Lithological Controls on Matrix Permeability of Organic-rich Shales: An Experimental Study

This manuscript discusses the influence of lithological factors on matrix permeability of organic-rich shales, differing in porosity (3.0-16.6%), mineralogy, TOC content (1.8-14.2%) and maturity (0.5-2.4% VRr). The lowest porosity and permeability coefficients were measured at intermediate maturity levels (0.88-1.01% VRr). Gas (He) permeability coefficients increased with porosity (3.0- 16.6%) ranging between 4·10-22 and 9.7·10-17 m2. Permeability coefficients (He, CH4) measured parallel to bedding were more than one order of magnitude higher than those measured perpendicular to bedding. Permeability coefficients measured with helium were consistently, up to two times, higher than those measured with argon and methane under similar experimental conditions.