Effects of polymer solutions on hydraulic fracture

Polymer solutions are widely used in hydraulic fracturing operations to enhance proppant transport, suppress turbulence, and reduce fluid loss. However, how their properties influence the local flow field and fracture dynamics, especially in the rapidly evolving region near the fracture tip, remains poorly understood. This study investigates the coupled fluid flow and fracture behavior near the tip of a propagating hydrofracture driven by polymer solutions using high-speed imaging within a transparent, three-dimensional-printed polymethyl methacrylate model. Solutions of high-molecular-weight polymers induce flow and fracture behavior that closely resemble those of water, while viscous Newtonian fluids produce different behavior. This is attributed to pronounced shear thinning, which significantly lowers the effective viscosity under high shear and hence alters the local flow field and stress distribution near the fracture tip. These findings underscore the importance of fluid rheology in shaping both flow patterns and fracture development during hydraulic fracturing.