The oil–oil and oil–source rock correlations, also termed as geochemical correlations, play an essential role in the construction of petroleum systems, guidance of petroleum exploration, and definition of reservoir compartments. In this study, the problems arising from oil–oil and oil–source rock correlations were investigated using chemometric methods on oil and source rock samples from the WZ12 oil field in the Weixinan sag in the Beibuwan Basin. Crude oil from the WZ12 oil field can be classified into two genetic families: group A and B, using multidimensional scaling and principal component analysis. Similarly, source rocks of the Liushagang Formation, including its first, second, and third members, can be classified into group I and II, corresponding to group B and A crude oils, respectively. The principle geochemical parameters in the geochemical correlation for the characterisation and classification of crude oils and source rocks were 4MSI, C27Dia/C27S, and C24 Tet/C26 TT. This study provides insights into the selection of appropriate geochemical parameters for oil–oil and oil–source rock correlations, which can also be applied to other sedimentary basins.

中文翻译：

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南海北部湾盆地渭西南凹陷石油化学计量学与地球化学对比

油-油和油-源岩对比，也称为地球化学对比，在油气系统构建、石油勘探指导和储层划分等方面发挥着重要作用。本研究采用化学计量学方法对北部湾盆地渭西南凹陷WZ12油田的油样和烃源岩样品进行油-油和油-源岩对比研究。WZ12油田原油通过多维标度和主成分分析可分为A组和B组两个成因家族。同理，流沙港组烃源岩包括一、二、三段，可分为Ⅰ组和Ⅱ组，分别对应B组和A组原油。用于原油和烃源岩表征和分类的地球化学对比中的主要地球化学参数为 4MSI、C27Dia/C27S 和 C24 Tet/C26 TT。本研究为油-油和油-源岩相关性选择合适的地球化学参数提供了见解，这些参数也可应用于其他沉积盆地。