Characterization of External Induced Corrosion Degradation of Ajaokuta- Abuja Gas Pipeline System, Nigeria

Abstract

Characterization of External Induced corrosion degradation of Ajaokuta- Abuja gas pipeline system was successfully carried out. The objective of this work is to analyze the mechanism of corrosion, analyze the effect of the corrosion on oil and gas pipeline and to evaluate the corrosion potential of a pipeline route. These were achieved by carrying out resistivity experiment on every one kilometer on the right of way (ROW) of the pipeline. Soil and water aggressiveness test was also carried out on soil and water sample of the pipeline route respectively. The resistivity result was considerably high, chemical analysis revealed that the soil and water acidity is between the pH of 6.7 and 8.2 respectively, which is moderately alkaline in nature, which makes the soil environment not conducive for pipelines due to potential for corrosion attack. The chloride content of the soil and water were also high. Based on the experimental results, it was proposed that the pipe should be laid on 2-5m below the ground and that the galvanic anode for cathodic protection be located 1m below the ground, in order to avoid corrosion. It is therefore necessary to note that characterization of external corrosion is quite different from internal pipeline corrosion characterization.