Study on law of fracture deflection in longitudinal slot hydraulic fracturing

被引：0
|
作者：
Xu C. [1 ,2 ]
Qiu H. [1 ,2 ]
Lyu X. [1 ,2 ]
Zhang K. [1 ,2 ]
Guo H. [1 ,2 ]
机构：
[1] China Coal Technology and Engineering Group, Shenyang Research Institute, Shenyang
[2] State Key Laboratory of Coal Mine Safety Technology, Fushun
来源：
Meitan Kexue Jishu/Coal Science and Technology (Peking) | 2021年 / 49卷 / 10期
关键词：
Crack deflection distance; Hydraulic fracturing; Longitudinal groove cutting; Top-cutting pressure relief;
D O I：
10.13199/j.cnki.cst.2021.10.011
中图分类号：
学科分类号：
摘要：
Longitudinal grooving hydraulic fracturing is a kind of pressure relief technology for roadway cutting under strong dynamic pressure. The core is to control the cracking and propagation direction of cracks. However, the cracks are usually deflected under the influence of the maximum principal stress after directional fracturing. The propagation direction of the crack is related to various factors such as insitu stress conditions, grooving angle, pump flow rate and rock mechanical properties. Research on the crack deflection law under the influence of multiple factors of longitudinal groove hydraulic fracturing is carried out to provide a reference method for the construction design of longitudinal groove hydraulic fracturing drilling. The XFEM module in ABAQUS software was used to establish the two-dimensional model of longitudinal grooving hydraulic fracturing. The feasibility verification of the numerical model was achieved by comparing with the previous physical test results of longitudinal grooving hydraulic fracturing, and then the large-scale longitudinal grooving hydraulic fracturing model was established, and the fracture deflection law of longitudinal grooving hydraulic fracturing under the condition of coal mine roof sandstone was studied in detail. The results show that the horizontal stress ratio is an important factor affecting the crack deflection distance. When the vertical principal stress is 10 MPa, the minimum horizontal principal stress is 6 MPa, and the horizontal stress ratio increases from 1.5 to 3.5, the crack deflection distance decreases by 55.3%, 56.9% and 41% respectively. The cutting angle has a great influence on the crack propagation path and a relatively small influence on the crack deflection distance; When the horizontal stress ratio is 1.5 and 2.0, the crack deflection distance increases continuously and has a large increase range when the pump flow increases from 30 L/min to 180 L/min. When the horizontal stress ratio is 2.5, the growth rate of the crack deflection distance is significantly reduced; When the horizontal stress ratio is 1.5, 2.0 and 2.5, respectively, the crack deflection distances corresponding to the pump flow of 90 L/min are 4.05, 1.81 and 0.75 m respectively. A large increase in the deflection distance can be achieved by greatly increasing the pump flow. The study provides significant reference for the selection of flow rate of longitudinal grooved hydraulic fracturing pump and the determination of borehole spacing under different conditions. © 2021 Meitan Kexun Jishu/Coal Science and Technology (Peking). All rights reserve.
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页码：78 / 84
页数：6
相关论文
共 18 条
  • [1] CHENG Peng, Research on hydraulic fracturing and pressure relief technology in ultra - thick coal seam dynamic pressure roadway, Coal Science and Technology, 47, 11, pp. 50-55, (2019)
  • [2] LIU Hongtao, WU Xiangye, HAO Zhen, Et al., Evolution law and stability control of plastic zones of retained entry of working face with double roadways layout, Journal of Mining & Safety Engineering, 34, 4, pp. 689-697, (2017)
  • [3] QI Qingxin, LI Yizhe, ZHAO Shankun, Et al., Seventy years development of coal mine rockburst in China: establishment and consideration of theory and technology system [J], Coal Science and Technology, 47, 9, pp. 6-45, (2019)
  • [4] JIAO Jiankang, JU Wenjun, WU Yongzheng, Et al., Multi - layer control technologies for surrounding rock stability of dynamic-loading rock burst roadway, Coal Science and Technology, 47, 12, pp. 10-17, (2019)
  • [5] YIN Shuaifeng, SHI Jianjun, FENG Jicheng, Et al., Study on roof breaking location of gateway retained along goaf with no gateway sidewall backfilling and support, Coal Science and Technology, 47, 1, pp. 193-198, (2019)
  • [6] SUN Zhiyong, ZHANG Zhen, WANG Ziyue, Et al., Application & research on hydraulic fracturing and cutting top pressure relief technology in large mining height retained roadway [J], Coal Science and Technology, 47, 10, pp. 190-197, (2019)
  • [7] HE Manchao, SONG Zhenqi, WANG An, Et al., Theory of longwall mining by using roof cuting shortwall team and 110 method:the third mining science and technology reform, Coal Science & Technology Magazine, 1, pp. 1-9, (2017)
  • [8] HE Manchao, MA Xingen, WANG Jiong, Et al., Application of selfforming roadway technology without coal pillar for roof-cutting and pressure-relief of composite roof in medium-thick seam [J], Tongmei Science and Technology, 4, pp. 1-6, (2018)
  • [9] FENG Zhaowei, CAO Yunlong, HUANG Wencai, Application of roof cutting and pressure relief of huge thick sandy conglomerate without coal pillar in self driving, Science and Technology Innovation Herald, 28, pp. 34-35, (2017)
  • [10] CHEN Xiaodong, KLJ7 intelligent chain arm roof cutting machine design, Coal Mine Machinery, 37, 5, pp. 112-113, (2019)
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