现代地质2025，Vol.39Issue(3)：801-813,13.DOI:10.19657/j.geoscience.1000-8527.2024.043
辽河西部凹陷原油单体烃硫同位素特征及其地球化学意义
Distribution Characteristics and Geochemical Significances of the Individual Hydrocarbon Sulfur Isotopes of Crude Oils in the Liaohe Western Depression
摘要
Abstract
The individual hydrocarbon sulfur isotopes in crude oil provides key geochemical information for de-termining oil maturity and depositional environment.The crude oils from the Liaohe Western Depression were analyzed using gas chromatography with multicollector inductively coupled plasma mass spectrometry(GC-MC-ICP MS),in conjunction with gas chromatography/mass spectrometry(GC-MS)technology.The δ34S values of individual hydrocarbon in three genetically different crude oils show significant differences.The δ34S value of freshwater mature oil from the Jinzhou oilfield(20.57‰)is the highest,and the individual hydrocarbon sulfur isotopes exhibit an initial increase followed by a decrease with increasing methylation degree.The δ34S value of low mature oil from the Shuguang-Gaosheng oilfield in a saline environment(19.23‰)is slightly lower than the former,and the monomeric hydrocarbon sulfur isotopes increase with the degree of methylation.The δ34S value of low mature oil from the Niuxintuo oilfield in a semi-saline environment(14.47‰)is the lowest.An increas-ing trend in δ34 S values with maturity is observed,and there is a good negative correlation between Δδ34 S1-mDBT-4-mDBT and the maturity parameter C29sterane ααα20S/(S+R),indicating the controlling role of matu-rity,which may be the primary factor affecting δ34S values.The δ34S values of crude oils with similar maturities show a good positive correlation with gamacerane/C30 hopane and an inverse correlation with C19/C23 tricyclic terpane,indicating that a reducing saline environment promotes the sulfurization of organic matter,resulting in heavier δ34S values.The mild biodegradation has a small impact on δ34S values and does not cause obvious iso-topic fractionation.Individual hydrocarbon sulfur isotopes serves as a reliable indicator for assessing crude oil maturity and depositional environments,offering a scientific foundation for hydrocarbon exploration and develop-ment.关键词
辽河西部凹陷/单体烃硫同位素/成熟度/沉积环境/生物降解Key words
Liaohe Western Depression/individual hydrocarbon sulfur isotope/thermal maturity/depositional environment/biodegradation分类
地质学引用本文复制引用
邓硕,李素梅,刘佳..辽河西部凹陷原油单体烃硫同位素特征及其地球化学意义[J].现代地质,2025,39(3):801-813,13.基金项目
国家自然科学基金项目(42073064 （）
41473047). （）
