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Petrobras In-House Report Reveals What Caused FPSO Explosion

One mistake after another- spanning from technical failures, proceedings, and poor decision making- may be the cause of the explosion on BW Offshore’s FPSO Cidade de São Mateus in February 2015, off the coast of Vitória, in the Espírito Santo state.

Nine workers were killed in the incident and twenty six were injured.

G1 News Service viewed an in-house report by Petrobras outlining the causes of the accident, which mentions the installation of out-of-standard parts on critical systems, poor planning and risk analysis on inter-tank fluid-transfer pipelines replacement, sending responding crews to the pump room with the gas alarm on, and the lack of previous simulations to enable responding crews dealing with hazardous situations of this kind.

Although the report disclosure was restricted to Petrobras teams only, neither Petrobras nor BW Offshore officials replied to any request for comments.

ANP, the Brazilian oil and gas regulator, said that seventy-four people were on board at the time of the explosion.

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FPSO Cidade de São Mateus. Image credit: G1 News Service


The local Vitória newspaper, A Gazeta was allowed to view an in-house HSE Alert which details the explosion. Sources connected with Petrobras have remarked that a blind flange had been installed onto a water and condensed oil transfer line. However, the flange was unable to withstand the pressure demanded by the operation.

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The HSE Alert viewed by A Gazeta. Image credit: G1 News Service.

According to the same sources, a mistake was made upon opening and closing valves on the pipeline, which caused a pressure build-up, rupturing the flange prior to the transfer pump being shut down, leading to a gas leak and the explosion.

Petrobras and BW declined to say when the FPSO will depart, nor have they provided information on the downtime period, which is expected to last for one and half years at a repair yard.


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