New Method for Evaluating Rock Stress Sensitivity for Low-Permeability Tight Gas Reservoirs

Conventional methods for determining rock stress sensitivity, in which the confining pressure is varied while the pore pressure is held at a constant level, are not suitable for the conditions in low-permeability tight gas reservoirs. In this work, we have studied an evaluation method that involves varying the pore pressure for constant confining pressure. In order to establish the actual reservoir pressures, we used a method involving simultaneous increase in the confining and pore pressures. We have derived an equation describing the dependence of the gas well productivity on the stress sensitivity of the reservoir and have demonstrated the validity of our model.