## 4 Conclusions  
Borehole SH wave and its coupling electric field make the waveform relatively simple and hence easy to analyze. SH-TE seismoelectric response is one of the potential logging methods. In this paper, based on the available studies on SH-TE seismoelectric responses [52, 53, 68], we investigate the special response law for fluid salinity and focus on the physical mechanisms. The following main conclusions and understandings are the results of this investigation:  
1. The salinity of the pore fluid has a significant effect on the induced electric fields of the SH waves. The electrokinetic coupling effect is weakened with the increasing pore fluid salinity level. The attenuation of electromagnetic waves monotonically increases with the increase of pore fluid salinity. The borehole electric field response amplitude decreases with the increasing formation's salinity. The monotonic change \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline  & \multicolumn{3}{c}{\(G^{o}\) = 14.41 Gpa, \(V_{ST}\) = 2492.2 m/s} \\ \hline \(V_{SR}\) (m/s) & \(d_{T}\) (m) & \(\delta t_{T}\) (ms) & \(\delta t_{R}\) (ms) & \(d_{R}\) (m) & Error (\%) \\ \hline  & 0.7 & 0.232 & 0.222 & 0.679 & 3.00 \\  & 1.0 & 0.353 & 0.343 & 0.980 & 2.00 \\  & 1.3 & 0.473 & 0.464 & 1.285 & 1.15 \\
2512 & 1.5 & 0.553 & 0.546 & 1.491 & 0.60 \\  & 1.7 & 0.634 & 0.623 & 1.672 & 1.64 \\ \hline  & \multicolumn{3}{c}{\(d_{T}\) = 1.5 m} \\ \hline \(G^{o}\) & \(V_{ST}\) (m/s) & \(V_{SR}\) (m/s) & \(\delta t_{T}\) (ms) & \(\delta t_{R}\) (ms) & \(d_{R}\) (m) & Error (\%) \\ \hline
13.21 & 2386.2 & 2393.1 & 0.578 & 0.568 & 1.479 & 1.40 \\
15.41 & 2577.3 & 2571.9 & 0.535 & 0.526 & 1.472 & 1.86 \\
20.51 & 2973.3 & 3032.7 & 0.464 & 0.453 & 1.493 & 0.47 \\
25.12 & 3290.5 & 3325.6 & 0.419 & 0.410 & 1.483 & 1.13 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Inversion results of interface position. of the amplitude is an advantage of using borehole SH-TE seismoelectric waves for pore fluid salinity monitoring. 2. Borehole fluid salinity hardly influences the borehole electric field response. This special influence mechanism is caused by the low-frequency band and the nature of the SH acoustic source. There is no need to artificially match the borehole fluid salinity with the formation's salinity when using the SH-TE logging method. 3. The SH acoustic wave does not respond to the salinity interface, but the electric field responds significantly to it. When the SH wave passes through the salinity difference interface, the electromagnetic interface responses that propagate with the electromagnetic wave speed are observed. Estimation of electrical interface position shows that the SH-TE coupling physical effect is a potential method for detecting the position of the electrical interface next to a borehole. When there is water pollution in a small area next to the well, the elastic properties of the formation next to the well may not be changed. It is effective to use the converted electric field of acoustic waves to judge the nature and location of groundwater. 4. The model used in this investigation is somewhat idealized. For example, exciting a pure SH wave downhole is still a challenging task. The fluid salinity on two sides of an interface is not expected to change abruptly; most of them are gradual. Besides, in normal circumstances, the earth is a horizontally layered medium. The problem of seismoelectric logging in horizontal layered porous media is one of the important issues for our future research. W.W.: Writing--original draft, Conceptualization, Methodology, Formal analysis. W.G. : Methodology, Formal analysis. J.L. : Funding acquisition, Methodology, Software. T.K. : Writing--review and editing, Z.C. : Supervision, writing--review and editing, Conceptualization, Methodology, Resources. All authors have read and agreed to the published version of the manuscript. This work was supported by the Natural Science Foundation of Jilin Province of China (Grant Nos.