Permeability and Porosity Changes in Unconsolidated Porous Medium Due to Variations of Confining Stress and Temperature

Thermal recovery processes are an efficient and commonly accepted technique for the exploitation of heavy oil reservoirs. The increase in the temperature of the porous medium because of steam injection in a thermal recovery processes, significantly reduces the oil viscosity and makes possible its flow to the producing wells. Experimental evidence suggests that the productivity of the wells and the flow capacity of the reservoir affected by thermal recovery processes depend not only on the temperature effect on the heavy oil viscosity but also on the effect of temperature on both petrophysical and mechanical properties of the porous medium. The paper presents laboratory results about the porosity and permeability behavior with temperature and effective confining stress for unconsolidated porous medium. At each confinement stress condition, pore volume, total volume and permeability of the core are recorded at different heating stages. The results show a significant dependence of the permeability and porosity with the confinement stress for each temperature condition. The greater the effective confinement stress, the greater the reduction of porosity and permeability as temperature increases. At low confinement stress, the tendency is maintained for permeability but not for the porosity of the porous medium.