沉积学报2025，Vol.43Issue(2)：683-700,18.DOI:10.14027/j.issn.1000-0550.2024.028
煤系烃源岩中四种类型高丰度重排藿烷组成特征及成因探讨
Composition Characteristics and Genesis of Four Types of High-Abundance Rearranged Hopanes in Coal Measure Source Rocks:A case study of Upper Paleozoic strata in the Ordos Basin
摘要
Abstract
[Objective]We explored the distribution pattern,composition characteristics,and main controlling fac-tors of four types of high-abnormally high abundant rearranged hopanes in coal measure source rocks in the Ordos Ba-sin.[Methods]The saturated hydrocarbons and aromatic hydrocarbons of 29 coal measure source rocks in the Upper Paleozoic of the Ordos Basin were analyzed in detail using gas chromatography-mass spectrometry(GC-MS).[Results]Based on the peak order and retention time of the compounds,GC-MS analysis of the coal measure source rocks in Ordos Basin was conducted.Four types of rearranged hopanes with different abundances were systematically identified:17α(H)-rearranged hopane series(C30*),18α(H)-neohopane series(Ts and C29Ts),early-eluting rear-ranged hopane series(C30E),and 28,30-dinor-21-methyl rearranged hopane series(29Nsp).The peak order of the four types of rearranged hopane compounds is:early-eluting rearranged hopane series＞17α(H)-rearranged hopane series＞18α(H)-neohopane series＞28,30-dinor-21-methyl rearranged hopane series(29Nsp).The study of the in-ternal composition of these four types of rearranged hopane compounds in the coal measure source rocks in the study area shows good correlation between the same types of rearranged hopane compounds;that is,there is a good correla-tion between C30*/C30 hopane and C29*/C29 hopane,C29Ts/C29 hopane and Ts/Tm.The correlation between different types of rearranged hopanes is different.The correlation between C30*/C30 hopane,C30E/C30 hopane and 29Nsp/C29 hopane is good,but the correlation between C29Ts/C29 hopane and the other three is poor,indicating that the formation mecha-nism of different types of rearranged hopanes may differ.In addition,the relative abundance of 17α(H)-diahopane series,early elution diahopane series,and 28,30-dinor-21-methyldiahopane series(29Nsp)in the coal measure source rock samples is significantly affected by water redox and salinity conditions.With the increase of thermal evo-lution degree of organic matter,the relative abundance of these rearranged hopane compounds shows an approximate normal distribution.In the peak stage of oil generation(Ro is between 0.80％and 0.90％),the relative abundance of high-abnormally high abundant rearranged hopanes compounds reaches the peak,but maturity has little effect on low abundance rearranged hopanes.Furthermore,the ratios of(C28+C29)tricyclic terpane(TT)/C30 hopane and regular sterane/C30-35 hopane in samples with high-abnormally high abundance and the ratios of rearranged hopanes to hopanes with the same carbon number(C30*/C30 hopane,C30E/C30 hopane,29Nsp/C29 hopane)have clear positive correlations,revealing that the biogenic materials of high-abnormally high abundant rearranged hopanes compounds are primarily lower aquatic organisms and bacteria and algae compounds.[Conclusions]Based on the same evolution path and for-mation mechanism of the same types of rearranged hopanes,there are 17α(H)-rearranged hopanes with high-abnor-mally high abundance,early elution rearranged hopanes,and 28,30-dinor-21-methyl rearranged hopanes in the coal measure source rocks,which formed in the sedimentary environment with Pr/Ph values between 1.00 and 2.00 and a gammacerane index between 0.10 and 0.13,and the biological precursors are mainly bacterial hopanes.The forma-tion of high-abnormally high abundance 18α(H)-neohopanes is mainly controlled by the biogenic parent material of organic matter,which may be limonene or C29 hopane compounds.关键词
重排藿烷/主控因素/沉积环境/煤系烃源岩/鄂尔多斯盆地Key words
rearranged hopane/main controlling factors/sedimentary environment/coal measure source rock/Ordos Basin分类
天文与地球科学引用本文复制引用
张文俊,林舒敏,柯行,张敏..煤系烃源岩中四种类型高丰度重排藿烷组成特征及成因探讨[J].沉积学报,2025,43(2):683-700,18.基金项目
国家自然科学基金项目(42072165,41272170)[National Natural Science Foundation of China,No.42072165,41272170] （42072165,41272170）
