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Albertine地堑是乌干达共和国具有油气勘探潜力的中新生代断陷。通过野外考察及对采集样品的地球化学分析及综合研究,对该地堑的油气潜力有了一些初步认识。油-油对比表明,Paraa和Kibiro油苗具有相似的生烃源岩,而且烃源岩母质类型较好,含丰富的淡水藻类,Kibuku油苗母质类型较差,以陆生高等植物输入为主;油苗应源自白垩系或下第三系地层中的某一套烃源岩;2块含沥青砂岩具有相同的有机质来源,以陆源有机质输入为主,且明显不同于油苗,可能来自上第三系地层本身,即该地堑至少存在两套成熟烃源岩。成熟度分析表明,Paraa和Kibiro油苗成熟度较高,为烃源岩在生烃高峰期的产物;Kibuku油苗成熟度稍低,为烃源岩在生烃高峰前的产物;含沥青砂岩成熟度低于油苗。沉积环境分析表明,该地堑沉积环境变化较大,特别是沉积水体的咸度变化较大,油苗的原始母质为淡水湖相沉积,Kibiro地区的生烃凹陷水体较深,淡水藻类发育;Kibuku地区生烃凹陷水体较浅,陆生植物繁盛;含沥青砂岩的原始母质为咸水沉积环境。
The Albertine Graben is a Meso-Cenozoic rift with potential for hydrocarbon exploration in Uganda. Through the field investigation and the geochemical analysis and comprehensive study of the collected samples, some preliminary understanding of the hydrocarbon potential of the graben has been made. Oil-oil comparisons show that Paraa and Kibiro oil-bearing seedlings have similar source rocks, and the source rocks have good parental types and are abundant in freshwater algae. Kibuku oil seedlings have a poor parental material type, mainly imported from higher terrestrial plants ; The oil sap should originate from a certain set of source rocks in the Cretaceous or Lower Tertiary strata; the two asphaltic sandstones have the same source of organic matter, with the input of terrigenous organic matter as the main source, and obviously different from that of the oil sap, probably from On the Tertiary strata itself, that is, there are at least two sets of mature source rocks in the graben. Maturity analysis shows that Paraa and Kibiro oil maturity is high, which is the product of hydrocarbon source rock during peak period of hydrocarbon generation. Kibuku oil maturity is slightly lower, which is the product of hydrocarbon source rock before peak production; Maturity lower than the oil seedlings. The analysis of sedimentary environment shows that the sedimentary environment of the graben varies greatly, especially the salinity of sedimentary water body changes greatly. The original parent material of the oil sap is the sediment of freshwater lacustrine. The water bodies in Kibiro are deeper and the freshwater algae develop. The hydrocarbon bodies in Kibuku area are shallower and the terrestrial plants prosperous. The original parent material of asphalt sandstone is salt water sedimentary environment.