Study On Reservoir Architecture And 3D Model Of The PI2 Braided River Reservoir In Lamadian Oilfield

The middle west-2 area in south block of Lamadian oilfield is located in the northern part of Daqing Placanticline in the central depression of Songliao Basin.The 2th layer of Putaohua I reservoir group is a typical braided river deposit in study area,the comprehensive moisture content is nearly 95% in this area.There are great importance for us to do the detailed study of reservoir building structure,the establishment of accurate three-dimensional geological model,and the analysis of the factors affecting the distribution of remaining oil.This study plays an important role in oilfield development and prediction of remaining oil,and provide theoretical basis for oil field to adjust measures.Based on the geological characteristics of the study area,on the basis of comprehensive field and satellite data,this paper integrates core,logging and drilling data to carry out fine stratigraphic division and correlation work.O n the basis of the study of reservoir architecture,the braided river deposits in the study area are divided into level three,which contains: core beach,braided channel and flood plain.Log recognition models are established to separate139 wells in the whole area into single-well and single-sand bodies,which are divided into three types of single sand bodies: braided river diara,braided river channel and flood plain.Based on the consideration of 5 criteria of lateral delimitation and 3 plane constraints,the model of unit level distribution of each sub-layer with level four architecture is set up,which provides a good preparation for the following work.On the basis of establishing the distribution pattern of the single sand body,according to the sedimentary model and the migration laws of the diara,it is found that the size of the diara body of the three-phase deposition diara is obviously reduced,and the braided river channel has obvious widening,but the characteristics of the "narrow channel of wide dam" are still presented in the whole.The diara is designated as the diara head,the diara tail,the diara wing and the main diara in the plane,and the vertical accumulation body and the silt layer are vertically arranged in the vertical direction.And the semi-quantitative recognition mode o f the interbed is established by utilizing the intersection map and the log return on the characterization of the interbed.The influence factors of the remaining oil distribution are considered from two aspects of the reservoir and the interbed at the well point scale,and the remaining oil enrichment degree is found to be positively correlated with the permeability level difference,the interbed thickness,the interbed frequency(after more than 0.5),and the remaining oil distribution composite prosody> positive rhythm> anti-prosody,There was no significant difference in the remaining oil distribution in the study area.In this paper,the multi-scale geological knowledge base is set up by combining the research results of the early stage and the modern sedimentary and multi-method of the satellite photo,and the preparation for later modeling is made.All kinds of scale data are integrated,the idea of facies-control modeling,level modeling and multi-method comprehensive modeling is adopted,and the accurate construction model is established by using the seismic data,and the method of deterministic modeling is selected to establish the lithofacies model under the 4-level architecture scale.Because the calcium interbed in the study area is only 4.5%,the division of the physical property interbed and the actual working area of the argillaceous interbed is low,the interbed is normalized and treated as a barrier layer,the interbed model with the accuracy of 86.8% is established according to the constraint of the early geological knowledge base and the scale and lithofacies model of the 4-level architecture,The three-dimensional geological model of the study area is obtained by uniformly assigning the interbed to the lithofacies model and the attribute model.The model is basically in good agreement with the actual situation of the study area through the geological law and the parameter distribution test,and has high reliability.