An optimization model for conductivity of hydraulic fracture networks in the Longmaxi shale, Sichuan basin, Southwest China

• Published in: Energy Geoscience Vol. 1; no. 1-2; pp. 47 - 54
• Main Authors: Zhao, Zhihong, Wu, Kaidi, Fan, Yu, Guo, Jianchun, Zeng, Bo, Yue, Wenhan
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.07.2020; KeAi Communications Co., Ltd
• Subjects: Conductivity optimization; Fracture network; Propped fracture; Self-propped fracture; Shale gas; Conductivity optimization; Propped fracture; Fracture network; Self-propped fracture; Shale gas
• ISSN: 2666-7592; 2666-7592
• DOI: 10.1016/j.engeos.2020.05.001

Shale gas is an important unconventional resource. The economic recovery of shale gas is only possible when a fracture network with sufficient conductivity is created by hydraulic fracturing, that, if effectively propped, connects fracturing fractures and natural fractures. Focusing on the Longmaxi shale in the Sichuan Basin, Southwest China, we built an optimization model for conductivity of multi-grade fractures based on equivalent seepage theory. We then experimentally analyzed the conductivity of self-propped and sand-propped fractures, and optimized the propping patterns of multi-grade hydraulic fractures in shale gas reservoirs. We concluded that the propping effectiveness of fracture networks could be improved by using low concentrations of small-sized sands and by focusing on creating a large number of self-propped fractures. By applying this understanding to the optimization of fracturing designs for the Longmaxi shale, we successfully created networks of well-propped fractures. [Display omitted] •Conductivity model covering the primary, secondary and micro fractures.•The secondary fractures and micro-fractures are most sensitive to the whole hydraulic fracture network.•The optimized proppant pattern for fracture networks is found ideal.