Abstract
The goal of this work is to develop alkaline-surfactant methods to improve recovery from a heavy oil reservoir in the north slope of Alaska. Phase behavior experiments were conducted to determine conditions under which oil-in-water emulsions form. The viscosity (and its shear dependence) was measured for some of these emulsions. Reservoir sand was assembled in sand packs. Water flood and alkaline-surfactant floods were conducted at several salinities. Several relatively hydrophilic surfactants were identified which formed oil-in-water emulsions with the reservoir oil at a low concentration in the presence of sodium carbonate. Emulsions formed at low salinity and high oil-water-ratio. Viscosity of these emulsions was relatively low compared to the oil viscosity. Waterflood recovery was of the order of 20-30% PV and it decreased as the injection rate increased. The alkaline-surfactant flood following the waterflood gave an incremental oil recovery of 20-40 % PV. Alkaline-surfactant floods look promising, but the mechanisms of this flood need to be understood to upscale this process to the field.