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塔里木盆地油气源长期争论不休.采用单体烃同位素、包裹体成分与年代指示生物标志物等途径,对塔里木盆地塔中、轮南典型油气藏进行了油气成因与混源成藏模式的研究.结果表明,塔中、轮南绝大部分原油生物标志物与中上奥陶统烃源岩相似,仅少部分原油显现与寒武系-下奥陶统烃源岩相近的特征,但正构烷烃单体烃碳同位素分析表明,原油绝大部分实质仍为混源油.塔中包裹烃成分分析进一步证实了原油的混源特性.利用同位素进行的混源定量结果表明,塔中原油中寒武系-下奥陶统成因原油的混入量约为11%～100%(均值45%);轮南地区约为11%～70%(均值36%),表明寒武系-下奥陶统、中上奥陶统均为塔里木盆地的主力烃源岩.油气运移地化指标与地质条件的综合研究认为,塔中地区断层是油气运移的重要通道,塔中I号断层与斜交的走滑断层的交汇点是油气的主要注入点;轮南地区侧向运移特征较明显.研究区存在调整型、多期充注型与原生型多种混源成藏模式.塔里木海相油气的普遍混源表明深层仍有油气勘探潜能.揭示海相混源油气成藏机制是指导塔里木海相油气勘探的关键.
The sources of oil and gas in the Tarim Basin have long been debated, and hydrocarbon generation and hydrocarbon accumulation models have been studied in the typical reservoirs of Tazhong and Lunnan in Tarim Basin by means of single hydrocarbon isotopes, inclusions and age-derived biomarkers. The results show that most of the crude biomarkers in the Tarim and Lunnan are similar to the Middle-Upper Ordovician source rocks, while only a few of the crude oils show features similar to the Cambrian-Lower Ordovician source rocks. However, The hydrocarbon carbon isotope analysis of alkane monomer showed that most of the crude oil remained as mixed source oil, and the composition analysis of the hydrocarbons in the tower further confirmed the mixed source characteristics of the crude oil.The quantitative results of mixed sources using isotopes showed that the middle cold The Lower Cambrian-Lower Ordovician mixed crude oil is about 11% -100% (average 45%); Lunnan is about 11-70% (average 36%), indicating that the Cambrian-Lower Ordovician , Middle-upper Ordovician are the main source rocks in the Tarim Basin.Comprehensive studies on the geochemical indicators and geological conditions of migration show that the fault in Tazhong area is an important channel for hydrocarbon migration. The strike-slip fault junction is the main injection of oil and gas . Lateral migration in Lunnan area is more obvious, and there are many mixed-source-forming models of adjustment type, multi-phase filling type and primary type in the study area. The universal mixed source of oil and gas in the Tarim Basin indicates that there is still potential for hydrocarbon exploration in the deep layer. It is the key to reveal the hydrocarbon accumulation mechanism of marine mixed source and oil in the marine oil and gas exploration in the Tarim Basin.