济阳坳陷新生界岩性油气藏特征及油气富集条件

济阳坳陷是一个富含油气的新生代断陷一坳陷盆地,不同区带上岩性油气藏的富集需要同时具备3个基本条件.1）丰富的油源是油气富集的物质条件,济阳坳陷发育多套有效烃源岩,其层系厚度大,分布面积广,资源规模大,与储集砂体之间具有利接触关系.2）优质的砂岩体岩性圈闭是油气富集的聚集条件,应具有圈闭规模大、发育有利的储集相类型和良好储集层的特点.圈闭规模大表现为大规模砂岩体岩性圈闭或数量众多的小型岩性圈闭叠合连片,有利的储集相主要集中在少数3种类型即（扇）三角洲相、浊积扇相和河流相,其中各类储集相的扇中亚相最有利于油气聚集,良好的储集层表现为具有好的砂体类型,并与次生孔隙带形成匹配.3）汇流通道的存在是油气富集的输导条件,充足的油气通过断层汇流通道和孔隙（裂隙）汇流通道运移,在砂岩体圈闭聚集成藏并形成油气富集.因此,济阳坳陷岩性油气藏表现出主元富集的特征,即上述的3个基本条件控制了油气在部分次级单元的少数区带发生富集.

Characteristics and enrichment conditions for Cenozoic lithological reservoirs in the Jiyang Depression

The Jiyang Depression is a Cenozoic rifted basin full of oil and gas.In different zones, there are apparent differences on the degree of hydrocarbon enrichment.There might be three conditions of enrichment for lithological reservoirs in the depression.1)Rich oil resources were substantial conditions of hydrocarbon enrichment,because there were many sets of source rocks with huge thickness, widespread distribution, large resource extent and favorable contact relation between sandbodies.2)High quality sandbody lithological traps were accumulating conditions of hydrocarbon enrichment.These traps should have characteristics of large-scale,favorable types of reservoir facies and favorable reservoirs.Large-sized sandbody lithological trap or many overlaying small-sized lithological traps were forms of expression for large-scale traps.Favorable reservoir facies involved fan delta,sublacustrine fan and river facies.In these fades, the middle of fan was the best place for hydrocarbon enrichment.Favorable reservoirs characterized with good types of sandbody and matching induced porosity.3)Confluence pathway was carrier condition of hydrocarbon enrichment.Abundant hydrocarbon enriched in high quality sandbody traps by fault confluence pathway and porous(or crack)confluence pathway which were important factors for hydrocarbon enrichment.So the conditions of enrichment in the Jiyang Depression displayed the characteristics of major factors.Three basic conditions controlled the formation of enrichment.To the distribution of hydrocarbon in space,only few districts could form the enrichment.