Sina Shaddel - Sahand PelroleulII Research Cenler. Sahand Universily o/Tec/Illology. fabriz, Iran
S.AR Tabatabae-Nejad
S. Jafar Fathi - Departmenl of Pe/roleulII Engineering. FacullY of Science and feellnology, University ojS/amnger

Extensive laboratory studies have now indicated that oil TL'(:OVl'ry in water flooding is dependent on the chemistry of the injccted water. [n this work, core flood cxperimcntswere performcd to investigatc the effect of injected watcr and crudc oil chemistry on thc oil recovery to further understand the low salinity waterflooding process. Two types of testoils were used to saturate the corcs: a) Oil-A with acid number (AN) 010.842 mgKOH/g,und b) Oil- B lu.:id number of 1.683 mgKOWg. The flooding experiments were pcrfonned by successive injection of lonnation brine, [ow salinity water, and surfac tant/alkalineimproved low salinity water. The results showed that low salinity water injection improved thc oil recovery by 4·22 % ofOOIP in a tertiary mode. Adding small amount of surfactantto low s;tiinity water (dFWO.O[+ [ wt% 50S) increased the recovcry by 22% ofOOIP. Thc effect of surfactant was discussed in tenns of reduced surfactant adsorption on the rock surface, improved wetting condition, and lowered interfacial tension (1FT). Alkalinesolution also improved the promising effect of low salinity water about 12.3% of 0011' The increased recovery by alkaline was attributed to the in-situ saopinification andwettability modification. 1t WaS concluded that combination of low salinity water with surfactUllt or alkaline had significant effcct on boosting the cffect of low salinity water flooding. The observations cmphasizc thc potcntial of low salinity water as the make- up water for thc chcmical cnhanccd oil rccovcry (EOR) proccsst-'S.

Low sali nity. Oil recovery. Surr.1ctant. Alkaline. Water flooding. EOR