A Productivity Prediction Equation Considering Rock PermeabilityStress-Sensitivity in Low-Permeability Gas Reservoirs
考虑渗透率应力敏感的低渗气藏产能预测公式

Pore pressure decreases, effective stress increases, and permeability declines due to matrix and pore compression as gas produces in low-permeability gas reservoirs. This affects the deliverability of lowpermeability gas reservoirs. Based on Darcy flow law and the universal cognition that the rock permeability varies with the effective stress exponentially, this paper presents a new equation considering rock permeability stress-sensitivity for estimating the productivity in low-permeability gas reservoirs. A ease calculation with this new equation shows that considering permeability stress-sensitivity in the prediction is necessary, especially for the high stress-sensitive low-permeability gas reservoirs, and this will provide necessary reference to determining reasonable producing pressure drop and producing rate.