Physical modeling of fluid-filled fractures using the dynamic photoelasticity technique

Abstract

We have developed an optical apparatus based on the dynamic photoelasticity technique to visualize and analyze the propagation of the Krauklis wave within an analog fluid-filled fracture. Although dynamic photoelasticity has been used by others to study seismic wave propagation, this study adds a quantitative analysis addressing dispersion properties. We physically modeled a fluid-filled fracture using transparent photoelastic-sensitive polycarbonate and nonsensitive acrylic plates. Then we used a pixel-based framework to analyze the dispersion of a Krauklis wave excited in the fracture. Through this pixel-based framework, we thus demonstrate that the dynamic photoelasticity technique can quantitatively describe seismic wave propagation with a quality similar to experiments using conventional transducers (receivers) while additionally visualizing the seismic stress field. We observe that an increase in the fluid viscosity results in a decrease in the velocity of the Krauklis wave. We also determine the capability of the method to analyze seismic data in the case of complex geometry by modeling a sawtooth fracture. The fracture’s geometry can strongly affect the characteristics of the Krauklis wave as we note a higher Krauklis wave velocity for the sawtooth case, as well as greater perturbation of the stress field.