Abstract:The inner interlayers are the main causes for forming multi-layer reservoirs with strong heterogeneity, which control the remaining oil distribution. Velasquez oilfield is located in the central part of Magdalenda basin in Columbia, and the paleogene group G sandstone reservoirs are of braided channel deposition. Muddy interlayer and interlayer of physical property are developed in the G reservoirs in Velasquez oilfield. Muddy interlayer consists mainly of flood argillaceous sediments, with the porosity less than 5%, and the permeability less than 1×10-3μm2. The porosity of physical interlayer is less than 11.3%, and the permeability is less than 23.3×10-3μm2. Two models for interlayers are built in order to identify interlayers in the whole area and to carry out lateral correlation. According to their planar distributions, the interlayers in the study area are divided into the steady, sub-steady and stochastic types, and then their interwell distributions are predicted by using the methods of interwell correlation, lower limit of physical property control and conditional simulation, respectively, in order to build the interlayer 3D distribution model and provide foundations for predicting remaining oil distribution. The method enjoys the necessary accuracy for the high water-cut reservoir interlining.