Abstract
This study investigated the impact of pore accessibility and complexity on gas storage, transport, and recovery potential in the little-studied thermally mature Raghampuram shale samples collected from 2930 to 2987 m depth of Krishna–Godavari basin, India. Our findings reveal that sample nature (powdered, chipped, or cores) and assessment methods significantly influence pore accessibility evaluation, highlighting a research gap in the interpretation of irregularity, complexity, and heterogeneity of shale pore structure using unreliable monofractal theories. Employing a multiscale methodology involving low-pressure N2 and CO2 sorption, synchrotron small-angle scattering, and He-pycnometry techniques, we estimated accessibility in powder and core samples. Powder samples displayed a pore accessibility range of 36.07–106.94%, which was a substantial increase (154.54–423.07%) compared to that of solid core samples (1.61–4.16%). Total organic carbon was found to influence closed pore formation, while clay, carbonate, and quartz + K-feldspar contributed to open pores. Multifractal analyses comparing pore heterogeneity and complexity between accessible and inaccessible pores demonstrated higher heterogeneity and complexity in the latter, with accessible pores exhibiting simpler characteristics. Pore size distributions of both accessible and total pores (includes both accessible and inaccessible pores) exhibited multifractal behavior. Our findings emphasize the significance of evaluating pore accessibility and heterogeneity in shale-gas analysis, providing fresh insights into the interlinked elements of pore structure, composition, and gas recovery potential, thus advancing reservoir characterization understanding.
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The raw data and materials related to this research are available in the Mendeley Data Repository (https://doi.org/10.17632/ztjbz25jpf.1).
References
Anovitz, L. M., Cole, D. R., Sheets, J. M., Swift, A., Elston, H. W., Welch, S., et al. (2015). Effects of maturation on multiscale (nanometer to millimeter) porosity in the Eagle Ford Shale. Interpretation, 3(3), SU59–SU70.
Bahadur, J., Radlinski, A. P., Melnichenko, Y. B., Mastalerz, M., & Schimmelmann, A. (2015). Small-angle and ultrasmall-angle neutron scattering (SANS/USANS) study of new Albany shale: A treatise on microporosity. Energy and Fuels, 29(2), 567–576.
Bahadur, J., Ruppert, L. F., Pipich, V., Sakurovs, R., & Melnichenko, Y. B. (2018). Porosity of the Marcellus shale: A contrast matching small-angle neutron scattering study. International Journal of Coal Geology, 188, 156–164.
Bal, A., Misra, S., Mukherjee, M., Dutta, T. K., Sen, D., Patra, A., & Raja, E. (2023). Concurrent influence of geological parameters on the integrated nano-pore structure and discretized pore families of the petroliferous Cambay shale assessed through multivariate dependence measure. Frontiers in Earth Science, 11, 1157122.
Bal, A., Misra, S., & Sen, D. (2022). Accessible to total nanopore structure and complexity in Cambay shales, India: An implication on storage and transport of hydrocarbon. In 56th U.S. rock mechanics/geomechanics symposium. https://doi.org/10.56952/ARMA-2022-0653
Biswas, S. K. (1992). Tectonic framework and evolution of graben basins of India. Indian Journal of Petroleum Geology, 1, 276–292.
Caniego, F. J., MartÃn, M. A., & San José, F. (2003). Rényi dimensions of soil pore size distribution. Geoderma, 112(3–4), 205–216.
Cao, T. T., Song, Z. G., Wang, S. B., & **a, J. (2015). A comparative study of the specific surface area and pore structure of different shales and their kerogens. Science China Earth Sciences, 58, 510–522. https://doi.org/10.1007/s11430-014-5021-2
Chandra, D., Vishal, V., Bahadur, J., Agrawal, A. K., Das, A., Hazra, B., & Sen, D. (2022). Nano-scale physicochemical attributes and their impact on pore heterogeneity in shale. Fuel, 314, 123070.s.
Chhabra, A., & Jensen, R. V. (1989). Direct Determination of the f(c) singularity spectrum. Physical Review Letters, 62(12), 1327–1330.
Clarkson, C. R., Solano, N., Bustin, R. M., Bustin, A. M. M., Chalmers, G. R. L., He, L., et al. (2013). Pore structure characterization of North American shale gas reservoirs using USANS/SANS, gas adsorption, and mercury intrusion. Fuel, 103, 606–616.
Crick, I. H., Boreham, C. J., Cook, A. C., & Powell, T. G. (1988). Petroleum geology and geochemistry of middle proterozoic McArthur Basin, Northern Australia II: Assessment of source rock potential. AAPG Bulletin, 72(12), 1495–1514.
Dai, X., Wei, C., Wang, M., Shi, X., Wang, X., & Vandeginste, V. (2023). Experimental investigation of storage space and adsorption capacity variation of shale under different reaction times in supercritical CO2. Natural Resources Research, 32(5), 2337–2353.
Feder, J. (1988). Random walks and fractals. In J. Feder (Ed.), Fractals. Physics of Solids and Liquids. Springer. https://doi.org/10.1007/978-1-4899-2124-6_9
Gentzis, T. (2013). A review of the thermal maturity and hydrocarbon potential of the Mancos and Lewis shales in parts of New Mexico, USA. International Journal of Coal Geology, 113, 64–75.
Glaser, K. S., Miller, C. K., Johnson, G. M., Toelle, B., Kleinberg, R. B., Miller, P., & Pennington, W. D. (2014). Seeking the sweet spot: Reservoir and completion quality in organic shales. Schlumberger, Oilfiled Review Winter, 25(4), 16–29.
Gordon, R. G., DeMets, C., & Argus, D. F. (1990). Kinematic constraints on distributed lithospheric deformation in the equatorial Indian ocean from present motion between the Australian and Indian plates. Tectonics, 9(3), 409–422.
Guo, T., Meng, X., Lei, W., Liu, M., & Huang, L. (2023). Characteristics and governing factors of pore structure and methane sorption in deep-marine shales: a case study of the Wufeng–Longmaxi formations, Weirong shale gas field, Sichuan Basin. Natural Resources Research, 32(4), 1733–1759.
Hazra, B., Wood, D. A., Kumar, S., Saha, S., Dutta, S., Kumari, P., & Singh, A. K. (2018). Fractal disposition, porosity characterization and relationships to thermal maturity for the Lower Permian Raniganj basin shales, India. Journal of Natural Gas Science and Engineering, 59, 452–465.
Hinde, A. L. (2004). PRINSAS - A windows-based computer program for the processing and interpretation of small-angle scattering data tailored to the analysis of sedimentary rocks. Journal of Applied Crystallography, 37(6), 1020–1024.
Ibad, S. M., & Padmanabhan, E. (2022). Lithofacies, mineralogy, and pore types in Paleozoic gas shales from Western Peninsular Malaysia. Journal of Petroleum Science and Engineering, 212, 110239.
Jarvie, D. M., Claxton, B. L., Henk, F., Breyer, J. T. (2001). Oil and shale gas from the Barnett Shale, Ft. Worth Basin, Texas. In AAPG annual meeting program (Vol. 10).
Kuila, U. (2013). Measurement and interpretation of porosity and pore-size distribution in mudrocks: The whole story of Shale. Colorado School of Mines.
Lafargue, E., Marquis, F., & Pillot, D. (1998). Rock-eval 6 applications in hydrocarbon exploration, production, and soil contamination studies. Revue de l'Institut Français du Pétrole, 53(4), 421–437.
Li, G., **ao, X., Gai, H., Feng, Y., Lu, C., & Meng, G. (2023). Nanopore structure evolution of lower Cambrian shale in the Western Hubei Area, Southern China, and its geological implications based on thermal simulation experimental results. Natural Resources Research, 32(2), 731–754.
Li, Q., **ng, H., Liu, J., & Liu, X. (2015). A review on hydraulic fracturing of unconventional reservoir. Petroleum, 1(1), 8–15.
Li, Y., Zhang, C., Tang, D., Gan, Q., Niu, X., Wang, K., & Shen, R. (2017). Coal pore size distributions controlled by the coalification process: An experimental study of coals from the Junggar, Ordos and Qinshui basins in China. Fuel, 206, 352–363.
Li, Z., Liu, D., Cai, Y., Wang, Y., & Teng, J. (2019). Adsorption pore structure and its fractal characteristics of coals by N2 adsorption/desorption and FESEM image analyses. Fuel, 257, 116031.
Liu, K., Ostadhassan, M., Sun, L., Zou, J., Yuan, Y., Gentzis, T., et al. (2019). A comprehensive pore structure study of the Bakken shale with SANS, N2 adsorption and mercury intrusion. Fuel, 245, 274–285.
Liu, K., Ostadhassan, M., Zhou, J., Gentzis, T., & Rezaee, R. (2017). Nanoscale pore structure characterization of the Bakken shale in the USA. Fuel, 209, 567–578.
Lowell, S., Shields, J. E., & Thomas, M. A. (2005). Characterization of porous solids and powders: Surface area, pore size, and density. Choice Reviews Online. https://doi.org/10.5860/choice.42-5288
Lowell, S., Shields, J. E., Lowell, S., Shields, J. E. (2014). Pore analysis by adsorption. In Powder surface area and porosity (pp. 52–71).
Lu, C., **ao, X., Xue, Z., Chen, Z., Li, G., & Feng, Y. (2023). Fractal and multifractal characteristics of nanopores and their controlling factors in marine-continental transitional shales and their Kerogens from Qinshui Basin, Northern China. Natural Resources Research, 32(5), 2313–2336.
Medina-Rodriguez, B. X. (2021). Shale pore architecture Characterization via TD- NMR and gas adsorption. University of Wyoming ProQuest Dissertations Publishing.
Memon, A., Li, A., Memon, B. S., Muther, T., Han, W., Kashif, M., et al. (2021). Gas adsorption and controlling factors of shale: Review, application, comparison and challenges. Natural Resources Research, 30(1), 827–848.
Meyer, K., & Klobes, P. (1999). Comparison between different presentations of pore size distribution in porous materials. Fresenius’ Journal of Analytical Chemistry, 363(2), 174–178.
Muller, J. (1996). Characterization of pore space in chalk by multifractal analysis. Journal of Hydrology, 187(1–2), 215–222.
Pandey, R., & Harpalani, S. (2018). An imaging and fractal approach towards understanding reservoir scale changes in coal due to bioconversion. Fuel, 230, 282–297.
Peters, K. E. (1986). Guidelines for evaluating petroleum source rock using programmed pyrolysis. AAPG Bulletin, 70(3), 318–329.
Peters, K. E., Cassa, M. R. (1994). Applied source rock geochemistry: Chapter 5: Part II. Essential elements. In AAPG special volume (pp. 93–120).
Radlinski, A. P. (2006). Small-angle neutron scattering and the microstructure of rocks. Reviews in Mineralogy and Geochemistry, 63, 363–397.
Radlinski, A. P., Blach, T., Vu, P., Ji, Y., de Campo, L., Gilbert, E. P., et al. (2021). Pore accessibility and trap** of methane in Marcellus shale. International Journal of Coal Geology, 248, 103850.
Rao, G. N. (2001). Sedimentation, stratigraphy, and petroleum potential of Krishna–Godavari basin. East Coast of India. AAPG Bulletin, 85(9), 1623–1643.
Rezaeyan, A., Pipich, V., Busch, A., Maier-Leibnitz Zentrum, H., & Jülich GmbH, F. (2021). MATSAS: A small-angle scattering computing tool for porous systems. Journal of Applied Crystallography, 54, 697–706.
Sun, M., Wen, J., Pan, Z., Liu, B., Blach, T. P., Ji, Y., et al. (2022). Pore accessibility by wettable fluids in overmature marine shales of China: Investigations from contrast-matching small-angle neutron scattering (CM-SANS). International Journal of Coal Geology, 255, 103987.
Sun, M., Yu, B., Hu, Q., Zhang, Y., Li, B., Yang, R., et al. (2017). Pore characteristics of Longmaxi shale gas reservoir in the Northwest of Guizhou, China: Investigations using small-angle neutron scattering (SANS), helium pycnometry, and gas sorption isotherm. International Journal of Coal Geology, 171, 61–68.
Sun, M., Zhang, L., Hu, Q., Pan, Z., Yu, B., Sun, L., et al. (2019). Pore connectivity and water accessibility in upper Permian transitional shales, southern China. Marine and Petroleum Geology, 107, 407–422.
Sun, M., Zhao, J., Pan, Z., Hu, Q., Yu, B., Tan, Y., et al. (2020). Pore characterization of shales: A review of small angle scattering technique. Journal of Natural Gas Science and Engineering, 78, 103294.
Thommes, M., Kaneko, K., Neimark, A. V., Olivier, J. P., Rodriguez-Reinoso, F., Rouquerol, J., & Sing, K. S. W. (2015). Physisorption of gases, with special reference to the evaluation of surface area and pore size distribution (IUPAC Technical Report). Pure and Applied Chemistry, 87(9–10), 1051–1069.
Tissot, B. P., du Petrole, E. N. S., & Welte, D. H. (1978). Petroleum formation and occurrence: A new approach to oil and gas exploration (Book in German). Springer. https://doi.org/10.1007/978-3-642-96446-6
Vázquez, E. V., Ferreiro, J. P., Miranda, J. G. V., & González, A. P. (2008). Multifractal analysis of pore size distributions as affected by simulated rainfall. Vadose Zone Journal, 7(2), 500–511.
Vishal, V., Chandra, D., Bahadur, J., Sen, D., Hazra, B., Mahanta, B., & Mani, D. (2019). Interpreting pore dimensions in gas shales using a combination of SEM imaging, small-angle neutron scattering, and low-pressure gas adsorption. Energy and Fuels, 33(6), 4835–4848.
Wang, F.-Y., Yang, K., & Zai, Y. (2020a). Multifractal characteristics of shale and tight sandstone pore structures with nitrogen adsorption and nuclear magnetic resonance. Petroleum Science, 17, 1209–1220.
Wang, P., Jiang, Z., Ji, W., Zhang, C., Yuan, Y., Chen, L., & Yin, L. (2016). Heterogeneity of intergranular, intraparticle and organic pores in Longmaxi shale in Sichuan basin, South China: Evidence from SEM digital images and fractal and multifractal geometries. Marine and Petroleum Geology, 72, 122–138.
Wang, X., Zhu, Y., & Wang, Y. (2020b). Fractal characteristics of micro-and mesopores in the Longmaxi shale. Energies, 13, 1349.
Wang, Y., Qin, Y., Zhang, R., He, L., Anovitz, L. M., Bleuel, M., et al. (2018). Evaluation of nanoscale accessible pore structures for improved prediction of gas production potential in Chinese marine shales. Energy and Fuels, 32, 12447–12461.
Wang, Z., Jiang, X., Pan, M., & Shi, Y. (2020c). Nano-scale pore structure and its multifractal characteristics of tight sandstone by N2 adsorption/desorption analyses: A case study of Shihezi formation from the Sulige gas filed, Ordos basin, China. Minerals, 10(4), 377.
Wu, B., **e, R., **, G., Liu, J., Wang, S., & Fan, W. (2021). Investigation on the pore structure and multifractal characteristics of tight sandstone using nitrogen gas adsorption and mercury injection capillary pressure experiments. Energy and Fuels, 36(1), 262–274.
Wu, B., **e, R., **, G., Liu, J., Wang, S., & Fan, W. (2022). Investigation on the pore structure and multifractal characteristics of tight sandstone using nitrogen gas adsorption and mercury injection capillary pressure experiments. Energy and Fuels, 36(1), 262–274.
Yang, R., He, S., Yi, J., & Hu, Q. (2016). Nano-scale pore structure and fractal dimension of organic-rich Wufeng–Longmaxi shale from Jiaoshiba area, Sichuan Basin: Investigations using FE-SEM, gas adsorption and helium pycnometry. Marine and Petroleum Geology, 70, 27–45.
Yu, S., Bo, J., Fengli, L., & Jiegang, L. (2017). Structure and fractal characteristic of micro- and meso-pores in low, middle-rank tectonic deformed coals by CO2 and N2 adsorption. Microporous and Mesoporous Materials, 253, 191–202.
Zendehboudi, S., & Bahadori, A. (2017). Shale gas: Introduction, basics, and definitions. Shale Oil and Gas Handbook. https://doi.org/10.1016/B978-0-12-802100-2.00001-0
Zhang, J., & Hu, Y. (2020). Comparative evaluation of pore structure heterogeneity in low-permeability tight sandstones using different fractal models based on NMR technology: A case study of Benxi formation in the central Ordos basin. Energy and Fuels, 34, 13924–13942.
Zhang, L., Zhang, X., Chai, H., Li, Y., & Zhou, Y. (2019). Pore structure characterization for a continental lacustrine shale parasequence based on fractal theory. Fractals, 27(1), 1–18.
Zhang, S., Liu, H., Wu, C., & **, Z. (2022). Influence of particle size on pore structure and multifractal characteristics in coal using low-pressure gas adsorption. Journal of Petroleum Science and Engineering, 212, 110273.
Acknowledgments
The authors acknowledge critical and constructive reviews from four anonymous reviewers and editorial guidance by John Carranza. The ACMS, IIT Kanpur supported the XRD and low-pressure N2 and CO2 adsorption tests. Solid State Physics Division, BARC, provided the SWAXS beamline for pore-analysis. AB acknowledges a senior research fellowship for his doctoral research. This work is supported by a Pan IIT-ONGC research grant awarded to SM and a collaboration with Keshava Deva Malaviya Institute of Petroleum Exploration (KDMIPE), ONGC, Dehradun.
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Bal, A., Misra, S. & Sen, D. Nanopore Heterogeneity and Accessibility in Oil and Gas Bearing Cretaceous KG (Raghampuram) Shale, KG Basin, India: An Advanced Multi-analytical Study. Nat Resour Res 33, 1131–1154 (2024). https://doi.org/10.1007/s11053-024-10319-3
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DOI: https://doi.org/10.1007/s11053-024-10319-3