Exploring the thermal evolution of highly- to over-mature source rocks using Raman spectroscopy and geochemical signatures

Abstract

This study investigated the heterogeneous responses of organic matter (OM) in highly- to over-mature source rocks during thermal maturation. An integrated analysis was conducted on the Raman spectroscopic and geochemical signatures of shales from the Lower Silurian Longmaxi Formation and the Lower Cambrian Qiongzhusi Formation, as well as anthracites from the Lower Permian Shanxi-Formation and the Upper Carboniferous Taiyuan Formation (collectively referred to as the Shanxi Taiyuan Formations). Additionally, burial and thermal evolution modeling was employed to support the analysis. A systematic assessment of Raman spectral parameters (e.g., the positions and intensity ratio of the D and G bands) revealed robust correlations between the thermal history patterns of source rocks and molecular structural evolution parameters. The subsequent mechanistic quantification demonstrated that the maturation state of the source rocks was subjected to the hierarchical control of three principal factors: Peak heating temperature, the duration of sustained thermal intensity, and effective maturation duration. In addition, comparative analyses demonstrated that the anthracites attained higher structural ordering under sustained thermal conditions. This contrasts with the disordered carbon matrices observed in the intermittently heated shales. Raman spectroscopy further revealed broader variations in the D and G band intensities of the Longmaxi Formation compared to the Qiongzhusi Formation. This difference is associated with their different thermal histories. The thermal burial histories confirm that shales in the Longmaxi Formation underwent thermal exposure at lower peak temperatures over a shorter duration compared to those in the Qiongzhusi Formation. Finally, this study established a maturity calibration model for over-mature source rocks through a systematic correlation between Raman peak height ratios (R_D/G) and vitrinite reflectance (R_o).

Keywords

Raman spectroscopy / Overmature source rock / Qiongzhusi Formation / Longmaxi Formation / Anthracite / Mineral exploration engineering

References

[1] Adsul T, Ghosh S, Ojha A, Bhattacharyya S, Varma AK. 2023. Spectral narratives of microstructural restyling and their controls on hydrocarbon generation potential from coal. International Journal of Coal Science & Technology, 10(1), 33. doi: 10.1007/s40789-023-00591-8.

[2] Arysanto A, Littke R, Dörner M, Erdmann M, Grohmann S. 2022. Maturation and migration processes in intact source rock micro plugs induced by chemical and thermal treatment: A new approach combining Rock-Eval pyrolysis and organic petrography. International Journal of Coal Geology, 251, 103938. doi: 10.1016/j.coal.2022.103938.

[3] Bao SJ, Zhai GY, Zhou Z, Yu SF, Chen K, Wang YF, Wang H, Liu YM. 2018. The evolution of the Huangling uplift and its control on the accumulation and preservation of shale gas. China Geology, 1(3), 346-353. doi: 10.31035/cg2018052.

[4] Chen C, Meng C, You QD, Luo C, Chen Y, Xiong Z, Xu PJ. 2022. Fluid charging and gas reservoir pressure evolution of Longmaxi Formation shale in southeastern Chongqing. Geofluids, 2022, 1544872. doi: 10.1155/2022/1544872.

[5] Chen SB, Wang HJ, Wang Y, Jiang TG, Zhang YK, Gong Z. 2021. Differences in shale gas accumulation process and its significance in exploration of Lower Silurian Longmaxi Formation in Northeast Yunnan. Frontiers of Earth Science, 15(2), 343-359. doi: 10.1007/s11707-021-0913-x.

[6] Chen SB, Zhu YM, Chen S, Han YF, Fu CQ, Fang JH. 2017. Hydrocarbon generation and shale gas accumulation in the Longmaxi Formation, Southern Sichuan Basin, China. Marine and Petroleum Geology, 86, 248-258. doi: 10.1016/j.marpetgeo.2017.05.017.

[7] Chen SB, Zhu YM, Qin Y, Wang HY, Liu HL, Fang JH. 2014. Reservoir evaluation of the Lower Silurian Longmaxi Formation shale gas in the southern Sichuan Basin of China. Marine and Petroleum Geology, 57, 619-630. doi: 10.1016/j.marpetgeo.2014.07.008.

[8] Chen SY, Zhang B, Zhang JJ, Wang Y, Zhang L, Li XR, Huang BY, Yan Y. 2022. Constraints of Raman spectroscopy on carbonaceous materials (RSCM) and quartz fabrics of tectonites on orogenic belt tectonothermal evolution: A case study on the North Himalayan Ramba Gneiss Dome. Acta Petrologica Sinica, 38(4), 1081-1106. doi: 10.18654/1000-0569/2022.04.08.

[9] Cheng M, Li C, Yin JT, Wang P, Hu CZ, Yu YX, Lei YH, Zhang LK. 2024. Modeling of burial history, source rock maturity, and hydrocarbon generation of marine-continental transitional shale of the Permian Shanxi formation, southeastern Ordos basin. ACS Omega, 9(18), 20532-20546. doi: 10.1021/acsomega.4c01725.

[10] Cheng NN, Pan JN, Shi MY, Hou QL, Han YZ. 2022. Using Raman spectroscopy to evaluate coal maturity: The problem. Fuel, 312, 122811. doi: 10.1016/j.fuel.2021.122811.

[11] Cui GD, Niu Z, Zhao DF, Kong YL, Feng B. 2023. High-temperature hydrothermal resource exploration and development: Comparison with oil and gas resource. Gondwana Research, 122, 306-314. doi: 10.1016/j.gr.2022.09.015.

[12] Dai JX, Ni YY, Liu QY, Wu XQ, Gong DY, Hong F, Zhang YL, Liao FR, Yan ZM, Li HW. 2021. Sichuan super gas basin in southwest China. Petroleum Exploration and Development, 48(6), 1251-1259. doi: 10.1016/s1876-3804(21)60284-7.

[13] Dai JX, Zou CN, Dong DZ, Ni YY, Wu W, Gong DY, Wang YM, Huang SP, Huang JL, Fang CC, Liu D. 2016. Geochemical characteristics of marine and terrestrial shale gas in China. Marine and Petroleum Geology, 76, 444-463. doi: 10.1016/j.marpetgeo.2016.04.027.

[14] Evans MA. 1995. Fluid inclusions in veins from the Middle Devonian shales: A record of deformation conditions and fluid evolution in the Appalachian Plateau. Geological Society of America Bulletin, 107(3), 327-339. doi: 10.1130/0016-7606(1995)1072.3.CO;2.

[15] Gao ZW, Zhang C, Li MJ, Fang RH, Borjigin T, Xiao H, Zhu ZL. 2022. Application of laser Raman spectroscopic parameters of coal maceral analysis with different maturity. Petroleum Geology and Experiment, 44(4), 705-711, 719. doi: 10.11781/sysydz202204705.

[16] Goldstein RH. 2001. Fluid inclusions in sedimentary and diagenetic systems. Lithos, 55(1-4), 159-193. doi: 10.1016/s0024-4937(00)00044-x.

[17] Hackley PC, Cardott BJ. 2016. Application of organic petrography in North American shale petroleum systems: A review. International Journal of Coal Geology, 163, 8-51. doi: 10.1016/j.coal.2016.06.010.

[18] Hackley PC, Jubb AM, McAleer RJ, Valentine BJ, Birdwell JE. 2021. A review of spatially resolved techniques and applications of organic petrography in shale petroleum systems. International Journal of Coal Geology, 241, 103745. doi: 10.1016/j.coal.2021.103745.

[19] He BZ, Zheng ML. 2016. Structural characteristics and formation dynamics: A review of the main sedimentary basins in the continent of China. Acta Geologica Sinica - English Edition, 90(4), 1156-1194. doi: 10.1111/1755-6724.12766.

[20] Henry DG, Jarvis I, Gillmore G, Stephenson M. 2019. Raman spectroscopy as a tool to determine the thermal maturity of organic matter: Application to sedimentary, metamorphic and structural geology. Earth-Science Reviews, 198, 102936. doi: 10.1016/j.earscirev.2019.102936.

[21] Hu G, Pang Q, Jiao K, Hu CW, Liao ZW. 2020. Development of organic pores in the Longmaxi Formation overmature shales: Combined effects of thermal maturity and organic matter composition. Marine and Petroleum Geology, 116, 104314. doi: 10.1016/j.marpetgeo.2020.104314.

[22] Huang BY, Zhang B, Zhang JJ, Tan Z, Zhang L, Chen SY, Li XR. 2020. Carbon material Raman spectroscopy metamorphic thermometer and its application in reconstruction and evolution of orogenic belt thermal structure. Acta Petrologica Sinica, 36(2), 526-540. doi: 10.18654/1000-0569/2020.02.12.

[23] Katz BJ, Lin F. 2021. Consideration of the limitations of thermal maturity with respect to vitrinite reflectance, Tmax, and other proxies. AAPG Bulletin, 105(4), 695-720. doi: 10.1306/09242019261.

[24] Kelemen SR, Fang HL. 2001. Maturity trends in Raman spectra from kerogen and coal. Energy & Fuels, 15(3), 653-658. doi: 10.1021/ef0002039.

[25] Liu B, Teng J, Mastalerz M, Schieber J. 2020. Assessing the thermal maturity of black shales using vitrinite reflectance: Insights from Devonian black shales in the eastern United States. International Journal of Coal Geology, 220, 103426. doi: 10.1016/j.coal.2020.103426.

[26] Liu DH, Xiao XM, Tian H, Min YS, Zhou Q, Cheng P, Shen JG. 2013. Sample maturation calculated using Raman spectroscopic parameters for solid organics: Methodology and geological applications. Chinese Science Bulletin, 58(11), 1285-1298. doi: 10.1007/s11434-012-5535-y.

[27] Mukhopadhyay PK. 1994. Vitrinite Reflectance as Maturity Parameter: Petrographic and Molecular Characterization and Its Applications to Basin Modeling. Washington, American Chemical Society Publications, America Chapter 1, 1-24.

[28] Nie HK, He ZL, Wang RY, Zhang GR, Chen Q, Li DH, Lu ZY, Sun CX. 2020. Temperature and origin of fluid inclusions in shale veins of Wufeng-Longmaxi Formations, Sichuan Basin, South China: Implications for shale gas preservation and enrichment. Journal of Petroleum Science and Engineering, 193, 107329. doi: 10.1016/j.petrol.2020.107329.

[29] Qiu NS, Liu W, Fu XD, Li WZ, Xu QC, Zhu CQ. 2021. Maturity evolution of lower Cambrian qiongzhusi formation shale of the Sichuan basin. Marine and Petroleum Geology, 128, 105061. doi: 10.1016/j.marpetgeo.2021.105061.

[30] Radke M, Welte DH, Willsch H. 1986. Maturity parameters based on aromatic hydrocarbons: Influence of the organic matter type. Organic Geochemistry, 10(1-3), 51-63. doi: 10.1016/0146-6380(86)90008-2.

[31] Randive KR, Hari KR, Dora ML, Malpe DB, Bhondwe AA. 2014. Study of fluid inclusions: Methods, techniques and applications. Geological Magazine, 29(1), 19-28.

[32] Roberts S, Tricker PM, Marshall JEA. 1995. Raman spectroscopy of chitinozoans as a maturation indicator. Organic Geochemistry, 23(3), 223-228. doi: 10.1016/0146-6380(94)00126-l.

[33] Schito A, Romano C, Corrado S, Grigo D, Poe B. 2017. Diagenetic thermal evolution of organic matter by Raman spectroscopy. Organic Geochemistry, 106, 57-67. doi: 10.1016/j.orggeochem.2016.12.006.

[34] Shang FH, Zhu YM, Hu QH, Zhu YW, Wang Y, Du MY, Liu RY, Han Y. 2020. Characterization of methane adsorption on shale of a complex tectonic area in Northeast Guizhou, China: Experimental results and geological significance. Journal of Natural Gas Science and Engineering, 84, 103676. doi: 10.1016/j.jngse.2020.103676.

[35] Sykes R, Snowdon LR. 2002. Guidelines for assessing the petroleum potential of coaly source rocks using Rock-Eval pyrolysis. Organic geochemistry, 33(12), 1441-1455. doi: 10.1016/S0146-6380(02)00183-3.

[36] Tang XL, Jiang ZX, Jiang S, Wang HY, He ZL, Feng J. 2021. Structure, burial, and gas accumulation mechanisms of lower Silurian Longmaxi Formation shale gas reservoirs in the Sichuan Basin (China) and its periphery. AAPG Bulletin, 105(12), 2425-2447. doi: 10.1306/0702211610418010.

[37] Tissot BP. 1984. Recent advances in petroleum geochemistry applied to hydrocarbon exploration. AAPG Bulletin, 68(5), 545-563. doi: 10.1306/AD461336-16F7-11D7-8645000102C1865D.

[38] Wang DD, Jiang ZX, Du W, Liu DD, Shao XD, Feng X, Chen Y, Chen WY, Yang Y. 2024. Fluid activity characteristics of shallow shale veins in the Wufeng-Longmaxi Formation in the Shixi syncline in northern Guizhou and their significance for shale gas preservation. Natural Gas Industry B, 11(5), 511-524. doi: 10.1016/j.ngib.2024.09.011.

[39] Watson MP, Hayward AB, Parkinson DN, Zhang ZM. 1987. Plate tectonic history, basin development and petroleum source rock deposition onshore China. Marine and Petroleum Geology, 4(3), 205-225. doi: 10.1016/0264-8172(87)90045-6.

[40] Wilkins RWT, Boudou R, Sherwood N, Xiao XM. 2014. Thermal maturity evaluation from inertinites by Raman spectroscopy: The ‘RaMM’ technique. International Journal of Coal Geology, 128-129, 143-152. doi: 10.1016/j.coal.2014.03.006.

[41] Wilkins RWT, Wang M, Gan HJ, Li ZS. 2015. A RaMM study of thermal maturity of dispersed organic matter in marine source rocks. International Journal of Coal Geology, 150-151, 252-264. doi: 10.1016/j.coal.2015.09.007.

[42] Xiao XM, Zhou Q, Cheng P, Sun J, Liu DH, Tian H. 2020. Thermal maturation as revealed by micro-Raman spectroscopy of mineral-organic aggregation (MOA) in marine shales with high and over maturities. Science China Earth Sciences, 63(10), 1540-1552. doi: 10.1007/s11430-020-9627-2.

[43] Xing YS, Luo HL. 1984. Precambrian-Cambrian boundary candidate, Meishucun, Jinning, Yunnan, China. Geological Magazine, 121(3), 143-154. doi: 10.1017/s0016756800028193.

[44] Xu J, He QC, Xiong Z, Yu Y, Zhang S, Hu X, Jiang L, Su S, Hu S, Wang Y, Xiang J. 2021. Raman spectroscopy as a versatile tool for investigating thermochemical processing of coal, biomass, and wastes: Recent advances and future perspectives. Energy & Fuels, 35(4), 2870-2913. doi: 10.1021/acs.energyfuels.0c03298.

[45] Yang SY, Horsfield B. 2020. Critical review of the uncertainty of Tmax in revealing the thermal maturity of organic matter in sedimentary rocks. International Journal of Coal Geology, 225, 103500. doi: 10.1016/j.coal.2020.103500.

[46] Yang W, He S, Su A, Iglauer S, Zhai GY, Zhou Z, Dong T, Tao Z, Wei SL. 2021. Paleo-temperature and-pressure characteristics of fluid inclusions in composite veins of the Doushantuo shale (Yichang area, South China): Implications for the preservation and enrichment of shale gas. Energy & Fuels, 35(5), 4091-4105. doi: 10.1021/acs.energyfuels.1c00040.

[47] Yu K, Ju YW, Qian J, Qu ZH, Shao CJ, Yu KL, Shi Y. 2018. Burial and thermal evolution of coal-bearing strata and its mechanisms in the southern North China Basin since the Late Paleozoic. International Journal of Coal Geology, 198, 100-115. doi: 10.1016/j.coal.2018.09.007.

[48] Yuan L, Liu QF, Li K, Quan Y, Li XG, Mathews JP. 2023. The evolution of coal, examining the transitions from anthracite to natural graphite: A spectroscopy and optical microscopy evaluation. Frontiers of Earth Science, 17(1), 87-99. doi: 10.1007/s11707-021-0967-4.

[49] Zhai GY, Wang YF, Zhou Z, Yu SF, Chen XL, Zhang YX. 2018. Exploration and research progress of shale gas in China. China Geology, 1(2), 257-272. doi: 10.31035/cg2018024.

[50] Zhao L, Mao WJ, Liu ZB, Cheng SJ. 2023. Research on the differential tectonic-thermal evolution of Longmaxi shale in the southern Sichuan Basin. Advances in Geo-Energy Research, 7(3), 152-163. doi: 10.46690/ager.2023.03.02.

[51] Zhao WZ, Wang XM, Hu SY, Zhang SC, Wang HJ, Guan SW, Ye YT, Ren R, Wang TS. 2019. Hydrocarbon generation characteristics and exploration prospects of Proterozoic source rocks in China. Science China Earth Sciences, 62(6), 909-934. doi: 10.1007/s11430-018-9312-4.

[52] Zou CN, Yang Z, Sun SS, Zhao Q, Bai WH, Liu HL, Pan SQ, Wu ST, Yuan YL. 2020. “Exploring petroleum inside source kitchen”: Shale oil and gas in Sichuan Basin. Science China Earth Sciences, 63(7), 934-953. doi: 10.1007/s11430-019-9591-5.

[53] Zou CN, Zhu RK, Chen ZQ, Ogg JG, Wu ST, Dong DZ, Qiu Z, Wang YM, Wang L, Lin SH, Cui JW, Su L, Yang Z. 2019. Organic-matter-rich shales of China. Earth-Science Reviews, 189, 51-78. doi: 10.1016/j.earscirev.2018.12.002.

[54] Zuo ZX, Cao J, Wang XL, Luo B, Zhong Y, Li KY, Hu K. 2022. Characterizing maturity of reservoir pyrobitumen with strong anisotropy: A calibration between reflectance and laser Raman spectral parameters. AAPG Bulletin, 106(7), 1373-1401. doi: 10.1306/02032221049.

[55] Zuo ZX, Chen SB, Shi Q, Han YF. 2016. Application of laser Raman spectroscopy to the evaluation of the high-and overhigh-maturity of shale and coal. Rock and Mineral Analysis, 35(2), 193-198 doi: 10.15898/j.cnki.11-2131/td.2016.02.012. (in Chinese with English abstract).