致密低渗气藏储层应力敏感性及其对单井产能的影响

Stress sensitivity of low-permeability tight gas reservoir and its effect on single well productivity

采用变出口端回压应力敏感实验方法，具体实测了大牛地致密低渗气藏储集层岩样不同驱替压差下的渗透率，根据实测的结果回归出大牛地致密低渗气藏储集层应力敏感性的幂函数关系式，总结了储层渗透率随气藏压力的变化规律。在考虑储集层应力敏感影响的情况下，推导出新的产能方程，计算了渗透率变化对单井产能的影响。研究表明：大牛地致密低渗气藏储集层应力敏感性在30％-70％之间，在考虑储集层应力敏感性的条件下，气藏单井产能降低，平均绝对无阻流量是渗透率为常数时的76．49％。

Applying method of stress sensitivity of backpressure on changing delivery end,this paper measures permeability under the different displacement pressure of rock samples of low permeability tight gas reservoir in Daniudi.It establishes relation of power function of stress sensitivity on the basis of measurement results,and summarizes rules of change in permeability with pressure of gas reservoir.Considering effect of stress sensitivity,it derives new productivity equation,and calculates effect of permeability change on single well productivity.Study shows that stress sensitivity of low permeability tight gas reservoir vary from 30% to 70%.With consideration of stress sensitivity,single well productivity declines.When permeability is constant,average non-resistance flow reaches 76.49%.This paper provides scientific foundation for the study on productivity and prediction of development performance of gas reservoir.