Study On The Sedimentary Facies Of The Third Member Of Quantou Formation In The Fuxin Uplift,Songliao Basin

The Fuxin Uplift in the south of Songliao Basin contains 6 oilfields,such as Fuyu oilfield and Xinli.oilfield.Since the Yangdachengzi oil reservoir in the third member of Quantou Formation of Lower Cretaceous was regarded as the minor drilling target for a long time in the Fuxin Uplift,there is no systemic research on the sedimentary facies of the third member of Quantou Formation in recent years,and the types of sedimentary facies and the distribution of the sandy bodies are still undefined,which severely constrained the further exploration and development in this area.High resolution stratigraphy was combined to analyze the stratigraphic division and correlation,based on which the microfacies type and the vertical and horizontal distribution of sand y body in this area were studied.Then the evolution of sedimentary facies was analyzed.Finally,the sedimentary facies model was established,which will provide a re ference for the further exploration of oil and gas in the third member of Quantou Formation in the Fuxin Uplift.Based on the core,well logging and seismic data,directed under the high resolution stratigraphy,six long-term base level cycles were recognized in the Lower Cretaceous,of which Quantou Formation developed a descending half cycle and a rising half cycle.The fine stratigraphic division and correlation of the third member of Quantou Formation within the sequence framework was carried out by recognizing the boundaries of each sand group and layer.As a result,the third member of Q uantou Formation were divided into 6 sand groups and 17 layers.According to analysis of core facies,the single well facies,profile well facies,seismic attribute extraction,combining with the heavy mineral analysis,stratigraphic distribution and sand thickness map comprehensivly,the third member of Q uantou Formation in the Fuxin Uplift developed a set of meandering river-delta sedimentary system.The main provenance direction of this area is from the southwest,while the secondary source is from the southeast.By analyzing the paleo-tectonics,paleoclimate and paleogeography of the study area,two sedimentary models were established in the early and late period of the third member of Q uantou Formation in Fuxin Uplift,namely the sedimentary models dominated by the early meandering river and the late meandering river delta.The stable tectonic setting in the region,the climatic co nditions from semi-arid to semi-humid and the stable source supply provided a sediment basis for the transition from the meandering river sedimentary environment to the shallow water delta sedimentary environment.