Abstract
The external steel surfaces of offshore oil and gas production systems are typically protected by anti-corrosion coatings and cathodic protection (CP) systems. CP systems for different components of an offshore production system (e.g. platform, risers and pipelines, subsea equipment and shore crossings) are often designed by different contractors. However, all these components should act as one integrated CP system unless isolation joints are installed, which is not common due to high cost and long fabrication lead time. Therefore, a systematic CP management program is often desired, to be studied and defined during design and implemented and managed during operation. This paper will present a systematic CP design strategy to manage and optimize the overall CP system for an offshore production system. Related key issues of CP will be discussed, including potentially inconsistent requirements between different design guidelines, materials compatibility issues (e.g. CP induced hydrogen embrittlement), current drains due to adjacent structures, coating concerns, and anode manufacturing quality. This paper will focus on how to address the major CP concerns from the system point of view during the design phase of offshore projects. It will also recommend solutions for potential issues that may arise during the installation and operation phases of projects. In addition, special CP design requirements such as shore crossing CP design and potential attenuation CP design will be discussed.
