对沾化凹陷馆上段沉积相的新认识

New Understanding of Sedimentary Facies of Upper Guantao Formation in Zhanhua Sag

通过岩心、录井、测井以及地球化学资料的综合研究,提出了该区段为浅水湖泊沉积新认识,并且引用大量的实例从浅水湖泊相的4个沉积特征进行类比验证。提出了确定浅水湖泊岸线的暗色泥岩百分含量方法,并且进一步勾画出沾化凹陷馆上段的沉积相分布。浅水湖泊相的席状砂和垛状滩坝砂体将成为新的有利含油砂体,在后期勘探开发中将起到相当重要的作用。

Former scholars always hold the views that the upper Guantao formation in Zhanhua sag belongs to fluvial deposit.In fact,this viewpoint of being fluvial facies or deposit can not be applied to explain such phenomena as stable distribution of fossil layers,subaqueous sedimentary structure and anticycle structural characteristic,etc.Through comprehensive study on the cores,well logs and geochemical data,the author believes that this upper Guantao formation should be classified as shallow water lacustrine deposit which has been testified by citing a great number of ancient or current cases about four sedimentary characteristics of shallow water lacustrine facies.Especially,a new method for determination the percentage of dark shale in this lacustrine shoreline and more detailed description of the deposit distribution of upper Guantao formation are provided.It is concluded that the discovery of shallow water lacustrine deposit is still a new interim understanding,but the widely distributed thin sand sheet and the lobate bar sands are favorable targets for further petroleum exploration and development.