涪陵页岩气田平桥区块深层气井压裂工艺优化与应用

涪陵页岩气田平桥区块深层页岩主力层位垂深约为3 900～4 100 m，地层倾角较大且位于强挤压应力区，地层压裂改造效果受限。采用实验模拟与现场工艺试验相结合的方法对深层压裂工艺优化开展研究。结果表明，工艺优化主要包括：①优化段间距，使之介于45～50 m；②采用定向3簇射孔可在一定程度上避免深层裂缝的顺层延伸问题，同时保证裂缝具有一定的复杂程度；③快速提高前置胶液的施工排量，然后在减阻水携砂阶段，呈阶梯式提高施工排量，有利于初期形成一定宽度的主缝，增加后期裂缝的复杂程度；④单段施工规模应控制在1 900～2 000 m³。研究成果所形成的新工艺与常规工艺相比，缝内净压力增加了12.5%，平均砂液比提高了75.56%，平均单段产气量提高了114.90%，具有广阔的应用前景。

Optimization and application of deep gas well fracturing in Pingqiao block of Fuling shale gas field

The main layer of the shale in Pingqiao block of Fuling shale gas field has a depth of 3 900-4 100 m, which is located in the strong compressive stress area and has large formation dip, so the effect of formation fracturing is limited. The optimization of deep fracturing technology was studied by combining experimental simulation with field test. The results show that optimizing deep fracturing technology mainly includes the following methods: (1)Optimizing the distance of stages between 45 m and 50 m; (2)Using directional three-cluster perfora-tion can avoid the problem of deep fracture extending along the bedding, but also can ensure that the fracture has a certain degree of complexity; (3)Rapidly increasing the construction displacement of pre-glue fluid and increasing the construction displacement step by step in the stage of drag-reducing water and sand-carrying, which is beneficial to increase the complexity of the fractures after forming a certain width of main fracture in the initial stage; (4)The single-stage construction scale should be controlled at 1 900-2 000 m³. Compared with the conventional fracturing process, the net pressure in fracture increased by 12.5%, the average sand-fluid ratio increased by 75.56%, and the average single-stage gas production increased by 114.90%. The optimized process has broad application prospects.