东北大学学报（自然科学版）

东北大学学报:自然科学版 ›› 2014, Vol. 35 ›› Issue (9): 1340-1344.DOI: 10.12068/j.issn.1005-3026.2014.09.028

• 资源与土木工程 • 上一篇    下一篇

煤岩交界面对水力压裂裂缝扩展的影响

宋晨鹏1,2，卢义玉1,2，贾云中1,2，夏彬伟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:2013-12-06 修回日期:2013-12-06 出版日期:2014-09-15 发布日期:2014-04-11
  • 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，重庆大学教授，博士生导师.
  • 基金资助:
    国家自然科学基金资助项目(51374258)；重庆市自然科学基金资助项目(CQCSTC，2010BB6069).

Effect of CoalRock Interface on Hydraulic Fracturing Propagation

SONG Chenpeng1,2， LU Yiyu1,2， JIA Yunzhong1,2， XIA Binwei1,2   

  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:2013-12-06 Revised:2013-12-06 Online:2014-09-15 Published:2014-04-11
  • Contact: SONG Chenpeng
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摘要： 针对井下煤层压裂过程中，压裂裂缝扩展至煤岩交界面处，受多种力学因素的综合影响，扩展方向可能会发生偏转.通过建立压裂裂缝遇煤岩交界面二维模型，采用理论分析结合数值模拟的方法，对煤岩交界面的破坏机理及压裂裂缝扩展规律进行研究.结果表明:煤岩交界面与水平剖面的相交角、水平主地应力差、最小水平主地应力、煤岩交界面的黏聚力及煤岩层弹性模量差异等是影响裂缝扩展方向的主要因素.随着相交角或水平主应力差的增加，裂缝直接穿过煤岩交界面的可能性增加；最小水平主地应力越大，裂缝直接穿过煤岩交界面的可能性越小；煤层交界面的黏聚力越小或煤层与顶板岩层的弹性模量差异越大，裂缝沿煤岩交界面扩展的趋势越明显.

关键词: 水力压裂, 裂缝扩展, 煤层, 煤岩交界面, 临界水压

Abstract: During hydraulic fracturing in coal seams， fractures expand to coalrock interface and the direction of fracture growth may change because of the effects of many mechanical factors. Based on the 2D model of coalrock interface in hydraulic fracturing， the theoretical analysis and numerical simulation were conducted to investigate the failure mechanism of coalrock interface and the propagation characteristics of fractures induced by hydraulic fracturing. It is shown that:the main factors which affect the development direction of fractures are intersecting angle between coalrock interface and horizontal profile， horizontal stress difference， minimum horizontal insitu stress， cohesive strength of coalrock interface and elastic modulus difference between coal and rock. With the decrease of intersecting angle or horizontal stress difference， the probability of fractures crossing coalrock interface will raise; while the minimum horizontal insitu stress increases， the probability of fractures crossing coalrock interface will reduce; with the decrease of cohesive strength of coalrock interface or increase of elastic modulus difference between coal and rock， the fractures will tend to extend along the coalrock interface.

Key words: hydraulic fracturing, fractures propagation, coal seam, coalrock interface, internal critical water pressure

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