Microfacies Study of No.2 Sand Beds Group of Saertu Servoirs in West Clinoform Region of North Songliao Basin

The characteristics of sedimentary mocrofacies of No.2 sand beds group of Saertu servoirs in the west clinoform region of north Songliao Basin are studied subtly.In the course of research,synthetically is applied up to date theories and methods of sedimentography,and geophysics,with using cores,logging,well logging,seismics,analysis assay data and paleontology data.No.2 sand beds group of Saertu servoirs distributes mainly middle part and east part.It composes mostly of delta facies and lacustrine facies in plane.Delta facies are mainly composed of delta estuarine bars,distal end bars microfacies and filling of erosion valley.Lacustrine facies aremainly composed of shore-shallow lacustrine sand bars and shore-shallow lacustrine mixing beaches mocrofacies.The scale of delta estuarine bars are relatively larger,and their physical properties are comparatively good.Delta estuarine bars are favorable servoirs of oil and gas migrating and gathering.The distribution of filling of erosion valley presents long-wide banding and its area is relatively larger.It connects eastern Qijia-gulong sag and western shore sand bars in Fulaerji region.Sandstones contain generally oil.Filling of erosion valley is important oil-gas migrating channel of Fulaerji servoirs.No.2 sand beds group of Saertu servoirs is overlain by regional caprocks of Nenjiang formation and strata of Nenjiang formation form caprock sealing.