T60井高、低阻油层特征及低阻油层识别方法

The Characteristics of High-Low Resistivity Oil Layers and the Identification of Low-Resistivity Oil Layers in Well Tai-60

从高、低阻两类油层的岩性、物性、孔隙结构特征入手,探讨了低电阻率油层形成的原因,认为,束缚水饱和度高及伊蒙混层矿物含量高是形成低电阻率油层的主要原因,在此基础上对高、低阻油层测井响应特征进行了分析,认为低阻油层与邻近泥岩、干层的测井响应特征相似,可应用密度-声波、密度-补偿中子曲线重叠方法,结合三电阻率曲线的相对关系,同时利用有机地化指标的约束,对低电阻率油层进行了有效识别。经试油资料验证,上述方法可以快速识别低电阻率油层。

Based on the features of the two types of reservoirs, the characteristics of lithologieal and physical properties, pore structures and their differences between high- and low-resistivity oil layers are studied for the purpose of effective identification of such oil layers in Well Tai-60. It is suggested that the origin of low-resistivity oil layers is the relatively high irreducible water saturation and high content of illite-montmorillonite mixed-layer minerals. And the low well log response differences between these oil layers show that the well log response of low-resistivity oil layers is similar to those of neighboring mudstones and dry layers. These results are not effectively used to identify the low-resistivity oil layers with conventional logging methods. This paper presents the method by well logs, overlapping density- sonic and density-compensated neutron logging curves, integrated with the relatively relationships among the three resistivity curves as well as the geochemical indices for effective identification of the low-resistiveiy oil layers. The production test data indicate that this method can be used to realize the fast-identification of low-resistivity oil layers.