A New Mathematical Model for Pressure Transient Analysis in Stress-Sensitive Reservoirs

For stress-sensitive reservoir, the permeability decreases with the increase of the effective overburden pressure, and pressure transient analysis based on constant rock properties, especially permeability, can lead to significant errors. In this paper, according to the permeability-pressure relationship described by a power function instead of the popularly used exponential function, a new mathematical model for transient fluid flow in stress-sensitive reservoirs is established. The numerical solution is obtained by the fully implicit finite difference method which has been validated by some published analytical solutions before it is used to compute pressure transient responses for stress-sensitive reservoirs. Pressure response curves are plotted and the effects of relevant parameters on both pressure drawdown and buildup responses have been studied. The presented model could provide an alternative method for understanding and predicting the performances for stress-sensitive reservoirs.