Effect of perforation technologies on the initiation and propagation of hydraulic fracture
FU Haifeng1，2，HUANG Liuke3，4，5，ZHANG Fengshou3，4，XU Yun1，2，CAI Bo1，2，LIANG Tiancheng1，2，WANG Xin1，2
(1. Petrochina Research Institute of Petroleum E&D，Langfang，Hebei 065007，China；2. CNPC Key Laboratory of Reservoir Stimulation，Langfang，Hebei 065007，China；3. Key Laboratory of Geotechnical and Underground Engineering of Ministry of Education，Tongji University，Shanghai 200092，China；4. College of Civil Engineering，Tongji University，Shanghai 200092，China；5. State Key Laboratory of Geomechanics and Geotechnical Engineering，Institute of Rock and Soil Mechanics，Chinese Academy of Sciences，Wuhan，Hubei 430071，China)
Abstract：The high efficient perforation technology provides important technical support for cost reduction and efficiency increase in oil and gas development. Due to the complex distribution of stress field around the perforation holes and the absence of effective simulation methods，the initiation and propagation of hydraulic fracture for perforated fracturing are not understood clearly. This paper proposes large-scale(762 mm×762 mm×914 mm) physical experiments that simulate fracture initiation and propagation under different perforation strategies. Furthermore，a full three-dimensional numerical model based on discrete lattice method is established. Through the combination of physical experiments and numerical simulation，the geometry of fracture initiation and propagation under different perforation technologies is revealed intuitively. The results show that the fracture initiation near the wellbore is more complicated due to the effect of beddings，perforation tunnels and in situ stress field. Increasing the perforation depth obviously decreases the fracture initiation pressure and propagation pressure. Compared with spiral perforation，directional perforation significantly reduces the fracture complexity of in the near wellbore area，improves the efficiency of fluid injection for perforation holes，and decreases propagation pressure by up to 25%. Directional perforation is conducive to migration of sand-carrying fluid. Field tests on Chang 7 reservoir show that the directional perforation significantly reduces the initiation pressure by 21% and extension pressure by 14.2%，respectively，showing a good application prospect.
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2021, Vol. 40 
