Application of anti-corrosion coating in offshore drilling platform

In a collaborative effort to improve critical protection on offshore drilling platforms, the Oil & Gas Technology Center successfully conducted trials of anticorrosive coatings on two offshore platforms.

Offshore platforms are one of the world's harshest climates.Usually cold and sea breezes blow, and the RIGS suffer constant corrosion from waves and salt spray.

Traditional coatings simply cannot withstand the environment.Rig maintenance costs can be as much as 100 times higher than land maintenance costs, as crews and supplies often have to be helicopted to the site, thus costing the platform owner huge amounts of money when paint fails.

After extensive research, an inorganic coating called spray coating was identified as a method of providing long-term protection for offshore drilling platforms.The anticorrosion coating represents a new class of tough chemically bonded phosphate ceramics (CBPC) that prevents corrosion, simplifies applications and reduces production downtime on offshore platforms, even in wet, storm or monsoon-sensitive conditions.

On 17 December 2017, the coating was applied to the severely corroded area of the deck below the platform and a topcoat was added for aesthetic effect?

In the test area, the existing coating system was completely removed from the structural steel tubes and plates.Power cleaning and degreasing of the structure to remove contaminants.All pipes are sprayed to SA2.5 and plate machine is prepared to ST3.

Although rusty skin can be seen in the area before the antiseptic coating is applied, this is considered acceptable due to its unique nature.It can be applied to damp substrates with rust/flash rust, and high salt levels do not degrade the coating, which reduces surface preparation requirements.

The coating can cure in a single coating within 15 minutes after application, depending on weather conditions, which requires a significant amount of drying time between coatings compared to conventional coatings.

In contrast to the traditional coating, which forms only a physical barrier to corrosion before being destroyed, the new coating chemically bonds with the exposed substrate surface to provide a ferro-magnesium phosphate layer that protects the steel from corrosion.The process provides long-lasting protection with a very thin layer (about 2 microns).

A second layer - a tough ceramic shell - provides further protection and can also be used as a storage container for the re-phosphorised steel if needed.This ensures that the alloy layer remains intact and allows it to "self-heal" if it is damaged by mechanical damage.

During this ongoing trial, the coating was tested by cross-cutting the bottom material approximately 6-8 inches to provide evidence of the coating's self-healing properties.

After the early success of the test, a second sea trial was carried out.

After assisting with fabric maintenance and surface treatment, apply anticorrosive paint to severely corroded platform areas.

Although the results of the second trial are still being considered, they look promising.

Oil and gas E&P companies want to protect against corrosion on offshore RIGS, expand safety and reduce costly maintenance and downtime.