DeltaFront Sandbody Genetic Assemblages and Their Distribution Patterns of the 4th Member of Quantou Formation in Dalaoyefu Oilfield, Southern Songliao Basin, China

Key words: 
• shortterm baselevel cycle /
• genetic assemblage /
• delta front /
• Dalayefu Oilfield /
• Songliao Basin

Abstract: Taking the 4th member of Cretaceous Quantou Formation in Dalaoyefu oilfield in Songliao Basin as Example, by using the shortterm baselevel cycle theory of high resolution sequence stratigraphy, the paper shows the variety of genetic assemblages of reservoir rocks in delta front depositional system that was dominated by the distributary channel and mouth bar. It can be classified as “distributary channel genetic assemblage” “distributary channel and mouth bar hybrid genetic assemblage” and “mouth bars genetic assemblage”. Based on a detailed characterization of these genetic assemblages, the abundant genetic assemblage can reflect different sedimentary environments, for example, submerged distributary channels genetic assemblage are divided into Abandoned Type, Integrity Type and Multiphase Overprint Type; mouth bar genetic assemblage can be divided into Complete Mouth Bar and Stackmouth Bar, and the hybrid genetic assemblage is identified. The analysis shows that these sandbodies are evidently controlled by the changing of shortterm baselevel and the relation of the accompanied accommodation and sediment alimentations. On the basis of the above, this paper has also discussed the distribution model of the genetic assemblages in delta front in chronostratigraphic framework.