The research on characteristics of physical sedimentation and oil-water separation of high calcium-type ASP produced water

摘要

ASP-flooding produced water contains polymers, surfactant, calcium carbonate and some other oil-displacing agents, which make the produced water complex and the oil-water stability increase dramatically, causing the difficult oil-water separation. This study has carried on the comparative study of the sedimentation characteristic of ASP-llooding produced water, which was examined in different pH conditions or in different gas flotation conditions. It showed that the adding of an oil-displacing agent would cause serious emulsifieation. which could make coalescence and sedimentation bad ol oil droplet and SS. The adding of HCI and NaOH could promote oil-water separation. Observed from SS, the SS decreased with the increase of pH, reducing from 282.32 mg/L to 78.53 mg/L. the oil content removal rate was 78.41%. The SS decreased following with the change of pH . 282.32 mg/L rising to 758.23 mg/L, then down to 121.42 mg/L. the oil content removal rate was 53.94%. Observed from residual oil content, the change of pH respectively made the oil content change to 27.52 mg/L and 58.74 mg/L. The oil removal efficiency of flotation was not very good without agents, the removal rate being only 26%, and the removal efficiency decreased with the decrease of raw oil content, which changed from 26% to 8.8%.