Shear-wave splitting, also known as shear-wave birefringence, has been used widely to evaluate subsurface anisotropy. Yet, the effect of stress and fluid saturation on S-wave anisotropy is still not well understood. We present a laboratory study carried out on a Bentheim sandstone sample subjected to different stress and saturation conditions. The S-wave stress-induced anisotropy of the sample is measured using a laser Doppler interferometer (LDI), which allows us to estimate the particle displacement vector at the central point onto the surface of the sample. Based on the derived hodograms, we infer the polarization of the fast S wave and the degree of the S-wave anisotropy. For the dry sample, we observe a shift of the polarization direction toward the direction of the applied stress and an increase of the anisotropy degree in some cases, most likely due to the preferential opening of cracks in the direction along the applied stress. For the water-saturated case, no significant change in the S-wave anisotropy is observed.

You do not have access to this content, please speak to your institutional administrator if you feel you should have access.