Acoustic properties of poorly cemented sandstones under temperature and stress

Most thermal heavy oil recovery methods entails changes of pore fluid, pressure and temperature which in turn induce complex changes in the elastic properties of reservoirs that are in general unconsolidated or weakly consolidated porous rocks. In this paper, laboratory measurements of velocities and attenuations under different conditions of temperature and stress were performed on samples of a weakly consolidated reconstituted sandstone saturated with various fluids (air, water and glycerol). The sample investigated is representative of weakly cemented sandstone reservoirs with high porosity and permeability. The experimental results demonstrate the strong impact of the nature of the pore fluid on the compressional and shear wave velocities and attenuations. The influence of temperature and stress are discussed, together with the wave dispersion mechanisms.