非热成熟度因素对高—过成熟页岩激光拉曼光谱的影响——以四川盆地南部下古生界海相页岩为例

Influence of non-thermal maturity factors on laser Raman spectroscopy of highly to overmature shale: a case study of Lower Paleozoic marine shale in southern Sichuan Basin

张鸿飞 焦堃 王佳玉 许宁 马丽君 刘岚锋 吴赟骏 邓宾 吴娟 叶玥豪 管全中 王周祥昕 张丛科

ZHANG Hongfei JIAO Kun WANG Jiayu XU Ning MA Lijun LIU Lanfeng WU Yunjun DENG Bin WU Juan YE Yuehao GUAN Quanzhong WANGZHOU Xiangxin ZHANG Congke

成都理工大学 能源学院(页岩气现代产业学院), 成都 610059 油气藏地质及开发工程全国重点实验室(成都理工大学), 成都 610059

College of Energy (College of Modern Shale Gas Industry), Chengdu University of Technology, Chengdu, Sichuan 610059, China State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation (Chengdu University of Technology), Chengdu, Sichuan 610059, China

激光拉曼光谱技术因其样品制备过程简单、测试便捷及具备无损分析等优势，在古老海相页岩热成熟度评价领域的应用日益广泛。目前，国内外研究主要聚焦于激光拉曼相关参数对热成熟度变化的响应，而对于非热成熟度因素(如谱图处理、样品预处理、激光波长设置等)对实验精度影响的研究相对匮乏且认识不一。采用激光拉曼光谱技术对四川盆地上奥陶统五峰组—下志留统龙马溪组及下寒武统筇竹寺组高—过成熟黑色页岩进行系统对比分析，重点探讨非热成熟度因素对激光拉曼光谱峰间距(RBS)、半峰宽(FWHM)、峰强比(ID/IG)等参数的影响，主要获得如下认识：(1)在图谱处理方法方面，双峰拟合较五峰拟合的不确定性更小、处理效率更高，更契合高—过成熟页岩热成熟度测试的需求，适用于筇竹寺组页岩拉曼谱图处理；(2)在参数选择方面，位置参数(WD、WG、RBS)经分峰拟合后，热成熟度差异小于2%，稳定性较高，而峰形参数(ID/IG、FWHM-D、FWHM-G)中的ID/IG受分峰拟合影响较小且样品间区分度高，建议在热成熟度相关性研究中优先选用位置参数RBS与峰形参数ID/IG；(3)在样品预处理方面，抛光处理对五峰组—龙马溪组高—过成熟黑色页岩拉曼参数的影响整体小于3%，但为确保能够准确定位黑色页岩中的分散有机质，建议在实验前对样品进行抛光处理。

Laser Raman spectroscopy has become increasingly prevalent in assessing the thermal maturity of ancient marine shale due to its advantages of simple sample preparation, easy operation, and non-destructive analysis. Current studies primarily focus on the response of Raman spectral parameters to thermal maturity variations, while research on the influence of non-thermal maturity factors, such as spectrum processing methods, sample pretreatment, and laser wavelength settings, on experimental accuracy remains relatively scarce and inconsistent. Using laser Raman spectroscopy, this study conducted a systematic comparative analysis of highly to overmature black shale samples from the Upper Ordovician Wufeng Formation and Lower Silurian Longmaxi Formation and Lower Cambrian Qiongzhusi Formation in the Sichuan Basin, with a particular focus on the impact of non-thermal maturity factors on parameters such as Raman band separation (RBS), full width at half maximum (FWHM), and the intensity ratio of D peak to G peak (ID/IG). The findings are as follows: (1) Spectrum processing methods: Two-peak fitting demonstrated lower uncertainty and higher efficiency than five-peak fitting, making it more suitable for thermal maturity assessment of highly to overmature shale, especially for the processing of Raman spectra of shale in Qiongzhusi Formation. (2) Parameter selection: Positional parameters (WD, WG, and RBS) showed thermal maturity differences of less than 2% after peak fitting, indicating high stability. Conversely, among the peak shape parameters (ID/IG, FWHM-D, FWHM-G), ID/IG was less affected by peak fitting and demonstrated better sample discrimination. Therefore, RBS and ID/IG are recommended as priority parameters in thermal maturity correlation studies. (3) Sample pretreatment: Polishing treatment has an overall impact of less than 3% on the Raman parameters of highly to overmature black shale from the Wufeng Formation and Longmaxi Formation. However, to accurately locate the dispersed organic matter within the black shale, polishing prior to Raman analysis is recommended.

国家自然科学基金面上项目 42372174;四川省自然科学基金面上项目 2023NSFSC0262

https://doi.org/10.11781/sysydz2025040895