Corrosion under insulation is considered as a major threat to offshore facilities, and that’s the reason nowadays industry is researching new technology to help identify the impact prior and more consistently.
The battle against corrosion is a pervasive issue for the offshore oil and gas industry, with structures, pipework, and tools broadly exposed to seawater and moist salty atmosphere. Mainly, Corrosion under insulation (CUI) affects steel gears, which corrode when they comes in the contact with water and air.
Insulation of plant and pipework can generate a space where water can gather and rest against the metal surface over extensive periods of time. With outdoor tools, even very small gaps in insulating shell can let in enough volumes of water to create significant corrosion issues. These days, advances in imaging technology are offering offshore safeguarding crews with much more data on the ‘hidden’ state of their assets than was accessible 10 years ago.
An additional dilemma created by insulation is that it can cover the effects of the corrosion from view, so that a heavily oxidized pipe can appear usual when visually inspected. But by the time the effects have become evidently noticeable from the outside – frequently in the form of particles of corroded metal or discoloured water running off – considerable damage may already have occurred. Removing insulation to make sure the form of pipework is a laborious procedure and a costly process of assessing the condition of an asset. Preservation specialists have developed a set of diverse solutions that can make controlling CUI across an installation more competent and help ensure pipes and structures conform to the set guidelines.
Inspection efficiency (prevention of corrosion)
The major cost linked with inspecting for corrosion is manpower, and this is intensified in the case of offshore facilities – activating the right employees onboard and ensuring that they obtain the accurate briefing is a time-consuming procedure. The focus must consequently be on lessening the resources required to carry out the work. The favoured approach is for the scrutiny and fabric safeguarding departments to work together, using three-man teams consists of an assessor, insulator and artist, all of whom are rope access-professionals. Keeping the teams as small as possible can escort to substantial reductions in rate.
It is better still to avoid the process of transferring new people to site to carry out an assessment by instead training team members previously on location to handle assessment work. Advances in technology to assist automate the procedure have played a huge part in making this achievable, increasing the competence and effectiveness of inspection team members. Equipping teams with CUI detection tools such as digital radiography and pulsed eddy current (PEC) expertise can considerably speed up site assessment processes and advance the likelihood of early exposure.
Though radiographic and PEC imaging are not innovative the techniques used to carry out inspections have advanced swiftly. Previously each radiographic coverage took several minutes to restrain and consequently needed to be processed using lab tools. These firm steps can now be taken in a matter of shot span of time and images can be viewed on the spot on any of the mobile device.
As lately as five years ago, PEC readings needed to be carrying out on a point-to-point basis, making it lengthy to confine all the angles and positions obligatory to scan a length of pipework. In response, there are major industries who worked with imaging specialists to develop a proper system that runs incessantly. This cuts the time taken and considerably increases the number of data points accessible, providing better assurance of results. Using mobile data processing devices, skilled engineers can now output easy-to-interpret situation reports presenting the location and amount of any faults without any need for desktop investigation. This means response times to priority corrosion issues can be much earlier.
These days, there are major global energy companies which are involved in renewing the insulation on all exterior pipework where generally CUI was discovered. The existing insulation was mineral wool, covered in neoprene shelling, and the reason of the CUI in each case was breakdown of the elastomeric sealant used in the joints between varied sections.
Where substitutes were required, the mineral wool was altered with foam glass. This was clad in banding tape preserved with Terostat PC vapor-barrier mastic, a durable sealant confirmed to deliver better resistance than elastomeric alternatives. The insulation was functional in the form of pre-fabricated shells supplied custom-made allowing fast fitting on site and dropping costs.
The extent of the project, which involved reinstating hundreds of meters of insulation, meant that the works took place over past several months. Throughout release, the project team offered a monthly report with information on efficiency, tool-time, expenses, man distribution hours, work pack tracker, health security, environment and quality CUI figures and linear distance re-insulated.
CUI is significant, particularly where ageing tools and infrastructure is involved, and the present trend for maximizing the existence of large pieces of offshore infrastructure involves increased challenges, particularly at mature fields on the various continental shelves. Failure to manage CUI can, at preeminent, lead to costly and time-consuming safeguarding operations; at worst, it can create a major threat to the protection of facilities and workers, so this is not an area offshore operator can pay for overlook.
The monetary burden involved in performing assessment can be considerable, but advances in both assessment technology and tactics have considerably augmented the competence of the procedure in recent years, lessening the temptation to push back or skip what is an imperative safety monitoring procedure.
Aurelius Corporate Solution organises an event on CUI on 22-23 October, 2019 in Amsterdam, The Netherlands. One can click on the below link o get registration details.