西非海岸盆地深水砂岩油气成藏规律研究

Reservoir Formation Rules of Deep-water Sandstone in Coastal Basin of West Africa

为深入认识与准确把握深水砂岩油藏的运移与富集规律,以西非海岸盆地为例,通过采用成藏体系要素分析法与地球化学指标分析法相结合,定量评价毛里塔尼亚、索维拉等海上盆地烃源岩潜力,逐一剖析了储层特征、盖层展布、圈闭类型、运移通道等成藏要素特征,分类总结了该区主要的油气成藏模式。结果表明:该深水油气藏烃源岩层为上白垩统的森诺曼-土伦阶源岩,储集层为上白垩及中新统的浊积水道砂岩,盖层主要为第三系泥岩,运移路径主要为断层或砂岩,圈闭类型多样,富集成藏为盐丘构造油气成藏模式、侧生型生物礁油气成藏模式和背斜断块构造油气成藏模式。深水砂岩油气的成藏模式与规律研究,为该地区油气勘探评价工作提供了依据。

In order to deeply understand and accurately grasp the migration and enrichment rules of deep-water sandstone reservoirs,this paper takes the coastal basin in west Africa as an example,combining with the analysis method of reservoir formation system elements and geochemical indicators,quantitatively evaluates the potential of source rocks in Mauritania,Essaouira and other offshore basins.The features of reservoir characteristics,cap formation distribution,trap types and migration channels are analyzed one by one,and the main reservoir formation models are classified and summarized.The results show that the hydrocarbon source rock is Senoman-Toulon order of source rocks in upper cretaceous deep-water reservoirs,and the reservoirs are turbidity channel sandstone of upper Cretaceous and Miocene.The cap rock is mainly tertiary mudstone,and main migration path for fault or sandstone,the trap type is various,including the reservoir formation pattern in the salt dome structure,lateral type biological reef of reservoir formation pattern and anticlinal fault block of reservoir formation pattern.The study of reservoir formation model of deep-water sandstone provides basis for oil and gas exploration and evaluation in this area.