Research On Residual Oil Distribution Of Meandering River Point Bar Based On Reservoir Numerical Simulation

Meandering river point bar is one of the most important reservoir unit incontinental reservoir,studyingit's architecture has important theoretical and practical significance,which will benefit the high efficient development and improvement the recovery factor of oil and gas fields.At present,using the graphic information of modern sedimentary and a few outcrop have reached a consensus on the surface morphology and migration processpoint of barin academic circles.However,there are many doubts on three-dimensional distribution of point bars' lithofacies,and the research on the distribution of remaining oil is not enough,these problems are mainly controlled by the studying methods.Therefore,this paper takes a point bar reservoir in DaQing oil field as an example,establishing three-dimensional geological model of point bar with the Petrel software,and carrying out the numerical simulation of remaining oil distribution of meandering river point bar with Eclipse software.First of all,applying the large number of information,which come from outcrop,satellite images,logging,core,dynamics and literature,to sum up the qualitative and quantitative data of point bars.Second,on the basis of sedimentary process and the stochastic modeling technology,mainly using the simulation method based on geometry,combined with the empirical formula of the meandering river morphology parameters and coring data,and setting curvature as 1.88,the length meandering river point bar as 700m,width as 900m,the width of abandoned channel as 104m,the thickness of point bar as 6m,the thickness of abandoned channel as 5.6m,the dip of lateral accretional layers as 5°?12°,average is 7°,the average migration rate of channel as 50m/year.Furthermore,applying the cosine curve to simulate the geometry of lateral accretional layers,and setting extension length ratio of lateral accretional layers between 88.9%and 46.6%,thus establishing point bar three-dimensional geometric model.Then,according to the core data,the point bar exhibits fining-upward lithologic successions.Medium sand,fine sand,silt and clay respectively,whose proportion is 17.5%,36.1%,17.8%and 28.6%.the clay is distributed in flood plain,abandoned channel and lateral accretion layers,thus the 3D facies model of point bar is set up.Finally,on the basis of core and logging data,setting different permeability value and porosity value to lithology,and establishing the three-dimensional property model,thus finishing 3D geological models of eleven point bars.On the basis of three-dimensional geological models of point bars,carrying out its numerical simulation.First of all,suming up point bars' oil-water relative permeability data,fluid and rock properties data,production dynamic data and well data,etc.Then,importing the related data establishs the numerical simulation,and making the whole region history matching and single well history matching.Finally,supported by reliable history matching and five point injection pattern,a total of 12 wells,has launched water-injection development forecast simulation of eleven point bars.The numerical simulation results show that the five main contents.First,with the decrease of the extension length of lateral accretional layers or with the enhancement of connectivity of lateral accretional sands,the recovery ratio of oil increases continuously,as well as the amount of crude oil and the amount of residual oil.Contrarily,the amount of remaining oil shrinks continuously.When the extension length ratio of lateral accretional layers be the maximum value 88.9%,the amount of remaining oil is maximum,and the total amount of crude oil that was not produced is 2.69×105 SM3,when the extension length ratio of lateral accretional layers be the minimum value 46.6%,the amount of remaining oil is minimum,and the total amount of crude oil that was not produced is 2.38×105 SM3.Second,the volumetric reserve of remaining oil are mainly concentrated in the fine sand and silt in the upper part of the point bar,and it is the smallest in the bottom of the point bar.Third,the lateral accretion layers has a stronger blocking effect for injection water in the transverse source direction than along the source direction.Fourthly,when different extension length of lateral accretional layers exist in the same point bar,the smaller that the lateral accretional layers' length be,the more weak its blocking effect for remaining oil,so that the remaining oil is mainly enriched in lateral accretional sands which is close to the lateral accretional layers whose extension length is larger.Fifty,the main factors that influence the distribution of remaining oil is extension length of the lateral accretional layers,followed by difference of permeability and injection-production pattern.