泡沫排水采气技术是目前较为常见,也是最为有效的一种被各大气田广泛采用的排水采气技术;但因为各气田的生产情况存在一定的差异,起泡剂的使用方式、型号、泡排制度等都不尽相同。目前平桥南区通过借鉴其他气田通常采用的24 h连续加注的方法,部分井在泡沫排水的应用上产生了一定的效果,但另外一部分井与现有泡排制度仍存在一定的不适应性。为了形成一套适合平桥南区页岩气井的泡排模式,结合实验室评价、现场试验及经济性评价,证明泡排工艺能够有效地携出井底积液,实现一定程度上的增产,但后期更侧重于降低页岩气井的产量递减,保证气井的稳产。优选出XHY-4M型液体起泡剂,在起泡剂浓度0.3 %,消泡剂浓度5 %~20 %,消泡剂与起泡剂量比为1.2∶1,泡排井水气比大于0.5时,整体泡排效果较好。同时不断对泡排制度进行调整优化,采用“少注多次”的间歇泡排制度,更加适用且经济评价效果最优。此研究结果对同类页岩气井的稳产具有一定的借鉴价值。

Foam drainage-gas recovery technology is the most common nowadays and is the most effective application technique. However, due to the certain difference in production conditions of different gas fields, the mode, type, and foam drainage system of foaming agents are different. At present, southern Pingqiao adopts the method of 24 h continuous injection which is commonly used in other gas fields. It works in some wells, but for other wells, this technology dose not works well. In order to form a set of foam drainage model suitable for shale gas wells in southern Pingqiao, combined with laboratory evaluation, field test and economic evaluation, it is proved that the foam drainage process can effectively carry out the bottom hole liquid accumulation and achieve a certain degree of production increase. But in the later stage, it is more focused on reducing the production decline of shale gas wells and ensuring the stable production of gas wells. The XHY-4M type liquid foaming agent is optimized for foaming. When the concentration of defoamer is 0.3 %, the concentration of defoamer is 5 % ~ 20 %, the ratio of defoamer and foaming dose is 1.2∶1, the ratio of water to gas in the well is greater than 0.5, and the overall foam drainage effect is better. Meanwhile, the foam drainage system is constantly adjusted and optimized, and the intermittent foam drainage system of “less injection and multiple times” is adopted, which is more applicable and the effect of economic evaluation is optimal. The results of this study have certain reference for the stable production of similar shale gas wells.