Abstract: Tarim Basin has rich oil and gas resources in the Paleozoic marine strata, and is the only basin where large-scale marine crude oil has been discovered in China. After nearly 40 years of exploration and development and scientific researches, marine oilfields with nearly 3 billion tons of reserves have been discovered. However, there have been some disputes on the source of marine oil and gas in the platform area from the source rock in the Cambrian-Lower Ordovician or the Middle-Upper Ordovician. On the one hand, based on fact that different geochemical indicators of biomarker compounds, carbon, and sulfur isotopes indicate different sources of oil and gas, great controversy has been aroused in the academic community; on the other hand, the geological exploration laws demonstrate that the enrichment and distribution of oil and gas are closely related with oil source fault, and most prospectors believe that the main source rocks are in the Cambrian strata. Based on a systematical summarization and comparison on the history of oil and gas sources in the Tarim Basin, the focus and basis of disputes, in combination with the simulation data and exploration knowledge obtained in recent years, it is found that the differences in thermal evolution and various secondary process of source rocks are the key reasons for disputes on the oil source correlation, and that the validity of the indicators such as biomarkers and carbon isotopes is within a limited range. According to aryl isoprenoid, sulfur isotope, and individual n-alkane isotope, new indicators of oil source correlation have been established, which reveal that the main source of oil and gas in the platform area is Cambrian source rocks. The Ordovician oil and gas discovered nowadays mainly migrated through the fault system of the Cambrian source rock.

Key words: oil source correlation, Cambrian, Ordovician, sulfur isotopes, source rock, Tarim Basin

摘要： 塔里木盆地古生代海相地层油气资源丰富，是中国唯一一个发现大规模海相石油的盆地。虽然经历了近40年的勘探开发与科学研究，海相油气探明储量近30×10⁸t，但盆地台盆区海相油气的来源问题（是来自于寒武系-下奥陶统烃源岩，还是来自于中-上奥陶统烃源岩）一直存在争议。一方面，生物标志化合物和碳、硫同位素等不同地球化学指标指示油气具多源性，在学术界产生较大争议；另一方面，地质勘探的实际规律表明，油气富集分布与油源断裂密切相关，绝大多数勘探家认为寒武系是台盆区海相油气的主力烃源岩。通过系统总结和对比塔里木盆地油气源研究的历史、争议的焦点与依据，结合近年来模拟实验数据和勘探认识，发现烃源岩的热演化差异性和各类次生作用是导致油源对比结果出现争议的关键原因，生物标志化合物、碳同位素等指标的有效性是在限定的范围内。基于芳基类异戊二烯、硫同位素、单体碳同位素等建立了油源对比的新指标，揭示了台盆区油气的主要来源是寒武系烃源岩。目前奥陶系发现的油气主要通过断穿寒武系的断裂体系运移而来。

关键词: 油源对比, 寒武系, 奥陶系, 硫同位素, 烃源岩, 塔里木盆地