复合缓蚀剂在油田采出水中的缓蚀性能研究

目的为了解决油田采出水的腐蚀问题,制备一种复合缓蚀剂,并研究环境因素对缓蚀性能的影响规律,为油田采出水的科学防腐提供理论上的依据。方法采用含磷咪唑啉季铵盐和钨酸钠复配了一种绿色的油田采出水处理复合缓蚀剂,用动态失重法对复合缓蚀剂的缓蚀性能进行了评价,并系统地研究了介质的温度、pH值、矿化度及流速对缓蚀性能的影响。结果油田采出水的温度为55℃、pH值=7.0、流速为2.5 m/s和矿化度为36 g/L时,复合缓蚀剂的最佳投加质量浓度为60 mg/L。该条件下Q235钢的腐蚀速率为0.0269 mm/a,能够满足油田采出水回注的标准要求。腐蚀速率随着缓蚀剂质量浓度的增加而减小,随着采出水温度的升高而增大。采出水的矿化度为32 g/L时,对腐蚀速率的影响最大。采出水的流速为1.2~3.0 m/s和采出水的pH值接近于中性时,其对腐蚀速率的影响较小。结论复合缓蚀剂是一种环境友好型油田采出水处理缓蚀剂,缓蚀性能优良。

Corrosion Inhibition of Composite Corrosion Inhibitor in Oilfield Produced Water

The work aims to solve the problem of corrosion in oilfield produced water. A composite corrosion inhibitor for oilfield produced water treatment was prepared, and the influence of environmental factors on corrosion inhibition was studied to provide theoretical basis for scientific anticorrosion of oilfield produced water. A green composite corrosion inhibitor was made from phosphonic imidazoline quaternary ammonium salts and sodium tungstate. Corrosion inhibition of the composite corrosion inhibitor was evaluated in dynamic weight-loss method, and effects of medium temperature, PH value, salinity and flow rate on corrosion resistance were systematically studied. The corrosion inhibition rate of Q235 steel was 0.0269 mm/a when optimum mass concentration of the composite corrosion inhibitor was 60 mg/L provided with water temperature of 55℃, pH=7, flow rate of 2.5 m/s and salinity of 36 g/L, it could meet the standard requirements of oilfield produced water reinjection. The corrosion rate in oilfield produced water decreased as mass concentration of the inhibitor increased, and increased as the temperature rose. The corrosion rate was greatly affected at the salinity of 32 g/L, and slightly affected at the flow rate of 1.2~3.0 m/s or pH value of near neutral level. The composite corrosion inhibitor is a environmental friendly inhibitor for oilfield produced water treatment and is of high inhibition efficiency.