Experimental Investigation Of Acid-Alkaline-Surfactant Optimization Using High Salinity Injection Water For Chemical EOR

In Chemical EOR, ASP flooding is proven to be cost-effective in recovering the
remaining oil. However, ASP flooding is not compatible to be used in hard brine due to
the reaction of alkali/surfactant with the divalent metal cations to produce insoluble
precipitation. So, the aim of the research is to produce a new formulation that can be
used together with hard brine without the occurrence of precipitations. A feasibility test
was conducted to observe the compatibility of the new formulation with the hard brine.
The acid was evaluated in this new formulation using alkalis (sodium carbonate and
sodium hydroxide) and surfactant (Alpha Olefin Sulfonate). The precipitation is the key
indicator to determine the compatibility of these chemicals in the hard brine that contain
large quantity of metals cations. The aspects that need to be studied are including Acid
- Alkali interaction in hard brine, Acid- Surfactant interaction in hard brine and AcidAlkali
- Surfactant interaction in hard brine. At the end in the experiment, it was found
out that the acid to alkali ratio of 1.33:1 is the most optimum ratio as no precipitation
was produced. So, this makes the new Acid - Alkali - Surfactant formulation an option
for the CEOR process, particularly in the offshore operation.