StatoilHydro Wraps Up Investigation of Internal Leak at Statfjord Platform

StatoilHydro has completed the group's investigation of the incident on the Statfjord A platform on May 24th, when an internal leak in the platform hull led to gas accumulation inside the shaft and discharge of oily water to sea. The investigation report was submitted to the Petroleum Safety Authority Norway today.

"The incident on Statfjord A at the end of May had the potential of causing serious harm to personnel and the platform," said Tore Torvund, Executive VP for Exploration & Production Norway.

"The investigation reveals the need to continue the effort of enhancing the quality and precision of planning and execution as well as compliance with regulations and management systems. The effort of simplifying our governing documentation and the restructuring of our offshore activities are important measures in this work."

Large potential

It was during modification work involving the use of a tool on an oil-bearing pipe (so-called hot tapping) inside one of the platform shafts of the Statfjord A platform that an oil leak occurred in the tool.

The pipe was connected to several storage cells (as indicated in the illustration).

During the effort of stopping the leak, 50-70 cubic meters of oil was pumped to sea, of which 20 cubic meters were gathered by mobilized standby vessels.

No personnel were injured during the incident.

It has been concluded that the incident had the potential of causing an explosion and damage to the shaft.

It is not probable that the shaft could have lost its carrying capacity.

Causal relation

StatoilHydro’s investigation has revealed the following main causes of the incident:

  • Defects in equipment and tools
  • Insufficient assessment of the risk of a leak and measures to limit the leak volume

The tool that was used for hot tapping when the incident occurred has been developed over a period of three years.

StatoilHydro personnel and the group's suppliers and sub-suppliers have not had sufficient understanding of the risks and impacts. Unclear roles of the various actors have contributed to insufficient quality and follow-up in connection with development of the tool.

Failing to comply with StatoilHydro's procedures for modifications of processing plants, Safe Job Analysis (SJA) and work permits has also been proven.

It was decided to complete the modifications during night work based on the desire to secure continuous operation and thereby reduce risks. The incident occurred at 06.00. The investigation group has not proven any causal connection between the incident and the night work.


Immediate technical actions have already been taken to ensure experience transfer to other hot tapping operations and work on hydrocarbon-bearing systems in platform shafts.

StatoilHydro has already started a process to establish common work procedures on all of the group's offshore facilities and has started intensified training of each individual leader of operational activities in relevant work processes.

These are important measures to increase each individual's understanding of his/her role, and to ensure compliance with procedures and regulations as well as increasing the quality of the planning and execution of operational functions.

The model for integration of StatoilHydro's offshore and onshore installations and base activities that was approved in June will enhance the HSE effort and the responsibilities in the group's operational activities.
Special training will be given in accordance with StatoilHydro’s procedures for modifications of processing plants, Safe Job Analysis and the work permit system for personnel on Statfjord A and other selected installations.

"We will also carry out a verification of selected modification projects on our facilities with regard to risk assessment, specially focusing on the major accident potential," added Torvund.