As offshore rigs are taken out of services, some owners neglect to preserve equipment. A Danish company is now making an effort to increase awareness among owners about preservation of equipment with the goal of saving millions.Offshore rigs are among the most complex technical structures globally, and many of their systems consist of both mechanical, hydraulic and electrical sub-systems and equipment. While mechanical equipment is most often placed in the open, some hydraulic systems are placed in machine rooms, and most electrical systems are built in enclosures. However, regardless of their position on the rig they are all subjected to rust attacks, particularly when out of service.

For many years, SH Group has preserved the system solutions and equipment they supply prior to delivery. They have used this extensive experience, to become engaged in preservation for a number of well-known owners in the offshore industry, and they know what it takes to make results.
- First, this is not something that everyone can do. Second, you need a combination of technical and process skills, and an understanding of what is required by the rules. Thirdly, this is not something you can do from behind a desk, but you need to get your hands on the equipment, says Jeppe Sonne, director at SH Group, and the person advocating preservation to the industry.

Why preserve equipment?
Fact is; corrosion is an incredibly destructive force facing everyone who works with metal. There are no valid estimates of the cost of corrosion in the offshore industry, but it is likely that for any given rig-owner it amounts to millions of dollars every year.

Therefore cost-saving is the most important aspect of preservation, and SH Group estimates, that the savings could amount to as much as 55-65% of the price of new equipment, depending on the complexity and the environment the equipment is in.
- It is our opinion that every owner should make an assessment of their equipment, so that they are prepared to actually do something, rather than hope for the best. The first natural step is to get an overview of the equipment on board, assess the combined value, then anyone will realize that preservation should be top-priority when taking rigs out of service, says Sonne.

Which preservation methods to choose?
Some corrosion protection methods employed are less effective and others are not environmentally friendly, so it is important to choose the right methods. SH Group works with various technologies when they assist customers with knowledge, training and on-site preservation jobs.

One method of corrosion protection is the Vapor phase Corrosion Inhibiting method (VpCI), that were initially nitrite-free multimetal solutions, and many of which are now water-based solutions. SH Group recommends using only the latest technology in VpCI for protecting rigs and offshore equipment, and their crew has been trained specifically for this technology. The effect of VpCI can be seen in photo No. 1 showing two test glasses with and without the inhibitor.

Another method is using a VpCI-368 liquid that is applied directly to the equipment that should be preserved. This technology is a wax based product that can be recommended for equipment in extremely aggressive environments and it make a real difference as can be seen from photo No. 2, showing a 14 days comparative test of bolts with and without protection.

René Aborrelund of SH Group has been in charge of gathering a comprehensive overview of the knowledge of all the technologies in SH Group, and it has not been a small task.
- Getting the overview of the technologies has taken quite some time, mainly because we want to be sure which technology is suitable for which applications. This way we can guarantee to our customers that it will be effective, he says.

What’s the process when preserving equipment?
Typically the need for preserving equipment arises in connection with 5-year classifications of equipment where the owner wants to achieve a care-free two-year period after the classification. Preservation is also relevant when equipment is being supplied from manufacturer to yard, when the rig leaves the yard, or when rigs are taken out of service temporarily.

SH Group has been involved in quite a few projects with preservation, and if there is one experience that applies generally, then it’s the fact that getting started early makes the best foundation for a good result.

An example of best practice is a leading drilling company who had asked SH Group to establish a procedure for preservation of their new jack-up rigs before leaving Singapore (Keppel Fels). During a one-month stay at the yard, a complete review of the equipment was made using all available documentation, and this was collated into one overall preservation procedure that contractors could follow. The consulting work later led to a co-operation on the preservation work itself, so that SH Group ended up taking full responsibility for preservation of everything from electrical equipment to mud pumps.
- Naturally, we were very humble towards a job as extensive as this, but given the fact that we had the necessary time to collate data and establish procedures that could actually be used for the contracting work, the project ran smoothly so that everything was ready in time for the transport from Singapore to the North Sea with heavy lifter, says René Aborrelund, who was project manager on the job.

Another example is storage preservation which is currently ongoing on 19 rigs for one of the largest oil companies in the world. On one of the rigs, the equipment had been subjected to airborne rust particles after commissioning, and thus corroded to a state where preservation procedures had to be combined with some repair. Costs accelerated to up to 500% of the budget, which could have been avoided, if action had been taken earlier.
- It is extremely important to consider preservation continuously in the building phase, and even though some equipment is supplied from the manufacturer with preservation, the quality doesn’t always live up to best practise standards, says Aborrelund. All rig owners should ensure that they have the correct procedures in place in time, if costs are to be avoided.

What can owners do by themselves?
Initially, rig owners could make an overview of the equipment that should be preserved when rigs are taken out of service temporarily. What is the value of the equipment, and what is the potential risk involved in not preserving equipment adequately? This way, owners get a picture and understanding of the potential risk of not doing anything when taking rigs out of service.

Having made this analysis, they could check if they have the right procedures in place for preservation of equipment when delivered, when commissioned, in connection with 5-year classifications, or when taken out of service. The right procedures ensure that contractors can follow a prescribed workflow that is both practical and will give the right protection of the equipment. It is not always enough to rely on manufacturers recommendations – so make your own.

Finally, it is necessary to place the responsibility of preserving equipment in the organization, so that no one is in doubt about who is in charge. The responsible person can than make sure contractors or own staff perform according to the company guidelines.

With these actions in place, it is my estimate that rig owners can save millions of dollars when taking rigs temporarily out of service, and we hope that this message is well received, concludes Jeppe Sonne.
Source: SH Group A/S