High Temperature Rheology Of CO2 Foam Fracturing Fluids

CO2 foam properties were measured to 300_F in a high temperature, high pressure pipe viscometer. The effects of foamer type and concentration on high temperature CO2 foam rheology were determined. It was found that, above a certain level, further increases in foamer concentration provide little corresponding increase in foam stability or rheology. CO2 foam stability can be improved by the use of higher concentrations of gelling agent. Test data indicates that higher concentrations of foamer and gellant are required to produce stable CO2 foams, as compared to N2 foams. It was found that rheological data generated for N2 foams will not be sufficient to describe the same system when pumped as a CO2 foam.