Shear Wave Propagation Characteristics And Influence Factors Analysis Of Complex Pore Medium

Shear wave exploration has great application potential and value in the identification of gas cloud areas.However,most of the current research is focused on the study of P-P and P-SV wave,and the field characteristics of pure shear wave and torsional transverse wave are less studied.Therefore,it is of great significance to study the propagation mechanism of S-wave source field by observing different media with different types of S-wave source.Firstly,by understanding the working principle of shear wave source in laboratory,shear wave transducer and torsional shear wave transducer with the same diameter and frequency were developed in laboratory.Single shot and different azimuths tests were carried out with shear and torsional shear waves in a single layer isotropic medium.On this basis,the single shot test of two dimensional variable offset and variable azimuth Angle are carried out for single layer anisotropic and fluid bearing sand.The experimental results show that the influence of surface waves can be greatly reduced by using torsional s-wave excitation and torsional s-wave reception.Torsional S-wave records are similar to SH-SH test records,and torsional S-wave sources are similar to SH wave sources without polarization characteristics.It is found that shear wave velocity is not sensitive to fluid in the test of fluid containing medium.