西南山区油气并行管道腐蚀速率分析

Corrosion rate analysis of parallel oil and gas pipelines in southwest mountainous area

关键词:  并行管道  阴极保护  相互干扰  腐蚀速率

Key words:  parallel pipeline  cathodic protection  mutual interference  corrosion rate

摘要:

西南山区管道埋设地质条件复杂,多条管道在同一管道廊带并行敷设,每条管线均采用独立的阴极保护系统,线路阴极保护系统之间存在相互干扰的风险。对西南山区并行管道阴极保护系统通断电后目标管线阴保系统产生的影响进行了研究,并对相互干扰的管地电位进行了长达数月的连续监测,选取2个典型并行管段共计5处测试点进行腐蚀速率分析。结果 表明,5处位置的土壤自然腐蚀速率为0.080~0.217 mm/a,阴保下的腐蚀速率为0~0.126 mm/a,阴极保护效果良好处腐蚀风险低,土壤自然腐蚀速率是阴极保护下腐蚀速率的几倍、十几倍,在阴极保护良好的条件下并行管道阴极保护间的相互干扰对管道的腐蚀影响效果并不显著。 

Abstract:

The geological conditions of buried pipelines in southwest mountainous areas are complicated, some pipelines are laid in parallel at the same pipeline corridor. Each pipeline adopts an independent cathodic protection system, the risk of mutual interference between the cathodic protection systems are exist. In this study, the influence of cathodic protection system on the target pipeline after power-off of the parallel pipeline cathodic protection system in southwest mountainous area was studied. The ground potential under mutual interference was continuously monitored for several months. The continuous monitoring of pipe-to-soil potential under mutual interference condition was sustained for several months. Two typical parallel pipeline segments and total of 5 test points were selected for corrosion rate analysis. The results showed that the natural corrosion rate of soil at this five locations is 0.080-0.217 mm/a, the corrosion rate under cathodic protection is 0-0.126 mm/a. The cathodic protection effect is good and corrosion risk is low, the corrosion rate of soil is several times or more than ten times of that under cathodic protection, and the influence of mutual interference between the parallel pipeline cathodic protection on the corrosion of pipeline is not significant.