关键词: 沙湾凹陷, 烃源岩, 油源对比, 原油地球化学特征, 单体烃碳同位素

Abstract: As an important oil and gas enrichment depression in the northwestern margin of Junggar basin, Shawan depression has significant oil and gas discoveries in Hongche fault zone and slope area. In order to clarify the source of crude oil in the structural periphery of Shawan depression, the geochemical indexes of four sets of hydrocarbon source rocks and crude oil in the northwestern margin of Junggar basin were analyzed, and the oil-source correlation was studied using the whole-hydrocarbon geochemistry. It is believed that the crude oil in Shawan depression can be divided into five types with different characteristics in biomarkers and carbon isotopes. Based on the geochemical characteristics of each set of hydrocarbon source rocks, it is considered that the Subtype A1  of crude oil in Shawan depression origins from the high matured source rocks of the Xiawuerhe Formation of Permian, the Subtype A2  of crude oil comes from the normal matured source rocks of the Xiawuerhe Formation, the  Type B of crude oil derives from the intermixture of the products of the source rocks of the Fengcheng Formation and the Xiawuerhe Formation, the  Type C of crude oil originates from the normal to high matured source rocks of the Fengcheng Formation of Permian, and the  Type D of crude oil are the product of the Jurassic source rocks.

Key words: Shawan depression, source rock, oil-source correlation, geochemical characteristics of crude oil, carbon isotope of n-alkanes