浅谈连续油管在页岩气井注塞封井中的应用

On Coiled Tubing Applied to Plugging Shale Gas Wells

连续油管注塞封井工艺是通过在井筒内先下入可钻式桥塞封堵生产层,再用连续油管在桥塞上注水泥塞。该工艺具有储层污染小、施工周期短、井控风险低等优点,但是一旦注水泥时发生"闪凝",造成"插旗杆"和"灌香肠"等事故,处理难度极大。连续油管注水泥塞封井工艺通过对水泥浆性能和施工工序进行优化,能有效降低该工艺的施工风险。工艺应用范围广泛,不但能用于页岩气井,对于含硫化氢的常规天然气井同样适用;针对页岩气井后期二次压裂,需要封堵原产层射孔炮眼;目前该工艺下桥塞和注水泥塞分两趟管柱施工,今后待工艺成熟,建议对坐封桥塞工具进行优化改进,在桥塞坐封后直接使用本趟管柱注水泥塞,起到节约工期和施工成本的目的。

Operation steps of coiled tubing plugging well technology are first to trip in drillable bridge plug to block off pay horizon and then to cement plug on the bridge plug using coiled tubing. This technology has advantages of lower reservoir pollution, short operation period and lower well control risk It is widely used for shale gas wells and conventional natural gas wells containing H2S. At present, however, in the process of tripping in bridge plug and cementing plug, two string operations have to be done. It is suggested to improve the tool for setting bridge plug once the technology takes shape completely.