东北大学学报:自然科学版 ›› 2014, Vol. 35 ›› Issue (5): 756-760.DOI: 10.12068/j.issn.1005-3026.2014.05.034

• 资源与土木工程 • 上一篇    

天然裂缝对煤层水力压裂裂缝扩展的影响

宋晨鹏1,2,卢义玉1,2,夏彬伟1,2,胡科1,2   

  1. (1重庆大学 煤矿灾害动力学与控制国家重点实验室, 重庆400030;2重庆大学 复杂煤气层瓦斯抽采国家地方联合工程实验室, 重庆400030)
  • 收稿日期:2013-05-22 修回日期:2013-05-22 出版日期:2014-05-15 发布日期:2014-08-18
  • 通讯作者: 宋晨鹏
  • 作者简介:宋晨鹏(1986-),男,山西太原人,重庆大学博士研究生;卢义玉(1972-),男,湖北京山人,重庆大学“长江学者奖励计划”特聘教授,博士生导师.
  • 基金资助:
    “十二五”国家科技重大专项(2011ZX05065);国家自然科学基金资助项目(51374258,51104191).

Effects of Natural Fractures on Hydraulic Fractures Propagation of Coal Seams

SONG Chenpeng1,2, LU Yiyu1,2, XIA Binwei1,2, HU Ke1,2   

  1. 1 State Key Laboratory of Coal Mine Disaster Dynamics and Control, Chongqing University, Chongqing 400030, China; 2 National & Local Joint Engineering Laboratory of Gas Drainage in Complex Coal Seam, Chongqing University, Chongqing 400030, China.
  • Received:2013-05-22 Revised:2013-05-22 Online:2014-05-15 Published:2014-08-18
  • Contact: SONG Chenpeng
  • About author:-
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摘要: 煤层井下水力压裂过程中,天然裂缝会对水压裂缝的扩展产生重要影响,通过建立水压压裂裂缝遇天然裂缝二维模型,采用理论分析结合数值模拟的方法,对裂缝扩展规律及天然裂缝破坏机理进行研究.研究表明:扩展中主裂缝与天然裂缝的相交角度、水平主应力差及天然裂缝的发育程度是影响扩展方向的主要因素.在低主应力差、低相交角的条件下,压裂裂缝趋于沿天然裂缝发生剪切破坏扩展;在高应力差和高相交角情况下,压裂裂缝易直接穿过天然裂缝扩展.当天然裂缝尺寸较长,压裂裂缝易沿天然裂缝扩展,而小尺寸的天然裂缝对裂缝扩展影响不大.

关键词: 水力压裂, 煤层, 天然裂缝, 水平主应力差, 相交角, 裂缝尺寸

Abstract: To investigate the effects of natural fractures on the hydraulic fracture propagation of underground coal seams, a twodimensional model of hydraulic fracture intersecting natural fractures was built, based on which, the laws of fracture propagation and the failure mechanisms of natural fractures were explored by applying theoretical analysis and numerical simulation. The research suggested that the angle of interaction, the horizontal differential principal stress and the development degree of natural fractures are the three main factors that affect the directions of fracture propagation. In the case of low horizontal differential principal stress and low angle of interaction, the propagation of hydraulic fractures is likely along the natural fractures due to shear failure; on the contrary, in the case of high horizontal differential principal stress and high angle of interaction, the propagating fracture is likely to cross the natural fractures. Smallsized natural fractures have little or no effect on the directions of hydraulic fracture propagation whereas the propagating fractures move along the natural fractures when they are bigger in size.

Key words: hydraulic fracture, coal seam, natural fracture, horizontal differential principal stress, angle of interaction, fracture size

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