Influence of existing natural fractures and beddings on the formation of fracture network during hydraulic fracturing ba
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LETTER TO THE EDITOR
Influence of existing natural fractures and beddings on the formation of fracture network during hydraulic fracturing based on the extended finite element method Zhen-Quan Li . Xue-Li Li . Jin-Biao Yu . Wei-Dong Cao . Zhi-Feng Liu . Min Wang . Zhi-Fan Liu . Xiao-Hong Wang
Received: 23 April 2020 / Accepted: 17 September 2020 Springer Nature Switzerland AG 2020
Abstract Numerical simulation of fracture propagation during hydraulic fracturing is performed based on the extended finite element method. The influences of existing natural fractures and beddings on the formation of fracture network are focused. It is shown that the hydraulic fracture network in the case of random distribution for natural fracture is more conducive to form than that in the case of the regular distribution, which indicates that the random arrangement of existing natural fractures is helpful for forming highly communicated and complicated fracture network. However, the randomly distributed natural fractures often cause fracture reorientation and a sudden drop of the fracture aperture of the new branch, which leads to an increasing proportion of ineffective fractures in the formed fracture networks due to that fracture apertures in the new branches may be too narrow to send the proppant inside. For the Z.-Q. Li (&) Shengli Oilfield Branch Company, SINOPEC, Dongying City 257015, Shandong Province, China e-mail: [email protected] X.-L. Li Z.-F. Liu M. Wang Z.-F. Liu X.-H. Wang Department of Thermal Science and Energy Engineering, University of Science and Technology of China, Hefei 230027, Anhui, China
existing beddings in the stratified rock, the bedding feature and distribution have the important influences upon the hydraulic fracture propagation. Numerical results show that the hydraulic fracture would be more easily to swerve again and form complex network under the condition of the smaller distance and larger bond strength between beddings. Keywords Hydraulic fracturing Fluid flows in porous media Extended finite element method Natural fracture Fracture network
1 Article Highlights 1. Based upon the XFEM simulation, the influences of existing natural fractures and beddings on the formation of fracture network are investigated. 2. The hydraulic fracture network in the case of random distribution for natural fracture is more conducive to form than in the case of the regular distribution. 3. The hydraulic fracture is easily to form complex network under the condition of the smaller distance and larger bond strength between beddings.
J.-B. Yu W.-D. Cao Exploration and Development Research Institute, Shengli Oilfield Branch Company, SINOPEC, Dongying City 257015, Shandong Province, China
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Geomech. Geophys. Geo-energ. Geo-resour. (2020)6:58
2 Introduction Unconventional reservoirs, such as shale gas, have an extremely tight matrix, but well-developed natural fractures (Gale et al. 2007). The hydraulic fracturing technique has become one of the key technologies in unconventi
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