考虑束缚水影响的变形介质气藏产能方程

低渗透致密砂岩气藏由于其高有效应力容易导致储层产生应力敏感损害，与常规气藏在生产动态及产能评价等方面存在着明显差异。常规方法通过增加干燥岩样的净围压来模拟地层有效应力的变化直接分析储层的应力敏感程度，忽略了实际储层孔隙空间中的束缚水，从而影响了应力敏感性分析的准确性。利用干气驱的方法建立岩心的束缚水饱和度，通过分析含束缚水饱和度的岩心渗透率随有效应力的变化关系，研究讨论了低渗透含束缚水岩心在覆压实验中的变形特征。结果表明，含束缚水岩样的储层应力敏感损害程度大于干燥岩样，其应力敏感实验曲线特征为早期随着有效应力升高渗透率降低幅度明显，后期则趋于平缓，其间存在一个与原地有效应力相对应的应力敏感区间。在综合考虑启动压力梯度和含束缚水的基础上，建立了变形介质气藏的产能方程，为今后矿场建立较为合理的产能方程提供了参考依据。

The deliverability equation of gas reservoirs with deformable porous medium considering the influence of irreducible water

The high effective stress from the low permeability reservoir of tight sand will easily result in reservoir damage by the stress sensibility. So, analyzing dynamic production state and evaluating production capability in the low permeability gas reservoir of tight sand is different from conventional gas reservoirs. Generally, by adding net confining pressure of dry rocks to simulate the change of effective stress in a layer, as a result, the accuracy of analyzing stress sensibility is decreased without considering irreducible water in reservoir. In this paper, by the method of dry gas drive, the irreducible water saturations in core samples are obtained. And the deformation characteristics of rocks with low permeability and irreducible water are analyzed. From the experiment, the damage extent of stress sensibility of the core samples with the immobile water is much bigger than that of the dry ones; from the plot character of the experiment, the permeability declines sharply at the early stage, but at the later stage, it gradually becomes flat; while there is a stress sensibility area corresponding with the previous effective stress. Based on the gradient of trigger pressure and correlated with immobile water, we built up a deliverability equation of the deformable medium gas reservoir, which provides a reference for the field to build up a more reasonable deliverability equation.