Experimental results on heavy-oil/CO₂ sysytems with regard to phase behavior, PVT characteristics, dynamic extraction, and recovery performance are used to evaluate the effectiveness of CO₂ as a heavy-oil mobilizing additive.

Under preselected pressure and temperature conditions, 360 SCF of CO₂ were found to dissolve in one barrel of the investigated 10° API heavy oil. The resulting swelling factor was 1.12 and the oil viscosity was reduced by a factor of 100. In flood experiments, recovery rates on the order of 5-20% OOIP were ahieved.

In general, up to 40 MMSCF 0f CO₂ per day are needed for a field project. This quantity can be obtained form natural sources or from industrial sources. CO₂ from natural sources is currently the cheapest. Extraction of CO₂ from industrial process gases can be done by physical or chemical methods. Among the chemical methods, the monoethanol (MEA) and the ammonia (NH₃) processes are the cheapest.

A CO₂-steam injection process for heavy-oil recovery requires 200-500 SCF of CO₂ per barrel of steam (water equivalent). The CO₂ can be delivered to the field at 1-2/MSCF. For an added oil recovery factor of 5-10% OOIP, costs of CO₂ may range between $1 and $8 per barrel of incremental oil. The economy and the specific demand on CO₂ should be calculated for each individual field project.