1. The Importance of Corrosion Protection for Offshore Platforms

Marine corrosion environments are extremely complex, with corrosion of steel along the coast being 400-500 times higher than in deserts. Steel samples 24 meters from the coast corrode 12 times faster than identical steel samples 240 meters from the coast.

In the design and construction of offshore platforms, corrosion is one of the important factors that must be considered. Understanding the characteristics of marine corrosion environments and implementing effective protection measures, along with regular inspections and maintenance, is critical to ensuring the effectiveness of the corrosion protection system and the safety and reliability of the offshore platform.

Currently, offshore platforms are located in increasingly deeper sea areas, are growing larger, with more complex structures, and higher investments. To develop oil and gas economically and ensure production safety, corrosion control for these platforms is essential.

Reference Standards

Relevant current national standards, mandatory provisions of the standards, etc.;

"Building Corrosion Protection Engineering Construction and Acceptance Specifications" (GB50212-2002)

"Standard for Surface Corrosion Level and Rust Removal Level of Steel before Coating" (GB8923-1988)

"Safety Regulations for Coating Operations, Safety Management Rules" (GB6514-1995)

"Quality Requirements for Anti-corrosion Coatings" (GB6514-1991)

"Safety Regulations for Coating Operations, Safety of Painting Process and Ventilation Purification" (DJ/T6931-1999)

"Industrial Equipment, Pipeline Anti-corrosion Engineering Construction and Acceptance Specifications" (HGJ229-91)

"Safety Regulations for Coating Operations, Surface Treatment Process Safety Before Coating" (GB7692-87)

"Noise Limit Values at Construction Site Boundaries" (GB12523-90)

ISO9001 Quality Management System Documents

ISO14001 Environmental Management System Documents

GB/T28001 Occupational Health and Safety Management System Documents

1. Design Basis

Environmental Conditions: The corrosion level of building steel structures under long-term exposure to atmospheric conditions can be determined according to Table 1.

I. Marine Atmospheric Corrosion Environment

The platform structure is completely exposed to the atmosphere. In atmospheric regions, corrosion is caused by moisture and oxygen in the air. With high humidity, prolonged exposure to sunlight, and the presence of salt particles and salt mist in the atmosphere, these substances accumulate on the surface of the structure, forming a good liquid film that creates favorable conditions for electrochemical corrosion. The corrosion is several times more severe than on land. The most severely corroded area is the underside of the deck, which remains in a damp environment for long periods.

Steel structures in atmospheric zones typically use coatings for corrosion protection. The platform deck, jetty, pipe racks, and non-insulated pipelines can all use a corrosion protection structure with a primer, intermediate coat, and finish coat.

Table 1: Graphene Coating Technology for Atmospheric Zone Steel Structures

Table 2: Hot-dip Galvanizing Using Graphene Coating Technology

I. Зона брызг/приливов: коррозионная среда

Платформа расположена в зоне чередования влажных и сухих поверхностей, воздействуемой приливами и волнами. Это наиболее корродированная часть морской среды. Поверхность часто остаётся влажной и контактирует с воздухом, что обеспечивает достаточное количество кислорода. Чередование увлажнённых поверхностей и кратковременных сухих поверхностей, воздействие брызг волн, столкновения с плавающими предметами и повреждения от морских микроорганизмов приводят к разрушению, вызванному физическими и электрохимическими процессами, с наибольшими разрушениями.

Для защиты от коррозии стальных конструкций в зонах брызг и приливов используется покрытие. Кроме того, поскольку эта зона является наиболее трудной для применения защиты от коррозии, необходимо увеличить запас коррозионной стойкости.

Таблица 1: Стальные конструкции зоны брызг и приливов с катодной защитой + технология покрытия из графена

I. Fully Immersed Zone Corrosion Environment

The platform is located below the splash zone and above the mudline. The corrosion of steel platforms in the fully immersed zone is primarily influenced by dissolved oxygen, leading to electrochemical corrosion. Corrosion in shallow waters may occur more rapidly than in the marine atmosphere, while in deep-sea areas, oxygen levels are often much lower, and the water temperature is close to 0°C, resulting in less corrosion.

Table 1: Steel Structure Corrosion Protection in Fully Immersed Zone Using Graphene Coating Technology

I. Subsea Mud Zone Corrosion Environment

The platform is fully embedded in the seabed mud, where there are sulfate-reducing bacteria and other microorganisms. The sources and characteristics of seabed sediments vary. This area is less affected by seawater, and the temperature is low, resulting in minimal corrosion. Only at the boundary where ocean currents act, there is some corrosion.

Table 1: Steel Structure Corrosion Protection in Fully Immersed and Mud Zones Using Cathodic Protection + Graphene Coating Technology