduction equation. In this paper, the range of applicability of the classical piezo-conduction equation is examined in the light of results derived from Biot's classical theory of poroelasticity, which takes into account complete coupling involving fluid flow and skeletal deformations along with influences of grain compressibility. Comparisons are made between the two approaches by considering typical low permeability rocks including Westerly Granite and Indiana Limestone, where the permeabilities can vary by orders of magnitude. These studies are complemented by experiments performed on samples of Stanstead Granite, the results of which were analyzed employing the different approaches. (C) 2012 Elsevier Ltd. All rights reserved.