低渗致密气藏气井水锁伤害研究

Study on the damage of water lock to gas wells in low permeability and tight gas reservoirs

针对川西中浅层气藏水锁伤害问题，通过动态分析、表皮系数变化、数模推演等手段，判断气井水锁伤害发生的时机，评价气井伤害程度，分析水锁产生的原因、部位、深度，形成气井水锁伤害识别方法；针对自主研发的新型水锁除垢解除剂，进行配套工艺优化，确定药剂井底用量、焖井时间、泡排加注制度等工艺参数：针对前期现场试验中存在的返排困难问题，优选、配套相应的返排工艺，使其更好地适应川西致密砂岩气藏气井和舍凝析油气井。开展了解水锁工艺现场试验和推广工作，达到了较好的增产、增压效果，完善了化学法解水锁技术方案．为川西主力气藏后期稳产提供新的技术手段。

Aiming the issues of water locking damage to mid-to-shallow gas reservoirs in Western Sichuan gas field, the timing at which the water loeking damage to the gas well occurred was determined by means of the performance analysis, skin factor variation, and numerical simulation deduction. The degree of the damage to gas wells was evaluated. The causes, locations, and depths of the water lock were analyzed. Therefore a method of identifying the water locking damage to gas wells was formed. According to the independently developed new water lock remover and desealing agent, the supporting technologies are oplimized, and the process parameters such as the amount of the agent applied to the bottomhole, well shut-in time （soaking time）, and the foam drainage and filling system, etc. In view of problems of flowbaek diffieulties that existed in the early field trials, the corresponding flowbaek process is optimized and matched, so as to better adapt to the wells in tight sandstone gas reservoirs and gas-condensate e^mtained gas-wells in western Sichuan gasfield. Field test and application promotion of the water-lock removal teehnology are carries out, and the good results of production and pressure increases are obtained. A program of chemical water-loek removal technology is formed so as to provide a new technology means for stabilizing the produetion at the late stage of the main gas reservoirs of western Sichuan gasfield.