鄂尔多斯盆地吴起地区长10段复杂油水层测井识别方法

Logging Identification Method of Chang 10 Member Complex Oil-water Layers in Wuqi Area of Ordos Basin

鄂尔多斯盆地吴起地区延长组长10段为主要的含油层系,储层非均质性强、地层水矿化度变化大,油、水层测井响应关系复杂,流体性质识别困难,测井解释符合率低。利用地质、测井、分析化验和试油等资料,分析了中高阻水层成因机理,认为地层水矿化度低、高阻填隙物体积分数高是导致油水关系复杂的主要原因。基于阿尔奇公式,利用常规测井资料反演了视地层水电阻率及视地层水电阻率谱,拾取了视地层水电阻率谱均值、方差及歪度等特征参数,创新构建了地层水特征指示参数和岩性非均质性表征参数,建立了基于岩性和水性的流体性质识别方法。应用结果表明,测井解释符合率大幅度提高,效果显著。

Chang 10 Member is the main oil-bearing layer of Yanchang Formation in Wuqi Area of Ordos Basin,which is characterized by strong reservoir heterogeneity,great variation of formation water salinity,complex logging response relationship between oil and water layer,difficult fluid property identification,and low logging interpretation compliance rate.Based on the geological,logging,analytical and well-testing data,and through the analysis of the genetic mechanism of the middle and high resistivity water layer,it is concluded that the low salinity of the formation water and the high volume content of the high resistivity interstitial materials are the main reasons for the complex oil-water relationship.Based on Archie formula,the resistivity and resistivity spectrum of apparent formation water were inverted by using conventional logging data,the characteristic parameters such as mean value,variance and skewness of resistivity spectrum of apparent formation water were picked up,the formation water characteristic indicator parameters and lithologic heterogeneity characterization parameters were constructed,and a method for fluid property identification based on lithology and water was established.The application results show that the coincidence rate of log interpretation is greatly improved and the effect is remarkable.