西非Rio Muni盆地油气地质与成藏特征

西非Rio Muni盆地经过50余年的油气勘探,在深水区取得显著的勘探成果。该盆地属于典型的被动大陆边缘含盐盆地,构造演化可以分为裂谷期、过渡期和漂移期。盆地内发育3套烃源岩,阿尔布—上阿普第阶海相泥岩和微晶灰岩是盆地的主力烃源岩,上白垩统坎佩尼阶和桑托阶深水浊积砂体是盆地的主力产层。盆地重力滑脱和盐拱作用较发育,油气成藏具有以下特征:盐拱冲断控制着有利勘探区带;构造和岩性双重控制油藏类型和分布;储层优劣控制着油藏的商业性。

Petroleum Geology and Reservoir Formation Characteristics of Rio Muni Basin in West Africa

Through hydrocarbon exploration for more than 50 years in Rio Muni Basin,distinguished hydrocarbon exploration results have been obtained in deep-water area.As a typical passive margin salt-bearing basin,Rio Muni Basin has experienced three tectonic evolution periods,mainly rifting,transitional and drift periods.Three sets of source rocks are developed in Rio Muni Basin,of which Albian-Upper Aptian marine shale and micrite are the main source rocks.Upper Cretaceous Campanian and Santonian deep-water turbidite sandstone are the main production layers in the basin.Gravity gliding and salt related structure are developed in the basin. The petroleum geologic conditions for HC accumulation are as follows:the favorable exploration zones are controlled by salt arched thrust faulting,the reservoir types and distribution are controlled by structures and lithology,and the commercial values of oil and gas reservoirs are controlled by reservoir quality.