During the summer of 2004 the Åsgard Transport pipeline System (ÅT) was successfully inspected by a Multi Diameter in-line Pipeline Tool (MDPT) launched sub-sea at a water depth of 300m. The project faced the following operational challenges:

  • Minimize reduction in ÅT production during MDPT installation and inspection

  • Installation of a 44 tonnes sub sea pig launcher module requiring strict weather limitations

  • Tie-in to a live gas system at 300 meter water depth

  • Removal of sea water - risk of hydrates

  • 350 valve operations and 700 procedure steps

  • High focus on HSE&Q and Risk Management

The worlds first internal inspection of an offshore, dual diameter, high pressure gas export pipeline, with a subsea launched Extra High Resolution (XHR) Magnetic Flux Leakage (MFL) tool, was successfully carried out both operationally and a with respect to inspection results. The offshore work took 11 days, the pig travelled for 5 days through the pipeline and the operation was completed on schedule and within budget. The main success factors of the Åsgard Transport inspection can be summarised as follows;

  • The responsibility for follow up of interfaces and contractors, where divided between the Statoil project members to ensure clear lines of communication and responsibilities.

  • All contractors were included in an integrated project team (ÅTPP) to ensure close co-operation and to make sure all parties had a good understanding of what was required.

  • Based on the criticality of the operation an extraordinary high focus on HSE and risk management was implemented.

  • A software procedure training model (colour coded P&ID's, 3D models, animations) was developed and used for training of operational personnel (ROV pilots) as a risk reducing measure and to increase the operating efficiency.

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