埃塞俄比亚Ogaden盆地侏罗系成藏组合地质特征与勘探潜力

Petroleum Geological Characteristics and Exploration Potential of Jurassic Play,Ogaden Basin,Ethopia

基于对Ogaden盆地侏罗系成藏组合成藏要素的系统解剖,认为其具备较好的油气成藏条件,并预测侏罗系成藏组合可能发育低幅度背斜、断块、鲕粒灰岩、白云岩透镜体、生物礁及局部溶蚀带等多种圈闭类型。在盆地不同部位,圈闭类型有所不同,但将以岩性及岩性—构造圈闭为主。Uarandab组为盆地内最重要的生油源岩,其与Hamanlei组储层上源下储的格局决定了原油侧向运移将处于主导地位,区域性古隆起为最有利富油区。储集体发育与岩性配置特征决定了油气的纵向分布,Hamanlei组中段可获多套源岩供烃,既可形成油藏,又可形成气藏;而Hamanlei组上段主要靠Uarandab组供烃,将主要以临近层序顶面的油藏为主。Calub隆起一带属于区域性古隆起,储层物性条件好,断裂和褶皱发育,被多套源岩生烃区围绕,油气成藏条件配置最佳,是目前最现实的勘探主攻区。

This paper analyzed the petroleum gelogical conditions of Jurassic play in Ogaden Basin,and the research shows that the conditions are favorable for hydrocarbon accmulation.Jurassic play could have many trap types,such as low amplitude anticline,fault block,oolitic limestone,dolomite lens,reef,local corrosin belt,and so on.In different part of the basin,the trap type may have some differences,but most of them will be lithology traps.The Uarandab Formation is the most important oil generation source rock in Ogaden Basin,and it is overlied on the Hamanlei Formation.Latteral migration will play a very important role in the oil accmulation,and regional palaeo uplift is the most favourable zone for oil accmulation.The vertical distribution of hydrocarbon is controlled by lithologic combination of Hamanlei Formation.The Middle Hamanlei Formation could be sourced by several sets of source rocks,so oil and gas pool all could be found.The most important source rock of Upper Hamanlei Formation is the Uarandab mud,and for it has poor interlayer seal,so oil pools are likely to be found near the top of the Upper Hamanlei Formation.The Calub uplift is a palaeo-uplift,reservoirs are best developed,fault and folds are also well developed in this area,and it is also surrounded by mature source rocks.The hydrocarbon accumulation conditions are good around Calub uplift,and it should be the most realistic exploration target.