Research On Purification And Use Of Oilfield Produced Water

China's oil production was declining in recent years. Many oil fields in China had entered stages of secondary oil recovery and tertiary oil recovery in order to enhance oil production. A large amount of fresh water was consumed during the implementation of polymer flooding technology in tertiary oil recovery. As a result, a lot of oilfield produced water was inevitably produced. These oil field produced water urgently needed treatments to achieve excellent utilization considering environmental protection and resources conservation.This thesis studied the oil field produced water with high salinity in Hao station where serious corrosion and fouling had occurred and the oil field produced water in Gu-2 station with low salinity.The application of "pre-oxidation" by electrochemical methods in Hao station can avoid problems of corrosion, scaling and instability of water quality.The oilfield produced water in Gu-2 station was treated by chemical methods and electrochemical methods(used homemade electrolyzer).Finally,the concentration of Ca2+,Mg2+ in oilfield produced water significantly decreased while the viscosity of polymer solution apparently increased.When the oilfield produced water was treated by chemical methods, it was found that the concentration of Ca2+,Mg2+ significantly decreased with the addition of OH-.And the viscosity of HPAM solution apparently increased and its stability enhanced and the optimized pH value is 12.The addition of oxalic acid and EDTA slightly increased the viscosity of HPAM solution, but it didnot enhance the stability of the HPAM solution.The optimized parameters through treating oilfield produced water by electrochemical methods using homemade electrolyzer were: ambient temperature and atmospheric pressure, 1500mL oil produced water from Gu-2 station, 5000mg/L HPAM solution, DC voltage 10V , current 12A, Ti/RuO2-IrO2 anode, graphites cathode, electrode area 150cm2,the gap of electrode 15mm,electrolysis time 12h,stirring. Both the initial viscosity and the stability of HPAM solution treated by electrochemical methods were higher than those treated by chemical methods.