北非叠合盆地中生界-古生界油气成藏组合划分与评价

北非含油气盆地经历了古生代早期的克拉通泛盆地及海西运动之后的拗陷作用阶段,形成古生代克拉通盆地和中生代拗陷盆地叠加而成的叠合盆地。在对三叠盆地中生界-古生界成藏组合研究中主要综合分析了:(1)烃源岩和储集砂体区域分布;(2)古构造、主要断裂及不整合面的特征与分布,油气运移输导系统特征及空间分布;(3)不同成藏组合烃源岩区域分布特征;(4)不同成藏组合盖层分布区域,特别是区域性盖层分布特征,同时结合不同类型圈闭的分布规律以及油气系统的保存状况,将盆地内中生界-古生界划分为三叠系Tagi组成藏组合、奥陶系Hamra组成藏组合及寒武系R组成藏组合。通过不同成藏组合的生、储、盖层基本要素的分析,认为盆地内海西期古隆起区,以及盆地斜坡区为有利成藏组合主要发育区带。

Division and Estimation of the Paleozoic-Mesozoic reservoir forming combination in North Africa superimposed basin

The North Africa petroliferous basin is a superimposed basin of Paleozoic cratonic basin and Mesozoic depression basin.The Paleozoic-Mesozoic reservoir forming combination is systematically divided into the Triassic basin based on following aspects:①regional distribution of source rocks and reservoir sandstones; ② characteristics and distribution of paleo-structure, main faults, unconformable surface, characteristics and spatial distribution of hydrocarbon migration and transportation systems;③distribution of main source rocks for each different reservoir forming combination;④distribution of cap rock,especially regional cap rock for each different reservoir forming combination. In addition, distribution of different kinds of known traps, as well as preservation conditions of petroleum system is used as factors to identify reservoir forming combination.Three large scales Paleozoic-Mesozoic reservoir forming combinations are recognized, such as Triassic Tagi Formation,Ordovician Hamra Formation and Cambrian R Formation.Based on analysis of source rocks,reservoir and cap rocks in different reservoir forming combinations,it reveals that the reservoir forming combinations are mainly distributed in Hercynian uplift zones and slope zones within the basin.