穆格莱德盆地的沉积充填与油气(英文)

Sedimentary fills and hydrocarbon potential of rift basin:a case study from the Muglad basin, Sudan

利用沉积学方法分析了穆格莱德盆地的沉积充填与油气勘探问题。研究表明 :该盆地发育冲积、扇三角洲、三角洲、湖泊和深水浊积岩相等 5种沉积相 ,分别构成河流 -三角洲 -湖泊和扇三角洲 -湖泊等两大沉积体系 ;主要烃源岩发育在下白垩统 AG组 ,该组上部以砂岩为主 ,生烃潜力差 ,下部主要是干旱气候期的沉积 ,生烃潜力亦差 ;AG组中部以暗色泥页岩沉积为主 ,发育在成盆早期 ,为中 -深湖泊沉积 ,但分布较为局限 ;该段地层厚 2 0 0 0 m,60 %以上为暗色泥、页岩 。

sedimentary fills and hydrocarbon potential of the Muglad basin have been discussed.A total of five depositional facies have been recognised in this basin,including alluvial,fan delta,delta,and lacustrine and distal turbidite facies.These facies have constituted two depositional systems:①alluvial delta lacustrine system,and ②fan delta and lacustrine system.The main hydrocarbon source rocks in the Muglad basin are developed in the Lower Cretaceous lacustrine rocks of the Abu Gabra (AG) formation.The AG formation can be roughly subdivided into the lower, middle and upper parts.The lower and upper parts of this formation are mainly composed of sandstone while the middle part is dominated by fine grained sediments with some dark shale. The AG formation was formed in environments ranging from alluvial fan, fan delta, to lacustrine that were developed during the early rifting stage. The AG formation in the Muglad basin has a thickness of over 2 000 m and 60% of it is dark shale (middle part). The sandstone of the lower and upper parts was formed under an arid climate and their hydrocarbon potentials are very poor, while the fine grained sediments of the middle part were formed under a humid climate and the locally distributed shale of this is of good potential of hydrocarbon.