定向钻穿越段管道阴极保护效果的检测及影响因素

Cathodic Protection Detection and Influencing Factor Analysis of Directional Drilling Crossing Pipeline

采用密间隔电位法和极化试片法对定向钻穿越段管道的通断电电位进行检测,采用数值模拟技术对无法测得通断电电位的管段进行模拟计算,并对影响定向钻穿越段管道电位的因素进行模拟计算分析。结果表明:该定向钻穿越段管道的阴极保护电位衰减小,阴极保护效果良好,实测结果和模拟计算结果一致。数值模拟计算结果表明:穿越段管道防腐蚀层破损率越大,管道电位分布越不均匀,破损率增大会使电位发生正向偏移,阴保效果下降;管道防腐蚀层性能整体较好时,土壤电阻率的改变几乎不引起管道电位发生变化;穿越段管道防腐蚀层质量降低时,随着该段土壤电阻率的增大,管道电位分布的不均匀性增加,非穿越段管道的电位变负,而穿越段管道的电位变正;穿越段管道埋深对管道整体的电位分布影响较小。

Close interval potential method and polarization test piece method were used to detect the on-off potentials of the pipeline in the crossing section of directional drilling.Numerical simulation technology was also used to simulate and calculate the pipe section where the on-off potentials could not be measured,and the factors that affect the pipeline potential of the directional drilling crossing section were simulated and analyzed.The results showed that the cathodic protection potential attenuation of the pipeline crossing section of the directional drilling was small,the cathodic protection effect was good,and the actual measurement and simulation calculation results were consistent.Numerical simulation results showd that the greater the damage rate of the anti-corrosion layer of the crossing section of the pipeline,the more uneven the pipeline potential distribution,and the increase of the damage rate would cause the potential to shift positively,and the cathodic protection effect would decrease.When the overall performance of the pipeline anti-corrosion layer was good,the change of soil resistivity hardly caused the pipeline potential to change.When the quality of the anti-corrosion layer of the crossing section of the pipeline decreased,as the soil resistivity of the section increased,the unevenness of the pipeline potential distribution increased,the potential of the non-crossing section of the pipeline became negative,and the potential of the crossing section of the pipeline became positive.The buried depth of the crossing section pipeline had little effect on the overall potential distribution of the pipeline.