Microfacies Combination and Characteristics of Delta Front within the 4~(th) Member of the Quantou Formation in the Dalaoyefu Oil Field, Southern Songliao Basin

The delta front was developed in Early Cretaceous strata of Dalaoyefu Songliao basin. This paper has studied the variety of microfacies combination, dominated by the channel and mouth bar, in the delta front depositional system. The microfacies combination can be classified into distributary channel area, distributary channel and mouth bar mixed zone and mouth bars area. A detailed study of characteristics of the delta front depositional facies shows that the abundant sandbodies can reflect different sedimentary environments. For example, submerged channels are divided into Abandon Type, Integrity Type and Multi-phase Overprint Type, and the mixed-facies combination is identified; The mouth bar can be divided into Complete Mouth Bar and Stack-mouth Bar. This paper has also discussed the formation mechanism and the model for distribution of the microfacies combinations of the reservoirs in delta front.