Laboratory results of the effect of sodium silicate in steam injection processes

In Venezuela, the feasibility of using alkaline solutions to increase the heavy oil recovery in steam injection processes has been recently under evaluation. This approach takes advantage of combining the thermal effect given by the steam and the interfacial tension reduction by effect of the spontaneous emulsification associated to the formation of natural surfactants produced by the crude-alkali reactions. The injection of alkaline solutions before steam injection could create favorable conditions to enhance crude mobility in zones not contacted by steam in previous stimulation steps, improving the vertical process efficiency. Also, an additional reduction of the crude saturation could be caused in those zones already invaded by the steam. Both phenomena could contribute to increase the crude recovery. Not only the reaction of the alkalis with the crude organic acids are associated to the alkali solution injection, but also its interactions with the porous medium and the formation water could be favored by the typically high temperature of the steam injection process. The severity of these reactions depends on the type of alkali applied, the crude characteristics, and the mineral composition of the formation. For this reason, the application of an alkaline solution in a steam injection project implies firstmore » a laboratory evaluation of the reservoir rock/fluid interactions, the study of the emulsion behavior, and the alkali effect on the oil recovery.« less