利用自然电位和NMR确定Waxman-Smits模型参数的方法

为准确评价低电阻率油气层饱和度,对Waxman-Smits模型中关键参数的定量计算方法进行了系统研究.通过大量岩石物理实验和现场实验,研究了利用自然电位、核磁共振测井技术确定Qv的方法.在自然电位测井资料可靠的情况下,利用自然电位法可准确获得泥质砂岩阳离子交换量;而核磁共振法计算的泥质砂岩阳离子交换量数值偏小.给出了考虑温度影响的阳离子当量电导和考虑泥质影响的胶结指数、饱和度指数的确定方法.利用该方法编制软件,在SUN工作站上对实际资料进行处理,结果表明该方法显著提高了低电阻率油气层饱和度评价精度,在多个油田应用取得了成功.

Determination Method of Waxman-Smits Model Parameters with SP and NMR Log Data

In order to evaluate oil saturation of low resistivity hydrocarbon zone accurately, sys-tematic study was done on quantitative calculation method for key parameters of Waxman-Smits model. Based on a lot of petrophysics experiments and field experiments, a method to get Qv was studied with SP and NMR log data. The Qv can be got by SP log if SP log is reliable. But the Qv calculated by NMR data has less real value. As NMR logging is affected by many factors, it needs further study. Determination methods of cation equivalent conductance, cementation expo-nent and saturation index were given, and the conductance was often impacted by temperature, others by shale. Software was developed based on the above idea and the field log data was pro-cessed on SUN workstation, the results of which showed that the evaluation precision of low re-sistivity reservoir saturation was increased significantly; applications of the method in several oil fields were successful.