Abstract: For the study of the development geology , the well logging data are the important materials.The more dense well network , the more precise understanding of reservoir sedimentary characteristics.In this paper the deposition theories were applied to dissect comprehensively oil-layers of high well-density ( 275 wells / km2 ) ZQ development zone by taking full advantage of the extremely rich well materials , the sand body plane and the profile changes after pattern infilling have been analyzed , and then the variation characteristics of the sand body have been summarized : Shrink narrow is primary for channel width variation , sand-body combining form changes from dendrite to mesh , Planar phase change quickly and the sand body distribution is complex.The results further reveal the fluvial facies reservoir in Songliao basin.