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.