应用流动带指数提高渗透率的处理精度

Application of "Flow Zone Index" to Enhance the Accuracy of Permeability Processing

夏子街油田夏26-27-35井区的储层为砾岩骨架结构、中间填充砂岩与黏土矿物的复模态复杂储层,岩心分析数据的孔隙度和渗透率数值分散,如不经处理而直接进行回归计算,回归模型的相关系数很低,无法在实际工作中使用。流动带指数是一个把砾岩骨架结构、矿物地质特征、孔喉特征等因素结合起来判定孔隙几何形态的参数,可以准确描述油藏的非均质特征。使用流动带指数作为分类指标,将岩心分析的孔隙度-渗透率数据按照流动带指数进行分类(通常可以分为3类),再对每类中的孔隙度、渗透率数据分别进行回归计算,建立分类回归模型,可得到相关系数很高的渗透率预测模型。实际经验表明,流动性指数的分类数值区间可以选为小于3、大于6,以及3与6之间;流动性指数的数值越大,渗透性越好。使用这种分类回归模型,可大幅提高渗透率的处理精度,便于地质解释和分析。

Xia 26-27--35 well field of Xiazijie oilfield has complex reservoirs with conglomerate skeleton structure and filling with sandstone and clay minerals.The porosity and permeability values from core analysis data are dispersed and can not be used directly in regression calculation without processing because of very low correlation factor.Flow zone index is a parameter of judging pore configuration by the integration of the conglomerate skeleton structure ,mineral geologic characteristics,pore throat features and some other factors,which may de- scribe heterogeneous features of oil reservoir accurately.This paper adopts flow zone index as a classification in- dex to classify porosity-permeability data,which can be usually classified into three categories;after the classifi- cation,the porosity and permeability data are calculated respectively to establish regression models,thus a predictive model of permeability may be derived with very high correlation factor.Actual experiences show that the value of the flow zone index may be less than 3, more than 6 and from 3 to 6,and more value better permeability.This regression model using flow zone index as classification index can greatly enhance permeability processing accuracy to facilitate geologic interpretation and analyses.