Subsea Power Cable Failure

Brief

HKA provided an expert opinion for a project which involved the installation of subsea power cables between two offshore platforms in the Indian Ocean.

A dispute evolved between the client and contractor who was engaged to install pipelines and umbilicals between the offshore platforms.

A cable fault was detected in the power cable and the client suspected this was caused by the Contractor during the pipelay barge operations. The Contractor refuted this assertion.

What we did

To establish how the fault had occurred we reviewed the procedures, reports, drawings, specifications, and photographic evidence including videos.

This included the investigation of the installation procedures and standards to ensure the correct procedures were followed, including:

• Pre-survey activities, and pre-construction activities
• Anchor handling policy, and anchor clearance survey, including anchor lay, anchor drag, and anchor drop and recovery locations
• Work method statement
• Mooring analysis
• Meteorological data and sea state conditions
• Seabed geotechnical survey
• Power cable installation and pre-installation surveys
• Cable lay operations including cable tension and cable pulling
• Cable burying and mud mat protection
• Pipeline crossings
• Cable design and technical review
• Review and interpretation of post damage surveys (photographic and diver)
• Review of test procedures and results

We then provided a report of the marine construction events and produced a timetable prior to and post the failure. The combined technical reports were then produced for the legal team to assist in an international arbitration.

Outcomes

From our investigative analysis of the project data, we were able to determine that the damage to the power cable was not due to the activities of the Contractor during pipeline and cable laying and we were able to provide an alternative theory.