应力敏感储层拟稳态流动产能分析

摘要

A new productivity equation was presented in pseudo-steady state in reservoir, considering the effect of stress sensitivity and bottom hole degassing. The computation result of an example showed that; the IPR curve of well bended to pressure axis when considered stress sensitivity in reservoir, the productivity was lower than Vogel equation in conventional reservoir. If bottom hole degassing was taken into account, there was a critical pressure drop in the well, when the actual pressure drop exceed the critical pressure drop, the productivity would decrease, this phenomena would not appear in conventional Vogel equation. The larger permeability deformation coefficient was, the earlier and heavier IPR curves bended, and the higher the critical pressure drop was. With the decrease of reservoir pressure, the bend degree of IPR curve declined, it meant that the effect of stress sensitivity was decreased with the decrease of reservoir pressure, When the reservoir pressure decreased to a certain degree, the critical pressure drop disappeared.%考虑应力敏感和井底脱气的影响,推导了外边界封闭油藏在拟稳态流动阶段的产能方程.实例计算结果表明:在相同的生产压差下,应力敏感油藏单井产能向压力轴弯曲;产能比常规Vogel方程低考虑脱气影响时,油井存在极限生产压差.当实际生产压差高于极限生产压差时,增大生产压差,油井产能反而减小;而常规Vogel方程不存在这种现象.渗透率伤害系数越大,曲线弯曲越早,弯曲度越大,极限井底压力也逐渐增大.地层压力下降后产能曲线弯曲程度下降,表明地层压力下降后应力敏感对产能的影响逐步降低.当平均地层压力下降到一定程度后,极限井底压力消失.