P and S wave anisotropy in fractured media: Experimental research using synthetic samples

• We use new construction method to build synthetic rocks with controlled fractures.
• We corroborate previous study and get more conclusions of fractured media.
• We analyze seismic anisotropy affected by fracture density and fluids.
• Shear wave splitting is controlled by fracture density; the relationship is analyzed.

Rock physics experimental research on fractured media always uses synthetic samples with fractures, but most previous work has used samples of very different material and structure from natural rocks. This study has used a new construction method to build samples with controlled fractures, which have a more realistic mineral compensation and pore structure, similar to natural rocks. A set of samples with different fracture densities was built, and the P and S wave velocities were measured with 0.5 MHz transducers. The measured data were compared with Hudson model predicted results in order to calibrate the theoretical model. P and S wave anisotropies were compared and results demonstrate the accuracy of theoretical prediction of P and S wave velocities and anisotropies influenced by fracture density and fluids. Shear wave splitting shows a strong relationship to fracture density, and the SWS (%) is with around 100 times fracture density.