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The project adopts the combined technology of " impressed current cathodic protection + sacrificial anode auxiliary protection " to ensure the safe service life of drilling rig jacket and attached steel pile structure for more than 30 years in view of the Marine environment of high salt (chloride concentration > 17g/L), high temperature and strong corrosion in the South China Sea. The system design covers the whole platform steel pile, underwater manifold and other key parts. Combined with intelligent monitoring and dynamic regulation, the corrosion rate can be reduced to ≤0.01mm/ year .
Impressed current cathodic protection system
Equipment configuration : titanium alloy mesh anode, Ag/AgCl reference electrode and explosion-proof potentioconstant instrument are deployed, and the protection current density is controlled in real time through centralized control room (design range: 5-20mA/m²). The protection potential is stabilized from -800mV to -1100mv (CSE) .
environmental adaptation : In view of wave impact and tide change, anti-erosion anode packaging technology was adopted. The uniformity and durability of anode layout was verified by Zhanjiang port simulation test .
sacrificial anode auxiliary protection
material selection : Al-Zinc-indium-cadmium alloy sacrific anodes are installed in high-risk parts such as jacket node and splash zone. The net weight of single anodes is 200kg, the design life is ≥25 years, and the ground resistance 24 is reduced by filling coke powder.
redundant design : double reference electrode verification mechanism is used to ensure the match between anode consumption rate and protection potential, to avoid local over-protection or under-protection .
Intelligent monitoring upgrade
The in-situ corrosion monitoring network is deployed, and the potential sensor, current density probe and wireless transmission module are integrated to realize remote real-time monitoring of protection potential and coating damage point .
The dynamic flow regulation algorithm is developed. Combining tidal period and seawater conductivity changes, the output current of potentiostat is automatically optimized, and the energy consumption is reduced by more than 15% .
Environmental Protection and Cost Optimization
Compared with the traditional aluminum alloy sacrificial anode solution, the impressed current system reduces metal consumption by 90% and reduces life-cycle carbon emissions .
Modular prefabricated anode components increase construction efficiency by 40% and reduce the risk of working at sea .
The project was successfully applied to deepwater oil and gas platforms such as Liwan and Liuhua in the South China Sea. The coverage rate of cathodic protection system exceeded 99%, and the corrosion rate of jacket decreased by 98% compared with that in unprotected areas 12. Its " intelligent regulation and control + dual protection " model provides a standardized solution for deep-sea engineering corrosion prevention, pushing the offshore oil and gas equipment corrosion prevention technology to reach the international leading level .
