心滩砂体内部构型及其剩余油分布特征研究

Internal Architecture Structure and Remained Oil of the Channel Bar

喇嘛甸油田PⅠ23沉积单元为辫状河沉积,主要发育辫状河道、心滩、河漫滩三种沉积微相,其中心滩砂体内部构型相对复杂,控制的剩余油较多。以4-4#站高浓度试验区储层为例,运用Mail提出的储层建筑结构界面分析方法,通过小井距井之间的连井剖面和测井曲线对比定义了6级界面。在沉积模式指导下得出了平面相组合模式,即平面以河道充填和心滩沉积为主。在明确心滩砂体沉积环境及形成机理基础上得出了沉积特征及识别方法,并对心滩内部构型进行了解剖,实现了垂积体追踪与预测。利用试验区内新钻井的测井解释结果,一方面完善了心滩砂体内部构型,另一方面新井解释的含油饱和度,水淹特征等信息直接揭示了高浓度聚合物对辫状河心滩的动用规律,位于心滩内部的新井解释结果表明,心滩中部水淹以高、中为主,而心滩两翼岩性夹层多、渗透性差,低、未水淹比例大,剩余油多。

The type of sedimentation unit PI23 in Lamadian Oil field is the braided fluvial river sedimentary environment which concludes three sedimentary microfacies： braided channel,channel bar,flood plain.The inner structure of the channel bar which contains more remaining oil is far more complicated than others.Taking the stratum of 4-4 station in the pilot site of high concentration for example,this paper divided the stratum of Lamadian oil field into six stratifications based on the principle of architecture-element analysis which is put forward by Mail and comparison of the correlation of cross sections and well logs.Based on the model of sedimentary,we have the composite pattern of planar phasing,which is the channel fill and channel bar mainly.Based on the cognition of the sedimentary environment of channel bar and the forming mechanism,this paper also discusses the characteristics of sedimentary and identification method.And it realizes the tracking and forecasting by analysing the inner structure of channel bar.On one hand,by using the consequence of well log interpretation,the inner structure of channel bar is improved,on the other hand,the information of oil saturation and the characteristics of water logging discloses the employmental laws of the braided fluvial river by high polymer flooding.The consequence of interpretation on the inner structure of the channel bar demonstrates that the middle part of channel bar is mainly high and intermediate level water logging,while there are more bands in the rim of channel bar.Hence the permeability there is lower than other parts,and the ratio of low water logging is little higher,so that there is more remaining oil.