Study on the macroscopic heterogeneity of the reservoir in Shen-84-An-12 area of the third Member of Shahejie Formation of Peleogene, Liaohe Oilfield

The macroscopic heterogeneity of the reservoir is revealed through the analyses of the plane and spatial distributions, geometric form, porosity and permeability of the sandbodies of the different microfacies in the braided channel delta system in the area. The characteristics of geometric forms and the distribution features of physical properties of the river mouth bar and subqueous gravity flow sandbody, subqueous distributary channel sandbody, braided distributary channel sandbody, crevasse splay and crevasse channel sandbody in the braided channel delta system are emphatically studied. It is held that the reservoir characteristics of this area are that the most sandbodies show positive rhythm, the sedimentary microfacies of the sandbodies vary frequently, there is clear difference in porosity and permeability in single layer; the number of single layer is much, the lateral, vertical, inter-layer and in-layer heterogeneities are all serious. And a conclusion is drawn that the delta front subqueous distributary channel sandbody and delta plain braided distributary channel sandbody in this area reach to the standards of middle-permeability and middle-porosity reservoir, and they are main oil-bearing sandbodies in this area.