Research On Lifetime Extension Technology Of Impressed Current Cathodic Protection For Submarine Pipelines

With the continuous development of offshore oil and gas fields,the exploitation of offshore oil fields is relatively saturated,oil field exploitation has been turned to deep-sea region.The submarine pipeline is the main component of offshore oil and gas production and development system,plays an indispensable role in oil and gas transportation.For the exploitation of offshore oil fields,considering the reasons of operability and economy,the cathodic protection systems of submarine pipelines generally adopt the combination of anti-corrosion coating and sacrificial anode protection system.With the increase of service life,the coating system of submarine pipeline will continue to deteriorate and degrade,and the sacrificial anode will consume a lot,which will pose a potential threat to the safety of submarine pipeline.Up to now,many submarine pipelines in the world are going to or have exceeded the initial design life of their cathodic protection system.Due to the exploitation of marginal oil field and other reasons,many submarine pipelines still need to continue to serve for 10 to 20 years.In order to ensure the safety of submarine pipeline,it is urgent to take measures to extend the life of the cathodic protection system of submarine pipeline.The impressed current cathodic protection method has the advantages of low installation cost,adjustable impressed current and environment-friendly.Compared with the traditional replacement and additional sacrificial anode system,it has never been used in the submarine pipeline.Therefore,the study of the impressed current lifetime extension technology applicable to the submarine pipeline is a breakthrough in the existing technology,which is of great significance to the life extension of the submarine pipeline in service.The main purpose of this paper is to put forward the method of extending the lifetime of submarine pipeline by remote impressed current cathodic protection,to study and verify the feasibility of the technology through numerical simulation and laboratory scale test,as well as the law of remote impressed current cathodic protection system.Firstly,by investigating and comparing various existing lifetime extension methods at home and abroad,a remote impressed current cathodic life extension method suitable for submarine pipeline is proposed,and the feasibility of this method is preliminarily verified by boundary element numerical simulation method,and the corresponding laws are studied;Secondly,according to the law obtained by numerical simulation,the laboratory scale model is established and the laboratory test is carried out to verify the feasibility and law of the method from the experimental level;Finally,on the basis of numerical simulation and laboratory scale test,the physical model of the real sea experiment is established in the real sea environment and the design of real sea experiment is built,so as to prepare for the subsequent sea experiment research.