Hostname: page-component-78c5997874-xbtfd Total loading time: 0 Render date: 2024-11-18T12:22:43.715Z Has data issue: false hasContentIssue false
  • English
  • Français

In Situ Scanning Electron Microscope (SEM) Observations of Damage and Crack Growth of Shale

Published online by Cambridge University Press:  27 April 2018

Zhendong Cui  and
Weige Han
Zhendong Cui*
Affiliation:
Key Laboratory of Shale Gas and Geoengineering, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China Institutions of Earth Science, Chinese Academy of Sciences, Beijing 100029, China College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
Weige Han
Affiliation:
Key Laboratory of Shale Gas and Geoengineering, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China Institutions of Earth Science, Chinese Academy of Sciences, Beijing 100029, China College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
*
Author for correspondence: Zhendong Cui, E-mail: cuizhendong@mail.iggcas.ac.cn
Get access

Abstract

To better understand the formation and evolution of hierarchical crack networks in shales, observations of microscopic damage, and crack growth were conducted using an in situ tensile apparatus inside a scanning electron microscope. An arched specimen with an artificial notch incised into the curved edge was shown to afford effective observation of the damage and crack growth process that occurs during the brittle fracturing of shale. Because this arched specimen design can induce a squeezing effect, reducing the tensile stress concentration at the crack tip, and preventing the brittle shale from unstable fracturing to some extent. Both induced and natural pores and cracks were observed at different scales around the main crack path or on fractured surfaces. Observations indicate that the crack initiation zone develops around the crack tip where tensile stresses are concentrated and micro/nanoscale cracks nucleate. Crack advancement generally occurs by the continuous generation and coalescence of damage zones having intermittent en echelon microscopic cracks located ahead of the crack tips. Mineral anisotropy and pressure build-up around crack tips causes crack kinking, deflection, and branching. Crack growth is often accompanied by the cessation or closure of former branch cracks due to elastic recovery and induced compressive stress. The branching and interactions of cracks form a three-dimensional hierarchical network that includes induced branch cracks having similar paths, as well as natural structures such as nanopores, bedding planes, and microscopic cracks.

Keywords

in situ SEM observationmicro/nanoscaledamagecrack growthshale gas
Type
Materials Science Applications
Information
Microscopy and Microanalysis , Volume 24 , Issue 2 , April 2018 , pp. 107 - 115
Copyright
© Microscopy Society of America 2018 

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Bai, BJ, Elgmati, M, Zhang, H and Wei, MZ (2013) Rock characterization of Fayetteville shale gas plays. Fuel 105, 645–652.Google Scholar
Bai, T, Pollard, DD and Gao, H (2000) Explanation for fracture spacing in layered materials. Nature 403, 753–756.CrossRefGoogle ScholarPubMed
Chen, L, Zhang, L, Kang, QJ, Viswanathan, HS, Yao, J and Tao, WQ (2014) Nanoscale simulation of shale transport properties using the lattice Boltzmann method: Permeability and diffusivity. Sci Rep 5, 80–89.Google Scholar
Dong, GJ, Chen, P (2017) A comparative experimental study of shale indentation fragmentation mechanism at the macroscale and mesoscale. Adv Mech Eng 9, 1–11.Google Scholar
Geng, Z, Chen, M, Jin, Y, Yang, S, Yi, ZC, Fang, X and Du, XY (2016) Experimental study of brittleness anisotropy of shale in triaxial compression. J Nat Gas Sci Eng 36, 510–518.Google Scholar
Huang, LK, Liu, JJ, Ji, YJ, Gong, XP and Qin, LK (2017) A review of multiscale expansion of low permeability reservoir cracks. Petroleum. doi: 10.1016/j.petlm.2017.09.002.Google Scholar
Kim, YS, Peacock, DCP and Sanderson, DJ (2003) Mesoscale strike-slip faults and damage zones at Marsalforn, Gozo Island, Malta. J Struct Geol 25, 793–812.Google Scholar
Kitamura, T, Hirakata, H, Sumigawa, T and Shimada, T (2011) Fracture Nanomechanics. Singapore: Pan Stanford Publishing Pte. Ltd.Google Scholar
Klaver, J, Desbois, G, Littke, R and Urai, JL (2015) BIB-SEM characterization of pore space morphology and distribution in post mature to over mature samples from the Haynesville and Bossier Shales. Mar Petrol Geol 59, 451–466.CrossRefGoogle Scholar
Li, PF, Liao, QL, Yang, SZ, Bai, XD, Huang, YH, Yan, XQ, Zhang, Z, Liu, S, Lin, P, Kang, Z and Zhang, Y (2014) In situ transmission electron microscopy investigation on fatigue behavior of single ZnO wires under high-cycle strain. Nano Lett 14, 480–485.Google Scholar
Liu, T, Cao, P and Lin, H (2014) Damage and fracture evolution of hydraulic fracturing in compression-shear rock cracks. Theor Appl Fract Mech 74, 55–63.Google Scholar
Liu, WK, Karpov, EG and Park, HS (2006) Nano Mechanics and Materials: Theory, Multiscale Methods and Applications. West Sussex, England: John Wiley & Sons Ltd.CrossRefGoogle Scholar
Loucks, RG, Reed, RM, Ruppel, SC and Jarvie, DM (2009) Morphology, genesis, and distribution of nanometer-scale pores in siliceous mudstones of the Mississippian Barnett shale. J Sed Res 79, 848–861.Google Scholar
Martel, SJ and Boger, WA (1998) Geometry and mechanics of secondary fracturing around small three-dimensional faults in granitic rock. J Geophys Res 103, 21299–21314.Google Scholar
Roering, C (1968) The geometrical significance of natural en-echelon crack-arrays. Tectonophysics 5, 107–123.Google Scholar
Slatt, RM and O’Brien, NR (2011) Pore types in the Barnett and Woodford gas shale: Contribution to understanding gas storage and migration pathways in fine-grained rocks. AAPG Bull 95, 2017–2030.Google Scholar
Wang, H, Boehlert, CJ, Wang, QD, Yin, DD and Ding, WJ (2016) In-situ analysis of the tensile deformation modes and anisotropy of extruded Mg-10Gd-3Y-0.5Zr (wt.%) at elevated temperatures. Int J Plasticity 84, 255–276.Google Scholar
Wang, H, Li, M and Shang, XF (2016) Current developments on micro-seismic data processing. J Nat Gas Sci Eng 32, 521–537.Google Scholar
Wang, L, Fu, YH, Li, J, Sima, LQ, Wu, QZ, Jin, WJ and Wang, T (2016) Mineral and pore structure characteristics of gas shale in Longmaxi formation: A case study of Jiaoshiba gas field in the southern Sichuan Basin, China. Arab J Geosci 9, 733.CrossRefGoogle Scholar
Wang, LH, Zhang, Z and Han, XD (2013) In situ experimental mechanics of nanomaterials at the atomic scale. NPG Asia Mater 5, 1–11.Google Scholar
Zhang, D, Ranjith, P and Perera, M (2016) The brittleness indices used in rock mechanics and their application in shale hydraulic fracturing: A review. J Pet Sci Eng 143, 158–170.Google Scholar
Zuo, JP, Wang, XS and Mao, DQ (2014) SEM in-situ study on the effect of offset-notch on basalt cracking behavior under three-point bending load. Eng Fract Mech 131, 504–513.Google Scholar
Zuo, JP, Wang, XS, Mao, DQ, Wang, CL and Jiang, GH (2016) T-M coupled effects on cracking behaviors and reliability analysis of double-notched crustal rocks. Eng Fract Mech 158, 106–115.Google Scholar
Zuo, JP, Wei, X, Pei, JL and Zhao, XP (2015) Investigation of meso-failure behaviors of Jinping marble using SEM with bending loading system. J Rock Mech Geotech Eng 7, 593–599.Google Scholar