Pore-Throat Structure in the Chang 7 Subformation Influencing the Differential Accumulation of Tight Sandstone Oil: Insight from SEM, Rate-Controlled Mercury, and High-Pressure Mercury Results
Publication: Journal of Energy Engineering
Volume 149, Issue 5
Abstract
The complicated pore-throat structure of unconventional resource formations such as tight sandstones influences petroleum accumulation and even exploitation, because the pore-throat structure is difficult to mark. A pore-throat system was distinguished quantitatively utilizing high-pressure mercury (HPM), scanning electron microscopy (SEM), casting film, and rate-controlled mercury (RCM) methods. According to the analysis of the reservoir, the factors of differential accumulation of tight oil in Longdong and Northern Shaanxi were assessed. The results showed that lamellar throats and tube bundle throats were the primary types of throats in the study area. Tight sandstones from Longdong have a higher content of large throats than those from Northern Shaanxi, both with pore radii of 100–200 μm, whereas Northern Shaanxi has better pore-throat connectivity and better homogeneity of pores and throats. The fractal dimension of fine pores (D2) is significantly correlated with the pore-throat structure, including the median pressure and mercury saturation of macropore throats. Therefore, the pore-throat structure can be characterized by the fractal dimensions of small pores and throats. The continuous distribution of tight oil in Northern Shaanxi, with a higher degree of tight oil than Longdong, is positively related to the good pore-throat connectivity of the reservoir and the relatively small fractal dimension of the small throat. Thus, the differential accumulation of tight oil was influenced by the pore-throat connectivity and heterogeneity of the reservoir structure. The results of this study can be helpful in evaluating reservoir characteristics and selecting exploration zones.
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Data Availability Statement
All data, models, or code generated or used during the study are available from the corresponding author upon reasonable request.
Acknowledgments
This research was funded by National Natural Science Foundation of China (Grant Nos. 42002176, 41872165, and 42072185), the Foundation of State Key Laboratory of Petroleum Resources and Prospecting, China University of Petroleum, Beijing (No. PRP/open-2002), and the Major Project of CNOOC (CNOOC-KJ135ZDXMLTD14). Thanks are given to eceshi (www.eceshi.com) for the Total organic matter (TOC) and isotopic analysis.
References
Anovitz, L. M., and D. R. Cole. 2015. “Characterization and analysis of porosity and pore structures.” Rev. Mineral. Geochem. 80 (1): 61–164. https://doi.org/10.2138/rmg.2015.80.04.
Chen, Q., J. Zhang, X. Tang, W. Dang, X. Zhang, C. Liu, and X. Zhang. 2016. “Pore structure characterization of the Lower Permian marine-continental transitional black shale in the Southern North China Basin, central China.” Energy Fuels 30 (12): 10092–10105. https://doi.org/10.1021/acs.energyfuels.6b01475.
Chinese Standard. 2005. Rock capillary pressure measurement. SY/T 5346-2005. Beijing: National Standards of the People’s Republic of China.
Clarkson, C. R., M. Freeman, L. He, M. Agamalian, Y. B. Melnichenko, M. Mastalerz, R. M. Bustin, A. P. Radlinski, and T. P. Blach. 2012. “Characterization of tight gas reservoir pore structure using USANS/SANS and gas adsorption analysis.” Fuel 95 (May): 371–385. https://doi.org/10.1016/j.fuel.2011.12.010.
Cui, J., S. Li, and Z. Mao. 2019. “Oil-bearing heterogeneity and threshold of tight sandstone reservoirs: A case study on Triassic Chang7 member, Ordos Basin.” Mar. Pet. Geol. 104 (Jun): 180–189. https://doi.org/10.1016/j.marpetgeo.2019.03.028.
Desbois, G., J. L. Urai, P. A. Kukla, J. Konstanty, and C. Baerle. 2011. “High-resolution 3D fabric and porosity model in a tight gas sandstone reservoir: A new approach to investigate microstructures from mm- to nm-scale combining argon beam cross-sectioning and SEM imaging.” J. Pet. Sci. Eng. 78 (2): 243–257. https://doi.org/10.1016/j.petrol.2011.06.004.
Gao, H., J. Cao, C. Wang, M. He, L. B. Dou, X. Huang, and T. T. Li. 2019. “Comprehensive characterization of pore and throat system for tight sandstone reservoirs and associated permeability determination method using SEM, rate-controlled mercury and high pressure mercury.” J. Pet. Sci. Eng. 174 (Mar): 514–524. https://doi.org/10.1016/j.petrol.2018.11.043.
Ghanizadeh, A., C. R. Clarkson, S. Aquino, O. H. Ardakani, and H. Sanei. 2015. “Petrophysical and geomechanical characteristics of Canadian tight oil and liquid-rich gas reservoirs: I. Pore network and permeability characterization.” Fuel 153 (1): 664–681. https://doi.org/10.1016/j.fuel.2015.03.020.
Grechka, V., P. Mazumdar, and S. A. Shapiro. 2010. “Predicting permeability and gas production of hydraulically fractured tight sands from microseismic data.” Geophysics 75 (1): B1. https://doi.org/10.1190/1.3278724.
Guo, C. H., J. W. Sun, and H. J. Liu. 2021. “Transport model for gas and water in nanopores of shale gas reservoirs.” J. Energy Eng. 147 (4): 04021022. https://doi.org/10.1061/(ASCE)EY.1943-7897.0000771.
Guo, Y. C., Y. Song, X. X. Fang, X. Q. Pang, and T. T. Li. 2018. “Reservoir characterization of an organic-rich dolomitic tight-oil reservoir, the Lower Cretaceous Xiagou Formation in the Qingxi Sag, Jiuquan Basin, NW China.” Mar. Pet. Geol. 89 (Mar): 541–559. https://doi.org/10.1016/j.marpetgeo.2017.10.020.
He, J., X. D. Liu, X. Y. Zhu, T. Jiang, H. He, L. Zhou, Q. H. Liu, Y. S. Zhu, and Y. Y. Liu. 2021. “Experimental study on the two-phase seepage law of tight sandstone reservoirs in Ordos Basin.” J. Energy Eng. 147 (6): 04021056. https://doi.org/10.1061/(ASCE)EY.1943-7897.0000797.
Ji, W., Y. Song, Z. Jiang, M. Meng, Q. Liu, L. Chen, P. Wang, F. Goa, and P. Huang. 2016. “Fractal characteristics of nano-pores in the Lower Silurian Longmaxi shales from the Upper Yangtze Platform, south China.” Mar. Pet. Geol. 78 (Dec): 88–98. https://doi.org/10.1016/j.marpetgeo.2016.08.023.
Kaufmann, J., R. Loser, and A. Leemann. 2009. “Analysis of cement-bonded materials by multi-cycle mercury intrusion and nitrogen sorption.” J. Colloid Interface Sci. 336 (2): 730–737. https://doi.org/10.1016/j.jcis.2009.05.029.
Lai, J., G. Wang, Z. Wang, J. Chen, X. Pang, S. Wang, Z. Zhou, Z. He, Z. Qin, and X. Fan. 2018. “A review on pore structure characterization in tight sandstones.” Earth Sci. Rev. 177: 436–457. https://doi.org/10.1016/j.earscirev.2017.12.003.
Li, A. F., X. X. Ren, G. J. Wang, Y. Z. Wang, and K. L. Jiang. 2015a. “Characterization of pore structure of low permeability reservoirs using a nuclear magnetic resonance method.” [In Chinese.] J. China Univ. Pet. 39 (6): 92–98. https://doi.org/10.3969/j.issn.1673-5005.2015.06.012.
Li, J. J., J. X. Yin, Y. N. Zhang, S. F. Lu, W. M. Wang, J. B. Li, F. W. Chen, and Y. L. Meng. 2015b. “A comparison of experimental methods for describing shale pore features—A case study in the Bohai Bay Basin of eastern China.” Int. J. Coal Geol. 152 (Dec): 39–49. https://doi.org/10.1016/j.coal.2015.10.009.
Li, K. W. 2004. “Characterization of rock heterogeneity using fractal geometry.” In Proc., SPE Int. Thermal Operations and Heavy Oil Symp. and Western Regional Meeting. Richardson, TX: Society of Petroleum Engineers.
Li, P., M. Zheng, H. Bi, S. T. Wu, and X. R. Wang. 2017. “Pore throat structure and fractal characteristics of tight oil sandstone: A case study in the Ordos Basin, China.” J. Pet. Sci. Eng. 149 (Mar): 665–674. https://doi.org/10.1016/j.petrol.2016.11.015.
Li, X. B., H. Q. Liu, W. Rong, L. H. Wei, J. B. Liao, and Y. H. Ma. 2009. “First discovery of the sandy debris flow from the Triassic Yanchang Formation, Ordos Basin.” Lithologic Reservoirs 21 (4): 19–21.
Lu, S., et al. 2017. “Lower limits and grading evaluation criteria of tight oil source rocks of southern Songliao Basin, NE China.” Pet. Explor. Dev. 44 (3): 505–512. https://doi.org/10.1016/S1876-3804(17)30058-7.
Peng, C., C. Zou, Y. Yang, G. Zhang, and W. Wang. 2017. “Fractal analysis of high rank coal from southeast Qinshui basin by using gas adsorption and mercury porosimetry.” J. Pet. Sci. Eng. 156 (Jul): 235–249. https://doi.org/10.1016/j.petrol.2017.06.001.
Qin, Y., S. P. Yao, and H. M. Xiao. 2020. “Study on pore-throat connectivity of tight sandstone reservoirs: A case study of Chang 7 reservoir in Ordos Basin. Journal of Nanjing University.” Nat. Sci. 56 (3): 338–353. https://doi.org/10.27235/d.cnki.gnjiu.2021.001540.
Stroker, T. M., N. B. Harris, W. C. Elliott, and J. M. Wampler. 2013. “Diagenesis of a tight gas sand reservoir: Upper Cretaceous Mesaverde Group, Piceance Basin, Colorado.” Mar. Pet. Geol. 40 (4): 48–68. https://doi.org/10.1016/j.marpetgeo.2012.08.003.
Su, P., Z. Xia, L. Qu, W. Yu, P. Wang, D. W. Li, and X. Kong. 2018. “Fractal characteristics of low-permeability gas sandstones based on a new model for mercury intrusion porosimetry.” J. Nat. Gas Sci. Eng. 60 (Dec): 246–255. https://doi.org/10.1016/j.jngse.2018.10.008.
Tang, X., J. C. Zhang, X. Z. Wang, B. S. Yu, W. H. Ding, J. Y. Xiong, Y. T. Yang, L. Wang, and C. Yang. 2014. “Shale characteristics in the southeastern Ordos Basin, China: Implications for hydrocarbon accumulation conditions and the potential of continental shales.” Int. J. Coal Geol. 128 (Aug): 32–46. https://doi.org/10.1016/j.coal.2014.03.005.
Tobin, R. C., T. McClain, R. B. Lieber, A. Ozkan, L. A. Banfield, A. M. E. Marchand, and L. E. McRae. 2010. “Reservoir quality modeling of tight-gas sands in Wamsutter field: Integration of diagenesis, petroleum systems, and production data.” AAPG Bull. 94 (8): 1229–1266. https://doi.org/10.1306/04211009140.
Wen, H. J., L. Yan, F. C. Jiang, and J. X. Yang. 2007. “The fractal characteristics of the pore texture in low porosity and low permeability reservoir.” [In Chinese.] J. Northeast Pet. Univ. 31 (1): 15.
Wen, Z. G., Y. S. Luo, J. Y. Liu, C. Y. Zhao, S. X. Li, W. C. Tian, Y. P. Fan, and H. T. Gao. 2022. “Pore structure characteristics and genesis mechanism of Triassic Chang 7 shale oil reservoir in Longdong area.” Lithologic Reservoirs 34 (6): 47–59. https://doi.org/10.12108/yxyqc.20220604.
Wu, S., R. Zhu, J. Cui, J. Cui, B. Bai, X. Zhang, X. Jin, D. Zhu, J. You, and X. Li. 2015. “Characteristics of lacustrine shale porosity evolution, Triassic Chang 7 Member, Ordos Basin, NW China.” Pet. Explor. Dev. 42 (2): 185–195. https://doi.org/10.1016/S1876-3804(15)30005-7.
Xu, Z., L. Liu, B. Liu, T. Wang, Z. Zhang, K. Wu, C. Feng, W. Dou, Y. Wang, and Y. Shu. 2019. “Geochemical characteristics of the Triassic Chang 7 lacustrine source rocks, Ordos Basin, China: Implications for paleoenvironment, petroleum potential and tight oil occurrence.” J. Asian Earth Sci. 178 (July): 112–138. https://doi.org/10.1016/j.jseaes.2018.03.005.
Yang, H., S. X. Li, and X. M. Liu. 2013. “Characteristics and resource prospects of tight oil and shale oil in Ordos Basin.” Acta Petrolei Sin. 34 (1): 1–11. https://doi.org/10.7623/syxb201301001.
Yang, H., X. Niu, L. Xu, S. Feng, L. You, X. Liang, F. Wang, and D. Zhang. 2016a. “Exploration potential of shale oil in Chang7 Member, Upper Triassic Yanchang Formation, Ordos Basin, NW China.” Pet. Explor. Dev. 43 (4): 560–569. https://doi.org/10.1016/S1876-3804(16)30066-0.
Yang, H., and W. Z. Zhang. 2005. “Leading effect of the Seventh Member high-quality source rock of Yanchang Formation in Ordos Basin during the enrichment of low-penetrating oil-gas accumulation: Geology and geochemistry.” Geochimica 34 (2): 147–154. https://doi.org/10.19700/j.0379-1726.2005.02.007.
Yang, R., S. He, J. Z. Yi, and Q. H. Hu. 2016b. “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.” Mar. Pet. Geol. 70 (Feb): 27–45. https://doi.org/10.1016/j.marpetgeo.2015.11.019.
Yao, Y., D. Liu, D. Tang, S. Tang, W. Huang, Z. Liu, and C. Yao. 2009. “Fractal characterization of seepage-pores of coals from China: An investigation on permeability of coals.” Comput. Geosci. 35 (6): 1159–1166. https://doi.org/10.1016/j.cageo.2008.09.005.
Yuan, H., G. F. Zhang, J. J. Chang, and W. H. Lv. 2002. “Application of OFA quantitative callophane in Henan oil field.” Pet. Explor. Dev. 29 (4): 63–65. https://doi.org/10.3321/j.issn:1000-0747.2002.04.019.
Yuan, H. H., and B. F. Swanson. 1989. “Resolving pore-space characteristics by rate-controlled porosimetry.” SPE Form. Eval. 4 (1): 17–24. https://doi.org/10.2118/14892-PA.
Zeng, L. B. 2010. “Microfracturing in the Upper Triassic Sichuan Basin tight-gas sandstones: Tectonic, overpressure, and diagenetic origins.” AAPG Bull. 94 (12): 1811–1825. https://doi.org/10.1306/06301009191.
Zhang, F., Z. X. Jiang, W. Sun, Y. H. Li, X. Zhang, L. Zhu, and M. Wen. 2019a. “A multiscale comprehensive study on pore structure of tight sandstone reservoir realized by nuclear magnetic resonance, high pressure mercury injection and constant-rate mercury injection penetration test.” Mar. Pet. Geol. 109 (Nov): 208–222. https://doi.org/10.1016/j.marpetgeo.2019.06.019.
Zhang, K. X., Y. C. Guo, G. P. Bai, Z. X. Wang, B. D. Fan, J. P. Wu, and X. J. Niu. 2018. “Pore-structure characterization of the Eocene Sha-3 sandstones in the Bohai Bay Basin, China.” Energy Fuels 32 (2): 1579–1591. https://doi.org/10.1021.acs.energyfuels.7b03660.
Zhang, P., S. Lu, J. Li, J. Zhang, H. Xue, and C. Chen. 2017. “Comparisons of SEM, low-field NMR, and mercury intrusion capillary pressure in characterization of the pore size distribution of lacustrine shale: A case study on the Dongying Depression, Bohai Bay Basin, China.” Energy Fuels 31 (9): 9232–9239. https://doi.org/10.1021/acs.energyfuels.7b01625.
Zhang, Y., X. Meng, and D. Wang. 2019b. “Provenance analysis of the Middle Triassic Ordos Basin: Constraints from zircon U-Pb geochronology.” Geochemistry 80 (1): 125521. https://doi.org/10.1016/j.chemer.2019.07.003.
Zhou, S. D., H. Wang, S. R. Jiang, D. T. Yan, D. M. Liu, Z. Y. Zhang, and G. Q. Li. 2022. “A novel approach to obtain fractal dimension in coals by LFNMR: Insights from the T2 peak and T2 geometric mean.” J. Energy Eng. 148 (3): 04022009. https://doi.org/10.1061/(ASCE)EY.1943-7897.0000827.
Zhou, Y. D., Y. Q. Jiang, J. Liang, Y. F. Gu, Y. H. Fu, and Y. Xiao. 2021. “Reservoir characteristics and major controlling factors of the Cambrian Xixiangchi formation, central Sichuan Basin, Southwest China.” J. Energy Eng. 147 (6): 04021051. https://doi.org/10.1061/(ASCE)EY.1943-7897.0000803.
Ziarani, A. S., and R. Aguilera. 2012. “Pore-throat radius and tortuosity estimation from formation resistivity data for tight-gas sandstone reservoirs.” J. Appl. Geophys. 83 (Aug): 65–73. https://doi.org/10.1016/j.jappgeo.2012.05.008.
Zou, C. N., et al. 2012a. “Types, characteristics, genesis and prospects of conventional and unconventional hydrocarbon accumulations: Taking tight oil and tight gas in China as an instance.” Acta Petrolei Sin. 33 (2): 173–187. https://doi.org/10.7623/syxb201202001.
Zou, C. N., et al. 2013. “Continuous hydrocarbon accumulation over a large area as a distinguishing characteristic of unconventional petroleum: The Ordos Basin, North-Central China.” Earth Sci. Rev. 126 (9): 358–369. https://doi.org/10.1016/j.earscirev.2013.08.006.
Zou, C. N., Z. Yang, L. H. Hou, R. K. Zhu, J. W. Cui, S. T. Wu, S. H. Lin, Q. L. Guo, S. J. Wang, and D. H. Li. 2015. “Geological characteristics and ‘sweet area’ evaluation for tight oil.” Pet. Sci. 12 (4): 606–617. https://doi.org/10.1007/s12182-015-0058-1.
Zou, C. N., R. K. Zhu, K. Y. Liu, L. Su, B. Bai, X. X. Zhang, X. J. Yuan, and J. H. Wang. 2012b. “Tight gas sandstone reservoirs in China: Characteristics and recognition criteria.” J. Pet. Sci. Eng. 88 (2): 8291. https://doi.org/10.1016/j.petrol.2012.02.001.
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Published In
Journal of Energy Engineering
Volume 149 • Issue 5 • October 2023
Copyright
© 2023 American Society of Civil Engineers.
History
Received: Dec 14, 2022
Accepted: May 15, 2023
Published online: Jul 31, 2023
Published in print: Oct 1, 2023
Discussion open until: Dec 31, 2023
ASCE Technical Topics:
- Chemical compounds
- Chemical elements
- Chemicals
- Chemistry
- Energy engineering
- Energy sources (by type)
- Engineering fundamentals
- Engineering materials (by type)
- Environmental engineering
- Fractals
- Fuels
- Geometry
- Heavy metals
- Hydraulic engineering
- Hydraulic structures
- Materials engineering
- Mathematics
- Mercury (chemical)
- Non-renewable energy
- Oils
- Petroleum
- Porous media
- Reservoirs
- Sandstone
- Stones
- Water and water resources
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