湖北宜昌震旦系陡山沱组储层特征及复杂体积压裂效果评价

Reservoir characteristics of the Sinian Doushantuo Formation and the effectevaluation of complex fracturing in Yichang, Hubei Province

鄂阳页2HF井是国内首口针对震旦系陡山沱组的页岩气水平井,该井钻遇的陡山沱组页岩厚度大,岩石脆性好,含气性好且天然裂缝发育,具备良好的压裂改造基础。针对陡山沱组储层“高云质、地层常压、水平应力差异大、隔夹层发育”等压裂改造难点,通过采用“密分切割、多簇射孔、转向压裂”等复杂裂缝体积压裂工艺,采取变排量、暂堵转向、停泵二次加砂等措施,提高裂缝复杂程度,并通过现场地面-井中微地震联合监测,实时监测压裂裂缝延伸规律,评价压裂改造效果。压后通过电潜泵排采工艺措施,最终获得了测试稳定产量5.53万m;/d的高产工业气流,进一步证实了该层系的勘探开发前景。

The Eyangye 2 HF well, in the Sinian Doushantuo Formation, is the first horizontal shale gas well in China. The shale thickness of this well is large, with good brittleness, good gas-bearing and developed natural fracture, which has a good foundation for fracturing reconstruction. But targeting the difficulties of complex fracturing such as high dolomite, ordinary pressure, great difference in horizontal stress and with interlayer, many fracturing technologies such as multiple segmentation, multi-cluster perforation, turnaround fracturing were innovatively adopted in the fracturing process. The fracturing complexity was improved by means of variable displacement, temporary plugging steering and secondary sand addition after shutdown of pumps. The combination of surface-borehole microseisms monitoringtechnology was first used in the fracturing, which can monitor the real-time fracture extension, evaluate the effect of fracturing transformation. After fracturing, the high-yield gas flow with a stable output of 553,300 cubic meters per day was finally obtained by means of the electric submersible pump, which further confirmed the prospects for exploration and development of the shale gas formation.