BOP recovery at the double

The Marin Subsea asset recovery team was recently called in to recover a blowout preventer and lower marine riser package from 488m of water in Brazil. Within 20 minutes of the initial phone call, the Marin team had made a preliminary assessment and advised the client on what immediate action to take – and, crucially, what to leave alone.

Forty-eight hours later, the team were en route to Rio de Janeiro from Scotland and less than 12 hours after that had drawn up a detailed work programme and been transferred to the installation.

Over the next 48 hours, the Marin team completed a surface investigation to establish what damage had been done to the BOP’s systems followed by an ROV survey to pinpoint the exact whereabouts and condition of the lost equipment and identify the excavation, fishing and pulling tooling needed to retrieve it.

The BOP had been dropped from 90m and had sunk 18m into the seabed. A total of 400m of riser had been dropped, comprising 26 joints less the slip joint. The riser hub had snapped at joint 9, and from joints 10-26 the riser had fallen back onto the seabed.

The client – under instruction – had already carried out several procedures, including an end-lift recovery of part of the riser and cutting the BOP choke and kill lines. Once its specialist tooling package had been assembled and arrived from Scotland, the Marin team took over. The recovery process included:

  • initial excavation to wash off broken material from the recovery site;
  • follow-up site investigation and further excavation;
  • unbolting the riser via ROV and disengaging above the pup joint;
  • recovering the riser to the surface;
  • further excavation to clear out the BOP impact crater;
  • applying tension on the BOP via the drill string in incremental values until movement was observed; and
  • final recovery of the BOP and pod lines to the surface.

The entire operation took less than five weeks – one of the fastest the Marin team has yet undertaken. This was in large measure because the client had not made a DIY recovery attempt, instead calling Marin Subsea immediately after the BOP was dropped and then undertaking only specified remedial actions before the team arrived. OE


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