NUMERICAL MODELING FOR CP DIAGNOSIS AND SOLUTIONS TO INTERFERENCE PROBLEMS IN SHORE FUEL OIL AND GAS PIPELINE NETWORKS IN THE PACIFIC COAST OF MEXICO

Numerical modeling is a valuable tool for the diagnosis and the development of solution scenarios for the CP systems of complex pipeline networks. It is also very valuable to perform comparative and validation analysis once the engineering of the retrofitting based on the numerical modeling has been completed. We report CP modeling employing Finite Boundary Element numerical techniques that were applied during the retrofitting of poorly performing CP systems in locations where the electrolyte resistivity varies significantly as is the case of shore pipelines involving soil and seawater environments in the coastal regions of Mazatlan and Rosarito in the Pacific Coasts of Mexico. The case of the gas and fuel oil pipeline network at Rosarito, due to the very special social environment around the pipeline ROW, allowed very few options for the location of new CP facilities. Therefore modeling and anticipating the results of the CP performance were crucial. We report the trial studies developed to reach a solution that, when the retrofitting was completed, substantially improved the CP performance and ensured a very good pipe to soil potential distribution coverage along the pipeline network considering the segments immersed both in seawater and in soil. The case of the pipeline network of Mazatlan, also for fuel oil and gas was successfully analyzed and solved employing the Finite Boundary Element methods. The calculations involved the solution to a CP interference problem in a segment of the pipeline, as well as the support for the retrofitting engineering that allowed to pass from a very limited CP coverage to a pipe to soil potential distribution in compliance with the standard codes.