Oil

Total’s first deepwater development in Nigeria, Akpo leverages the full range of cutting-edge expertise we had already acquired in the deep offshore. As a result, tested, robust technological solutions have been deployed in one of the biggest projects of its kind.

Heat and high pressure

Building on the extensive deep offshore expertise first acquired when developing Girassol in Angola, we once again demonstrated our matchless skills and capabilities by bringing Nigeria’s Akpo field on stream in 2009, nine years after it was discovered in OML 130. Like similar fields, Akpo’s reservoirs are located offshore an immense oil and gas-rich river delta, in this case the Niger River Delta. But they differ in one important aspect: they are much warmer than was the case for our earlier Gulf of Guinea deepwater developments, and reservoir pressures are much higher. Temperatures reach 112°C at their hottest and the pressure is 700 bar at its highest. These conditions account for the fact that the hydrocarbons trapped inside them is so light. This "critical fluid" separates into condensate and gas when extracted from the well.

Striking the perfect balance

A major challenge of deep offshore operations is designing systems that keep fluids from cooling too much as they travel the glacial environment on the seabed, where temperatures do not exceed 4°C. Engineers must strive to prevent the formation of hydrates — blocks of ice that might plug the pipelines, although the high temperature of Akpo’s hydrocarbons made this a less critical requirement than in previous Total deepwater developments. On the other hand, fending off the ill effects of cold was combined with another, seemingly mutually exclusive challenge: protecting subsea production equipment electronics from the scalding heat of the fluids bubbling up from the reservoirs. Our subsea production specialists developed a highly specific system, in which essential pipeline insulation was designed to create certain cold spots near heat-sensitive devices.

Leveraging experience

Our expertise and the invaluable lessons we learned from our experience with these extreme environment fields drove the design of the technological solutions used to develop Akpo. The solutions deployed — looping subsea production lines tied to immense steel risers that carry the oil and gas to a huge floating production, storage and offloading (FPSO) vessel — had all proved their effectiveness in previous projects. Redundant seafloor installation of the subsea production system’s most sensitive equipment provides immediate backup in the event of a technical failure. This ensures the technical robustness of the entire system, optimal reliability and subsea installation availability of over 99%.

A dual oil and gas strategy

Akpo not only boosts Nigeria’s petroleum production, it is a major cog in the development of the country’s liquefied natural gas sector. In addition to plateau production of 175,000 barrels of condensate daily, 9 million cubic meters of gas are produced and exported each day to the Nigeria Liquefied Natural Gas Ltd (NLNG) liquefaction plant. The leftover gas — some 5 million cubic meters — is reinjected into reservoirs to maximize condensate and gas recovery. Complying with Nigerian legislation banning the flaring of associated gas, Akpo is fully integrated in our assertive strategy to limit greenhouse gas emissions.

Sustainable development for Nigeria

The Akpo development has generated more than 11 million hours of work in Nigeria, a record figure expected to climb to 15 million by the time the project is complete. Akpo is another example of our commitment to maximizing the local economic benefits of our major projects and supporting the growth of industry in our host countries. Not only have a number of Nigerian companies been awarded related manufacturing contracts, ultimately 90% of the operators working on the FPSO will be locals, hired and trained by Total.