|
|
|
| PROPAGATION OF HYDRAULIC FISSURES AND BEDDING PLANES IN HYDRAULIC FRACTURING OF SHALE |
| LI Zhi1，JIA Changgui2，YANG Chunhe1，3，ZENG Yijin2，GUO Yintong1，HENG Shuai1，
WANG Lei1，HOU Zhenkun3 |
(1. State Key Laboratory of Geomechanics and Geotechnical Engineering，Institute of Rock and Soil Mechanics，Chinese Academy of Sciences，Wuhan，Hubei 430071，China；2. Sinopec Research Institute of Petroleum Engineering，Beijing 100101，China；
3. State Key Laboratory for Coal Mine Disaster Dynamics and Control，Chongqing University，Chongqing 400044，China) |
|
|
|
|
Abstract In order to investigate the interaction of the hydraulic fractures and the bedding planes of shale in hydraulic fracturing，the hydraulic fracturing experiments under triaxial conditions were carried out with the acoustic emission system monitoring the process of hydraulic fracturing and the CT scanning system scanning the sections of rock samples before and after hydraulic fracturing for capturing the distribution of fractures. The initiation and propagation of the hydraulic fracture was captured experimentally. At the situation of small difference of stresses，the critical pressure for initiation was found to be differed little in different angels，the fracture grew along the direction of after initiation. The critical pressure for the propagation of major hydraulic fractures was related to the length of fracture and . The small sections of the bedding planes in shale were opened up when the major hydraulic fracture approached. The passage was created at the intersection of the hydraulic fracture and the bedding plane due to shearing tension. The shear zone was larger than opened one，with a ratio of 13 at maximum，functioning as the major passage for fluid flow. The length of the shear zone is sensitive to the cohesion of bedding planes, and the angle of intersection of hydraulic fracture and bedding plane.
|
|
Received: 17 January 2014
|
|
|
|
| [1] 陈 勉，庞 飞，金 衍. 大尺寸真三轴水力压裂模拟分析[J]. 岩石力学与工程学报，2000，19(增)：868–872.(CHEN Mian，PANG Fei，JIN Yan. Simulation and analysis of real triaxial hydraulic fracturing[J]. Chinese Journal of Rock Mechanics and Engineering，2000，19(Supp.)：868–872.(in Chinese))
[2] 胡永全，贾锁刚，赵金州，等. 缝网压裂控制条件研究[J]. 西南石油大学学报：自然科学版，2013，35(4)：126–132.(HU Yongquan，JIA Suogang，ZHAO Jinzhou，et al. Study on controlling conditions in network hydraulic fracturing[J]. Journal of Southwest Petroleum University：Science and Technology，2013，35(4)：126–132.(in Chinese))
[3] FREEMAN C M，MORIDIS G，ILK D，et al. A numerical study of performance for tight gas and shale gas reservoir systems[J]. Journal of Petroleum Science and Engineering，2013，108(8)：22–39.
[4] ZHOU J，CHEN M，JIN Y，et al. Analysis of fracture propagation behavior and fracture geometry using a triaxial fracturing system in naturally fractured reservoirs[J]. International Journal of Rock Mechanics and Mining Sciences，2008，45(7)：1 143–1 152.
[5] ZHAO H F，CHEN H，LIU G H，et al. New insight into mechanisms of fracture network generation in shale gas reservoir[J]. Journal of Petroleum Science and Engineering，2013，110(10)：193–198.
[6] TAHERI S J. Numerical Modeling of hydraulic fracture propagation：accounting for the effect of stresses on the interaction between hydraulic and parallel natural fractures[J]. Egyptian Journal of Petroleum，2013，22(4)：557–563.
[7] CHUPRAKOV D A，ZHUBAYEV A S. A variational approach to analyze a natural fault with hydraulic fracture based on the strain energy density criterion[J]. Theoretical and Applied Fracture Mechanics，2010，53(3)：221–232.
[8] AADNOY B，LOOYEH R. Petroleum rock mechanics：drilling operations and well design[M]. [S.l.]：Gulf Professional Publishing，2011：122–127.
[9] IRWIN G R. Analysis of stress and strains near the end of a crack traversing a plate[J]. Journal of Applied Mechanics，1957，24：361–364.
[10] WESTGAARD H M. Bearing pressures and cracks[J]. Journal of Applied Mechanics，1939，61：49–53.
[11] GRIFFITH A A. The phenomena of rupture and flow in solids[J]. Philosophical Transactions of the Royal Society of London，1920，A221：163–198. |
|
|
|
2015, Vol. 34 
