Abstract
Natural fractures and weak bedding planes are important for forming complex fracture networks in shale reservoirs. There are many sets of shale layers with different bedding densities in Sichuan, China. In this paper, three typical drilling cores with different bedding densities were collected. The shale rock mechanical properties and fracture morphology are investigated. Bedding density affects the strength and deformation characteristics. A fracture characterization model is proposed, and the hydraulic fracturing effects are evaluated. It is shown that with decreasing bedding density, the peak strength and elastic modulus increase, and Poisson’s ratio decreases gradually. The effect of natural fractures on hydraulic fracturing is investigated by analyzing the expansion of hydraulic fracture. The research shows that natural fractures have a significantly induced effect on the initiation and propagation of hydraulic fracture. According to the results of physical simulation of hydraulic fracturing, three types fracture extension models are established: a strong extended complex fracture model, a weak bedding extended complex fracture model, and a natural fracture crack propagation model. Natural fractures with different bedding structural properties may result in different propagation types of hydraulic fracture.
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Zhang, J.C.; Jin, Z.J.; Yuan, M.S.: Reservoiring mechanism of shale gas and its distribution. Nat. Gas Ind. 24(7), 15–18 (2004)
Zhang, J.C.; Wang, Z.Y.; Nie, H.K.; Bo, X.; Deng, F.Y.: Shale gas and its significance for exploration. Geoscience 22(4), 640–646 (2008)
Wang, L.S.; Zou, C.Y.; Zhen, P.; Chen, S.J.; Zhang, Q.: Geochemical evidence of shale gas existed in the Lower Paleozoic Sichuan basin. Nat. Gas Ind. 29(5), 59–62 (2009)
Dong, D.Z.; Cheng, K.M.; Wang, S.Q.: An evaluation method of shale gas resource and its application in the Sichuan basin. Nat. Gas Ind. 29(5), 33–39 (2009)
Zeng, X.L.; Liu, S.G.; Huang, W.M.; Zhang, C.J.: Comparison of Silurian Longmaxi formation shale of Sichuan basin in China and carboniferous Barnett formation shale of Fort Worth basin in United States. Geol. Bull. China 30, 372–384 (2011)
Lei, M.; Liang, L.X.; Xiong, J.; Zhuang, D.L.; Luo, C.: Experiment of the fundamental physical properties and analysis of the wellbore stability on hard brittle shale. Sci. Technol. Eng. 15, 34–40 (2015)
Guo, T.K.; Zhang, S.C.; Ge, H.K.: A new method for evaluating ability of forming fracture network in shale reservoir. Rock Soil Mech. 34, 947–954 (2013)
Xie, H.P.; Gao, F.; Ju, Y.; Xie, L.Z.; Yang, Y.M.: Novel idea of the theory and application of 3D volume fracturing for stimulation of shale gas reservoirs. Chin. Sci. Bull. 61, 36–46 (2016)
Johnston, J.E.; Christensen, N.I.: Seismic anisotropy of shales. J. Geophys. Res. Solid Earth 100, 5991–6003 (1995)
Wang, Q.; Wang, P.; Xiang, D.G.; Feng, Y.: Anisotropic property of mechanical parameters of shales. Nat. Gas Ind. 32(12), 62–65 (2012)
Chen, T.Y.; Feng, X.T.; Zhang, X.W.: Experimental study on mechanical and anisotropic properties of black shale. Chin. J. Rock Mech. Eng. 33, 1772–1779 (2014)
Jung, W.C.; Hanna, K.; Seokwon, J.: Deformation and strength anisotropy of Asan gneiss, Boryeong shale, and Yeoncheon schist. Int. J. Rock Mech. Min. Sci. 50, 158–169 (2002)
Simpson, N.D.; Stroisz, A.; Bauer, A.: Failure mechanics of anisotropic shale during Brazilian tests. In: Proceedings of the 48th US Rock Mechanics/Geomechanics Symposium (2014)
Ma, T.S.; Chen, P.: Influence of shale bedding plane on wellbore stability for horizontal wells. J. Southwest Pet. Univ. Sci. Technol. Ed. 36, 97–104 (2014)
Yu, B.H.; Yan, W.; Li, B.; Zhang, C.; Zhou, J.: Mechanical borehole stability test study in highly-dipped laminated formation. Oil Drill. Product. Technol. 31(2), 48–50 (2009)
Yuan, J.L.; Deng, J.G.; Yu, B.H.; Tan, Q.; Fan, B.T.: Wellbore stability of horizontal wells in shale gas reservoirs. Nat. Gas Ind. 32(9), 66–70 (2012)
Heng, S.; Yang, C.H.; Guo, Y.T.; Wang, C.Y.; Wang, L.: Influence of bedding plane on hydraulic fracture propagation in shale formations. Chin. J. Rock Mech. Eng. 34, 228–237 (2015)
Lu, Y.H.; Chen, M.; Jin, Y.; Zhang, G.Q.: A mechanical model of borehole stability for weak plane formation under porous flow. Pet. Sci. Technol. 30, 1629–1638 (2012)
Lu, Y.H.; Chen, M.; Jin, Y.; Ge, W.F.; An, S.; Zhou, Z.: Influence of porous flow on wellbore stability for an inclined well with weak plane formation. Pet. Sci. Technol. 31, 616–624 (2013)
Daneshy, A.A.: Hydraulic fracture propagation in the presence of planes of weakness. In: Proceedings of SPE European Spring Meeting, pp. 1–8 (1974)
Blanton, T.L.: An experimental study of interaction between hydraulically induced and pre-existing fractures. In: Proceedings of SPE Unconventional Gas Recovery Symposium, pp. 1–13 (1982)
Blanton, T.L.: Propagation of hydraulically and dynamically induced fractures in naturally fractured reservoirs. In: Proceedings of SPE Unconventional Gas Technology Symposium, pp 1–15 (1986)
Anderson, G.D.: Effects of friction on hydraulic fracture growth near unbonded interfaces in rocks. SPE 21(1), 21–29 (1981)
Guo, Y.T.; Yang, C.H.; Jia, C.G.; Xu, J.B.; Wang, L.; Li, D.: Research on hydraulic fracturing physical simulation of shale and fracture characterization methods. Chin. J. Rock Mech. Eng. 33, 52–59 (2014)
Warpinskin, R.; Clark, J.A.; Schmidt, R.A.: Laboratory investigation on the-effect of in-situ stresses on hydraulic fracture containment. SPE 22(3), 333–340 (1982)
Blair, S.C.; Thorpe, R.K.; Heuze, F.E.: Laboratory observations of the effect of geological discontinuities on hydrofracture propagation. In: Proceedings of the 30th US Symposium on Rock Mechanics, pp. 433–450 (1989)
East, L.; Soliman, M.Y.; Augustine, J.: Methods for enhancing far-field complexity in fracturing operations. In: SPE 133380(2010)
Romanson, R.; East, L.; Stanojcic, M.: Novel, multistage stimulation processes can help achieve and control branch fracturing and increasing stimulated reservoir volume for unconventional reservoirs. In: SPE 142959 (2011).
Sun, K.M.; Zhang, S.C.; Xin, L.W.: Impacts of bedding directions of shale gas reservoirs on hydraulically induced crack propagation. Nat. Gas Ind. 36(2), 45–51 (2014)
Zhao, J.Z.; Li, Y.M.; Wang, S.; Jiang, Y.S.; Zhang, L.H.: Simulation of complex fracture networks influenced by natural fractures in shale gas reservoir. Nat. Gas Ind. 1, 89–95 (2014)
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Guo, Y., Yang, C., Wang, L. et al. Study on the Influence of Bedding Density on Hydraulic Fracturing in Shale. Arab J Sci Eng 43, 6493–6508 (2018). https://doi.org/10.1007/s13369-018-3263-6
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DOI: https://doi.org/10.1007/s13369-018-3263-6