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Analysis

Corrosion-Erosion Monitors for Subsea Pipelines

Tue, 01/22/2013 - 12:25

Corrosion-erosion monitors (CEM) for subsea pipelines keep operators informed on the level of sand that could cause any potential erosion and/or corrosion damage to pipelines. Pedro Ramírez Jurado, General Manager at Metromex, believes that this state-of-the-art technology is of vital importance to operators in the oil and gas industry. The technology, which is licensed to Metromex by Norwegian company ClampOn, estimates the rate at which corrosion and/or erosion is occurring in pipelines by the use of clamp-on sensors, preventing not only any potential damage to infrastructure, personnel, or the environment, but keeping pipelines functioning at their highest potential. CEMs work by transmitting ultrasonic signals that travel through pipelines and send real-time data back to the operators, informing them of any changes in wall thickness, originating from corrosion or erosion.

Currently, there are two di† erent types of CEMs for subsea pipelines: an ROV-installable mechanism and a preinstallable solution that is installed before the structure is submerged. Both mechanisms o† er the same solution and operate in the same manner, o† ering the same level of reliability and basically functioning on the same principles. The permanently installed CEMs have the advantage of monitoring the pipeline and always eliminating the weaknesses involved in manual ultrasonic thickness gauging. The corrosion-erosion monitor is comprised of eight small transducers, which convert signals in one form of energy to another form of energy, transferring the information to the head unit and generating data on the thickness of the wall of the pipeline.

The state-of-the-art CEMs are most commonly applied to pipelines, pipe components, storage tanks, and plate sections of refi neries, chemical plants, power plants, and transport lines. Additionally, the CEMs have an ability to perform measurements on pipe diameters of 50mm upwards, measuring changes of wall thickness of as little as 1%, withstanding changes in surface temperature of -40 to 180°C, and operating in pipe temperatures of -40 to 150°C. Even though this is a proven and e· cient technology, Ramírez Jurado fi nds that there is little interest from Pemex to implement it. However, he believes that it is just a matter of time until this situation changes due to the multiple advantages this technology o† ers, which includes a wide temperature range, operator independence, an ability to cover large pipeline areas, high sensitivity, easy to install, and most importantly, being designed for a lifetime of operation.

Over the coming years, more technologies like CEMs are expected to be implemented by Pemex in order to improve the monitoring and maintenance of its infrastructure. Besides helping operators monitor the status of pipelines and the e† ects corrosion or erosion might have on them and their performance, the CEM is also an e† ective tool in helping operators comply with newer standards and regulations regarding the need for condition monitoring of pipelines and other subsea infrastructure.