Sedimentary Facies Analysis And Sand Body Prediction Of Nm? Oil Group In Bozhong 34-1 Oilfield

Bozhong 34-1 oilfield is located in the central structural ridge of Huanghekou sag,southern Bohai Sea.As a result of the effect of the right strike-slip movement in Tan Lu fault zone,numerous fault blocks and broken anticline traps were formed,complicating the fault system.The lower member of Minghuazhen Formation is the main layer that produces oil and gas,whose reservoir burial depth is between 1000m and 2000m.The sandstone reservoir in shallow water is mainly developed,however,the level of awareness of sand body development law is not mature and effectively predict the law in Nm? oil series is of great importance.Based on the theoretical guidance of different subjects such as Development Geology,Petroleum Geology,Sedimentology,Seismic Sedimentology and so on,this paper accomplished the stratigraphic classification and correlation in Nm? oil series combined with the previous research results by core observation,comprehensive analysis of log and seismic data.Then,on the basis of isochronous stratigraphy framework,the seismic amplitude attribute was extracted with the seismic horizon interpretation results.Subsequently,study on the sedimentary facies and predict the distribution of sand-body in every single layer.Finally,the logging identification mark of river channel sedimentary boundary was summarized and the contact mode of channel boundary on the seismic section was also established.Therefore,we can make the fine characterization of the river channel distribution.Results show that:?According to the existing data analysis and combined with previous research results,we have determined the stratigraphic division scheme of Nm ? oil group in the study area,which is divided into 9 sub layers,namely Nm?-1,Nm?-2,Nm?-3,Nm?-4,Nm?-5,Nm?-6,Nm?-7,Nm?-8,Nm?-9.?the delta front and the delta plain of shallow water delta are mainly developed in the study area,the development characteristics of sand bodies are good,which are mainly from underwater distributary channel and the plain distributary channel.? The logging identification marks of channel sand body boundary were summarized,including the vertical and the lateral mainly.The vertical identification mark is depended on the argillaceous depositional gap,and the lateral's mainly include the top surface difference of channel sand body,the discontinuous change of the sand transverse thickness,the morphological difference of adjacent well logging and the lithology variation.? The channel sand body boundary contacting modes of seismic facies were summarized by combining analysis of logging facies and seismic facies,they are disconnect-type,contact-type and overlap-type.?Through the portrayal of the channel in the development layer of the main sand body,we Found there are 5 large river in the southwest region of the Nm?-5 layer.There are 4 large scale rivers in the northeast region of the study area;And of the Nm?-2 layer,in the southwest region,a total of 3 large rivers are portrayed,and there are 4 large scale rivers in the northeast region of the study area;There are more rivers in the Nm?-1 layer,The southwest region mainly depicts 6 large rivers,and the northeast region mainly portrays 4 large rivers.?Through the production dynamic data,it is effective to predict the Channel sand body by combining analysis of logging and seismic facies,which is conform to the actual underground conditions.