Abstract: Interlayers commonly found in the river sand inside, by studying how it is formed, for the restoration of river sand deposition process，reservoir genetic mechanism has an irreplaceable role. Based on the principle of sedimentology analysis, interlayers and sand body is the product of a certain deposition, both closely integrated into a unified whole, by studying the causes interlayers can be assisted genesis of reservoir sand bodies. Different types of channel sand bodies have different internal configuration, the underground reservoir sands internal structure is difficult to directly study, such as changes in its occurrence is difficult to identify, and interlayer is relatively easy to study. Thus, the sand can be studied by studying the interior configuration thin interlayer. Because of its low permeability or permeable, interlayer flooding on oil displacement agent has a certain shielding effect, interlayer internal fluid reservoir seepage can play spoiler, limiting the role. Channel sand reservoir characteristics can be changed according to their internal Interlayer displacement path, influence displacement efficiency, thereby affecting the inner layer of remaining oil distribution, especially for high water cut stage remaining oil distribution in complicated situations, interlayer study can effectively guide field development.