PSA: Oil spill on ConocoPhillips’ Eldfisk caused by blowdown valve

The Petroleum Safety Authority Norway (PSA) has completed its investigation into two incidents which occurred on ConocoPhillips’ Eldfisk complex, in the Norwegian North Sea, on 6-8 August 2014. According to the regulator, several breaches of the regulations have been identified.

Eldfisk is an oilfield, that also contains some gas, discovered in 1970 and started production in 1979. ConocoPhillips is the operator with an ownership interest of 35.11 percent.

To remind, the highest emergency shutdown level (yellow ESD – abandon platform) was initiated on the Eldfisk complex and Embla on the morning of August 6, 2014. This caused total loss of power and all systems shut down on the Eldfisk A, Eldfisk FTP and Embla installations, while Eldfisk E lost main power.

The PSA says that the ESD was unplanned and its direct cause was the technical failure of an electronic component combined with a design error.

Oil spill

When restarting production after the ESD, a blowdown valve remained in the open position. According to the regulator, it should have been reset to the closed position as part of the start-up procedure. That caused produced oil to flow into the flare system, on into the drain system and from there to the sea.

At dawn on August 7, 2014, more oil appeared to be discharging to the sea, but production was not shut down until 13.30 on August 7 after which the review of the facility began. The PSA says that the oil spill is estimated to have been in the order of 50-70 m3.

The PSA’s investigation of the incident has identified several breaches of the regulations of a technical and operational character. Some of the technical non-conformities relate to Eldfisk FTP’s condition at the time of the incident. This facility has subsequently been shut down and now functions primarily as a bridge support.

Non-conformity

The PSA reports that insufficient attention was paid when planning the production start-up after the yellow ESD to keeping important risk contributors under control, both individually and collectively.

According to the PSA, the platform management decided to resume production without adequately checking and confirming that the conditions for start-up and operation were fulfilled. Furthermore, no action was taken to handle risk-affecting factors specific to the conditions, such as difficult working conditions, high workload and insufficient rest for control room operators.

“These factors must be viewed in relation to known challenges with operating parameters and the staffing level in the CCR on Eldfisk FTP,” the PSA said.

The investigation revealed the following conditions which collectively support the non-conformity:

1. Human factors – Requirements for off-duty periods were not met, and difficult working conditions in the control room;

2. Increased scope of work for control room operators. Assistance was given for normalisation on Embla in parallel with their own production start-up.

3. Factors influencing risk – CCR combined with human factors and non-specific start-up procedures.

4. The facility, systems and equipment were not cleared in safety terms and systematically checked as gas-free before the decision was taken to resume production and introduce ignition sources.

The PSA has asked operator ConocoPhillips to describe how it intends to deal with the non-conformities.

Offshore Energy Today Staff

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