A maintenance program was designed to improve the cathoclc protection level of two oil gathering pipeiines of an oil production facility in Eastern Venezuela. The program was built upon the information obtained from a coating condition evaluation and the soil resistivity proiile along the pipeline corridors. The external coating was inspected with the Direct Current Voltage Gradient technique, DCVG; the soil resistivity of the pipeline corridor was measured every 100 meters (328 ft.). All the geographical information was obtained with Differential Global Positioning System (DGPS). This allowed the pipeline operator to relocate all coating defects with a sub metric accuracy that considerably reduced the rehabilitation costs. The coating inspection covered a total distance of twelve thousand, nine hundred and thirty-six meters (12,936 meters). Two hundred and ninety two (292) defects were found; 54 defects belonged to Category 3 and will need immediate repair. The soil corrosiveness along the pipeline corridors was established by the resistivity gradient. Critical areas were established and exploratory digs were recommended to asses exposed metal condition.
Keywords Direct Current Voltage Gradient technique, cathodic protection, soil resistivity, %IR, Differential GPS.