USE OF CHEMICAL ADDITIVES WITH STEAM INJECTION TO INCREASE OIL RECOVERY.

Various surfactants are being evaluated for their potential as additives for steamflooding to reduce oil-steam ratios. Of particular interest is the effect of temperature on adsorption of the surfactants on reservoir rocks. Two classes of surfactants have been investigated. The anionic sodium dodecylbenzene sulfonate showed a decreasing adsorption with increasing temperature but at higher concentrations and in brine solutions the sulfonate precipitated. A definitive measurement of adsorption under these circumstances was not possible, but substantial loss of surfactant during floods was observed. The nonionic lgepal CO-850 was, on the other hand, well-behaved in the adsorption experiments. It does show, however, a cloud point. The adsorption as a function of temperature is the inverse at high temperatures over that at lower temperatures. Near the cloud point adsorption increases with increasing temperatures.