The Lower Cretaceous Abu Gabra Formation (AG) is considered to contain the major source rocks in the Sufyan sub-basin, Sudan. Although prior studies have established the presence of organic-rich lacustrine mudstones, the geochemical heterogeneity of organic facies, thermal maturity, and molecular nature of individual members of the Abu Gabra Formation are insufficiently characterized for oil-source rock correlation. Here, we report on geochemical analysis of 228 cutting samples utilizing Rock-Eval pyrolysis and TOC measurements, from which twenty samples were chosen for investigation of saturated biomarkers. The well cutting samples are from four members (AG₁, AG₁², AG₂² and AG₃) comprising the Abu Gabra Formation. These analyses were compared to eleven oils produced from the Abu Gabra sandstones to establish member-specific oil-source correlation. The AG₂² and AG₃ members have the greatest source potential, containing a higher content of oil-prone organic matter and more favorable maturity than those of the AG₁² and AG₁ members. Biomarker data for the AG₂² and AG₃ source rocks indicate that deposition occurred under a moderately stratified and somewhat saline water column with a predominance of algal/bacterial input (Type I kerogen). The AG₂² and AG₃ source rocks have entered the window of oil generation. In contrast, the AG₁ and AG₁² source rocks were possibly deposited in fresh to slightly saline water conditions, have a greater input of terrigenous organic matter input, and are immature to marginally mature. Oil-oil and oil-source rock correlations suggest that the crude oils in the Sufyan sub-basin are genetically homogenous, belong to a single oil family, and are mainly derived from the AG₂² and AG₃ source rocks. Contribution from the AG₁ and AG₁² source rocks is not apparent from the molecular distributions and is considered to be negligible. The current study provides valuable guidance of source rock evaluation and oil-source rock correlation, which can be a benefit to future petroleum exploration work in the Sufyan sub-basin.

下白垩统 Abu Gabra 组 (AG) 被认为包含苏丹 Sufyan 次盆地的主要烃源岩。虽然先前的研究已经确定了富含有机质的湖相泥岩的存在，但阿布加布拉组各个成员的有机相地球化学异质性、热成熟度和分子性质还不足以表征油源岩相关性。在这里，我们报告了利用 Rock-Eval 热解和 TOC 测量对 228 个切割样品进行的地球化学分析，从中选择了 20 个样品来研究饱和生物标志物。井下样品来自四个成员（AG ₁、AG ₁ ²、AG ₂ ²和AG ₃) 包括 Abu Gabra 组。将这些分析与从 Abu Gabra 砂岩生产的 11 种油进行比较，以建立特定成员的油源相关性。AG ₂ ²和 AG ₃成员具有最大的源潜力，比 AG ₁ ²和 AG ₁成员含有更高的油性有机质含量和更有利的成熟度。AG ₂ ²和 AG ₃烃源岩的生物标志数据表明沉积发生在中等分层和略带咸水的水柱下，主要是藻类/细菌输入（I 型干酪根）。AG ₂ ²和 AG ₃烃源岩已进入生油窗口。相比之下，AG ₁和AG ₁ ²烃源岩可能沉积在淡水至微咸水条件下，陆源有机质输入量较大，未成熟至边缘成熟。油-油和油-源岩对比表明苏夫扬盆地原油成因均一，属于单一油族，主要来源于AG ₂ ²和AG ₃烃源岩。AG ₁和 AG ₁ ^{2 的}贡献从分子分布看，烃源岩不明显，可以忽略不计。本研究为烃源岩评价和油源岩对比提供了有价值的指导，对苏夫延盆地未来的油气勘探工作具有指导意义。