Challenges and Advantages to Nigerian Deepwater Floating Plant

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The following is an advisory by Industrialinfo.com (Industrial Information Resources, Incorporated; Houston, Texas). An innovative project plan from Norway's Statoil at the company's Nigerian Nnwa field could see a floating liquefied natural gas plant in action by 2007. The plan is to construct a concrete or steel barge 300 meters long in 1,280 meters depth of water on a turret mooring.

The Nnwa field holds 269 billion cubic meters of gas. It is not the major oil resource Statoil had expected on discovering the field in 1999. Harbors are too shallow to handle LNG tankers from an onshore plant so the company is now looking to solve the challenges of the floating plant, such as movement of the plant and offloading into tankers, which until now has not been seen to stand in the way of installing a large land-based type plant onto a floating structure.

A positive benefit of locating the plant floating over deepwater is that sea water could be used to cool the stored LNG. This option could score against standing the plant in shallow water and building a long two-phase pipeline from the Nnwa field. This shallow water option presents other technical problems but is still under consideration. In the block adjacent to Nnwa, Texaco's Agbami field holds oil reserves of about one billion barrels and is due to start producing in the middle of 2005 and plateau at 200,000 barrels per day. Texaco is also looking at a large scale floating production, storage and offloading vessel to process the output.