中原油田采油一厂腐蚀严重井的治理

Corrosion Control of Oil Well in 1st Oil Production Plant of Zhongyuan Oil Field

中原油田分公司采油一厂地质状况复杂,产出液具有"四高一低"的特点,产出液Cl-含量为3～11×104mg/L、矿化度为(7～22)×104mg/L、HCO3-为50～400 mg/L、井底温度高达130～150℃、pH值低(5.5左右)的特点,腐蚀性较强。通过对采油一厂10口油井腐蚀因素调查,摸清了腐蚀原因是产出液中Cl-,HCO3-等强腐蚀性离子含量高,同时含有一定量的CO2,并含SRB,从而形成弱酸性腐蚀水体。经向套管中注入KY-2高效缓性剂(加药浓度100μg/g)后,腐蚀速率由0.0 913 mm/a降为0.0 223 mm/a,总铁值由36.1 mg/L降为26.6 mg/L;治理后减少腐蚀作业14井次,防腐效果明显。

The geological conditions in 1 st Oil Production Plant of Zhongyuan Oil Field are very complex. The production liquid is characterized by higher C1 （3 - 11 ） × 104mg/L, higher minerality （7 -22）×104mg/L, higher temperature （well bottom temperature 130 - 150℃ ） and lower pH value （about 5.5 ）. The liquid is very corrosive. The investigation of the corrosion in the 10 oil wells in 1 st Oil Production Plant revealed that the corrosion culprit was the weak acid body resulted from higher C1- , HCO3 , CO2 and sulfate reducing bacteria（SRB） in the production liquid. After injection of high - efficiency corrosion inhibitor KY -2 in the conduit at a dosage of 100 ppm, the corrosion rate was reduced from 0. 0913mm/a to 0. 0223mm/a. The iron ion in the production water was lowered from 36.1 mg,/L to 26.6 mg/L. The underground work for corrosion control has been reduced by 14 well times as compared with that before the injection. The corrosion prevention effect is obvious.