胜利油田渤南洼陷古近系沙河街组沉积相

Sedimentary facies of the Paleogene Shahejie Formation in the Bonan depression, Shengli Oil Field

渤南洼陷古近系沙河街组为一套冲积 湖泊沉积 ,由曲流河三角洲相、辫状河三角洲相、扇三角洲相、水下扇相和湖泊相组成 ,可分出 14个亚相 ,35个微相 ,其中辫状河三角洲最发育 ,其特征显著 ,明显有别于其它四种类型的三角洲。研究区辫状河三角洲由辫状河三角洲前缘及前三角洲构成 ,辫状河三角洲前缘的主体是由含砾砂岩及中粗粒砂岩组成的水下分流河道砂坝 ,三角洲中交错层理发育 。

The alluvial lacustrine deposits from the Paleogene Shahejie Formation in the Bonan depression, Shengli Oil Field consist of the meandering delta facies, braided delta facies, fan delta facies, subaqueous fan facies and lacustrine facies, including 14 subfacies and 35 microfacies. Among them the braided delta facies is best developed and distinctive from the other types. The braided delta facies comprises the braided delta front subfacies and prodelta subfacies. The braided delta front subfacies consists chiefly of the subaqueous distributary channel bars composed of gravel bearing sandstones and medium to coarse grained sandstones. In the deltas outlined above, there occur the cross beddings, especially the horizontally aggraded cross beddings produced by the lateral migration of the channel bars.