Extensional Viscosity of a Water-Soluble Hydrocarbon Stimulation or Enhanced Oil Recovery Polymer

Measuring extensional viscosity is critical for the study of polymers used in hydraulic fracturing or enhanced oil recovery (EOR) because it captures how the polymer behaves under the elongational flow it experiences in the tubular goods that carry proppant to the reservoir, and in the pay zone of the hydrocarbon-bearing formation.

The key reasons these drag reducing polymers are used in hydraulic fracturing stimulations are to reduce the horsepower required to move a set flow rate of stimulation fluid through the tubulars to the pay zone, and to transport proppant, usually sand, to the reservoir.

In addition, as EOR polymer solutions travel through the converging–diverging pore throats of porous rock, they are subjected to strong extensional (stretching) deformation, not just shear. 

Because shear viscosity alone cannot predict these effects, extensional viscosity measurements provide essential information for screening these polymer candidates and anticipating their performance under field flow conditions.