考虑压敏效应的气井产能预测新方法

在气藏开发过程中,随着储层压力的下降,有效应力随之增加,引起气藏渗透率和产能的降低。基于岩石本体有效应力理论,对源于Terzaghi有效应力的渗透率应力敏感状态方程进行修正,在达西渗流理论基础上,结合岩心应力敏感实验,推导出考虑渗透率应力敏感的气井产能方程,提出了一种新的产能预测思路。通过实例分析了压敏效应对气井产能的影响,结果表明:渗透率应力敏感伤害对气井产能影响明显,压敏效应越强,气井产量降低越严重。

A New Method for Forecast the Productivity of Gas Well under the Consideration of Pressure Sensitive Effect

In the development process of gas reservoirs, the effective stress increases with the decline in reservoir pressure, resulting in decreasing in the permeability and gas well productivity. Based on the rock body effective stress theory, the permeability stress sensitivity state equation which is under the Terzaghi effective stress has been modified. Based on Darcy percolation theory, com- bined with core stress sensitivity experiments, the gas well deliverability calculation equation considering the permeability stress sen- sitivity has been derivated; new gas productivity forecast method has been put forward. The influence of stress sensitive on the gas well productivity has been discussed with an example. The results show that the permeability stress sensitivity damage has influenced the gas well productivity significantly. When the stress sensitive effect becomes stronger, the production of gas well decreases more serious.