准噶尔盆地沙南油田原油来源分析

Source Analysis of Crude Oil in Sha'nan Oilfield,Junggar Basin

为了明确沙南地区原油的来源,采用全烃地球化学方法,分析准噶尔盆地沙南油田的原油各项地球化学指标,并进行油源对比。研究认为沙南地区原油碳同位素较轻,与二叠系烃源岩抽提物的碳同位素一致。轻烃庚烷值和异庚烷值整体较高,原油属于典型的成熟—高成熟阶段产物;甲基环已烷含量小于50%,原油母质类型以腐泥型为主。原油姥植比(Pr/Ph)在1.10~1.67,是典型的还原环境下的产物。综合原油的物性特征和地球化学特征,沙南地区与三台—北三台地区原油来自于同一套烃源岩,主要为二叠系烃源岩成熟—高成熟阶段的产物,与沙北地区存在差异。

In order to clarify the source of crude oil in Sha'nan area,the geochemical indexes of the crude oil and oil-source correlation by the whole hydrocarbon geochemistry. The result shows that the carbon isotopes of the crude oil in Sha'nan area is light,which is similar to that of Permian extracts. The heptane value and isoheptane value of the crude oil light hydrocarbons are high,so the crude oil is a typical mature-highly mature product; the methyl cyclohexanecontent of the crude oil is less than 50%,and the parent material of the crude oilis mainly sapropelic material. The pristane/phytane ratio Pr/Ph of the crude oil is 1. 10 ~ 1. 67,so the crude oil is a typical product of reduction environment. According to the physical and geochemical properties,the crude oil of Sha'nan area and Santai-Beisantai area is sourced from the same source rocks,which is mainly the mature-highly mature product of Permian hydrocarbon source rock,and is different from the crude oil in Shabei area.