Fig. 1. Double-cylindrical-layer porous medium electrokinetic effect logging model.柱状双层孔隙介质声电效应测井模型

Fig. 2. Branch point distribution of the vertical secant integral.垂直割线积分支点分布示意图

Fig. 3. Normalized interface converted electromagnetic waveform of double-cylindrical-layer medium.柱状双层介质界面转换电磁波归一化波形

Fig. 4. Comparison of electrokinetic logging interface converted electromagnetic wave waveforms between two-layer medium and single-layer infinite medium: (a) Interface converted electromagnetic waveform when porous medium 1 parameters are consistent with single layer infinite medium; (b) interface converted electromagnetic wave when double-layer medium degenerates into single-layer medium (the solid line corresponds to the single-layer infinite medium, the dashed line corresponds to the double-layer medium).双层介质与单层无限大介质声电测井界面转换电磁波波形对比　(a)孔隙介质1与单层无限大介质参数一致时的界面转换电磁波; (b)双层介质退化为单层介质时的界面转换电磁波(实线对应单层无限大介质, 虚线对应双层介质)

Fig. 5. Interface converted electromagnetic wave waveforms of different interlayer medium thickness (the solid and dashed lines correspond to the interlayer dielectric layer thickness of 5 m and 7 m, respectively).不同夹层介质层厚的界面转换电磁波(实线和虚线分别对应夹层介质层厚5 m和7 m)

Fig. 6. Arrival time difference of different components of the interface converted electromagnetic wave: (a) Component b; (b) component c; (c) component d (the solid and dashed lines correspond to the interlayer medium thickness of 5 m and 7 m, respectively).界面转换电磁波不同成分到时差　(a)成分b; (b)成分c; (c)成分d (实线和虚线分别对应夹层介质层厚5和7 m)

Fig. 7. Interface converted electromagnetic wave waveforms under different porous medium fluid salinity: (a) Interface converted electromagnetic wave waveforms of different interlayer porous medium fluid salinity (solid line, dashed line, dash-dotted line corresponding to interlayer porous medium fluid salinity C₁ = 0.01, 0.005, 0.0025 mol/L respectively); (b) interface converted electromagnetic wave waveforms of different outermost porous medium fluid salinity (solid line, dashed line, dash-dotted line corresponding to outermost porous medium fluid salinity C₂ = 0.01, 0.005, 0.0025 mol/Lrespectively). 不同孔隙介质流体矿化度下的界面转换电磁波波形(a)不同夹层孔隙介质流体矿化度的界面转换电磁波波形(实线, 虚线, 点划线分别对应夹层孔隙介质流体矿化度C₁ = 0.01, 0.005, 0.0025 mol/L); (b)不同最外层孔隙介质流体矿化度的界面转换电磁波波形(实线, 虚线, 点划线分别对应最外层孔隙介质流体矿化度C₂ = 0.01, 0.005, 0.0025 mol/L)

Fig. 8. Waveform comparison of interface converted electromagnetic wave waveforms of different salinity interface position (the solid line corresponds to the interface converted electromagnetic wave when there is no salinity interface, the dashed line and the dash-dotted line respectively correspond to the interface converted electromagnetic waves when the salinity interface is 5 m and 6 m away from the well wall).不同矿化度界面位置的界面转换电磁波波形对比(实线对应不存在矿化度界面时的界面转换电磁波, 虚线和点划线分别对应矿化度界面距离井壁5 m和6 m时的界面转换电磁波)

Fig. 9. Effect of salinity difference on interface converted electromagnetic waves (the solid line, the dashed line and the dash-dotted line respectively correspond to the salinity difference of 0.0005, 0.0015, 0.0025 mol/L). 矿化度差异对界面转换电磁波的影响(实线, 虚线和点划线分别对应矿化度差异为 0.0005, 0.0015, 0.0025 mol/L)

Table 1. Porous medium and borehole fluid parameters.