Abstract
The experimental work described in this paper was carried out in order to discover more about the effects of bedding planes on wave velocity and acoustic emission (AE) characteristics of shale. Two groups of specimens, which were collected from the Longmaxi shale outcrop in Chongqing, China and cored perpendicular and parallel to the bedding planes, were tested under uniaxial compression, and the wave velocity and AE were monitored. There were obvious differences in the acoustic characteristics of shale with different bedding plane orientations. The experimental results show that (1) the average increasing rates of P- and S-wave velocities were 39.86 and 54.41%, respectively, for the specimen with a load perpendicular to the bedding planes (Y-0). The P-wave velocity and axial strain of specimen show a marked logarithmic relationship. However, the average increasing rates of P- and S-wave velocities were 5.44 and 10.54%, respectively, for the specimen with a load parallel to the bedding planes (Y-90). The good linear relationship between P-wave velocity and axial strain before failure of specimen has been built. Generally, S-wave velocity was more sensitive to axial strain than P-wave velocity. (2) AE characteristics for Y-0 showed that a few signals → quiet period → stable increase → steep increase; for Y-90: quiet period → stable increase → sudden increase → sharp increase. The AE energy for two groups of specimens was concentrated on low and middle of amplitudes (45-80 dB), but the proportion of amplitudes (80–100 dB) and the total counts of AE for Y-0 was 1.95, 2.2 times as much as that for Y-90, respectively. The results preliminarily revealed the effect of bedding orientation on the wave velocity and AE properties of shale and may provide guidance for the improvement of acoustic logging and microseismic monitoring in the field.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Brown ET (1981) Rock characterization testing & monitoring: ISRM suggested methods. Pergamon Press, Oxford
Chen Y, Huang TF, Liu ER (2009) Rock physics. Press of University of Science and Technology of China, Hefei
Dai F, Xia K, Nasseri MHB (2013a) Micromechanical model for the rate dependence of the fracture toughness anisotropy of Barre granite. Int J Rock Mech Min Sci 63:113–121
Dai F, Xia K, Zuo JP et al (2013b) Static and dynamic flexural strength anisotropy of Barre granite. Rock Mech Rock Eng 46:1589–1602
Ge MC (2012) Source location error analysis and optimization methods. Chin J Rock Mech Eng 04:1–10
Heng S, Yang CH, Guo YT et al (2015a) Influence of bedding planes on hydraulic fracture propagation in shale formations. Chin J Rock Mech Eng 34:3624–3632
Heng S, Guo YT, Yang CH et al (2015b) Experimental and theoretical study of the anisotropic properties of shale. Int J Rock Mech Min Sci 74:58–68
Heng S, Yang CH, Guo YT et al (2015c) Experimental research on anisotropic properties of shale. Rock Soil Mech 36:610–616
Hou ZK, Yang CH, Guo YT et al (2015) Experimental study on anisotropic properties of longmaxi formation shale under uniaxial compression. Rock Soil Mech 36:2541–2550
Ibanez WD, Kronenberg AK (1993) Experimental deformation of shale: mechanical properties and microstructural indicators of mechanisms. Int J Rock Mech Min Sci 30:723–734
Kuila U, Dewhurst DN, Siggins AF et al (2011) Stress anisotropy and velocity anisotropy in low porosity shale. Tectonophysics 503:34–44
Li HR, Yang CH, Chen F et al (2016) Development and application of an integrative testing device for acoustic waves and acoustic emission of rock. Rock Soil Mech 37:287–296
Liu JX, Liu W, Yang CH et al (2014) Experimental research on effects of strain rate on mechanical properties of shale. Rock Soil Mech 35:3093–3100
Liu M, Jin Y, Lu YH et al (2016) A wellbore stability model for a deviated well in a transversely isotropic formation considering poroelastic effects. Rock Mech Rock Eng 49:3671–3686
Ma Y, Pan ZJ, Zhong NN et al (2016) Experimental study of anisotropic gas permeability and its relationship with fracture structure of longmaxi shales, Sichuan basin, China. Fuel 180:106–115
Wang J, Xie LZ, Xie HP et al (2016) Effect of layer orientation on acoustic emission characteristics of anisotropic shale in brazilian tests. J Nat Gas Sci Eng
Xu F, Yang CH, Guo YT et al (2016) Development and application of experimental apparatus of hydraulic sand fracturing. Chin J Geotech Eng 38:187–192
Zhang S, Liu QL, Zhao Q et al (2002) Application of microseismic monitoring technology in development of oil field. Geophy Pros Pet 41:226–231
Zhang ZP, Zhang R, Xie HP et al (2015a) Differences in the acoustic emission characteristics of rock salt compared with granite and marble during the damage evolution process. Environ Earth Sci 73:6987–6999
Zhang R, Dai F, Gao MZ et al (2015b) Fractal analysis of acoustic emission during uniaxial and triaxial loading of rock. Int J Rock Mech Min Sci 79:241–249
Zou CN, Dong DZ, Wang YM et al (2015a) Shale gas in China: characteristics, challenges and prospects (I). Pet Explor Dev 42:753–767
Zou CN, Dong DZ, Wang YM et al (2015b) Shale gas in China: characteristics, challenges and prospects (II). Pet Explor Dev 43:182–196
Acknowledgments
The authors would like to acknowledge professor J. J. K. Daemen at the University of Nevada, USA, for his English help, and the financial support of the Strategic Priority Research Program (B) of the Chinese Academy of Sciences (XDB10040200), National Science and Technology Major Project (2016ZX05060), the National Natural Science Foundation of China (51574218, 41602328).
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Xu, F., Yang, C., Guo, Y. et al. Effect of bedding planes on wave velocity and AE characteristics of the Longmaxi shale in China. Arab J Geosci 10, 141 (2017). https://doi.org/10.1007/s12517-017-2943-y
Received:
Accepted:
Published:
DOI: https://doi.org/10.1007/s12517-017-2943-y