NR油田油井井筒腐蚀影响因素实验研究

摘要

In view of the increasingly serious problems of corrosion in NR Oilfield,experimental study on wellbore corrosion of produced water and influence factors of oil well are carried out. Produced water in typical wells is chosen as the research object,The influence of corrosion time,pH value,CO2 and H2S concentration on the corrosion rate is systematically studied by the method of static weight loss. Orthogonal experimental study is applied to investigate several factors which influence the corrosion rate degree. Experimental results suggested that the corrosion rate reaches the maximum when the corrosion reaction time is 24 h,then with time increasing the corrosion rate gradually decreased,after 72 h,the corrosion rate maintained constant;The higher temperature the more serious corrosion that the effect of produced water on coupons. When the temperature gradually increased,corrosion products turned from yellow to black. And dark red flocculent precipitate created in brown red solution. At 65 ◦C the lower pH the more serious corrosion that the effect of produced water on the corrosion rate. The effect of H2S concentration and CO2 concentration on corrosion rate is almost the same. The influence of several factors on corrosion rate determined by the orthogonal experiment are put in the order of temperature,pH value,H2S concentration,CO2 concentration, which is consistent with the single factor experimental results.%针对NR油田油井井筒腐蚀日益严重的问题，展开了产出水对油井井筒腐蚀原因及影响因素实验研究。采用了静态挂片法，以典型井产出水为研究对象，系统研究产出水在不同腐蚀时间、pH值、CO2浓度、H2S浓度条件下对腐蚀速率的影响，应用正交实验研究这几种因素对腐蚀速率的影响程度。实验结果表明，腐蚀反应时间在24 h时腐蚀速率达到最大，超过24 h后随着时间延长腐蚀速率慢慢降低，当超过72 h时腐蚀速率基本不变。温度越高，产出水对挂片腐蚀越严重，挂片为均匀腐蚀，随温度逐渐升高，腐蚀产物由黄色变成黑色，棕红色的溶液中含有暗红色絮状沉淀；在65◦C时，pH值越低的产出水对挂片腐蚀速率影响越大，产出水中H2S浓度与CO2浓度对挂片腐蚀速率影响相当，由正交实验确定了腐蚀速率影响程度大小顺序，依次为温度、pH值、H2S浓度、CO2浓度，与单因素影响实验结果一致。