The complete paper presents recent results from a rigorous pilot-scale demonstration of natural-gas (NG) foam over a range of operating scenarios relevant to surface and bottomhole conditions with a variety of base-fluid mixtures. The NG foams explored in these investigations exhibited typical shear-thinning behavior observed in rheological studies of nitrogen- (N2) and carbon-dioxide- (CO2) based foams. The measured viscosity and observed stability indicate that NG foams are well-suited for fracturing applications.
Test Facilities
Two test facilities were used to explore properties of NG foams at a variety of relevant operating conditions to determine whether NG foam is a suitable alternative to typical water-based fracturing fluids.
Pilot-Scale Foam-Test Facility. The pilot-scale foam-test facility (PFTF) is a single-pass pilot plant used to generate and characterize foams at conditions relevant to surface and reservoir conditions. The facility is capable of generating aqueous and oil-based foams using a variety of gases for the internal phase [e.g., methane (CH4), N2, and CO2]. Foams can be characterized at pressures up to 7,500 psi and temperatures up to 300°F. A key benefit of the PFTF is that it can be used to demonstrate new or challenging foaming processes before large-scale or field demonstrations.
