Study On The Effect Of Water Quality Characteristics Of ASP Produced Water Mixed With Polymer Flooding

The polymer, alkali and surfactant have a significant synergic effect on the ASP produced water of oilfield, which leads to high emulsification of oil-water and high viscosity.It resulted in low floating speed of oil droplet and slow settling velocity of suspended solids,which added to the difficulty for oil-water separation ultimately. The experiment found that water quality is improved as the ratio of synthetic wastewater increased by mixing ASP produced water with synthetic wastewater. To effectively remove the oil content and suspended solids of the ASP produced water is urgent issue of the oilfield production.Research on water quality and settlement characteristics of mixed produced water have important reference values on the treatment of ASP produced water.The analysis of water quality showed that ASP produced water contained high concentration of oil content, polymer and viscosity. It's up to 2000?2600 mg/L,789.16 mg/L and 9.562 mPa·s,respectively,while flooding produced water is generally 100?600 mg/L.Polymer concentration is relative to viscosity of produced water and there is no perfect positive correlation between polymer concentration and viscosity of different plays.The mixing experiments indicate that surfactant and viscosity of the oil-water are the biggest changes and the measured value is lower than calculated value.The gap is gradually narrowing with the increased ratio of the ASP produced water. The main factors of the viscosity was characterized and results indicated that high-speed spinning mechanical shear power, shearing time, salinity, temperature, pH value and settling time are the main factors to viscosity.The higher rotating speed and the longer shearing time is, the smaller viscosity is The solution viscosity decreased with the increase of the concentration of ions, and the influence of two kinds of ions is more influential than metal ions, divalent cation is higher than monovalent cation. As the temperature rose and the settling time extended, the viscosity of HPAM reduced. Viscosity increased at first and then decreased with the increase of pH value. The viscosity is up to the highest when the pH value reached 9.5.The settlement characteristics experiment demonstrated that residual oil content of different polymer concentrations could decrease to 100 mg/L by mixing. Settling time varies with two kinds of water quality. The settlement time of high polymer concentration of ASP wastewater mixed with low concentration of flooding produced water is 12h, while medium concentration of ASP wastewater mixed with high concentration of flooding produced water is 10 hours, medium concentration of of ASP wastewater and low concentration of flooding produced water is only 8 hours. Moreover, the removal rate of oil content is higher at the first of the settlment and oil content of water samples begins to decrease gradually.