Arabian Journal for Science and Engineering

, Volume 43, Issue 11, pp 6639–6652 | Cite as

Fracability Estimation for Longmaxi Shale: Coupled Brittleness, Stress–Strain and Fracture

  • Haiyan ZhuEmail author
  • Lei Tao
  • Dongqiao Liu
  • Qingyou Liu
  • Xiaochun Jin
Research Article - Petroleum Engineering


The ability of fracture propagation (fracability) is a key parameter of evaluating the fracture network generation during hydraulic fracturing. In order to consider the in situ conditions of the shale formation, four factors should be taken into consideration, which are brittleness, fracability, in situ stresses and natural fractures. The current shale brittleness and fracability evaluation methods rarely involve all the above factors. In this paper, coupling brittleness, stress–strain data and fracture morphology, a new shale fracability evaluation method is proposed. The brittleness is calculated by the mineral components and elastic parameters; the stress–strain data obtained by triaxial compression experiments are used to describe the shale breaking process; and the fracture morphology is evaluated by the fractal dimension method. This method is used to calculate the fracability index of the Longmaxi shale in Sichuan, China. The results show that: (1) the shale fracability under 5 MPa confining pressure is higher than that of under 20 MPa confining pressure; (2) the fracability in 7 coring angles shows a significant difference under the same confining pressure, the highest fracability is at \(15^{\circ }\) and the lowest is from \(60^{\circ }\) to \(75^{\circ }\). Compared with Jin and Rickman’s models, our model matches to the fracture morphologies and the fragments distribution closely.


Fracability Brittleness Stress–strain data Fracture morphology Longmaxi shale 


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This work was funded by the National Key Basic Research Program of China (973 Program,No. 2014CB239205) and the National Natural Science Foundation of China (No. 51604232). This work was also supported by Research Project of State Key Laboratory for Geomechanics & Deep Underground Engineering under No. SKLGDUEK1816, and the Research Foundation of Sichuan Province under Grant No. 2018FZ0069. The authors sincerely thank Yinghua Zhang senior technician, Dr. Qiang Tan, Dr. Wei Yan of China University of Petroleum, Beijing, who provided enthusiastic help during the experiments.


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Copyright information

© King Fahd University of Petroleum & Minerals 2018

Authors and Affiliations

  • Haiyan Zhu
    • 1
    Email author
  • Lei Tao
    • 1
  • Dongqiao Liu
    • 2
  • Qingyou Liu
    • 1
  • Xiaochun Jin
    • 3
  1. 1.State Key Laboratory of Oil and Gas Reservoir Geology and ExploitationSouthwest Petroleum UniversityChengduChina
  2. 2.State Key Laboratory for Geomechanics and Deep Underground EngineeringBeijingChina
  3. 3.Energy Geoscience InstituteThe University of UtahSalt LakeUSA

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