The Effect of Anionic and Alkaline Surfactant Synthesis in Spontaneous Imbibition on Sandstone

The aim of this research is to determine the effect of anionic and alkali surfactant on oil acquisition in the process of spontaneous imbibition on sandstone reservoir. Anionic surfactant synthesized by compatibility test was done with addition of alkali. There were five (5) types of alkaline surfactant solution used. Solution compatibility tests included aqueous stability, interfacial tension (IFT) or critical micelle concentration (CMC) at reservoir temperature (60°C), phase behavior test by observing the microemulsion formation for 24 hours, filtration test with a filtration ratio limit value of less than 1.2, thermal stability test for 7 days and spontaneous imbibition test with observation for 42 hours. There were two types of solutions that passed the aqueous stability test, interfacial tension test (IFT), phase behavior test, and thermal stability test, namely, alkali surfactant (AS) 1 ((NaOH) 0.1% + O400O 0.3%) and alkaline surfactant (AS) 2 ((Na2CO3) 0.5% + O400O 0.3%). The filtration test result from AS 1 showed FR value of 1.15 and AS 2 showed FR value of 1.17. In the imbibition test stage, the test was carried out at reservoir temperature of 60°C. From 42 hours of observation, 39% of oil was obtained by using brine, AS 2 solution attained 57%, and AS 1 solution attained 75.5%. This could be used as a basis in EOR implementation on sandstone reservoirs.