What to learn about hydraulic fracturing fluids

Success of a hydraulic-fracture treatment depends on selection of the proper fracturing fluid, among other things. This study reviews the evaluation of hydraulic properties of fracturing fluids. Present-day fracturing fluids are classed as Newtonian, polymer solutions, cross-linked polymer solutions, emulsions, micellar solutions, and gelled organic liquids in solution with a liquefied gas. Fracturing fluids exhibit many different forms of time-independent and time-dependent non-Newtonian fluid behavior. New experimental techniques are required in many instances to evaluate these fluids.A fracturing fluid should be compatible with both rock-matrix material and natural fluids contained within matrix pores. Sometimes salt solutions or acidic water base fluids are used to help prevent damage to the rock matrix by clay swelling. In the case of extreme water sensitivity, an oil-base fluid might be used rather than a water-base fluid. (24 refs.)