苏里格上古生界盒8段致密砂岩气藏在开发阶段会发生一定程度的水锁堵塞效应，进而影响单井产能。通过开展压裂液水锁伤害实验，以典型致密砂岩储层的真实岩心样本为研究对象并结合低场核磁共振测试技术，定量评价了束缚水微观滞留特征，明确了微纳米尺度孔喉内的水锁伤害程度和规律。实验结果表明，岩心渗透率与水锁程度呈负相关关系，且初始渗透率低、微观孔喉发育程度差的岩心更容易发生水锁堵塞伤害。不同品质储层的岩心水锁伤害特征存在较大差异，Ⅰ类和Ⅱ储层的水锁伤害程度低于Ⅲ类储层，Ⅲ类储层滞留的束缚水更多，水锁伤害程度也更高。微孔内的束缚水滞留率与水锁伤害高度相关。水锁伤害主要发生在小于50 nm孔隙，特别是小于2 nm孔隙内束缚水含量增加会显著影响岩心渗透性。研究成果进一步揭示了苏里格气田致密砂岩储层水锁伤害机理，为降低水锁伤害、实现气田的高效开发提供理论支撑。

In the development stage of the Upper Paleozoic He 8 Member tight sandstone gas reservoir in Sulige, a certain degree of water lock damage will occur, which in turn affects the productivity of a single well. By conducting water lock damage experiments on fracturing fluid and taking the real core samples of typical tight sandstone reservoirs as the research objects, combined with the low-field nuclear magnetic resonance (NMR) testing technology, the microscopic retention characteristics of immovable water were quantitatively evaluated, and the degree and laws of water lock damage within micro-nano scale pore throats were clarified. The experimental results show that there is a negative correlation between core permeability and the degree of water lock, and cores with low initial permeability and poor development degree of micro-pore throats are more likely to suffer from water block damage. There are significant differences in the water lock damage characteristics of cores in reservoirs of different qualities. The degree of water lock damage in Class Ⅰ and Ⅱreservoirs is lower than that in Class Ⅲ reservoirs. Class Ⅲ reservoirs retain more immovable water, and the degree of water lock damage is also higher. The retention rate of immovable water in micropores is highly correlated with water lock damage. Water lock damage mainly occurs in pores smaller than 50 nm, especially when the content of immovable water in pores smaller than 2 nm increases, it will significantly affect the permeability of the core. This study reveals the mechanism of water blocking damage in tight sandstone reservoirs in the Sulige gas field, providing theoretical guidance for enhanced production in tight sandstone gas fields.