A contribution to flotation technique as a reliable wettability alteration measurement method for carbonate minerals in separation processes involving hydrocarbons, low salinity water and nanofluids

Abstract

A reliable flotation method was developed and experimentally evaluated as a fast and repeatable quantitative wettability measurement technique for Enhanced Oil Recovery (EOR) purposes by comparing its performance with the well-known and reliable method of contact angle measurement. In both methods, oil-wet carbonate specimens were contacted with brines of different salinities and nanoparticle concentrations, and the trend of test results were compared. In the salinity tests, it was observed that flotation results are in full consistency with contact angle measurements. In both methods, salinity reduction from seawater (SW) to 10 times diluted seawater (TDSW) resulted in reaching the maximum hydrophilicity while further dilution to 40 TDSW hindered the wettability alteration process. Nanofluid tests in both methods were also in great consistency at nanoparticle concentrations below 0.1%wt due to particle stability limitations. Finally, two flotation mechanisms for the oil/water/rock system were introduced and one of them was empirically confirmed.