注甲醇段塞解除凝析气井近井带堵塞实验

针对反凝析积液和水锁严重影响深层低渗透凝析气井产能的问题，基于室内实验，研究了先注甲醇段塞然后再注干气吞吐来解除反凝析积液和反渗吸水锁提高气井产能的机理和效果。实验测试了甲醇与地层水的配伍性、甲醇注入后地层水的饱和蒸气压和矿化度变化；利用RUSKA长岩心驱替实验设备，使用２个回压阀动态建立反凝析油饱和度，完成了先注甲醇段塞解除水锁，然后注干气吞吐的长岩心实验，测试了注甲醇前后的相对渗透率变化和注入压差的变化。研究表明，甲醇的注入使地层水饱和蒸气压升高，地层水矿化度降低，能与地层水完全互溶；水锁的存在增加了注甲醇的压差，甲醇的注入使注气吞吐的压差降低，从而提高了气井产能。

An Experimental Study on Blockage Relieving by Using Injecting Methanol Slug in Near Wellbore Zone of Gas-condensate Wells

The retrograde condensate liquid and water lock will seriously affect the gas production in deep layers of low permeability gas condensate wells. To solve this problem,a long core experiment of injecting methanol slug firstly and then dry gas soak was conducted to evaluate the effect of blockage relieving in gas wells. The experiment tested the compatibility of methanol and formation water,the saturated vapor pressure and the salinity changed when injecting methanol into formation water. In long core experiment,two back pressure valves were applied to establish the retrograde gas condensate saturation dynamically. The effective permeability and injection pressure difference changed before and after methanol injection was tested in this experiment. The result shows that the injection of methanol makes the saturated vapor pressure of formation water elevated and salinity decreased,and the methanol can be completely soluble with the formation water; the existence of water locking increases the pressure difference of methanol injection,and methanol injection makes the pressure of gas injection soak decreased,thus can improve the gas well productivity.