Advertisement

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 Zhu
  • Lei Tao
  • Dongqiao Liu
  • Qingyou Liu
  • Xiaochun Jin
Research Article - Petroleum Engineering
  • 34 Downloads

Abstract

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.

Keywords

Fracability Brittleness Stress–strain data Fracture morphology Longmaxi shale 

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

Notes

Acknowledgements

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.

References

  1. 1.
    Jin, X.; Shah, S.N.; Roegiers, J.: Fracability Evaluation in Shale Reservoirs-An Integrated Petrophysics and Geomechanics Approach. In: The Paper at SPE-168589, SPE Hydraulic Fracturing Technology Conference. The Woodlands, Society of Petroleum Engineers, Texas, USA (2014)Google Scholar
  2. 2.
    Jin, X.; Shah, S.N.; Truax, J.A.; Roegiers, J.: A Practical Petrophysical Approach for Brittleness Prediction from Porosity and Sonic Logging in Shale Reservoirs. In: The Paper at SPE-170972, SPE Annual Technical Conference and Exhibition. Society of Petroleum Engineers, Amsterdam, The Netherlands (2014)Google Scholar
  3. 3.
    Wang, D.; Ge, H.; Wang, X.; Wang, J.; Meng, F.; Suo, Y.; Han, P.: A novel experimental approach for fracability evaluation in tight-gas reservoirs. J. Nat. Gas Sci. Eng. 23, 239 (2015)CrossRefGoogle Scholar
  4. 4.
    Fang, C.; Amro, M.: Influence factors of fracability in nonmarine shale. In: European Unconventional Resources Conference and Exhibition 2014: Unlocking European Potential, vol. 2, p. 1196. Society of Petroleum Engineers, Vienna, Austria (2014)Google Scholar
  5. 5.
    Jarvie, D.M.; Hill, R.J.; Ruble, T.E.; Pollastro, R.M.: Unconventional shale-gas systems: the Mississippian Barnett Shale of north-central Texas as one model for thermogenic shale-gas assessment. AAPG Bull. 91, 475 (2007)CrossRefGoogle Scholar
  6. 6.
    Wang, F.P.; Gale, J.F.: Screening criteria for shale-gas systems. Gulf Coast Assoc. Geol. Soc. 59, 779 (2009)Google Scholar
  7. 7.
    Liu, Z.; Sun, Z.: New brittleness indexes and their application in shale/clay gas reservoir prediction. Pet. Explor. Dev. 42, 129 (2015)CrossRefGoogle Scholar
  8. 8.
    Hucka, V.; Das, B.: Brittleness determination of rocks by different methods. Int. J. Rock Mech. Min. Sci. Geomech. Abstr. 10, 389 (1974)CrossRefGoogle Scholar
  9. 9.
    Altindag, R.: Correlation of specific energy with rock brittleness concepts on rock cutting. J. S. Afr. Inst. Min. Metall. 103, 163 (2003)Google Scholar
  10. 10.
    Lawn, B.R.; Marshall, D.B.: Hardness, toughness, and brittleness: an indentation analysis. J. Am. Ceram. Soc. 62, 347 (1979)CrossRefGoogle Scholar
  11. 11.
    Quinn, J.B.; Quinn, G.D.: Indentation brittleness of ceramics: a fresh approach. J. Mater. Sci. 32, 4331 (1997)CrossRefGoogle Scholar
  12. 12.
    Copur, H.; Bilgin, N.; Tuncdemir, H.; Balci, C.: A set of indices based on indentation tests for assessment of rock cutting performance and rock properties. J. S. Afr. Inst. Min. Metall. 103, 589 (2003)Google Scholar
  13. 13.
    Yagiz, S.: Assessment of brittleness using rock strength and density with punch penetration test. Tunn. Undergr. Space Technol. 24, 66 (2009)CrossRefGoogle Scholar
  14. 14.
    Yagiz, S.; Gokceoglu, C.: Application of fuzzy inference system and nonlinear regression models for predicting rock brittleness. Expert Syst. Appl. 37, 2265 (2010)CrossRefGoogle Scholar
  15. 15.
    Rickman, R.; Mullen, M.J.; Petre, J.E.; Grieser, W.V.; Kundert, D.; Others: a practical use of shale petrophysics for stimulation design optimization: all shale plays are not clones of the Barnett Shale. In: SPE-115258, SPE Annual Technical Conference and Exhibition. Society of Petroleum Engineers, Denver, Colorado, USA (2008)Google Scholar
  16. 16.
    Hajiabdolmajid, V.; Kaiser, P.: Brittleness of rock and stability assessment in hard rock tunneling. Tunn. Undergr. Space Technol. 18, 35 (2003)CrossRefGoogle Scholar
  17. 17.
    Zhou, H.; Meng, F.; Zhang, C.; Xu, R.; Lu, J.: Quantitative evaluation of rock brittleness based on stress–strain curve. Chin. J. Rock Mech. Eng. 33, 1114 (2014)Google Scholar
  18. 18.
    Li, Q.; Chen, M.; Jin, Y.; Wang, F.P.; Hou, B.; Zhang, B.: Indoor evaluation method for shale brittleness and improve. Chin. J. Rock Mech. Eng. 31, 1681 (2012)Google Scholar
  19. 19.
    Yuan, J.; Deng, J.; Zhang, D.: Fracability evaluation of shale-gas reservoirs. Acta Pet. Sin. 34, 523 (2013)Google Scholar
  20. 20.
    Guo, J.; Luo, B.; Zhu, H.; Wang, Y.; Lu, Q.; Zhao, X.: Evaluation of fracability and screening of perforation interval for tight sandstone gas reservoir in western Sichuan Basin. J. Nat. Gas Sci. Eng. 25, 77 (2015)CrossRefGoogle Scholar
  21. 21.
    Guo, T.; Zhang, S.; Ge, H.; Wang, X.; Lei, X.; Xiao, B.: A new method for evaluation of fracture network formation capacity of rock. Fuel 140, 778 (2015)CrossRefGoogle Scholar
  22. 22.
    Wu, K.; Olson, J.E.: Mechanics Analysis of Interaction Between Hydraulic and Natural Fractures in Shale Reservoirs. In: Paper at the SPE-1922946, Unconventional Resources Technology Conference. Society of Petroleum Engineers, Denver, Colorado, USA (2014)Google Scholar
  23. 23.
    Wu, K.; Olson, J.E.: Numerical Investigation of Complex Hydraulic Fracture Development in Naturally Fractured Reservoirs. In: Paper at the SPE-173326, SPE Hydraulic Fracturing Technology Conference. Society of Petroleum Engineers, Woodlands, Texas, USA (2015)Google Scholar
  24. 24.
    Vallejo, L.E.: Mechanics of the slaking of shales. Geomech. Eng. 3, 219 (2011)CrossRefGoogle Scholar
  25. 25.
    Guo, T.; Zhang, H.: Formation and enrichment mode of Jiaoshiba shale gas field, Sichuan basin. Pet. Explor. Dev. 41, 31 (2014)CrossRefGoogle Scholar
  26. 26.
    Liang, C.; Jiang, Z.; Yang, Y.; Wei, X.: Shale lithofacies and reservoir space of the Wufeng–Longmaxi formation, Sichuan Basin, China. Pet. Explor. Dev. 39, 736 (2012)CrossRefGoogle Scholar
  27. 27.
    Zhu, H.; Guo, J.; Zhao, X.; Lu, Q.; Luo, B.; Feng, Y.: Hydraulic fracture initiation pressure of anisotropic shale gas reservoirs. Geomech. Eng. 7, 403 (2014)CrossRefGoogle Scholar
  28. 28.
    Yang, X.; Zhang, L.; Ji, X.: Strength characteristics of transversely isotropic rock materials. Geomech. Eng. 5, 71 (2013)CrossRefGoogle Scholar
  29. 29.
    Tang, X.; Paluszny, A.; Zimmerman, R.W.: A Study of the Influence of Fragmentation in Ore-Pass Hang-up Phenomena. In: 47th US Rock Mechanics/Geomechanics Symposium. American Rock Mechanics Association, San Francisco, CA, USA (2013)Google Scholar
  30. 30.
    Hou, B.; Chen, M.; Cheng, W.; Diao, C.: Investigation of hydraulic fracture networks in shale gas reservoirs with random fractures. Arab. J. Sci. Eng. 41, 2681 (2016)CrossRefGoogle Scholar

Copyright information

© King Fahd University of Petroleum & Minerals 2018

Authors and Affiliations

  • Haiyan Zhu
    • 1
  • 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

Personalised recommendations