Sedimentary microfacies to mono-sandstone body in high water cut stage——taking PII oil-bearing formation of Lamadian oil field as an example

While oil field enters into extra high water stage,water-flooding is getting more serious in layer series of development,remaining oil in reservoir rocks becomes high dispersive,which makes tapping potentiality more difficult.In the highly dense well pattern,well logging and drilling core datum are employed to study in detail the sedimentary microfacies to monosandstone body,which provides effective approach for recognizing the distribution of remaining oil.A large amount of well logging and drilling core information demonstrates that SⅡ oil-bearing formation of Lamadian oil field develops delta plain and delta front.Delta plain can be divided into distributary channel microfacies,abandoned channel microfacies,crevasse channel microfacies,sheet sand microfacies,interdistributary microfacies and so on,delta front mainly develops sedimentary microfacies of submerged distributary channel,submerged abandoned channel,submerged crevasse channel,submerged sheet sand and submerged interdistributary.By the division and correlation of depositional time unit,combined with analysis of core datum,logging sedimentary microfacies model is established.On the basis of it,the distribution feature of sedimentary microfacies is made definite and the space-time distribution characters of mono-sandstone body are predicted.It provides important geological foundation for remaining oil forecast and development adjustment of oil fields.