Low-temperature oxidation characteristics and reaction pathways of crude oil within tight shale during air injection

Abstract

The investigation of low-temperature oxidation (LTO) of crude oil within tight shale holds significant importance due to its implications for subsequent oxidation reactions and enhanced oil recovery in the process of air injection. In this study, the tight shale sample underwent oxidation at various LTO temperatures, followed by an analysis of the resulting gas composition. Furthermore, the oxidized oil was separated from the tight shale and subjected to characterization using electron paramagnetic resonance, nuclear magnetic resonance, and negative ion electrospray Fourier transform-ion cyclotron resonance mass spectrometry techniques. The primary focus was on examining the distinct LTO reaction pathways observable across different temperature ranges. The findings demonstrated a correlation between LTO temperature and the concentration of free radicals, which predominantly resided on aromatic hydrocarbons, alkanes, and oxygen atoms. Additionally, the proton count of polycyclic aromatic hydrocarbons exhibited a continuous increase from 83 to 350 ° C, suggesting intensified aromatization and condensation reactions involving aliphatic and aromatic compounds. With rising LTO temperature, the molecular structure of O₂ compounds underwent significant transformations, characterized by increased condensation degree and a decrease in low carbon number molecular structures, while higher equivalent double bonds and carbon number molecular structures became more prevalent. The LTO reaction pathways of shale oil included cycle paths 1, 2, and 3. The influence of cycle path 1 diminished at temperatures ranging from 83 to 150 ° C and 250 to 350 ° C, whereas the significance of cycle paths 2 and 3 increased, resulting in an overall escalation of the oxidation rate with temperature elevation. It was observed that the shale oil LTO process exhibited a negative temperature coefficient within the temperature range of 150 to 250 ° C, emphasizing the criticality of overcoming the energy barrier in this region to achieve stable combustion. This comprehensive investigation provides valuable insights into the mechanisms underlying LTO in crude oil confined within tight shale.

Keywords

Low-temperature oxidation / Shale oil / Air injection / Electron paramagnetic resonance

CRediT authorship contribution statement

Shuai Zhao: Conceptualization, Methodology, Writing-original draft. Wanfen Pu: Methodology, Supervision. Yibo Li: Investigation, Writing-review & editing. Qi Jiang: Supervision, Writing-review & editing.

Declaration of competing interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Acknowledgements

This work was supported by National Natural Science Foundation of China (No. 52204049) and Open Fund (PLN020-23) of State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation (Southwest Petroleum University), and Ministry of Science and Higher Education of the Russian Federation under Agreement No. 075-15-2022-299 within the framework of the development program for a world-class Research Center “Efficient development of the global liquid hydrocarbon reserves”.

References

[1] W. Lv, S. Chen, Y. Gao, C. Kong, N. Jia, L. He, et al., Evaluating seepage radius of tight oil reservoir using digital core modeling approach, J. Petrol. Sci. Eng. 178 (2019) 609-615.

[2] E. Mukhina, A. Cheremisin, L. Khakimova, A. Garipova, E. Dvoretskaya, M. Zvada, et al., Enhanced oil recovery method selection for shale oil based on numerical simulations, ACS Omega 6 (2021) 23731-23741.

[3] B.T. Hoffman,Comparison of various gases for enhanced recovery from shale oil reservoirs, SPE Improved Oil Recovery Symposium (2012), https://doi.org/10.2118/154329-MS.

[4] B. Jia, J.S. Tsau, R. Barati, A review of the current progress of CO2 injection EOR and carbon storage in shale oil reservoirs, Fuel 236 (2019) 404-427.

[5] L.H. Bai, B. Liu, Y.J. Du, B.Y. Wang, S.S. Tian, L. Wang, et al., Distribution characteristics and oil mobility thresholds in lacustrine shale reservoir: insights from N2 adsorption experiments on samples prior to and following hydrocarbon extraction, Petrol. Sci. 19 (2022) 486-497.

[6] H. Jia, J.J. Sheng, Simulation study of huff-n-puff air injection for enhanced oil recovery in shale oil reservoirs, Petroleum 4 (2018) 7-14.

[7] L. Khakimova, T. Bondarenko, A. Cheremisin, A. Myasnikov, M. Varfolomeev, High pressure air injection kinetic model for Bazhenov Shale Formation based on a set of oxidation studies, J. Petrol. Sci. Eng. 172 (2019) 1120-1132.

[8] H. Jia, J.J. Sheng, Discussion of the feasibility of air injection for enhanced oil recovery in shale oil reservoirs, Petroleum 3 (2017) 249-257.

[9] S. Huang, J.J. Sheng, Effect of nanopore confinement on crude oil thermal-oxidative behavior, Energy Fuel. 32 (2018) 9322-9329.

[10] S. Zhao, C. Xu, W. Pu, M.A. Varfolomeev, Y. Zhou, C. Yuan, et al., Oxidation characteristics and kinetics of shale oil using high-pressure differential scanning calorimetry, Energy Fuel. 35 (2021) 18726-18732.

[11] S. Zhao, W. Pu, M.A. Varfolomeev, C. Yuan, C. Xu, Influence of water on thermo-oxidative behavior and kinetic triplets of shale oil during combustion, Fuel 318 (2022) 123690.

[12] Y. Zhang, S. Huang, J.J. Sheng, Q. Jiang, Experimental and analytical study of oxygen consumption during air injection in shale oil reservoirs, Fuel 262 (2020) 116462.

[13] M. Du, W.F. Lv, Z.M. Yang, N.H. Jia, J.G. Zhang, Z.K. Niu, et al., An online physical simulation method for enhanced oil recovery by air injection in shale oil, Petrol. Explor. Dev. 50 (2023) 1-13.

[14] H. Jia, P. Jiang, Z. Yan, J.J. Sheng, Modelling air injection in shale oil reservoirs: physical process and recovery mechanism, Int. J. Oil Gas Coal Technol. 24 (2020) 143-160.

[15] J. Tingas, Numerical Simulation of Air Injection Processes in High-Pressure Light and Medium Oil Reservoirs, 2003.

[16] D. Gafurova, A. Kalmykov, D. Korost, G. Kalmykov, Macropores generation in the domanic formation shales: insights from pyrolysis experiments, Fuel 289 (2021) 119933.

[17] C.B. Cockreham, X. Zhang, M.L. Lau, M. Long, X. Guo, H. Xu, et al., Thermal evolutions and resulting microstructural changes in kerogen-rich marcellus shale, ACS Earth Space Chem. 4 (2020) 2461-2469.

[18] S. Li, Y. Liu, Y. Zhang, J. Wu, W. Zhang, Q. Shi, Molecular characterization of olefins in petroleum fractions by iodine monochloride addition and atmospheric pressure chemical ionization mass spectrometry, Energy Fuel. 36 (23) (2022) 14187-14193.

[19] S.S. Mehrabi-Kalajahi, M.A. Varfolomeev, C. Yuan, D.A. Emelianov, K.R. Khayarov, A.A. Rodionov, et al., EPR as a complimentary tool for the analysis of low-temperature oxidation reactions of crude oils, J. Petrol. Sci. Eng. 169 (2018) 673-682.

[20] W. Wang, Y. Ma, S. Li, J. Shi, J. Teng, Effect of temperature on the EPR properties of oil shale pyrolysates, Energy Fuel. 30 (2016) 830-834.

[21] J. Shi, Y. Ma, S. Li, L. Zhang, Characteristics of thermal bitumen structure as the pyrolysis intermediate of Longkou oil shale, Energy Fuel. 31 (2017) 10535-10544.

[22] R. Zhao, J. Sun, Q. Fang, Y. Wei, G. Song, C. Xu, et al., Evolution of acidic compounds in crude oil, Energy Fuel. 31 (2017) 5926-5932.

[23] N.P. Freitag, Chemical reaction mechanisms that govern oxidation rates during in-situ combustion and high-pressure air injection, SPE Reservoir Eval. Eng. 19 (2016) 645-654.

[24] L. Yang, J.J. Sheng, Experimental study on the oxidation behaviors of Wolfcamp light crude oil and its saturate, aromatic and resin fractions using accelerated rate calorimetry tests, Fuel 276 (2020) 117927.

[25] S. Zhao, W. Pu, M.A. Varfolomeev, C. Yuan, A.A. Rodionov, Integrative investigation of low-temperature oxidation characteristics and mechanisms of heavy crude oil, Ind. Eng. Chem. Res. 58 (2019) 14595-14602.

[26] A. Ushakova, V. Zatsepin, M. Varfolomeev, D. Emelyanov, Study of the radical chain mechanism of hydrocarbon oxidation for in situ combustion process, Journal of Combustion 1 (2017) 1-11.

[27] N.P. Freitag, Evidence that naturally occurring inhibitors affect the low-temperature oxidation kinetics of heavy oil, J. Can. Petrol. Technol. 49 (2010) 36-41.

[28] L. Petrakis, D.W. Grandy, Electron spin resonance spectrometric study of free radicals in coals, Anal. Chem. 50 (1978) 303-308.

[29] S. Mehrabi-Kalajahi, M. Varfolomeev, C. Yuan, W. Pu, A. Rodionov, S. Orlinskii, et al., Using EPR Technique for Monitoring of Isc Processes and Reservoirs Temperature in Enhanced Oil Recovery, SPE Russian Petroleum Technology Conference, 2018.

[30] I.Z. Rakhmatullin, S.V. Efimov, B.Ya Margulis, V.V. Klochkov, Qualitative and quantitative analysis of oil samples extracted from some Bashkortostan and Tatarstan oilfields based on NMR spectroscopy data, J. Petrol. Sci. Eng. 156 (2017) 12-18.

[31] A.M. Elbaz, A. Gani, N. Hourani, A.H. Emwas, S.M. Sarathy, W.L. Roberts, TG/DTG, FT-ICR mass spectrometry, and NMR spectroscopy study of heavy fuel oil, Energy Fuel. 29 (12) (2015) 7825-7835.

[32] W. Meredith, S.J. Kelland, D.M. Jones, Influence of biodegradation on crude oil acidity and carboxylic acid composition, Org. Geochem. 31 (2000) 1059-1073.

[33] W.K. Seifert, R.M. Teeter, Identification of polycyclic aromatic and heterocyclic crude oil carboxylic acids, Anal. Chem. 42 (1970) 750-758.

[34] S. Zhao, W. Pu, X. Peng, J. Zhang, H. Ren, Low-temperature oxidation of heavy crude oil characterized by TG, DSC, GC-MS, and negative ion ESI FT-ICR MS, Energy 214 (2021) 119004.

[35] C. Yuan, D.A. Emelianov, M.A. Varfolomeev, M. Abaas, Comparison of oxidation behavior of linear and branched alkanes, Fuel Process. Technol. 188 (2019) 203-211.

[36] F. Battin-Leclerc, O. Herbinet, P.-A. Glaude, R. Fournet, Z. Zhou, L. Deng, et al., Experimental confirmation of the low-temperature oxidation scheme of alkanes, Angew. Chem. Int. Ed. 49 (2010) 3169-3172.

[37] W.F. Pu, A. Ushakova, V. Zatsepin, Chain reactions approach to the initial stages of crude oil oxidation, Energy Fuel. 32 (2018) 11936-11946.