Studying the effectiveness of a modernized cathodic protection system for an offshore platform

Abstract

Purpose

The aim of this paper is to present the modernization of an old cathodic protection system installed on the legs of an offshore platform and to discuss the results of the research performed in order to investigate the anticorrosive effectiveness of this solution.

Design/methodology/approach

The modernization of the cathodic protection system consisted of connecting to the platform legs a sacrificial anode system placed at the sea bottom. The effectiveness of the modernized system was assessed on the basis of the measurements of the potential profiles of the platform legs, i.e. the distribution of their potential over the entire length.

Findings

After connecting sacrificial anode systems, the potential of the legs kept changing towards more negative values. The extent of cathodic polarization increased, and already after a week the potential of the legs fell within the range of full cathodic protection almost along their entire length. The polarization was higher at the lower parts and decreased close to the water surface, which was a result of the distance of a given fragment from the anodic system. The results of the measurements confirmed the correctness of the design assumptions and the effectiveness of the performed modernization.

Originality/value

The results obtained show that the modernization of the cathodic protection system on the legs of an offshore platform consisting of connecting sacrificial anode systems placed at the sea bottom can ensure the achievement of full cathodic protection potential for long legs (these were 80 m long in this study).

Citation

Zakowski, K. (2011), "Studying the effectiveness of a modernized cathodic protection system for an offshore platform", Anti-Corrosion Methods and Materials, Vol. 58 No. 4, pp. 167-172. https://doi.org/10.1108/00035591111148876