石油实验地质2017,Vol.39Issue(2):247-252,6.DOI:10.11781/sysydz201702247
渤海湾盆地东营凹陷烃源岩碳氧同位素组成及地质意义
Composition and geologic significance of carbon and oxygen isotopes in hydrocarbon source rocks, Dongying Sag, Bohai Bay Basin
摘要
Abstract
Lacustrine hydrocarbon source rocks of the Shahejie Formation in the Dongying Sag were sampled, and the carbon and oxygen isotope composition of carbonates were analyzed. Combined with previous references and precise stratigraphic division, the isotope composition in different stratigraphic units and the evolution of ancient lacustrine environment were discussed. Theδ13 C and δ18 O of carbonates in the lower section of the fourth member of Shahejie Formation are positively correlated, which indicated that the basin was hydrologically closed during the initial period of rifting. But the carbon and oxygen isotopes are relatively light on the whole, which indicated that the water body of the salt lake was not stable, and was frequently influenced by fresh water. The δ13 C and δ18 O of carbonates in the upper section of the fourth member of Shahejie Formation are relatively heavy and positively correlated, which indicated that the salt lake was closed and stable during the acceleration phase of rifting. The carbon and oxygen isotopes of carbonate rocks with different lithologies in the lower section of the third member of Shahejie Formation varied. Theδ13 C andδ18 O of non-calcium shale vary very little and are highly concentrated, which implied that the brackish lacustrine environment during peak rifting period was very stable and hydrologically closed. The middle and lower sections of the third member of Shahejie Formation have similar properties to the non-calcium shale, which suggested that the former may have inherited the isotope features of the latter.关键词
碳氧同位素/闭流湖/湖相烃源岩/沙河街组/东营凹陷/渤海湾盆地Key words
carbon and oxygen isotopes/hydrologically closed lake/lacustrine hydrocarbon source rock/Shahe-jie Formation/Dongying Sag/Bohai Bay Basin分类
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刘庆..渤海湾盆地东营凹陷烃源岩碳氧同位素组成及地质意义[J].石油实验地质,2017,39(2):247-252,6.基金项目
国家科技重大专项(2016ZX05006-001)和国家自然科学基金(41072096)资助. (2016ZX05006-001)