武隆区块常压页岩气水平井分段压裂技术

Multi-Stage Fracturing Technology of Normally Pressured Shale Gas in Horizontal Wells in the Wulong Block

渝东南武隆区块页岩气储层水平应力差较大,高角度裂缝及层理缝发育,难以形成复杂体积裂缝,低角度裂缝较难开启,裂缝转向难度大,同时储层为常压储层,要实现经济开发难度较大。为此,在分析武隆区块常压页岩气储层压裂改造技术难点的基础上,以提高裂缝的复杂程度、增大储层改造体积为目标,以滑溜水为压裂液,通过优化射孔簇间距、射孔簇长度和簇间暂堵,提高高应力差异系数下裂缝的复杂程度;采用连续加砂工艺和优化压裂规模,提高裂缝导流能力和保证裂缝在页岩气储层中延伸,形成了适用于武隆区块常压页岩气水平井的分段压裂技术,并在隆页2HF井进行了现场试验,压裂后产气量达9. 4×10~4m^3/d。分析隆页2HF井压裂资料发现,应用该技术可以提高裂缝复杂程度,形成网络裂缝,提高常压页岩气单井产量,从而实现常压页岩气的经济开发。

In-situ horizontal stress differences within shale gas reservoirs in the Wulong Block,southeast Chongqing are large.It is difficult to create complex volumetric fractures for high-angle and bedding fractures,to open low-angle fractures,and to change the fracture extention orientation.In addition,in-situ stress differences make economic development of normal pressure gas reservoir very difficult.Based on the analysis of technical difficulties of normal pressure shale gas in the Wulong Block,it is planned to increase the complexity of the fractures and so as to increase stimulated reservoir volume under high stress difference taking slick water as the fracturing fluid and perforation cluster spacing,perforation cluster length optimization as well as inter-cluster temporary plugging.To improve fractures conductivity and ensure that the fractures extend sufficiently in shale gas reservoirs,a multi-stage fracturing technology suitable for normal pressure shale gas in horizontal well of the Wulong Block has been developed by using continuous gravel filling and optimizing fracturing scale.The technology was successfully applied in Well Longye 2HF and it resulted in gas production of 9.4×10^4 m^3/d.Based on the fracturing data analysis of Well Longye 2HF,the application of this technology can improve fracture complexity,form network fractures,and increase individual-well production of normal pressure shale gas well,and realize economic development in normal pressure shale gas.