| The formation of complex fracturings and net by hydraulic fracturing is one of the key factors for obtaining high productivity during developing shale gas.According to the research on the characteristics of reservoir cracks in Yongchuan area,the difference of horizontal pressure of rock in this area is large(7.3-25.4MPa).The spilt mode is dominated by tensile slits,and the whole tends to form branch cracks or even single cracks.The area ratio of shear joints,crack density and natural crack is abundant in the area and the southern area are higher than those in the north area.It is relatively easy to form complex fracturing.Based on the net pressure test on the core,the oprate project has been optimized.Tthe formation of "large displacement,temporary temporary blocking steering,end sand removal,low viscosity drop water fracturing,etc." is fit to the explore aimed reservoir.Other series of technical measures to improve the complexity of cracks.For becoming the fracture network in Yongchuan area,the proppant type,sand ratio and combination ratio were optimized through self-supporting and supporting crack mechanism and experimental research.Combining compressibility index evaluation,G function analysis,MEYER software simulation and other means to evaluate the current fractures in Yongchuan area,there were more complex cracks,especially for the northern area.To increase the complexity of the cracks,further field tests of ultra-high pressure,temporary internal plugging and other means was needed. |
