Successful fracturing treatments in ultra low permeability reservoirs require combining the most recent innovations in fracturing technologies. Viscoelastic surfactants, foams and ultra lightweight proppants have specific properties that when combined offer the unique performance required by the demands of fracturing these reservoirs. Inexpensive, logistically simple, polymer-free viscoelastic surfactants provide exceptionally high viscosity under low shear conditions required for proppant transport. They also provide excellent cleanup characteristics. Foamed viscoelastic surfactants provide increased viscosity for frac width, better leak off control and further improve fluid cleanup characteristics, particularly in low pressure reservoirs. Ultra-lightweight proppants provide excellent transport properties in conventional fracturing fluids with minimal viscosity, which ensures desired effective propped fracture conductivity. Utilization of these revolutionary ultra lightweight proppants in foamed viscoelastic fluids provides fracturing treatments with optimum proppant placement and excellent cleanup. As with all successfully applied fracturing fluids the fluid systems must be optimized. These combined systems require significant laboratory testing to successfully characterize and optimize the fluid system for the demands of ultra low permeability reservoirs. This paper focuses on small and large scale laboratory testing performed to optimize these viscoelastic-foamed systems in an effort to test the technical limit of this new technology for future field developments.

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