Health Monitoring of New and Aging Pipelines- Development and Application of Instrumented Pigs

Abstract

More than 3 million kilometers of high pressure liquid and gas pipelines are installed all over the world.Usually steel is the safest means to transport large quantities of oil and oil related products and natural gas however, just like any other technical component, pipelines also deteriorate with time, result of which, flaws appear and they grows until the pipeline fails. That is why Pipeline operators worldwide maintain the good health of buried cross-country pipelines with a combination of good quality external coating and cathodic protection. Beside this various other techniques like cleaning and debris removal by scrapper pigging at intervals depending upon the life of pipeline and the products being transported through the same are used. Use of corrosion inhibitors and internal coating is also done to protect the internal surface from corrosion. It is of greatest importance to ensure the safety, efficiency,environmental integrity and regulatory compliance of the worldwide pipeline infrastructure. Achieving this objective entails the need for effective inspection technologies, incorporating the accuracy and reliability required for optimized maintenance strategies. Intelligent pigs are used for inline inspection of buried pipelines to monitor their thorough health,assess the risks associated with their operation,pilferage checking and cracks etc. These IPIGS are capable of detecting metal loss upto 5-10 percent of wall thickness on inner as well as external surfaces of pipeline. IPIGS based on ultrasonic and eddy current sensors are capable of detecting cracks also.[10] On the basis of the wall thickness loss and the intensity of defects, pipeline risk assessment is done and preventive and corrective measures are planned. This paper presents the technical details of instrumented pig with its advantages and disadvantages over conventional methods of pipeline protection and inspection. It also elaborates the concept of multiple technology intelligent pig and scope for future research on intelligent pigging. (abstract)