Investigation of Alternating Current Density and its effect on Corrosion of Underground Hydrocarbon Pipelines in the Niger Delta Area of Nigeria

The Niger Delta area of Nigeria is crisscrossed by several pipelines carrying hydrocarbon products from the oil and gas fields to the export terminals and refineries. However, due to the need to improve surveillance and avoid human population, most of the pipelines have been laid along the right of way of high voltage transmission lines (HVTL) resulting to Alternating Current (AC) interference on the pipelines which has led to a unique form of corrosion known as AC corrosion. This study sought to investigate AC density and its effect on corrosion of underground hydrocarbon pipelines within the Niger Delta area of Nigeria. Four hydrocarbon underground pipelines were chosen for the study. AC interference was measured daily for 92 consecutive days. Soil resistivity measurement and location / sizing of defects on the pipeline coating were carried out. AC density was determined and the rate of AC corrosion was measured using Electrical Resistance probes. The results indicated that AC density  on the selected pipelines ranged from 1 to 70 A/m² and AC corrosion  rate ranged from 0.001 to 0.1 mm/yr. Based on the results, this study, established that the higher the AC density, the higher the rate of AC corrosion.