海上热采井防砂筛管腐蚀的影响因素

Influence Factors of Corrosion of Sand Screen Pipeline in Offshore Thermal Production Well

针对海上油田热采井出现的防砂筛管腐蚀问题,采用室内模拟腐蚀试验,研究了注入流体中各种组分在油藏条件下对防砂筛管结构造成的损害,分析了筛管腐蚀破坏的可能性。结果表明,在含氧的CO2腐蚀环境中,筛管基管发生了严重的局部腐蚀,并且腐蚀速率极值温度在60℃附近;当油层温度在60℃附近,CO2/O2分压比大于6时,为CO2主导的腐蚀环境,主要表现为均匀腐蚀;CO2/O2分压比小于5时,为氧气主导的腐蚀环境,筛管基管会发生大面积的台地腐蚀和严重的局部腐蚀;筛管基管材质与金属棉或者金属网布耦合后,存在明显的电偶腐蚀作用,腐蚀速率大幅增加。

Aiming at the corrosion problem of screen pipeline of thermal production well in offshore oilfield, simulated experiment was used to study the influence of components of inj ection fluid on the damage of sand screen pipeline under reservoir condition,the probability of screen pipeline corrosion damage was also analyzed.The results showed that in the CO2 corrosion environment containing oxygen,serious localized corrosion occurred in parent tube, and the maximum corrosion rate was at 60 ℃.When the oil temperature was at 60 ℃,CO2/O2 partial pressure ratio was more than 6 ,gave priority to CO2 corrosion,showed uniform corrosion.When CO2/O2 partial pressure ratio was less than 5 ,O2 corrosion took priority,platform corrosion and severe localized corrosion occurred in parent tube for a large area.When parent tube and metal wool or metal net were coupled,bimetallic corrosion occurred,thus corrosion rate increased.