Static Adsorption of Amphoteric Surfactant

Abstract The purpose of this study was to investigate the maximum amphoteric surfactant adsorption by studying parameters like rock type, salinity, alkali type, alkali concentration and surfactant concentration and to evaluate optimum parameters that would provide minimum amphoteric surfactant adsorption. The amphoteric surfactant was studied had been tested in Malaysia’s first chemical enhanced oil recovery (CEOR) pilot in Angsi Field. Hence, it is very important to properly understand the adsorption mechanism, parameters and potential for this surfactant to reduce uncertainty. First rock samples were characterized. Existing static adsorption methodogy was being improved to reduce redundant samples and long experiments duration to produce repeatable results. Then, actual experiments with varying adsorption parameters were carried out. Amphoteric adsorption increased when clay content of reservoir rock increase and so did the surface area. Alkali had been demonstrated to significantly decrease adsorption of amphoteric surfactants and a novel kind of alkali, organic alkali and ammonia are introduced with advantages of lowering adsorption better than the conventional alkali (sodium carbonate). The dynamic adsorption experiments were performed by injecting the chemical solution through reservoir core until an equilibrium state was reached. The dynamic method better described the adsorption process and the result was more reliable. Dynamic adsorptions were about 10 to 13 times lower than static adsorption. Further studies incorporating surface area, grain size, accessible pore volume and mineralogy including clay type were required to build robust correlation from static to dynamic adsorption.