Influence of the spatial position of horizontal well in roof strata of crushed soft coal seam on the propagation of fracturing fractures

被引：0
作者：
Pang T. [1 ,2 ]
Jiang Z. [2 ]
Li H. [2 ]
Yang J. [2 ]
机构：
[1] China Coal Research Institute, Beijing
[2] Xi’an Research Institute Co., Ltd., China Coal Technology and Engineering Group Corp., Xi’an
来源：
Meitan Xuebao/Journal of the China Coal Society | 2022年 / 47卷
关键词：
coal seam roof; fracture propagation; horizontal well; hydraulic fracturing; spatial location;
D O I：
10.13225/j.cnki.jccs.2022.0096
中图分类号：
学科分类号：
摘要：
The staged fracturing technology of horizontal wells in the coal roof is a new method for the development of coalbed methane in the development area of soft, low-permeability coal seams. In order to explore the influence law of horizontal well spatial position on fractured fracture propagation, based on the related theories of elasticity and fracture mechanics, a fracture propagation stress analysis model considering formation dip angle and wellbore trajectory is established. The crack propagation process and influencing factors were theoretically analyzed. The critical water pressure for crack initiation, diversion and interlayer propagation is deduced. The numerical simulation is used to reveal the influence law of horizontal wellbore spatial position on fracture propagation. Results show that:① the relative position of horizontal wellbore and coal seam space affects the expansion and shape of fractured fractures. It is mainly affected by factors such as vertical stress, horizontal stress of roof rock layer, horizontal stress of coal seam, perforation angle, perforation depth, formation dip angle, distance between wellbore and coal, coal-rock interface properties, roof rock and coal-rock mechanical properties. ② The smaller the angle between the perforation hole and the formation, the larger the fracture turning angle and turning distance, the higher the fracture initiation pressure. Also, the crack height is not easy to control, the length of the crack extending to the upper part of the roof is large. The closer the wellbore is to the coal seam, the more favorable it is for the fracture to propagate through the layer, and the farther the distance is, the higher the fracture propagation pressure. The longer the perforation hole length, the lower the fracture initiation pressure. The longer the perforation hole length, the lower the fracture initiation pressure. When the dip angle of the coal seam increases to 45°, the fractures mainly expand in the roof of the coal seam, and the fracture extension pressure fluctuates greatly and the extension pressure is high. ③ The perforation position of a horizontal well is optimized through the research results. The field application results show that the research results are useful to the promotion and application of the staged fracturing coalbed methane drainage mode of coal roof horizontal well. © 2022 China Coal Society. All rights reserved.
引用
收藏
页码：196 / 203
页数：7
相关论文
共 24 条
  • [1] ZOU Caineng, YANG Zhi, HUANG Shipeng, Et al., Resource types, formation, distribution and prospects of coal-measure gas, Petroleum Exploration and Development, 46, 3, pp. 433-442, (2019)
  • [2] FU Xuehai, ZHANG Miao, ZHANG Qinghui, Et al., Evaluation index system for the Permo-Carboniferous mud shale reservoirs of coal measures in Shanxi Province [ J ], Journal of China Coal Society, 43, 6, pp. 1654-1660, (2018)
  • [3] LIU Jianzhong, SUN Haitao, LEI Yi, Et al., Current situation and development trend of coalbed methane development and utilization technology in coal mine area, Journal of China Coal Society, 45, 1, pp. 258-267, (2020)
  • [4] ZHANG Sui'an, LIU Xinjia, WEN Qingzhi, Et al., Development situation and trend of stimulation and reforming technology of coalbed methane, Acta Petrolei Sinica, 42, 1, pp. 105-118, (2021)
  • [5] CHENG Yuanping, LEI Yang, Causality between tectonic coal and coal and gas outbursts, Journal of China Coal Society, 46, 1, pp. 180-198, (2021)
  • [6] YIN Qingkui, JIAO Zhonghua, Analysis of reasons for lowyield of certain cbm well in jiaozuo, China Coalbed Methane, 9, 3, pp. 16-19, (2012)
  • [7] DONG Kui, Study on geological conditions affected to produc-tion of coalbed methane well of broken soft coal reservoir, (2019)
  • [8] ZHANG Qun, GE Chungui, LI Wei, Et al., A new model and application of coalbed methane high efficiency production from broken soft and low permeable coal seam by roof strata-in horizontal well and staged hydraulic fracture, Journal of China Coal Society, 43, 1, pp. 150-159, (2018)
  • [9] JIANG Zaibing, LI Haozhe, FANG Liangcai, Et al., Fracture propagation mechanism of staged through-layer fracturing for horizontal well in roof adjacent to broken-soft coal seams, Journal of China Coal Society, 45, S2, pp. 922-931, (2020)
  • [10] XU Yaobo, GUO Shengqiang, Technology and application of staged fractuiing in coalbed methane horizontal well of soft and hard coal composite coal seam, Journal of China Coal Society, 44, 4, pp. 1167-1177, (2019)
123