北非切里夫盆地油气成藏组合及勘探方向

Hydrocarbon Accumulation Assemblages and Exploration Targets in Cheliff Basin in North Africa

北非切里夫(Cheliff)盆地为中、新生界叠合盆地,以海相石灰岩、白云岩和滨岸砂岩沉积为主,资料证实白垩系泥灰岩有机质丰度高,为主要烃源岩。其有机质类型、热演化程度均表明该套烃源岩处于生烃成熟阶段,中新统海相滨岸砂岩为主要储层。盆地主要成藏组合划分为白垩系石灰岩、砂岩和泥灰岩自生自储成藏组合、白垩系—中新统下生上储成藏组合、中新统自生自储成藏组合。提出了盆地的下一步勘探方向:位于切里夫盆地Tliouanet隆起埃利赞弧形带和主力生烃坳陷的中央低隆背斜带是下一步勘探的有利区带;北部山前背斜带也是较为有利的勘探区带,可作为勘探的接替区。

Cheliff Basin is a superimposed Mesozoic-Cenozoic basin and it is mainly dominated by marine limestones,dolostones,and onshore sandstones. According to the data,the Cretaceous mudstones are the major hydrocarbon source rocks with high abundance of organic matter.The types of organic matter and the degree of thermal evolution show that the Cretaceous mudstones have entered into the stage of hydrocarbon generation,as well as the Miocene marine and onshore mudstones are major reservoirs.The major hydrocarbon accumulation assemblages of the basin can be classified into the self-generating and self-preserving assemblage of Cretaceous limestones,sandstones,and mudstones,the Cretaceous-Miocene lower-generating and upper-preserving assemblage,and the Miocene self-generating and self-preserving assemblage.The targets for further exploration in the basin are proposed.The central anticlinal zone with lower uplifts in the Relizane arcuate zone and the major source depressions of Tliouanet uplift is the favorable zones for further exploration.T.he piedmont anticlinal zone north of the basin is relatively a favorable zone for exploration and it can be a replacement area for exploration.