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tion is still a valid part of ponent is magnetized at the same the process, service compa- time.” With this technique, inter- nies have developed tools nal defects such as corrosion, pit- to address speci? c chal- ting and cracks can be detected lenges. New technologies from the external surface.

The MEC technique can be and techniques have been used on caissons with an outer developed in order to obtain

PRODUCTION diameter of 10-42in, wall thick- the most accurate assess- ness up to 25.4mm and coating ment on caisson degradation. thickness up to 15mm, Boenisch

Ultrasonic corrosion testing says. This method requires only is becoming the standard the removal of heavy marine tool for internal and external growth prior to the inspection inspection for many service and can also be used in con- companies. Other technolo- junction with other advanced gies include visual inspection,

A Stork worker conducting an inspection.

inspection techniques such as 3D laser scanning, high-pressure ultrasonic testing.

cleaning, and ROVs for external deepwa- and reliability of inspection results with ter inspection. existing tools currently in the market

AISUS Offshore place. Limited reliability of the inspec-

Stork Technical Services tion information from existing tools can AISUS Offshore, also based in Aberdeen,

Utrecht, Netherlands-headquartered lead to less than optimal integrity deci- specializes in remotely deployed visual

Stork Technical Services, an asset sions, with costly outcomes for opera- and ultrasonic inspections. For the com- integrity management specialist, uses tors, he says. pany, the high-pressure cleaning goes

Also tools becoming stuck within the ultrasonic corrosion mapping and 3D hand in hand with the ultrasonic inspec- structures were an issue, “This was hav- laser scanning for nondestructive test- tion method because the data obtained ing major impacts on operations offshore,” ing (NDT) internal inspection. They from the ultrasonic is more accurate

Bulloch says. “Our tool has several fail- also have a visual camera with bright when the marine debris is removed. safe mechanisms in it. With any loss of “We use a zone 2 diesel driven high- lighting to check for any corrosion. This power, the whole tool collapses and we pressured water jetting unit to remove method is conducted simultaneously in can retrieve it, we have other mechanisms all scale, marine growth and loose debris order to make sure the data is accurate. that prevent it from getting jammed from from the caisson interior,” says Stuart “The laser is a beam of light on a ro- unexpected obstructions, thereby lower- Lawson, managing director, AISUS Off- tating head,” Vaverka says. “As the unit ing risk of downtime to the asset.” shore. “The cleaning apparatus can oper- goes down, the laser head is circulat- ate at pressures between 6000-10,000 psi.” ing. That pinpoint of laser light, when it Sonomatic’s tool can inspect both re? ects back from an object, the unit is the dry section and submerged section The visual inspection method uses a able to see that. And it can tell based on with ultrasonic corrosion mapping to remotely deployed camera that scans the the speed of light, how long that took, complete the internal inspection for re- internal walls. The camera is backed up and how far something is. When you get maining wall thickness, and can inspect with LED lights and lasers that looks for no return, then there’s a hole. If you get welds from the corroded surface looking degradation, blockages, internal diame- a return, you can calculate how deep for fatigue cracking. The company also ter changes, wall loss defects, corrosion, that return goes.” deploys subsea tools deployed by ROV scale and any other anomalies identi? ed

Stork’s tool allows for both the laser for external inspections with various during the inspection. scanning and ultrasonic corrosion test- ultrasonic imaging techniques.

Conclusion ing. The method uses sound waves to

Innospection travel through the steel walls. Based on Caisson inspections are important for the return, the data analyzed reveals the Aberdeen, Scotland-based Innospection maintaining the integrity and safety of thickness of the steel walls. specializes in electromagnetic inspec- the rig. The inspection process has al- tion technologies for its NDT solutions, ways posed a challenge because of hard

Sonomatic speci? cally the Magnetic Eddy Current to reach places that limit or hinder ob-

Both Stork and Warrington, England- (MEC) technique. taining accurate data. The industry has

Standard Eddy Current is only sensi- based Sonomatic have a tool in their developed many techniques to address tive at the surface of the metallic mate- arsenal, which the companies say is able these challenges both for internal and rial. “Modi? cation to the standard Eddy to squeeze into tight places. external topside and subsea inspection current enables the deeper inspection of

Sonomatic, which specializes in ad- from visual inspection, 3D laser scan- the metallic structures,” says Andreas vanced ultrasonic inspections and asset ning, ultrasonic corrosion scanning, and

Boenisch, managing director at Innospec- integrity solutions introduced its new electromagnetic currents. Often running tion. “Defect detection using the MEC internal caisson inspection tool at the one or more of these techniques increas- technique is achieved by superimposing 2015 SPE Offshore Europe conference in es the accuracy of the data obtained. As direct current magnetization with an

September. Scott Bulloch, topside proj- technology improves in these ? elds, so

Eddy current ? eld i.e. an Eddy Current ect manager Sonomatic, says the tool does the quality of data, and the ability coil is used on the ferromagnetic material was developed because operators were to make decisions on how best to im- while the section of the ferritic steel com- experiencing problems with data quality prove the life of offshore assets.

January 2016 | OE oedigital.com 48 046_OE0116_ProdOps3_Ella.indd 48 12/24/15 9:11 AM