Sedimentary Facies In The First Member Of Dainan Formation In Jinhu Sag Of Subei Basin

During the sedimentary period of Dai 1 member of Dainan formation,Jinhu sag in Subei basin developed many types of sedimentary facies,which are very rich in oil and gas resources.In this paper,through the fine study of sedimentary facies in this area,It is expected to provide a strong geological basis for further exploration and development in the study area.Through the close combination of the original stratigraphic division scheme of Dai I member of Dainan formation in Jinhu sag,with reference to the stratigraphic development characteristics of the study area,Comprehensive use of regional geological data,logging,a large number of core data and seismic profile data in the study area,on this basis,under the guidance of Cross' s high-resolution sequence stratigraphy theory,Through the analysis of heavy minerals,clastic components,trace elements and rare earth elements in the study area,the provenance direction of the study area is delineated,and it is considered that the study area is affected by multiple provenances in Dai period.The Zhangbaling uplift in the southwest and the Jianhu uplift in the northwest provide a large number of provenance to the southwest and northwest of the basin.Xiaoguan and cheap areas are affected by the small-scale influence from Tianchang uplift,the low uplift of Lingtang Bridge provides the eastern provenance for Bian Minyang area,and the northern part of the basin is identified for the first time from the northern provenance.On the basis of sequence division scheme and combined with the results of provenance analysis,the sedimentary facies and evolution of Dai 1 member in Jinhu sag are studied.Dai I developed fan delta,braided river delta and lacustrine facies.Through the analysis of the formation mechanism of sublacustrine fan,combined with a large number of core photos and palaeogeomorphological data,the distribution range of sublacustrine fan in each sedimentary period of Dai I was reasonably predicted.The plane distribution law of each facies belt in the first period of Dai period in the study area is described in detail.The sedimentary evolution law of Dai 1 stage is clarified,and the reliable facies model in this area is established,which provides a reliable theoretical basis for the next exploration,production and reservoir evaluation of the oil field.Figure 81;Table 13;Reference 71...