Nanoscale pore and crack evolution in shear thin layers of shales and the shale gas reservoir effect

Yan Sun, Yiwen Ju, Wei Zhou, Peng Qiao, Liru Tao, Lei Xiao

Abstract view|5|times       PDF download|1|times


Studies on matrix-related pores from the nanometer to the micrometer scale in shales have made considerable progress in recent decades. However, nanoscale pores and cracks developed in the shear thin layers have not been systematically discussed. In this work, interlayer shear slip occurring in shales are observed through practical examples. The results show that the shear thin layer constructed by nanograin coating is widely distributed on superimposed shear slip planes. Usually, the development of the shear thin layer undergoes viscoelastic-rheological-embrittling deformation stages, and the nanograin texture assembled in the shear thin layer can demonstrate three pore and crack structure types. Based on the mechanical analysis concerning nanoscale cohesion force, it is identified that, as long as force remains a state, the shear thin layer must bear a nanoscale pore and crack character. Furthermore, the shale gas reservoir effect of the nanoscale pore and crack is simply discussed. Obviously, the adsorbed gas effect of the nanograin itself has a larger nanoscale size and surface functionality than those of kerogen and clay particles in the shales; three structure types of the nanoscale pore and crack can act as given controlling factors of storage and permeability for the free gas. Both the matrix-related pores and the three pore and crack structures have an intimate connection with respect to each other in the genetic mechanism and temporal-spatial evolution. This work has important theoretical implications for supplementing the pore and crack classification of shale. Moreover, it makes a significant contribution to shale gas exploration and development.

Cited as: Sun, Y., Ju, Y., Zhou, W., Qiao, P., Tao, L., Xiao, L. Nanoscale pore and crack evolution in shear thin layers of shales and the shale gas reservoir effect. Advances in Geo-Energy Research, 2022, 6(3): 221-229.


Shale, shear thin layers, pore and crack, shale gas, reservoir effect

Full Text:



Aringhieri, R. Nanoporosity characteristics of some natural clay minerals and soils. Clays and Clay Minerals, 2004, 52(6): 700-704.

Apraiz, A., Eguiluz, L. Hercynian tectono-thermal evolution associated with crustal extension and exhumation of the Lora del Rio metamorphic core complex (Ossa-Morena zone, Iberian Massif, SW Spain). International Journal of Earth Sciences, 2002, 91(1): 76-92.

Berger, L. L. On the mechanism of craze fibril breakdown in glassy polymers. Macromolecules, 1990, 23(11): 2926-2934.

Braun, O. M., Naumovets, A. G. Nanotribology: Microscopic mechanisms of friction. Surface Science Reports, 2006, 60(6-7): 79-158.

Chen, G., Dong, D., Wang, S., et al. A preliminary study on accumulation mechanism and enrichment pattern of shale gas. Natural Gas Industry, 2009, 29(5): 17-21+ 134-135.(in Chinese)

Chen, L., Jiang, Z., Liu, K., et al. Quantitative evaluation of free gas and adsorbed gas content of Wufeng-Longmaxi shales in the Jiaoshiba area, Sichuan Basin, China. Advanced in Geo-Energy Research, 2017, 1(2): 112-123.

Comer, J. B. Reservoir characteristics and production potential of the Woodford shale. World Oil, 2008, 229(8): 83-87.

Curtis, J. B. Fractured shale gas systems. AAPG Bulletin, 2002, 86(11): 1921-1938.

Desbois, G., Urai, J. L., Kukla, P. A. Morphology of the pore space in claystones-evidence from BIB/FIB ion beam sectioning and cryo-SEM observations. eEarth Discusion, 2009, 4(1): 1-19.

De Paola, N. Nano-powder coating can make fault surfaces smooth and shiny: Implications for fault mechanics? Geology, 2013, 41(6): 719-720.

Gale, J. F. W., Reed, R. M., Holder, J. Natural fractures in the Barnett shale and their importance for hydraulic fracture treatments. AAPG Bulletin, 2007, 91(4): 603-622.

Gao, Z., Fan, Y., Xuan, Q., et al. A review of shale pore structure evolution characteristics with increasing thermal maturities. Advanced in Geo-Energy Research, 2020, 4(3): 247-259.

Goodwin, L. B., Wenk, H. R. Development of phyllonite from granodiorite: Mechanisms of grain-size reduction in the Santa-Rosa mylonite zone, California. Journal of Structural Geology, 1995, 17(5): 689-697+699-707.

Guo, J., Sun, Y., Zhu, W., et al. A new explanation for the genetic mechanism on the smear efficiency within oil-gas sealing covers. Journal of Nanjing University (Natural Sciences), 2002, 38(6): 766-770. (in Chinese)

Guo, W., Dong, H., Lu, M., et al. The coupled effects of thickness and delamination on cracking resistance of X70 pipeline steel. International Journal of Pressure Vessels and Piping, 2002, 79(6): 403-412.

Hirose, T., Bystricky, M., Kunze, K., et al. Semi-brittle flow during dehydration of lizardite-chrysotile serpentinite deformed in torsion: Implications for the rheology of oceanic lithosphere. Earth and Planetary Science Letters, 2006, 249(3-4): 484-493.

Hochella, M. F., Lower, S. K., Maurice, P. A., et al. Nanomin-erals, mineral nanoparticles and earth systems. Science, 2008, 319(5870): 1631-1635.

Holdsworth, R. E. Weak faults-Rotten cores. Science, 2004, 303(5655): 181-182.

Hunt, G. W., Peletier, M. A., Wadee, M. A. The maxwell stability criterion in pseudo-energy models of kink banding. Journal of Structural Geology, 2000, 22(5): 669-681.

Janssen, C., Wirth, R., Reinicke, A., et al. Nanoscale porosity in SAFOD core samples (San Andreas Fault). Earth and Planetary Science Letters, 2011, 301(1-2): 179-189.

Javadpour, F. Nanopores and apparent permeability of gas flow in mudrocks (shales and siltstone). Journal of Canadian Petroleum Technology, 2009, 48(8): 16-21.

John, W., Roger, R. The shale shaker: An investor’s guide to shale gas. Oil and Gas Investor, 2007, 1: 2-9.

Ju, Y., Huang, C., Sun, Y., et al. Nanogeosciences: Research history, current status, and development trends. Journal of Nanoscience and Nanotechnology. 2017, 17(9): 5930-5965.

Ju, Y., Huang, C., Sun, Y., et al. Nanogeology in China: A review. China Geology, 2018, 1: 286-303.

Ju, Y., Yu, Q., Fang, L., et al. Chinese shale gas reservoir types and their controlling factors. Advances in Earth Science, 2016, 31(8): 782-799. (in Chinese)

Kambe, N. Highly-uniform nano-structured building blocks of metal-(O, C, N, S) and their complex compounds. Scripta Materialia, 2001, 44(8-9): 1671-1675.

Keulen, N., Heilbronner, R., Stuenitz, H., et al. Grain size distributions of fault rocks: A comparison between experimentally and naturally deformed granitoids. Journal of Structural Geology, 2007, 29(8): 1282-1300.

Krása, D., Wilkinson, C. D. W., Gadegaard, N., et al. Nanofabrication of two-dimensional arrays of magnetite particles for fundamental rock magnetic studies. Journal of Geophysical Research: Solid Earth, 2009, 114: B02104.

Li, K. J., Kong, S. Q., Xia, P., et al. Microstructural characterisation of organic matter pores in coal-measure shale. Advances in Geo-Energy Research, 2020, 4(4): 372-391.

Lin, A. M. Fossil Earthquakes: The Formation And Preservation of Pseudotachylytes. New York, USA, Springer, 2008.

Long, P., Zhang, J., Tang, X., et al. Feature of muddy shale fissure and its effect for shale gas exploration and development. Natural Gas Geoscience, 2011, 22(3): 525-532. (in Chinese)

Loucks, R. G., Reed, R. M., Ruppel, S. C., et al. Morphology, genesis, and distribution of nanometer-scale pores in siliceous mudstones of the Mississippian Barnett shale. Journal of Sedimentary Research, 2009, 79(11-12): 848-861.

Loucks, R. G., Reed, R. M., Ruppel, S. C., et al. Spectrum of pore types and networks in mudrocks and a descriptive classification for matrix-related mudrock pores. AAPG Bulletin, 2012, 96(6): 1071-1098.

Lu, X., Sun, Y., Shu, L., et al. Cataclastic rheology of carbonate rocks. Science in China Series D: Earth Sciences, 2005, 48(8): 1227-1233.

Luo, W., Yang, T. Computer simulation of conic-shaped patterns on fracture surfaces of polymers. Journal of Applied Polymer Science, 2003, 89(6): 1722-1725.

Luo, W., Yang, T. Crack tip damage and crazing in polymers under loading. Acta Mechanica Sinica, 1990, 35(5): 553-560. (in Chinese)

Masch, L., Wenk, H. R., Preuss, E. Electron microscopy study of hyalomylonites-evidence for frictional melting in landslides. Tectonophysics, 1985, 115(1-2): 131-160.

Mclaren, A. C., Pryer, L. L. Microstructural investigation of the interaction and interdependence of cataclastic and plastic mechanisms in feldspar crystals deformed in the semi-brittle field. Tectonophysics, 2001, 335(1-2): 1-15.

Montgomery, S. L., Jarvie, D. M., Bowker, K. A., et al. Mississippian Barnett shale, Fort Worth basin, north-central Texas: Gas-shale play with multi-trillion cubic foot potential. AAPG Bulletin, 2005, 89(2): 155-175.

Morley, C. K., von Hagke, C., Hansberry, R. L., et al. Review of major shale-dominated detachment and thrust characteristics in the diagenetic zone: Part I, meso-and macro-scopic scale. Earth-Science Reviews, 2017, 173: 168-228.

Musil, J. Hard and superhard nanocomposite coatings. Surface & Coatings Technology, 2000, 125(1-3): 322-330.

Raimbourg, H., Toyoshima, T., Harima, Y., et al. Grain-size reduction mechanisms and rheological consequences in high-temperature gabbro mylonites of Hidaka, Japan. Earth and Planetary Science Letters, 2008, 267(3-4): 637-653.

Slatt, R. M., O’Brien, N. R. Pore types in the Barnett and Woodford gas shales: Contribution to understanding gas storage and migration pathways in fine-grained rocks. AAPG Bulletin, 2011, 95(12): 2017-2030.

Sun, Y., Ge, H., Lu, X., et al. Discovery and analysis of the ultra-micro nano texture in the ductile-brittle shear zone. Science China Earth Sciences, 2003, 33(7): 619-625. (in Chinese)

Sun, Y., Jiang, S., Zhou, W., et al. Mechanical analysis and identification markings of nanoparticle distribution in narrow friction zones. Advanced Materials Research, 2014a, 924: 312-318.

Sun, Y., Jiang, S., Zhou, W., et al. Nano-coating texture on the shear slip surface in rocky materials. Advanced Materials Research, 2013, 669: 108-114.

Sun, Y., Ju, Y., Jiang, S., et al. A preliminary identification of micro/nano scale textures on mineralization, hydrocarbon accumulation and seismic formation structure. Journal of Nanoscience and Nanotechnology, 2017, 17(9): 7048-7054.

Sun, Y., Ju, Y., Wang, G., et al. Five types of micro/nano pore-crack in shale and their unconventional gas accumulation effect. 2014 Annual Meeting of Chinese Geoscience Union-Topic 57: Basin Dynamics and Unconventional Energy, 2014b: 2451-2453. (in Chinese)

Sun, Y., Lu, X., Ju, Y. Nano texture and mineralization in fault shear zones. Geological Journal of China Universities, 2018, 24(3): 307-324. (in Chinese)

Sun, Y., Lu, X., Liu, D., et al. Discovery, nomenclature of the centimeter scale grinding gravels and the nanometer scale grinding grains in fault shearing zones and the significance for oil-gas geology. Geological Journal of China Universities, 2005, 11(4): 521-526. (in Chinese)

Sun, Y., Lu, X., Zhang, X., et al. Nano-texture of penetrative foliation in metamorphic rocks. Science in China Series D: Earth Sciences, 2008a, 51(12): 1750-1758.

Sun, Y., Shu, L., Lu, X., et al. A comparative study of natural and experimental nano-sized grinding grain textures in rocks. Chinese Science Bulletin, 2008b, 53(8): 1217-1221.

Sun, Y., Shu, L., Lu, X., et al. Recent progress in studies on the nano-sized particle layer in rock shear planes. Progress in Natural Science, 2008c, 18(4): 367-373.

Suvorov, A. I. Tectonic layering and tectonic motions in the continental lithosphere. Geotectonics, 2000, 34(6): 442-451.

Tahirkheli, S. N. Becoming digital. Geotimes, 2001, 46(1): 5-5.

Urbakh, M., Klafter, J., Gourdon, D., et al. The nonlinear nature of friction. Nature, 2004, 430(6999): 525-528.

Veprek, S., Niederhofer, A., Moto, K., et al. Composition, nanostructure and origin of the ultrahardness in nc-TiN/a-Si3N4/a-and nc-TiSi2 nanocomposites with Hv=80 to≥105 GPa. Surface and Coatings Technology, 2000, 133-134: 152-159.

Wang, C., Sun, Y. Oriented microfractures in Cajon pass drill cores: Stress field near the San Andreas fault. Journal of Geophysical Research: Solid Earth and Planets, 1990, 95(B7): 11135-11142.

Wang, G, Ju, Y. Organic shale micropore and mesopore structure characterization by ultra-low pressure N2 physisorption: Experimental procedure and interpretation model. Journal of Natural Gas Science and Engineering, 2015, 27: 452-465.

Wang, Y., Gao, H., Xu, H. Nanogeochemistry: Nanostructures and their reactivity in natural systems. Frontiers in Geo-chemistry: Contribution of Geochemistry to the Study of the Earth, edited by R. Hamon and A. Parker, Blackwell, New Jersey, 2011, 200-220.

Yang, T. Rheology of bodies with defects. Mechanics and Practice, 1996, 18(3): 13-17. (in Chinese)

Zhu, H., Ju, Y., Huang, C., et al. Pore structure variations across structural deformation of Silurian Longmaxi Shale: An example from the Chuandong Thrust-Fold Belt. Fuel, 2019, 241: 914-932.



  • There are currently no refbacks.

Copyright (c) 2022 The Author(s)

Creative Commons License
This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Copyright ©2018. All Rights Reserved