During the installation of flexible pipe riser systems connecting floating production facilities to subsea equipment and production flowlines, several incidents resulted in consequential damage to multiple flexible risers. To determine incident causes and responsibilities, Baker & O’Brien investigated the design, project procedures, and execution of offshore installation and diving operations. We presented our findings and conclusions in a preliminary report to assist pre-arbitration discussions.

Offshore oil and gas projects often require the installation of complex floating production systems and subsea equipment, including flowlines, manifolds, and control systems. Piping riser systems connect floating offshore production systems (platforms and FPSOs) to production flowlines from subsea wells located on the seabed and nearby facilities, like other platforms. It is in these flowlines that oil and gas produced from the wellhead flow to surface treating facilities. Flexible pipe riser systems (flexible risers) accommodate the range of motions between the facility above the water and the static production flowlines resting on the seabed in water depths of up to 1,500 meters.

During an offshore installation of flexible risers in shallow water, several unrelated incidents resulted in project delays and additional costs. The incidents occurred over the period of the installation campaign at various subsea locations and involved mechanical damage to flexible flowline risers and a subsea clamp device. The clamp device was used to connect one of the flexible risers to an existing flowline resting on the seabed. Baker & O’Brien was engaged to identify incident causes concerning the responsibilities for technical design, project procedures, and the execution of offshore installation and diving operations.

As part of our investigation, we reviewed the engineering design, installation tolerances, project installation plans and procedures, risk assessment, and video and audio recordings of the divers installing the flexible risers and subsea clamp. Our work was carried out expeditiously as part of a pre-arbitration process, and we understand that our preliminary report assisted the parties in settling.