Preventing Corrosion in Offshore O&G Installations
Published on : Wednesday 03-06-2020
Offshore oil & gas (O&G) installations are comprised of fixed and floating installations of the O&G production platform and pipelines. In addition, these platforms are exposed to corrosive, hostile, environments, and need preventive maintenance to safeguard prolonged and safe operation for many years. Corrosion in Offshore O&G installations primarily identifies above water, in the splash zone, and subsea.
In the offshore installations, the prime factors include coating systems, surface preparation, application, and maintenance to evaluate the corrosion prevention in the end-use application. The offshore companies primarily emphasize the use of cathodic protection (CP). Also, as per offshore O&G companies, corrosion is acting as the main challenge in the development of the project due to the harsh marine environment around it. This caters to the highest percentage of investment from the companies for the prevention process.
The Current Corrosion Issues in Offshore O&G installations
Offshore wells primarily hold over 23% of the world's oil production in 2019. Although there is no clear identification of offshore platforms in the global market, it is predicted that there are more than 17,000 offshore wells worldwide. These wells can be categorized from single-well structures to complex structures, which cover the range of 10 ft to 1,000 ft in depths of water. Offshore O&G installations are primarily built for 20 to 40 years at a million-dollar cost.
Offshore installations are primarily facing three kinds of corrosive zones along with unique corrosion issues –
• Atmospheric zone (primarily above water)
• Splash zone (tidal)
• Subsea zone (underwater and sea bottom)
It is also stated that the mechanically and electrically connected well casings to the platform also have corrosion issues.
The Rectification Process of Corrosion Monitoring
The primary aim of corrosion monitoring in Offshore O&G installations is to prevent corrosion through getting continuous real-time, statistical, and periodic data. The corrosion monitoring is categorized into three parameters –
The use of online monitoring primarily detects and identifies the water corrosivity based on online equipment following linear polarization resistance or electrochemical impedance spectroscopy. The process is evaluating the real-time data and further provides an indication related to the level of corrosion on the installed lines.
Continuous Monitoring aims to provide a collection of data related to know the corrosion protection level of an O&G production platform pipeline over a trend or period. This also provides the reveals and pop-out to indicate about the failures of corrosion prevention programs over a defined period.
It is primarily periodic monitoring and identifies the cumulative corrosion rate over a period of time. For instance, the microbiologically influenced corrosion (MIC) of the pipeline and structure installed, while this cannot identify or evaluate through online monitoring. In other words, periodic monitoring can be used to get Coupons, intelligent pigging, and other recently introduced techniques to prevent corrosion in Offshore O&G installations.
In conclusion, it is expected that the prevention of any kind of corrosion of the O&G production platform and pipelines involves the above three steps, which are primarily incorporated by the offshore application operating companies. These steps are also expected to assist in ensuring the integrity of oil and gas field pipelines to further minimizes or reduce the risk of uninterrupted oil and gas supply in the global market. In the ecosystem of offshore oil & gas, the companies involved have high investment power to adopt such steps to enhance their supply with any production issues.