With the increasing demand for petroleum, shale oil with considerable reserves has become an important part of global oil resources. The shale oil reservoir has a large number of nanopores and a complicated mineral composition, and the effect of nanopore confinement and pore type usually makes the effective development of shale oil challenging. For a shale oil reservoir, CO2 flooding can effectively reduce the oil viscosity and improve the reservoir properties, which can thus improve the recovery performance. In this study, the method of non-equilibrium molecular dynamics (NEMD) simulation is used to simulate the CO2 flooding process in the nanoscale pores of shale oil reservoir. The performance difference between the organic kerogen slit nanopore and four types of inorganic nanopores is discussed. Thus, the effects of nanopore type and displacement velocity on the nanoscale displacement behavior of CO2 are analyzed. Results indicate that the CO2 flooding process of different inorganic pores is different. In comparison, the displacement efficiency of light oil components is higher, and the transport distance is longer. The intermolecular interaction can significantly affect the CO2 displacement behavior in nanopores. The CO2 displacement efficiency is shown as montmorillonite, feldspar > quartz > calcite > kerogen. On the other hand, it is found that a lower displacement velocity can benefit the miscibility process between alkane and CO2, which is conducive to the overall displacement process of CO2. The displacement efficiency can significantly decrease with the increase in displacement velocity. But once the displacement velocity is very high, the strong driving force can promote the alkane to move forward, and the displacement efficiency will recover slightly. This study further reveals the microscopic oil displacement mechanism of CO2 in shale nanopores, which is of great significance for the effective development of shale oil reservoirs by using the method of CO2 injection.
Agi, A., Junin, R., Abdullah, M.O., Jaafar, M.Z., Arsad, A., Sulaiman, W.R.W., Mohd Norddin, M.N.A., Abdurrahman, M., Abbas, A., Gbadamosi, A., Azli, N.B., 2020. Application of polymeric nanofluid in enhancing oil recovery at reservoir condition. J. Petrol. Sci. Eng. 194, 107476. https://doi.org/10.1016/j.petrol.2020.107476.
Bousige, C., Ghimbeu, C.M., Vix-Guterl, C., Pomerantz, A.E., Suleimenova, A., Vaughan, G., Garbarino, G., Feygenson, M., Wildgruber, C., Ulm, F.-J., Pellenq, R.J.-M., Coasne, B., 2016. Realistic molecular model of kerogen's nanostructure. Nat. Mater. 15 (5), 576-582. https://doi.org/10.1038/nmat4541.
Canneva, A., Giordana, I.S., Erra, G., Calvo, A., 2017. Organic matter characterization of shale rock by X-ray photoelectron spectroscopy: adventitious carbon contamination and radiation damage. Energy Fuels 31 (10), 10414-10419. https://doi.org/10.1021/acs.energyfuels.7b01143.
Chen, J., Yu, H., Fan, J., Wang, F., Lu, D., Liu, H., Wu, H., 2017. Channel-width dependent pressure-driven flow characteristics of shale gas in nanopores. AIP Adv. 7 (4), 045217. https://doi.org/10.1063/1.4982729.
Chen, Z., Dong, X., Chen, Z., 2021. n-decane diffusion in carbon nanotubes with vibration. J. Chem. Phys. 154, 074505. https://doi.org/10.1063/5.0038869.
Cygan, R.T., Liang, J.J., Kalinichev, A.G., 2004. Molecular models of hydroxide, oxyhydroxide, and clay phases and the development of a general force field. J. Phys. Chem. B 108 (4), 1255-1266. https://doi.org/10.1021/jp0363287.
Dauber-Osguthorpe, P., Roberts, V.A., Osguthorpe, D.J., Wolff, J., Genest, M., Hagler, A.T., 1988. Structure and energetics of ligand binding to proteins: Escherichia coli dihydrofolate reductase-trimethoprim, a drug-receptor system. Proteins: Struct., Funct., Bioinf. 4 (1), 31-47. https://doi.org/10.1002/prot.340040106.
Dong, X., Xu, W., Liu, R., Chen, Z., Lu, N., Guo, W., 2022. Insights into adsorption and diffusion behavior of shale oil in slit nanopores: a molecular dynamics simulation study. J. Mol. Liq. 359, 119322. https://doi.org/10.1016/j.molliq.2022.119322.
Dong, X., Xu, W., Liu, H., Chen, Z., Lu, N., Wang, W., 2023. On the replacement behavior of CO2 in nanopores of shale oil reservoirs: insights from wettability tests and molecular dynamics simulations. Geoenergy Sci. Eng. 223, 211528. https://doi.org/10.1016/j.geoen.2023.211528.
Etha, S.A., Desai, P.R., Sachar, H.S., Das, S., 2021. Wetting dynamics on solvophilic, soft, porous, and responsive surfaces. Macromolecules 54 (2), 584-596. https://doi.org/10.1021/acs.macromol.0c02234.
Fan, L., Chen, J., Zhu, J., Nie, X., Li, B., Shi, Z., 2022. Experimental study on enhanced shale oil recovery and remaining oil distribution by CO2 flooding with nuclear magnetic resonance technology. Energy Fuels 36 (4), 1973-1985. https://doi.org/10.1021/acs.energyfuels.1c02982.
Fang, T., Wang, M., Wang, C., Liu, B., Shen, Y., Dai, C., Zhang, J., 2017. Oil detachment mechanism in CO2 flooding from silica surface: molecular dynamics simulation. Chem. Eng. Sci. 164, 17-22. https://doi.org/10.1016/j.ces.2017.01.067.
Fang, T., Zhang, Y., Ding, B., Yan, Y., Zhang, J., 2020. Static and dynamic behavior of CO2 enhanced oil recovery in nanoslits: effects of mineral type and oil components. Int. J. Heat Mass Tran. 153, 119583. https://doi.org/10.1016/j.ijheatmasstransfer.2020.119583.
Feng, Q., Xu, S., Xing, X., Zhang, W., Wang, S., 2020. Advances and challenges in shale oil development: a critical review. Adv. Geo-Energy Res. 4 (4), 406-418. https://doi.org/10.46690/ager.2020.04.06.
Goumans, T.P.M., Wander, A., Brown, W.A., Catlow, C.R.A., 2007. Structure and stability of the (0 0 1) α-quartz surface. Phys. Chem. Chem. Phys. 9 (17), 2146-2152. https://doi.org/10.1039/B701176H.
Han, M.L., Wei, X.L., Zhang, J.C., Liu, Y., Tang, X., Li, P., Liu, Z.Y., 2022. Influence of structural damage on evaluation of microscopic pore structure in marine continental transitional shale of the Southern North China Basin: a method based on the low-temperature N2 adsorption experiment. Petrol. Sci. 19 (1), 100-115. https://doi.org/10.1016/j.petsci.2021.10.016.
Hoffman, B.T., Shoaib, S., 2014. CO2 flooding to increase recovery for unconventional liquids-rich reservoirs. J. Energy Resour. Technol. 136 (2), 022801. https://doi.org/10.1115/1.4025843.
Hu, M., Cheng, Z., Zhang, M., Liu, M., Song, L., Zhang, Y., Li, J., 2014. Effect of calcite, kaolinite, gypsum, and montmorillonite on Huadian oil shale kerogen pyrolysis. Energy Fuels 28 (3), 1860-1867. https://doi.org/10.1021/ef4024417.
Huang, X., Tian, Z., Zuo, X., Li, X., Yang, W., Lu, J., 2023. The microscopic pore crude oil production characteristics and influencing factors by DME-assisted CO2 injection in shale oil reservoirs. Fuel 331, 125843. https://doi.org/10.1016/j.fuel.2022.125843.
Jia, B., Tsau, J.S., Barati, R., 2019. A review of the current progress of CO2 injection EOR and carbon storage in shale oil reservoirs. Fuel 236, 404-427. https://doi.org/10.1016/j.fuel.2018.08.103.
Jorgensen, W.L., Madura, J.D., Swenson, C.J., 1984. Optimized intermolecular potential functions for liquid hydrocarbons. J. Am. Chem. Soc. 106 (22), 6638-6646. https://doi.org/10.1021/ja00334a030.
Kerisit, S., Liu, C., 2012. Diffusion and adsorption of uranyl carbonate species in nanosized mineral fractures. Environ. Sci. Technol. 46 (3), 1632-1640. https://doi.org/10.1021/es2027696.
Li, H.B., Yang, Z.M., Li, R.S., Zhou, T.Y., Guo, H.K., Liu, X.W., Dai, Y.X., Hu, Z.G., Meng, H., 2021. Mechanism of CO2 enhanced oil recovery in shale reservoirs. Petrol. Sci. 18 (6), 1788-1796. https://doi.org/10.1016/j.petsci.2021.09.040.
Li, X., Wang, P., Yan, Z., Yu, S., Wei, K., Zhu, X., Xue, Q., 2022. The miscible behaviors of C3H8/C8H18 (C7H17N) system in nanoslits: effects of pore size and rock surface wettability. Chem. Eng. J. 431, 133988. https://doi.org/10.1016/j.cej.2021.133988.
Li, Z., Yao, J., Ren, Z., Sun, H., Zhang, L., Yang, Y., Fan, T., Kou, J., 2019. Accumulation behaviors of methane in the aqueous environment with organic matters. Fuel 236, 836-842. https://doi.org/10.1016/j.fuel.2018.09.071.
Liu, H., Tao, J., Meng, S., Li, D., Cao, G., Gao, Y., 2022a. Application and prospects of CO2 enhanced oil recovery technology in shale oil reservoir. China Petrol. Explor. 27 (1), 127-134. https://doi.org/10.3969/j.issn.1672-7703.2022.01.012.inChinese.
Liu, B., Wang, C., Zhang, J., Xiao, S., Zhang, Z., Shen, Y., Sun, B., He, J., 2017. Displacement mechanism of oil in shale inorganic nanopores by supercritical carbon dioxide from molecular dynamics simulations. Energy Fuels 31 (1), 738-746. https://doi.org/10.1021/acs.energyfuels.6b02377.
Liu, S.Y., Ren, B., Li, H.Y., Yang, Y.Z., Wang, Z.Q., Wang, B., Agarwal, R., 2022b. CO2 storage with enhanced gas recovery (CSEGR): a review of experimental and numerical studies. Petrol. Sci. 19 (2), 594-607. https://doi.org/10.1016/j.petsci.2021.12.009.
Liu, X., Zhang, D., 2019. A review of phase behavior simulation of hydrocarbons in confined space: implications for shale oil and shale gas. J. Nat. Gas Sci. Eng. 68, 102901. https://doi.org/10.1016/j.jngse.2019.102901.
Liu, Y., Wilcox, J., 2012. Effects of surface heterogeneity on the adsorption of CO2 in microporous carbons. Environ. Sci. Technol. 46 (3), 1940-1947. https://doi.org/10.1021/es204071g.
Loucks, R.G., Reed, R.M., Ruppel, S.C., Jarvie, D.M., 2009. Morphology, genesis, and distribution of nanometer-scale pores in siliceous mudstones of the Mississippian Barnett Shale. J. Sediment. Res. 79 (12), 848-861. https://doi.org/10.2110/jsr.2009.092.
Meyer, J.C., Geim, A.K., Katsnelson, M.I., Novoselov, K.S., Booth, T.J., Roth, S., 2007. The structure of suspended graphene sheets. Nature 446 (7131), 60-63. https://doi.org/10.1038/nature05545.
Prieve, D.C., Russel, W.B., 1988. Simplified predictions of Hamaker constants from Lifshitz theory. J. Colloid Interface Sci. 125 (1), 1-13. https://doi.org/10.1016/0021-9797(88)90048-3.
Safi, R., Agarwal, R.K., Banerjee, S., 2016. Numerical simulation and optimization of CO2 utilization for enhanced oil recovery from depleted reservoirs. Chem. Eng. Sci. 144, 30-38. https://doi.org/10.1016/j.ces.2016.01.021.
Shaw, D.B., Weaver, C.E., 1965. The mineralogical composition of shales. J. Sediment. Res. 35 (1), 213-222. https://doi.org/10.1306/74D71221-2B21-11D7-8648000102C1865D.
Soni, A., Patey, G.N., 2019. Simulations of water structure and the possibility of ice nucleation on selected crystal planes of K-feldspar. J. Chem. Phys. 150 (21), 214501. https://doi.org/10.1063/1.5094645.
Sun, J., Chen, Z., Wang, X., Zhang, Y., Qin, Y., Chen, C., Li, W., Zhou, W., 2023. Displacement characteristics of CO2 to CH4 in heterogeneous surface slit pores. Energy Fuels 37 (4), 2926-2944. https://doi.org/10.1021/acs.energyfuels.2c03610.
Ungerer, P., Collell, J., Yiannourakou, M., 2015. Molecular modeling of the volumetric and thermodynamic properties of kerogen: influence of organic type and maturity. Energy Fuels 29 (1), 91-105. https://doi.org/10.1021/ef502154k.
Wang, Q., Ye, J.B., Yang, H.Y., Liu, Q., 2016b. Chemical composition and structural characteristics of oil shales and their kerogens using Fourier Transform Infrared (FTIR) spectroscopy and solid-state 13C Nuclear Magnetic Resonance (NMR). Energy Fuels 30 (8), 6271-6280. https://doi.org/10.1021/acs.energyfuels.6b00770.
Wang, S., Feng, Q., Zha, M., Lu, S., Qin, Y., Xia, T., Zhang, C., 2015. Molecular dynamics simulation of liquid alkane occurrence state in pores and slits of shale organic matter. Petrol. Explor. Dev. 42 (6), 844-851. https://doi.org/10.1016/S1876-3804(15)30081-1.
Wang, S., Javadpour, F., Feng, Q., 2016a. Fast mass transport of oil and supercritical carbon dioxide through organic nanopores in shale. Fuel 181, 741-758. https://doi.org/10.1016/j.fuel.2016.05.057.
Wang, X., Huang, X., Lin, K., Zhao, Y.P., 2019. The constructions and pyrolysis of 3D kerogen macromolecular models: experiments and simulations. Glob. Chall. 3 (5), 1900006. https://doi.org/10.1002/gch2.201900006.
Wei, B., Zhang, X., Liu, J., Xu, X., Pu, W., Bai, M., 2020. Adsorptive behaviors of supercritical CO2 in tight porous media and triggered chemical reactions with rock minerals during CO2-EOR and-sequestration. Chem. Eng. J. 381, 122577. https://doi.org/10.1016/j.cej.2019.122577.
Wu, T., Zhang, D., 2016. Impact of adsorption on gas transport in nanopores. Sci. Rep. 6 (1), 23629. https://doi.org/10.1038/srep23629.
Xiao, S., Edwards, S.A., Gräter, F., 2011. A new transferable forcefield for simulating the mechanics of CaCO3 crystals. J. Phys. Chem. C 115 (41), 20067-20075. https://doi.org/10.1021/jp202743v.
Xiong, C., Li, S., Ding, B., Geng, X., Zhang, J., Yan, Y., 2021. Molecular insight into the oil displacement mechanism of gas flooding in deep oil reservoir. Chem. Phys. Lett. 783, 139044. https://doi.org/10.1016/j.cplett.2021.139044.
Yan, Y., Li, C., Dong, Z., Fang, T., Sun, B., Zhang, J., 2017. Enhanced oil recovery mechanism of CO2 water-alternating-gas injection in silica nanochannel. Fuel 190, 253-259. https://doi.org/10.1016/j.fuel.2016.11.019.
Yang, L., Jin, Z., 2019. Global shale oil development and prospects. China Petrol. Explor. 24 (5), 553. https://doi.org/10.3969/j.issn.1672-7703.2019.05.002. (in Chinese).
Yang, M., Stipp, S.S., Harding, J., 2008. Biological control on calcite crystallization by polysaccharides. Cryst. Growth Des. 8 (11), 4066-4074. https://doi.org/10.1021/cg300772h.
Yu, H., Fan, J., Xia, J., Liu, H., Wu, H., 2020a. Multiscale gas transport behavior in heterogeneous shale matrix consisting of organic and inorganic nanopores. J. Nat. Gas Sci. Eng. 75, 103139. https://doi.org/10.1016/j.jngse.2019.103139.
Yu, H., Xu, H., Xia, J., Fan, J., Wang, F., Wu, H., 2020b. Nanoconfined transport characteristic of methane in organic shale nanopores: the applicability of the continuous model. Energy Fuels 34 (8), 9552-9562. https://doi.org/10.1021/acs.energyfuels.0c01789.
Zhang, Q., Su, Y., Wang, W., Lu, M., Sheng, G., 2017. Apparent permeability for liquid transport in nanopores of shale reservoirs: coupling flow enhancement and near wall flow. Int. J. Heat Mass Tran. 115, 224-234. https://doi.org/10.1016/j.ijheatmasstransfer.2017.08.024.
Zhang, W., Feng, Q., Wang, S., Xing, X., 2019. Oil diffusion in shale nanopores: insight of molecular dynamics simulation. J. Mol. Liq. 290, 111183. https://doi.org/10.1016/j.molliq.2019.111183.
Zhang, Y., Fang, T., Ding, B., Wang, W., Yan, Y., Li, Z., Guo, W., Zhang, J., 2020. Migration of oil/methane mixture in shale inorganic nano-pore throat: a molecular dynamics simulation study. J. Petrol. Sci. Eng. 187, 106784. https://doi.org/10.1016/j.petrol.2019.106784.
Zhou, W., Jiang, L., Liu, X., Hu, Y., Yan, Y., 2022. Molecular insights into the effect of anionic-nonionic and cationic surfactant mixtures on interfacial properties of oil-water interface. Colloids Surf. A Physicochem. Eng. Asp. 637, 128259. https://doi.org/10.1016/j.colsurfa.2022.128259.
Zhou, X., Yuan, Q., Zhang, Y., Wang, H., Zeng, F., Zhang, L., 2019. Performance evaluation of CO2 flooding process in tight oil reservoir via experimental and numerical simulation studies. Fuel 236, 730-746. https://doi.org/10.1016/j.fuel.2018.09.035.