LETS Global is an engineering and consulting company. Our main field of business is the life extension of welded structures and components subjected to fatigue loads. We have developed our own technologies, processes and equipment based on ultrasonic technology.
We are proud to be the pioneers with the successful application of ultrasonic peening treatment as a life extension technique since 2005 on a number of offshore installations, earth moving equipment and mining industry machinery. The ultrasonic peening treatment used as a complement to advanced stress analysis techniques entails the enhancement of structural integrity of the installation.
_HERE IS the READ button, when you click at the READ button you move to About us: The picture you will insert is the first picture attached (no lady in office please) The picture is ok now so do not make it blurry or disproportionate please. Text continues below._
What is the most environmentally friendly and economical wise alternative for any ageing offshore installation? In view of an evident economical insecure situation on the energy markets worldwide and as a consequence of it the continuous increase of oil and gas prices, it seems to us that the life extension would be by time being the absolute wiser and solely alternative.
HOW DO WE BEST CARE FOR OUR OLD OFFSHORE INSTALLATIONS?
The subject of life extension of ageing offshore structures is becoming a hotter topic than ever. The reasons are among others: costs of life extension against new-built, continuous increase of oil price, increased environmental concerns in the an already crowded seas where oil and gas is found; from design to production a new platform will take no less than five years, the cost of life extension is normally a fraction of new production of an installation, etc.
Several seminars around the world showed that the interest is growing steady and it seems to have all the right to do so. Over 100 platforms in the Nord Sea have reached the typical design life of 25 years. (John Sharp, Cranfield University, Aberdeen). An overwhelming amount that as every day pass also implies growing risks and need for maintenance.
The last years we have seen a growing number of standards and regulations developing in this specific field. When planning to use an offshore installation beyond its original design life there is usually a demand for applying for consent or revision of the safety case, depending on geographical spot among others.
As original design lives are reached and as standards are continuously developing it is now a growing concern how to extend the original fatigue design life with reasonable work and cost expenditure. Managing life extension will therefore become a key activity for companies that wish to reduce downtime and avoid increasing future costs connected to structural maintenance including replacement of parts or the whole installation.
As the time goes the cracks growth
The risk growths as every day passes and to reduce downtime as well as to avoid to every price accidents, preventive treatment is essential. Companies seek understanding on what to do as it is still a new situation to many, life extension is still a vague concept to many ears. But what do we actually do to maintain service life for a long period to come, to extend life? After design life is reached new assessments have to be made on how much longer the structure is fit-for-service. Structural integrity analysis is the first step on analysing the state of structure. Usually, no assessments and little maintenance work have been done until it reaches design life so surprises as well as expectations may occur. Discovered flaws are then to be treated and the best treatment available today is the ultrasonic peening technique. However, it is far wiser to prevent the cracks to appear. It is necessary then to know where they will appear and to which extent.
Ultrasonic peening technique is an old treatment method for welds. It was first developed during the second world war by the German army to treat welds with hamring in order to avoid cracks. In the Soviet Union during the Cold War the hamring was combined with magnetostrictive high frequency devices so the hamring where then ultrasonic and in that way, it was used in submarines. The technique is proven to be better than all other peening techniques and is the best one available on the market today and can extend the life up to 4 times for the concerned weld.
The treatment, consisting of ultrasonic waves, is able to reduce welding stresses and deformations while increasing the compressive stresses needed to prevent the origin and/or propagation of fatigue cracks. LETS Global, the only company working with the concept of UP treatment in the North Sea, but also working globally we are pioneers in the field of treating welds in offshore installations. The company is currently working on an ongoing project in the North Sea and in the Campos Basin in order to extend the service life of the installations to reach a further design life of 20 years. The contractors of the life extension project at an FPSO, says that: it is the best technique we’ve found!
Due to the fact that the UP machine is a practical handheld tool makes access to difficult areas possible and treatment is efficient. It is important to remember that fatigue cracks may occur in parts of very difficult access. LETS Global is performing services to assess possible life extension and provide treatment.