an experimental examination of adsorption phenomenon in foamassisted water alternative gas: the effect of injection rate

the main factor affecting the economics of foam-assisted water alternative gas (fawag) process isthe loss of foaming agent by adsorption onto reservoir rocks. in this study, the effects of phases,surfactant concentration, salinity, adsorbents, and sacrificial agent on adsorption density wereinvestigated by special adsorption experiments. moreover, a series of fawag tests were performedto examine the effect of injection rates on final adsorption density and adsorption variation during thetest. a clean and fast spectrophotometric method was used for the determination of sodium dodecylsulfate (sds) concentration based on the formation of an ion-pair, sds-safranin o. higher sdsadsorption was observed at the first cycle of fawag flooding. fawag injection rate had nonoticeable effect on the adsorption density. however, using high injection rate decreased thepossibility that gas faces surfactant, and thereby reducing the ultimate oil recovery. the presence ofcls increases the ultimate oil recovery slightly, while it decreases the adsorption density of sds by22%.