多裂缝系统致密砂岩气藏的水锁及应力敏感叠加伤害研究--以川西蓬莱镇组致密砂岩为例

Overlaying damage of water lock and stress sensitivity to tight sandstone with multiple fractures: taking tight sandstone of Penglaizhen formation in western Sichuan

为研究水锁、有效应力对裂缝储层的叠加损害,选取川西蓬莱镇组致密砂岩气藏岩样,进行了干岩样和不同含水饱和度条件下岩样应力敏感实验。实验结果表明,随着岩样含水饱和度的增大,水锁程度增大,应力敏感程度增强;同含水饱和度下,有效应力增加,水锁程度增强。在压裂后的多裂缝系统储层中水锁和储层有效应力两者的协同作用对多裂缝网络储层渗透率造成叠加损害,可以为多裂缝致密砂岩储层开发方案的设计提供依据。

The overlaying damage of water lock and effective stress to the dry rock samples and the wet rock samples of different water saturation from the tight sandstone of Penglaizhen formation in western Sichuan is studied through stress sensitivity experiments. It is shown that,with the increase of the water saturation of rock samples,their water lock and stress sensitivity damage increase; under the same water saturation,the water lock damage increases with the increase of effective stress. The synergistic effect of water lock with effective stress will produce overlaying damage to the permeability of fractured tight sandstone reservoir,which will provide the basis for the development plan design of tight sandstone reservoir with multiple fractures.