Abstract

This paper discusses the low hardness alkali water composition (LHAW) application in a secondary and tertiary EOR operations. It was presented impact of low salinity (LSW) and low hardness alkali water composition on surface tension reduction, contact angle changes, adsorption, emulsion stability and clay swelling. It was observed more stable emulsion (w/o) formation and clay swelling decrease while LHAW deployment. LHAW-2 and LHAW-1 application in secondary treatment mode increased oil recovery (%OOIP) more than 29% and 25% consequently at water-free period in compare to SSW, but finite oil recovery increase was 21% and 15% respectively. Oil recovery increased in tertiary treatment mode was more than 13% and 10% for LHAW-2 and LHAW -1 injections consequently in compare to LSW. It was observed that oil recovery rates for LHAW solutions has not linear relationship as it was for LSW. The observed effect was explained by emulsions generation while water-cut is up to 50%, but while it exceeds 50% the rate stabilizes.

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