(270f) Interactions of Proppant with Dynamically Complexing, pH-Responsive Viscosity Modifying Agents for Hydraulic Fracture Fluids

Hydraulic Fracturing is now a key technique of extracting unconventional oil and unconventional gas to improve the recovery of oil and gas. One of the essential components of fracking fluid is the viscosity modifying agent, which prevents settling and non-homogenous dispersion of proppant and provides a strong driving force on the proppant to follow the fluid into cracks, fractures, and fissures. It is impossible to acquire adequate and effective transportation of proppants from the ground to the fissure without the system including viscosity modifying agent. Therefore, we report a novel type of viscosity modifying agent based on dynamic binary complexation of a long-chain betaine and amine to actively and reversibly control the settling velocity of proppant. With these viscosity modifiers, the settling velocity of sand could be changed a few orders of magnitudes reversibly by adjusting pH value. The enhanced proppant suspension stability is ascribed to the combination of viscosity effects and attractive intermolecular interactions between the complexes and proppant. Besides, the rheology and interfacial phenomena of the system containing the viscosity modifying agent will be discussed. Furthermore, the proppant settling behavior of these viscosity modifiers has been investigated as a function of temperature and salinity in the conditions relevant to major shale basins in the US to evaluate the potential of applicability in the next-generation hydraulic fracturing fluids.