Study on Computational Methods of Parameter B and Q_V in Waxman-Smits Model

It is difficult that the shaly sandstone's cation-exchange capacity(QV) and exchanged-cation equivalent conductivity(B) in Waxman-Smits model are calculated exactly by well logging data,which is the main reason why the Waxman-Smits model cannot be widely used in practical reservoir evaluation.The law is analyzed how the temperature affects the parameter B and exchanged-cation maximum equivalent conductivity(Bmax),from which a new calculation method of parameter B is put forward.Based on the statistic analyses of logging data and core sample data,the conventional log data,nuclear magnetic resonance log data and core sample data are used to calcuate the clay's cation-exchange capacity in shaly sandstone,dry clay volume,dry clay matrix density and shaly sandstone's total porosity.And then the QV of the clay sandstone reservoir is calculated.Especially,studied are applications of the nuclear magnetic resonance log data and shale volume calculated from conventional log data.The research results are applied to several blocks in Shengli oilfield where there are lower resistivity payzones.The application effect is fine,that is verified by formation testing data and core sample analysis data.