An oil platform, oil rig, offshore platform, or oil and/or gas production platform is a large steel structure with facilities to extract, and process petroleum and natural gas that lie in rock formations beneath the seabed. Many oil platforms also include facilities to accommodate their workforce. Steel in terms of plates, supporting structural bars, hollow sections and other types of structural elements is the most common material used in the construction of all parts of the platform.

The oil platform is a truss consisting of tubes. Typical oil platforms are more than 60m heigh and 40m wide.

Protecting the platform against corrosion is crucial as it affects its operational lifetime. Cathodic protection (CP) is the most used method towards this scope. CP uses sacrificial anodes, impressed current or a hybrid combination of the two methods.

It is of utmost importance for CP engineers, to have a reliable tool that can help them perform solid calculations of the corrosion effect. SC3D PITHIA-CP has become the add-on of choice for Siemens Digital Industries Software, as it provides realistic virtual models of Cathodic Protection systems in structures with accurate prediction of current and potential distribution. Through this partnership SC3D PITHIA-CP can enable data exchange between the SC3D PITHIA-CP solver and existing Simcenter solvers, such as the Simcenter NASTRAN software solvers, for coupling and solving advanced simulation problems.

As an example, we present an immersed in seawater platform with overall dimensions of 48m Χ 48m Χ 90 m. The immersed area of the platform is 10.350 m2. 

The CP system consists of 274 identical cylindrical aluminum sacrificial anodes with specific length and diameter. The anodes are mounded at 20cm away from the platform. The upper part of the frame, as shown in red in Figure, exceeds the waterline and thus is the limit of the semi-infinite space. 

SC3D PITHIA-CP provides all tools necessary to conduct this study. Some contour plots are shown below:

Contour plot of electrochemical potential φ (mV vs. Ag/AgCl/seawater) on the surface of the platform for Case Study 1 (Steel-Aluminum).

Contour plot of electric current density i (A/m2 vs. Ag/AgCl/seawater) on the surface of the platform (Steel-Aluminum).

If you have any questions, you are always welcome to contact us at info@feacomp.com