油田采出水的改性回注处理工艺研究

针对安塞油田采出水偏酸性、浊度高、含油量高的特征,采用"中和—H2O2氧化—絮凝—过滤"处理工艺进行回注处理,探讨了采出水的pH值、H2O2和絮凝剂投加量等因素对采出水水质改性处理效果的影响.结果表明:以NaOH作为pH调节剂将采出废水pH值调至7.5,H2O2投加体积分数为0.6%,投加XN-90、PAM的质量浓度分别为80mg/L和2.5 mg/L时,处理后采出水的悬浮物、含油量、总铁含量、静态平均腐蚀速率、SRB及TGB含量由处理前的110～145 mg/L,96.6～124.3mg/L,24.8～35.5mg/L,0.310 3mm/a,105～106个/mL和102～103个/mL分别降至处理后的1.1～6.0mg/L,2.5～6.0mg/L,0.05～0.23mg/L,0.0108mm/a和101～102个/mL,处理后采出水的各项指标达到了安塞油田注水水质标准.

Study on the reinjection treatment technology of oilfield produced water

The produced water from Ansai Oilfield is characterized by weak acidity,high turbidity and high oil content.Its reinjection treatment technology is neutralization-H2O2 oxidation-flocculation--filtration.The effects of the pH value of the produced water,the dosage of H2O2 and flocculants on the treatment result of the produced water are studied.The results show that,the mass concentrations of suspended solid,oil and total iron in the produced water are reduced to 1.1~6.0 mg/L,2.5~6.0 mg/L and 0.05~0.23 mg/L from 110~145 mg/L,96.6~124.3 mg/L and 24.8~35.5mg/L respectively,the average corrosion is decreased to 0.010 8 mm/a from 0.310 3 mm/a ,and the quantity of SRB and TGB is reduced to 101~02个/mL from 105~106个/mL and 102~103个/mL respectively when the pH of the produced water is adjusted to 7.5 with NaOH,the volume fraction of H2O2 is 0.6%,the concentration of XN-90 and PAM is 80 mg/L and 2.5 mg/L separately.The main quality parameters of the treated produced water can meet the requirement of the water quality standard to oilfield injection water.