The In Amenas plant - a joint venture between state-owned oil firm Sonatrach, UK multinational BP and Norway's Statoil - has been operating since 2006 and has a production capacity of nine billion cubic meters per year.
BP's UK logistics infrastructure manager, Mark Hardie, said the contract was part of BP's long-term marine strategy to support its UK offshore operations.
Earlier this week, the UK's Daily Telegraph newspaper reported that a vice-president of the British oil giant BP was also at the plant at the time of the attack and was killed - a claim BP on which has also not commented.