Sedimentary Facies And Reservoir Characteristics Of The Lower Third Member Of The Sanchunji Area In The Dongpu Depression

The Sanchunji area is located in the south of Dongpu Depression.Due to limited data of well position,complexity of stratigraphic correlations of local structure units,ambiguity of the guiding bed of stratigraphic correlation,limited studies on stratigraphic or sedimentary system,and the reservoir property being unclear in the study area.Based on problems,this paper has the following cognition of the Lower Third Member of the Sanchunji area using the sedimentary reservoir theory and core,logging and other laboratory data.This thesis applies the research approach of"point to face".the Lower Third Member of the Sanchunji area is delta plain and delta front sedimentary subfacies.According to the data,further sedimentary microfacies are divided into the study area and Sedimentary microfacies of the mouth bar are mainly developed.The lithology of the reservoir is mainly lithic feldspathic sandstone.Interstitial matter is mainly dominated by clouds and grey matter.The main clastic particles constituents observed in sandstones are moderate to fine in separation,sub-angular in psephicity.And the grains mainly have line-point contact,particle supported.Diagenesis is mainly caused by compaction,dissolution and cementation.The diagenetic stage belongs to middle diagenetic A stage.The porosity range is from 0.81%to 19.40%,with an average of7.96%.The permeability range is from 0.005 10^-3?m²to20.80×10^-3?m²,with an average of 0.51×10^-3?m².The study area belongs to extra low porosity and ultra-low permeability reservoir.There are four types of reservoirs in the study area,mainly I reservoirs and II reservoirs.