Experimental Determination of Poroperm Properties of Fractured Porous Geomaterials within the Framework of Dual-Permeability Model

Abstract

The experimental procedure is developed and tested on a laboratory scale and using layered samples of manmade geomaterials. Within the dual-permeability model, the procedure enables determining parameters that govern fluid flow and poroelastic deformation in fractured porous rock masses, namely, fracture permeability \(k_1\) and mass transfer coefficient \(\beta\), as well as their dependence on stresses \(\sigma\). The testing procedure is proposed and implemented. In the procedure, under the stepwise increasing normal stress \(\sigma\), the stationary flow rates \(Q_1(\sigma)\) and \(Q_2(\sigma)\) are measured in a quasiregular fractured porous sample at the preset pressure difference: using a standard setup (\(Q_1\)) and in closed end-face fractures (\(Q_2\)). The mathematical model of the experiment is constructed, and the analytical solution of the problem on stationary flow is obtained: pressure patterns in fractures, and stress-dependence of flow rates. The experimental data interpretation algorithm enables calculating \(k_1\) and \(\beta\) by the recorded flow rates \(Q_1\) and \(Q_2\). It is shown that the permeability \(k_1\) is proportional to \(\sigma^{-2}\), and \(\beta\) remains almost unchanged.