Impacts of multi-scale water-rock interaction on mineral alteration, mechanical weakening and pore-fracture evolution in marine shales
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Abstract
Water-rock interaction triggered by drilling and fracturing fluid retention in shale gas reservoirs induces secondary processes and the subsequent alteration of rock physical properties, critically modulating reservoir productivity. In this study, X-ray diffraction, nanoindentation, focused ion beam-scanning electron microscopy, and micro-computed tomography were utilized to characterize and analyze the mineral alteration, mechanical weakening and pore-fracture evolution of marine shale in the Longmaxi Formation, Sichuan Basin. The results reveal that the water-rock interaction preferentially dissolves clay minerals (mainly illite), feldspars and pyrite via hydration and redox reactions while promoting quartz and carbonate mineral recrystallization. The hydration-dissolution precipitation process significantly weakens the rock mass by reducing cohesion and the friction angle. This mechanical degradation is evidenced by a substantial decrease in elastic modulus, exhibiting pronounced anisotropy relative to stratifications. The resultant hetero-geneous stress fields initiate and propagate secondary pores and fractures, dramatically increasing the number, volume and surface area of pores. These newly formed structures integrate with pre-existing pore-fracture networks, markedly elevating overall porosity and enhancing interconnectivity, which consequently amplifies permeability by orders of magnitude. Additionally, water preferentially enters the reservoir through stratification, and the associated difference in water-rock interaction strength further enhances the heterogeneity of structural and mechanical heterogeneity. These findings link micro-scale physical-chemical reactions with the meso-scale mechanical properties and macro-scale pore-fracture structures, emphasize the key role of water-rock interaction in reshaping reservoir characteristics, and provide important insights for optimizing hydraulic fracturing strategies and improving shale gas recovery.
Document Type: Original article
Cited as: Mu, Y., Zou, C., Hu, Z., Duan, X., Guo, Q., Jing, Z. Impacts of multi-scale water-rock interaction on mineral alteration, mechanical weakening and pore-fracture evolution in marine shales. Advances in Geo-Energy Research, 2025, 17(1): 68-81. https://doi.org/10.46690/ager.2025.07.06
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Cai, J., Jiao, X., Wang, H., et al. Multiphase fluid-rock interactions and flow behaviors in shale nanopores: A comprehensive review. Earth-Science Reviews, 2024, 257: 104884.
Chen, X., Eichhubl, P., Olson, J. E. Effect of water on critical and subcritical fracture properties of Woodford shale. Journal of Geophysical Research: Solid Earth, 2017, 122(4): 2736-2750.
Das, D., Mishra, B., Gupta, N. Understanding the influence of petrographic parameters on strength of differently sized shale specimens using XRD and SEM. International Journal of Mining Science and Technology, 2021, 31(5): 953-961.
Dautriat, J., Sarout, J., David, C., et al. Remote monitoring of the mechanical instability induced by fluid substitution and water weakening in the laboratory. Physics of the Earth and Planetary Interiors, 2016, 261: 69-87.
Deon, F., van Ruitenbeek, F., van der Werff, H., et al. Detection of interlayered Illite/Smectite clay minerals with XRD, SEM analyses and reflectance spectroscopy. Sensors, 2022, 22(9): 3602.
Elton, L. R. B., Jackson, D. F. X-ray diffraction and the Bragg law. American Journal of Physics, 1966, 34(11): 1036- 1038.
Emmings, J. F., Poulton, S. W., Walsh, J., et al. Pyrite megaanalysis reveals modes of anoxia through geological time. Science Advances, 2022, 8(11): eabj5687.
Fatah, A., Mahmud, H. B., Bennour, Z., et al. Geochemical modelling of CO2 interactions with shale: Kinetics of mineral dissolution and precipitation on geological time scales. Chemical Geology, 2022, 592: 120742.
Feng, R., Zhang, Y., Rezagholilou, A., et al. Brittleness index: From conventional to hydraulic fracturing energy model. Rock Mechanics and Rock Engineering, 2020, 53(2): 739-753.
Garum, M., Glover, P. W. J., Lorinczi, P., et al. Micro- and nano-scale pore structure in gas shale using Xµ-CT and FIB-SEM techniques. Energy & Fuels, 2020, 34(10): 12340-12353.
Ghasemi, M., Sharifi, M. Effects of layer-charge distribution on swelling behavior of mixed-layer illite-montmorillonite clays: A molecular dynamics simulation study. Journal of Molecular Liquids, 2021, 335: 116188.
Heng, S., Li, X., Liu, X., et al. Experimental study on the mechanical properties of bedding planes in shale. Journal of Natural Gas Science and Engineering, 2020, 76: 103161.
Hua, G., Wu, S., Jing, Z., et al. Rock physical and chemical alterations during the in-situ interaction between fracturing fluid and Silurian organic-rich shales in China. Journal of Natural Gas Science and Engineering, 2021, 94: 104075.
Jing, Z., Balucan, R. D., Underschultz, J. R., et al. Oxidant stimulation for enhancing coal seam permeability: swelling and solubilisation behaviour of unconfined coal particles in oxidants. Fuel, 2018a, 221: 320-328.
Jing, Z., Mahoney, S. A., Rodrigues, S., et al. A preliminary study of oxidant stimulation for enhancing coal seam permeability: Effects of sodium hypochlorite oxidation on subbituminous and bituminous Australian coals. International Journal of Coal Geology, 2018b, 200: 36-44.
Jin, Z., Nie, H., Liu, Q., et al. Source and seal coupling mechanism for shale gas enrichment in upper Ordovician Wufeng Formation - Lower Silurian Longmaxi Formation in Sichuan Basin and its periphery. Marine and Petroleum Geology, 2018, 97: 78-93.
Kang, Y., She, J., Zhang, H., et al. Strengthening shale wellbore with silica nanoparticles drilling fluid. Petroleum, 2016, 2(2): 189-195.
Kelly, S., El-Sobky, H., Torres-Verdín, C., et al. Assessing the utility of FIB-SEM images for shale digital rock physics. Advances in Water Resources, 2016, 95: 302-316.
Lin, H., Sun, X., Yuan, Y., et al. Experimental investigation on the dynamic volume changes of varied-size pores during shale hydration. Journal of Natural Gas Science and Engineering, 2022, 101: 104506.
Li, N., Zhou, T., Zhao, M., et al. Thermal-shock-induced surface softening and conductivity evolution of hydraulic fracture in enhanced geothermal system. Geothermics, 2022, 102: 102405.
Liu, B., Fu, X., Li, Z. Impacts of CO2-brine-rock interaction on sealing efficiency of sand caprock: A case study of Shihezi formation in Ordos basin. Advances in Geo-Energy Research, 2018, 2(4): 380-392.
Liu, G., Liu, K., Zhai, G., et al. Crystallinity and formation of silica in Palaeozoic shales: A new quantification calculation method based on X-Ray diffraction. Marine and Petroleum Geology, 2023, 150: 106124.
Liu, K., Ostadhassan, M., Bubach, B. Applications of nanoindentation methods to estimate nanoscale mechanical properties of shale reservoir rocks. Journal of Natural Gas Science and Engineering, 2016a, 35: 1310-1319.
Liu, K., Ostadhassan, M., Bubach, B., et al. Nano-dynamic mechanical analysis (nano-DMA) of creep behavior of shales: Bakken case study. Journal of Materials Science, 2018, 53(6): 4417-4432.
Liu, X., Zeng, W., Liang, L., et al. Experimental study on hydration damage mechanism of shale from the Longmaxi Formation in southern Sichuan Basin, China. Petroleum, 2016b, 2(1): 54-60.
Liu, Y., Liu, A., Liu, S., et al. Nano-scale mechanical properties of constituent minerals in shales investigated by combined nanoindentation statistical analyses and SEM-EDS-XRD techniques. International Journal of Rock Mechanics and Mining Sciences, 2022a, 159: 105187.
Liu, Y., Yang, C., Wang, J., et al. New insights into hydration-induced creep behavior of shale: A comparison study of brittle black shale and clayey oil shale at micro-scale. Marine and Petroleum Geology, 2022b, 138: 105554.
Lu, Y., Li, Y., Wu, Y., et al. Characterization of shale softening by large volume-based nanoindentation. Rock Mechanics and Rock Engineering, 2020, 53(3): 1393-1409.
Lyu, Q., Long, X., Ranjith, P. G., et al. Experimental investigation on the mechanical properties of a low-clay shale with different adsorption times in sub-/super-critical CO2. Energy, 2018, 147: 1288-1298.
Ma, T., Yang, C., Chen, P., et al. On the damage constitutive model for hydrated shale using CT scanning technology. Journal of Natural Gas Science and Engineering, 2016, 28: 204-214.
Molčanov, K., Stilinović, V. Chemical crystallography before X-ray diffraction. Angewandte Chemie International Edition, 2014, 53(3), 638-652.
Richter, A., Ries, R., Smith, R., et al. Nanoindentation of diamond, graphite and fullerene films. Diamond and Related Materials, 2000, 9(2): 170-184.
Roshan, H., Ehsani, S., Marjo, C. E., et al. Mechanisms of water adsorption into partially saturated fractured shales: An experimental study. Fuel, 2015, 159: 628-637.
Røyne, A., Dalby, K.N., Hassenkam, T. Repulsive hydration forces between calcite surfaces and their effect on the brittle strength of calcite-bearing rocks. Geophysical Research Letters, 2015, 42(12): 4786-4794.
Song, J., Xiang, D., Hu, D., et al. Creep characteristics of a fracturing fluid-softened shale investigated by microindentation. International Journal of Rock Mechanics and Mining Sciences, 2022, 152: 105067.
Sui, W., Tian, Y., Yao, C. Investigation of microscopic pore structure variations of shale due to hydration effects through SEM fixed-point observation experiments. Petroleum Exploration and Development, 2018, 45(5): 955-962.
Tang, J., Lan, T., Lai, Y., et al. Softening mechanism and characteristics of mudstone after absorbing moisture. Applied Clay Science, 2024, 254: 107398.
Thibault, P., Elser, V. X-Ray Diffraction Microscopy. Annual Review of Condensed Matter Physics, 2010, 1: 237-255.
Velcin, H., Dautriat, J., Sarout, J., et al. Experimental reactivation of shear-fractured berea and boise sandstones by brine or liquid CO2 injection at depth. Journal of Geophysical Research: Solid Earth, 2020, 125(2): e2019JB018281.
Wang, Y., Liu, X., Liang, L., et al. Experimental study on the damage of organic-rich shale during water-shale interaction. Journal of Natural Gas Science and Engineering, 2020, 74: 103103.
Wang, Y., Zhang, P., Wang, Z., et al. The role of water in the change of the fracture toughness during the ScCO2 interactions with shale samples. Journal of CO2 Utilization, 2024, 85: 102883.
Wei, Z., Wang, M., Shan, W., et al. Synergistic effects of potassium alginate and silicates co-inhibition performance in shale hydration. Journal of Molecular Liquids, 2024, 393: 123538.
Xu, S., Zhou, S., Zhou, J., et al. Multiscale pore structure evolution of Longmaxi shale induced by acid treatment. SPE Journal, 2023, 28(2): 831-844.
Xue, H., Zhou, S., Jiang, Y., et al. Effects of hydration on the microstructure and physical properties of shale. Petroleum Exploration and Development, 2018, 45(6): 1146-1153.
Yang, C., Xiong, Y., Zhang, J. A comprehensive reunderstanding of the OM-hosted nanopores in the marine Wufeng–Longmaxi shale formation in South China by organic petrology, gas adsorption, and X-ray diffraction studies. International Journal of Coal Geology, 2020, 218: 103362.
Yang, J., Sun, J., Wang, R., et al. Treatment of drilling fluid waste during oil and gas drilling: A review. Environmental Science and Pollution Research, 2023, 30(8): 19662-19682.
Zeng, F., Zhang, Q., Guo, J., et al. Mechanisms of shale hydration and water block removal. Petroleum Exploration and Development, 2021, 48(3): 752-761.
Zeng, L., Chen, Y., Lu, Y., et al. Role of brine composition on rock surface energy and its implications for subcritical crack growth in calcite. Journal of Molecular Liquids, 2020, 303: 112638.
Zhong, Y., Kuru, E., Zhang, H., et al. Effect of fracturing fluid/shale rock interaction on the rock physical and mechanical properties, the proppant embedment depth and the fracture conductivity. Rock Mechanics and Rock Engineering, 2019, 52(4): 1011-1022.
Zhou, S., Yan, G., Xue, H., et al. 2D and 3D nanopore characterization of gas shale in Longmaxi formation based on FIB-SEM. Marine and Petroleum Geology, 2016a, 73: 174-180.
Zhou, T., Zhang, S., Yang, L., et al. Experimental investigation on fracture surface strength softening induced by fracturing fluid imbibition and its impacts on flow conductivity in shale reservoirs. Journal of Natural Gas Science and Engineering, 2016b, 36: 893-905.
Zou, C., Zhao, Z., Pan, S., et al. Unveiling the oldest industrial shale gas reservoir: Insights for the enrichment pattern and exploration direction of lower cambrian shale gas in the Sichuan Basin. Engineering, 2024, 42: 278-294.
DOI: https://doi.org/10.46690/ager.2025.07.06
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