Adding relatively low molecular weight water-soluble friction loss
reduction polymers to an aqueous fluid gelled with a viscoelastic
surfactant (VES) increases the critical generalized Reynold's number at
which the Fanning friction factor increases and friction pressure starts
to increase rapidly. The water-soluble polymeric friction loss reduction
additives lower surface pumping pressure in VES-gelled fracturing fluids
for a given pump rate, thus lowering hydraulic horsepower (HHP)
requirements for pumping fluids downhole, e.g. for hydraulic fracturing
or frac packing treatments of subterranean formations.