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 passing from a very limited CP coverage to a pipe to soil potential
distribution in compliance with the standard codes.
Key words. Numerical Modeling, Cathodic Protection Systems, Marine conditions