Numerical modeling for cp diagnosis and solutions

PublisherNACE Internationaal

Docum ment ID 100 029 Content Type Con nference Pap per Title NUMERICA AL MODELING FOR CP DIAGNOSIS A ND SOLUTIO ONS TO INTEERFERENCE PROBLLEMS IN SHO ORE FUEL OIL AND GAS P PIPELINE NE TWORKS IN THE PACIFIC C COAST OF MEXIC CO. Autho ors Arturo Godoy, JJorge Canto,, Roberto Raamíreez, Hernan Rivera, Lorenzo M. Maartinez‐dela‐‐ Escalera,Co orrosion y Prroteccion Inggeneria;Jorgge A. Ascencio, and Lorenzzo Martínez,Instittuto de Cien ncias Fॉsicas, Universidad Nacional Autonoma de Mexxico Source e CORROSIO ON 2010, March 14 ‐ 18, 2010 , San A Antonio, TX Copyright

201 10. NACE International

Keywo ords

Num merical Mod deling, Catho odic Protectiion Systems, Marine con nditions.

Previe ew

ABSSTRACT.

Numerical modeliing is a valuable tool for the diagnoosis and thee developmeent of solution ex pipeline networks. Itt is also verry valuable to scenarrios for the CP systemss of comple perforrm comparaative and vaalidation an nalysis oncee the engineeering of th he retrofittiing based on the num merical mode eling has bee en completeed. We repo ort CP modelling employiing Finite Boundary Element num merical techn niques that w were applied d during the retrofitting of poorlyy performin ng CP syste ems in locaations wherre the elecctrolyte ressistivity varies significcantly as is the case of shore pipelines involvinng soil and sseawater en nvironments in the co oastal region ns of Mazatlan and Rosaarito in the Pacific Coassts of Mexico. The case of the gas and fue el oil pipeline networkk at Rosarito, due to the very special soccial enviro onment arou und the pipe eline ROW, aallowed veryy few option ns for the lo ocation of neew CP faccilities. There efore modelling and anticipating thee results of tthe CP perfo ormance weere crucial. We repo ort the triall studies de eveloped too reach a solution that, when tthe c substantially s y improved the CP perrformance aand ensured d a retrofiitting was completed, very good g pipe to soil pottential distrribution covverage alon ng the pipeeline netwo ork

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.

INTRODUCTION. During the last years, the use of numerical modeling by Computers has increased its power and consequently the impact to different fields has been increasing in a equivalent proportion to the new computers capabilities. Particularly the us of numerical modeling in corrosion and pipelines industries has been vastly applied because the opportunity that it gives to understand the right of way (ROW) behavior and also to understand the cathodic protection behavior with its multiple variables.

A specific opportunity segment is the use of this kind of virtual laboratory in the study and prediction of the behavior of ROWs that show a complicated access, or when there are not simple mechanisms to monitor enough elements. Lets remember that the tremendous capabilities of the numerical modeling can be observed in the three different stages: To evaluate the behavior of structures that already exist and just a few punctual data can be obtained; this allows understanding the possible complication, specific risk points or critical operation condition.

During the building and setup of structures, which allows improving the capabilities of the system, besides to reduce the resources because the perspective that the modeling can offer to evaluate alternatives in case of simple or grave complications during the construction or the setup of the installations.