Permeability Reduction Induced by Pore Pressure Decrease in Clay-Rich Sandstones

C-39 PERMEABILITY REDUCTION INDUCED BY PORE PRESSURE DECREASE IN CLAY-RICH SANDSTONES Abstract 1 UTE TRAUTWEIN and ERNST HUENGES GeoForschungsZentrum Potsdam Telegrafenberg D-14473 Potsdam Germany Summary Laboratory experiments on two clay-rich sandstones were performed to investigate the influence of pore pressure change on reservoir properties during production. Triaxial experiments under uniaxial strain boundary condition show that an imposed pore pressure drop of 30 MPa results in a remarkable decrease of porosity and permeability. Sandstones with initially higher permeability exhibited a stronger stress dependency of permeability with pore pressure variations. Introduction Understanding the evolution of stress and strain in a reservoir during