Abstract A study of petroleum inclusions based on ultraviolet fluorescence petrography, microspectrophotometry and biomarker analyses was carried out on samples from two wells of the onshore Lorena and the offshore Ubarana oilfields, Potiguar Basin, Brazil. This study aimed to evaluate the contribution and compositional variability of oils associated with different source rocks through the geochemical correlation of petroleum inclusions and crude oils. Three groups of inclusions were identified: (i) a group from the Lorena reservoir (Pendencia Formation); (ii) a second from the Ubarana siliciclastic reservoir (Acu Formation); and (iii) a third from the carbonates adjacent to the Ubarana reservoir (Ponta do Mel Formation, PML). Fluorescence microspectrophotometry shows that the three groups of inclusions have different API gravity oils, variable proportion of saturate, aromatic, resins and asphaltenes and are not biodegraded. Moreover, Pendencia and PML inclusions suggest multiple pulses of hydrocarbon migration, while Acu inclusions record a homogeneous pulse. Biomarkers indicate that the Pendencia and Acu inclusion oils correlate with reservoir oil extracts. The Pendencia inclusion oils are similar to the lacustrine oils of the Umbuzeiro graben (Pendencia Formation), whereas the Acu inclusion oil displays closer biomarker signature to the Areia Branca trend of mixed oils (Alagamar Formation source rock). However, the oil from fluid inclusions of the PML has characteristics of the Alagamar Formation lacustrine organic facies. The absence of mixed oils in the PML suggests an earlier lacustrine oil migration through the carbonate fractures prior to the main infill of mixed oils in the Ubarana oilfield.

中文翻译：

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将 Ubarana 和 Lorena 油田、Potiguar 盆地、巴西赤道边缘的原油和石油包裹体的地球化学联系起来

摘要 基于紫外荧光岩相学、显微分光光度法和生物标志物分析，对巴西 Potiguar 盆地陆上 Lorena 和海上 Ubarana 油田 2 口井的样品进行了石油包裹体研究。本研究旨在通过石油包裹体和原油的地球化学相关性，评估与不同烃源岩相关的石油的贡献和成分变异性。确定了三组包裹体：(i) 一组来自 Lorena 储层（Pendencia 组）；(ii) 第二个来自 Ubarana 硅质碎屑岩储层（Acu 组）；(iii) 来自 Ubarana 储层（Ponta do Mel Formation，PML）附近碳酸盐岩的三分之一。荧光显微分光光度法显示三组包裹体具有不同的API比重油，不同比例的饱和物、芳香物、树脂和沥青质，并且不会被生物降解。此外，Pendencia 和 PML 包裹体表明油气运移的多次脉冲，而 Acu 包裹体记录了均匀的脉冲。生物标志物表明 Pendencia 和 Acu 包裹体油与储层油提取物相关。Pendencia 包裹体油类似于 Umbuzeiro 地堑（Pendencia 组）的湖相油，而 Acu 包裹体油显示出与混合油（Alagamar 组烃源岩）的 Areia Branca 趋势更接近的生物标志物特征。但是，PML 流体包裹体中的油具有 Alagamar 组湖相有机相的特征。