Abstract: Water lock damage is one of the main damage ways in low porosity and low permeability oil and gas fields, seriously affecting the normal exploitation of oil and gas fields. In order to find out the main factors affecting the water lock effect and effective methods to remove water lock damage, the variation of gas permeability before and after the reservoir core water lock was studied and the degree of water lock of rock samples was quantitatively evaluated using the rock samples from the condensate gas reservoir in Jilin oilfield as raw materials, through the indoor water lock damage experiment of reservoir core. The results showed that water lock effect was mainly caused by the water saturation, pore throat radius, the watersensitive illite, Yimeng mixed layer in the clay minerals with high content and hair and tufted convex. On this basis, the effect of methanol, slippery water and N₂ injection on water lock damage was evaluated. It is proved that N₂ unlocking effect is the best, permeability can be restored to about 30% of the original, methanol injection unlocking effect is better than sliver water, and the best amount of alcohol injection is 0.4 PV.

Key words: Low permeability condensate gas reservoir, Water lock, Degree of damage, Unlocking

摘要： 水锁损害是低孔低渗油气田损害的主要方式之一，严重影响油气田的正常开采。为找出影响水锁效应的主要因素及解除水锁损害的有效方法，采用来自吉林油田某凝析气藏区块的岩样，通过储层岩心室内水锁损害实验，对储层岩心水锁前后的气相渗透率的变化程度进行研究，定量评价岩样水锁程度，认为含水饱和度、孔喉半径小、黏土矿物中水敏感性伊利石、伊蒙混层的高含量及其毛发状、丛生状凸起的结构特征是造成水锁效应的主要原因。在此基础上，评价了甲醇、滑溜水和注N₂解除水锁损害的效果，实验证明，N₂解锁效果最好，渗透率可以恢复到最初的30%左右，注甲醇解锁效果好于滑溜水，且最佳注醇量为0.4 PV。

关键词: 低渗凝析气藏, 水锁, 损害程度, 解锁