Modifications of petroleum industry effluent treatment Method: An approach for quality improvement of process water for ASP flooding and chemical EOR

Abstract

Several Alkali Surfactant Polymer (ASP) pilot facilities are currently being put into operation across India. The physicochemical parameters of the process water play an important role in the success of ASP flood to improve the recovery. In the current study treated effluent from an effluent treatment plant (ETP) is used as process water for the ASP pilot. The ETP sample water collected shows a lack of improvement in quality in terms of iron content, higher total suspends solids (TSS), high turbidity, and low filterability. The process water has calcium (as Ca + ) 60 mg/L and magnesium (as Mg2 + ) 33 mg/L. These ions are critical in the ASP designing process. The increase in the rate of filtration was determined by plotting the rate of filtration against the cumulative volume (Cerini filtration). The MTSN values were observed to be −1.35 and −1.09. The RPI values are 7.15 and 2.60 at two different time periods. The sample collected showed a lack of improvement in quality. This tube well water after filtration was best suited for ASP flooding. However, the high concentration of calcium results in the formation of calcium carbonate in addition to sodium carbonate (to be used as alkali for ASP). Hence calcium should be removed by softening the process water in the softening plant. The water was treated in the laboratory with a calculated amount of sodium carbonate to remove calcium and magnesium. Which comes out to be 0.30 gm/l of water. After treatment water was filtered and calcium and magnesium concentrations were determined. The calcium concentration was calculated 13 mg/l as compared to 60 mg/l in treated water.