Statfjord Oil Spill Investigation Report Submitted to PSA Norway
StatoilHydro has submitted the company's investigation report on the 12 December 2007 oil spill on the Statfjord field to the Petroleum Safety Authority Norway.
"The oil spill at Statfjord is very serious. The investigation has revealed weaknesses both of a technical and organisational nature that we have immediately addressed," says Tore Torvund, executive vice president, Exploration & Production Norway.
In connection with oil loading from Statfjord A to the tanker Navion Britannia on 12 December 2007 the loading hose ruptured. The rupture resulted in a spill of about 4400 cubic metres of oil to the sea. An investigation team was appointed by StatoilHydro’s management to identify the causes of the oil spill.
The investigation has identified the following main reasons for the loading hose rupture: Rupture in a hydraulic hose on Navion Britannia caused the vessel's coupler valve to close quicker than expected. This generated a strong pressure surge in the loading hose. The loading hose pressure capacity was about half that of the original Coflexip hose and the quick valve closing generated pressure build-up, which resulted in rupture of the loading hose.
The investigation has identified that the root causes of the hose rupture are mainly related to inadequate use of process and risk analyses in connection with modifications and change of loading hose.
The resumption of the loading operation after the rupture of the hydraulic hose to the coupler valve was mainly due to inadequate knowledge by the involved personnel of its consequences. The failure to discover the oil spill before approx. 4400 m3 had been spilled was mainly due to inadequate oil flow measurement on board the tanker.
A review of former incidents related to single-point loading systems has shown that a similar incident on the Gullfaks field in 2004 has not been adequately followed up.
The investigation team recommends a number of actions within StatoilHydro, the shipowner Teekay and the system supplier APL. The actions are of a technical, organisational and managerial nature.
"Based on the weaknesses that are identified StatoilHydro has already implemented several technical and operational actions in order to ensure safe operation of our single-point loading systems. We will immediately initiate work to address the organisational and managerial weaknesses identified in the report," Tore Torvund says.
An extensive environmental monitoring programme after the spill has not identified any significant environmental consequences. Thanks to the nature of the oil and weather conditions in the area the oil has evaporated and dissolved in the water.
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