复杂页岩气井无限级砂塞分段压裂先导性试验

滇黔北昭通页岩气示范区YSA井钻遇断层且存在3个水平井眼，考虑到压裂过程中可能产生套管变形等复杂问题，不宜采用常规的桥塞分段工艺，因此开展了连续油管无限级砂塞分段工艺进行分段压裂。该工艺分段数不受井筒条件限制，分段方式以砂塞封隔分段代替了常规的桥塞分段，配套的新型工具只需起下1次连续油管就能完成单段的冲砂、填砂和多簇喷砂射孔作业，整个施工过程中井筒全通径，能有效应对页岩气井套管变形对压裂施工的影响。YSA井在发生套管变形的情况下完成了13级分段压裂，解决了由于套管变形而无法使用桥塞分段的难题，压后测试产量达11.3×104 m3/d，增产效果显著。该工艺的成功应用为我国页岩气井提供了一种新的分段改造手段。

Pilot test on in fi nite-order sand plug staged fracturing of complex shale gas wells

Well YSA in Zhaotong Shale gas Demonstration Region in North Yunnan-Guizhou Area encounters faults and it has three horizontal holes. The conventional bridge plug staged fracturing is not capable of dealing with the possible complicated problems in the process of fracturing, e.g. casing deformation, so a new type of in fi nite-order sand plug staged fracturing is carried out. By virtue of this technology, the number of stages is beyond the limitation of hole conditions, and the conventional bridge plug staging is replaced with the sand plug packing off and staging. Its support tools can fi nish sand washing, sand packing and multi-cluster sand blasting and perforation only by one trip of coiled tubing. In the whole process of fracturing, the borehole is fully open to diminish the effect of casing deformation of shale gas wells on the fracturing effect effectively. When this technology is actually used in Well YSA, the 13-order staged fracturing is carried out in the case of casing deformation in the process of fracturing. And thus, its technical difficulty that bridge plug staged fracturing is unsuitable due to casing deformation is settled down. The stimulation effect is remarkable, with production rate of 11.3×104 m3/d after the fracturing. The successful application of this technology provides a new staged stimulation method for domestic shale gas wells.