混源油比例定量分析对于判识不同成藏期的油源贡献度具有重要意义, 为建立一种快捷确定混源油贡献度的方法, 采用显微荧光光谱技术对同源混合原油贡献度进行了定量表征。 以东营凹陷王家岗地区为例, 通过γ蜡烷/C30霍烷、 Ts/(Tm+Ts)、 Ts/Tm及C2920S/(20S+20R)等生物标志化合物参数对沙四段原油进行了的原油组群划分与油源对比, 对原油类型和成熟度进行了限定。 选择具有代表性的X1和X2井作为沙四型成熟原油和低熟原油的两个端元组分进行人工配比实验, 在验证端元组分可靠性的基础上, 对端元油按照质量分数进行了配比, 分别为0∶10, 2∶8, 4∶6, 6∶4, 8∶2, 10∶0。 对配比进行了原油族组分和显微荧光光谱分析, 分析了混合原油成熟度、 端元油贡献度和荧光光谱参数之间的关系。 结果表明: 配比混源油继承了端元油“三峰型”的荧光光谱谱形特征, 混源油荧光颜色明显不同, 通过荧光颜色定量系数(CIE-X, CIE-Y)分析可知, 在CIE色度图上表现为近线性渐变的荧光特征; 随着沙四型成熟油混入量的增加, 混源油中芳香烃含量逐渐减少, 荧光强度也逐渐降低, 荧光颜色发生了明显的蓝移; 原油混合使荧光光谱参数发生了变化, 荧光光谱参数(QF-535、 荧光强度-567 nm、 红绿商、 黄绿商)与混合比例呈现良好的线性关系, 能够较好的反映原油成熟度; 随着混源油成熟度增高, 高分子量烃类组分含量降低, 荧光光谱参数逐渐降低。 通过配比实验建立的数学关系能够定量判别原油混合比例, 实验证实可以利用荧光光谱参数定量表征混源油中端元组分的贡献度。

The quantitative analysis of the proportion of mixed source oil is of great significance to the determination of the contribution of oil source in different accumulation periods. In order to establish a fast and effective method to determine the contribution of mixed oil, micro-fluorescence spectroscopy was addressed to quantitatively determine relative contribution. Taking Wangjiagang area in the Dongying Depression as an example, biomarkers, including Gammacerane/C30Hoxane, Ts/(Tm+Ts), Ts/Tm and C2920S/(20S+20R), are used to fine classification of petroleum groups and oil source correlation of Es4 crude oil, and the type and maturity of crude oil are constrained. The mature(from well X1) and low-mature(from well X2) crude oil from the upper Es4 in the Dongying Depression were selected as two typical end members for mixing experiment. On the basis of verifying the reliability of components of the end member, the mass proportions of mixed oil(X1∶X2) are respectively 0∶10, 2∶8, 4∶6, 6∶4, 8∶2 and 10∶0. The relationships of maturity of mixed crude oil, contribution of end member and fluorescence spectrum parameters were analyzed. The results show that the fluorescence spectra of end-component are mainly three-peak type, and the mixed crude oil inherits the spectral spectrum shape features of end-component. The fluorescence color of mixed oil was obviously different. According to analysis of quantitative coefficient of fluorescence color(CIE-X, CIE-Y), the CIE chromaticity diagram shows nearly-linear changeof fluorescence color. With the increase of the amount of ES4 mature crude oil, the aromatic hydrocarbon content in the mixed oil decreased, and the fluorescence intensity also decreased, and the fluorescence color showed a significant blue shift. The fluorescence spectrum parameters(QF-535, fluorescence intensity at 567 nm, ratio of red to green, ratio of yellow to green) and the mixing proportion showed a good linear relationship, which could reflect the maturity of crude oil. As the maturity of mixed oil increases, the content of macromolecular hydrocarbons decreases, so the fluorescence spectrum parameters become small. The mathematical relation established by the mixing experiment can be used to identify the mixture ratio quantitatively, so as to determine the contribution of end member oil. This experiment can prove that these spectral parameters of fluorescence are effective to quantitatively characterize the contribution of end-member in mixed oil.