陆相湖盆可容空间变化与油气的关系

The Relationship between Accommodation Space Changes and Oil-Gas Reservoir

以松辽盆地上侏罗统—白垩系为例,综合利用钻井、岩心和地球化学资料对陆相盆地中可容空间的变化与油气的关系进行了研究。青山口组一段,嫩江组一、二段沉积时期,由于可容空间短期内急剧增加,导致有机碳含量高、有机质类型好的生油岩广泛发育;构造和气候周期性变化产生的可容空间变化,控制着生储盖组合特征并发育下生上储顶盖型和上生下储型等生储盖组合;可容空间变化控制着层序演化和体系域分布,其中低水位体系域的盆底扇和斜坡扇最有利于油气聚集。

Taking Upper Jurassic-Cretaceous strata in Songliao basin as a research target,the relationship between the accommo -dation space changes and oil-gas reservoir in lacustrine basin is studied by way of comprehensive explanation of geochemical,drilling and core data.During the deposition of the first member of Qingshankou formation and the first-second members of Nen-jiang formation,tremendous growth of the accommodation space resulted in wide distribution of source rocks with high organic carbon content and good organic matter type.The accommodation space change caused by periodically tectonic and climatic changes controlled the characteristics of source-reservoir-caprock assemblage,and formed some types of different assemblages with source bed in ancient formations and reservoir bed in recent formations as well as source bed in recent formations and reservoir bed in ancient formations.Also,the accommodation space changes controlled the evolution of sequences and the distribution of system tracts,in which base fan and slope fan of lowstand system tracts are the most favorable for the oil and gas accumulations.