A synthetic study of such indica。tots as’the mudstone color，sandstone maturity，grain size，sedimentai’y structures and sequences and paleontology indicates that there OCCUr fan— delta facies deposits in‘the first member of the Kongdian Formation in the Zhaoyuan 0订 Field．Six lithofacies。types may be distinguished：red sandstone—mudstone，greyish green bioturbation very fine--fine sandstone，cross—bedding sandstone，graded bedding sand— stone，greyish green and grey mudstone and evaporite．The characteristics of reservoir heterogeneity of the first member of the Kongdian Formation in this area are determinated by these different types of lithofacies．Facies analysis is an important part of the descrip— fion and characterization of a reservoir．