Study of the Effect of Precipitation Inhibitor on Static and Dynamic Surfactant Adsorption Using High Salinity Injection Water

Adsorption of surfactants from aqueous solutions in porous media is very important in
enhanced oil recovery {EOR) of oil reservoirs because surfactant loss due to adsorption on the
reservoir rocks impairs the effectiveness of the chemical slurry injected to reduce the oil-water
interfacial tension (1FT) and renders the process economically unfeasible. Surfactant adsorption
is due to the different charges between slug and rock that will create attraction force. The
different charges between the slug and rocks can be solved by increasing the pH of the slug.
New developed method for surfactant formulation which is AAS is to overcome the problem of
precipitation when using hard brine or high salinity water. In AAS, acid and alkali will react to
form a salt that will coat the metal divalent ions such as magnesium and calcium from reacting
with surfactant and alkali to form insoluble precipitation [1]. So, this research will study the
effect of precipitation inhibitor {PI) on the surfactant adsorption using high salinity water
injection. Surfactant that will be used is Alpha Olefin Sulfonate which is anionic surfactant. The
acid and alkali are used are acrylic acid and sodium hydroxide. The surfactant adsorption will be
measured in two different methods which are static and dynamic. For the static method, the
experiment will be divided into 3 phases which are first phases is to find the optimum
concentration of surfactant, second phase is to find the optimum concentration of the alkali
and the third phase is to find the optimum concentration of acid. For dynamic method, the
experiment will be conducted by varying the acid concentration in the surfactant solution that
already included optimum concentration of surfactant and alkali. The surfactant concentration
after each test will be measured by using two phase titration which will use Hyamine 1622 as
titrant and mixed acid as indicator.