EP-A油田岩石分类及储层流动单元研究

Research on Rock Classification and Reservoir Flow Units for EP-A Oilfield

储层流动单元划分对认识油藏的非均质性、注水开发效果和剩余油分布规律研究提供了有效手段。EP-A油田处于开发初期,存在两个问题有待解决:一是没有明确的孔渗关系,如果使用单一的孔渗关系计算渗透率,储层非均质性会被忽略,开发过程中历史拟合和开发指标预测也会受到影响;二是如何将岩石分类结果运用在三维地质模型中。本次研究运用岩心观察和实验数据进行岩石类型精细划分,共分为三类,每一类岩石类型给予相应的孔渗关系,并运用相应的孔渗关系计算渗透率,解决了储层非均质性无法准确表征渗透率的难题。在取心井上建立岩石类型与电性特征的关系,采用神经网络方法运用到非取心井中,进而运用到三维地质模型中,通过流动带指数(FZI指数)进行流动单元划分,从而有利于动态历史拟合,使下一步调整井的开发指标预测更加合理,降低了潜在开发风险。

Reservoir flow unit division provides an effective means for understanding reservoir heterogeneity,waterflooding effect and remaining oil distribution rule.EP-A Oilfield is in the early development period.There are two problems to be solved.One is that there is no clear porosity-permeability relationship.If single porosi-ty-permeability relationship is used to calculate permeability,the reservoir heterogeneity will be neglected,and history matching and development index forecast will be affected in the development process.The other is that how to apply rock classification results to three-dimensional geological model.In this study,core observation and experimental data were applied to detailed classification on rock types.Three types were divided.Each rock type has corresponding porosity-permeability relationship,which is used to calculate the permeability.This method solved the difficulty of accurate permeability characterization by the reservoir heterogeneity.The relationship be-tween rock types and electrical characteristics was established for the cored wells.The neural network method was applied to non-cored wells,and then to the three-dimensional geological model.The flow units were di-vided by flow zone index( FZI), which is beneficial to dynamic history match and will make the develop-ment index forecast of the adjustment wells more reasonable and reduce the potential development risk.