Block 18 is located in the Angolan offshore, 140 km northeast of Luanda. Eight discoveries were made in this block, of which the fields Galio, Cromio, Cobalto, Paladio, and Plutonio make up the first producing development known as Greater Plutonio. Platina, one of the other field in this block was approved by the Concessionaire in December 2018 and it is the next development of the this block.
The Greater Plutonio development plays a major role in BP’s portfolio. Development drilling began in 2005 and the project came on-stream in the 1 October, 2007. BP and SSI are the developments shareholders. Production is based on a spread-moored FPSO 1.75 million barrel capacity vessel, a subsea production system with intelligent well technology, and water and gas injection wells. Manifolds, flowlines and risers connect the wells to the FPSO for export to trading tankers via a remote offloading system. Gas is able to be exported to the Angola LNG scheme or re-injected into the reservoirs. The major contractors were KBR, responsible for EPCM, Hyundai Heavy Industries in Ulsan, South Korea, which built the FPSO hull and topsides, Stolt/Technip in Paris, who supplied the umbilicals, risers and flowlines (URF), and FMC Kongsberg in Norway, which has supplied the subsea production system (SPS).
Partners: BP 46%; Sonangol Sinopec International 46%;Sonangol P&P 8%.
Area: 5,000 sq. kilometres
Water depth: 1,200-1,600 metres
Fields: The Greater Plutonio development, some 160 kilometres offshore, consists of five fields: Cobalto, Plutonio, Paladio, Cromio and Galio. Platina is the next development of the block.
Current Installed Capacity:76,000 (220 000 nameplate)
In 2016, the FPSO celebrated its 500 millionth barrel of oil since production began in 2007 - marking a production milestone from wells through the FPSO’s processing plant and onwards for export to refineries across the world.
Subsea Production Systems (SPS)
The initial project was for 20 trees, three manifolds, production controls and the connection system. The first 15 trees were supplied from FMC’s Dunfermline and Houston facilities. The remaining trees were shipped for assembly and testing to FMC’s facility in Angola. The nine subsea manifolds, each around 100 tonnes and comprising piping, valves, chemical injection and multi-phase flow meters and ROV intervention facilities, were constructed at NLI Larvik in Norway and at Sonamet in Lobito.
Umbilicals, risers and flowlines (URF)
The Stolt Offshore and Technip consortium provided the umbilicals, risers and flowlines. The FPSO is held in position for its 25-year life by a spread of 12 mooring lines connected to anchor piles on the seabed 1,300 metres below. Twenty-one flexible risers, seven umbilicals and four steel risers, arranged in a bundle within a riser tower, connect the subsea equipment to the FPSO. Buoyancy is provided by a tank at the top of the tower and the bottom of the tower - containing gas lift manifolds and the spools which connect the risers to the flowlines - is suction anchored to the seabed and a flex joint element allows the tower to rotate and move with waves and current. More than 20 specialist suppliers from around the world provided materials and equipment and the whole bundle were assembled into the riser tower at the Sonamet yard in Lobito in 2006 and 2007. The offloading buoy, manufactured by MIS Dubai, was also completed by Sonamet.
Floating production, storage, and offloading (FPSO)
The FPSO hull is a double-sided/single bottom construction, fabricated from steel plate with sections ranging in thickness from 12 - 40 mm. When fully loaded it has a 23 metre draft and a 14 metre draft when empty. It includes accommodation for up to 160 people, helideck, lifeboats, control room, galley/catering facilities, gym, lounge and cinema. The main equipment packages installed in the hull are cargo and ballast pumps, fire and deluge pumps, seawater lift pumps, a desulphation plant, two diesel generators and an emergency generator. The generators are used during shut down of the topsides power plant. Construction began in 2005 and concluded with the completion of outfitting in January 2006. The KBR designed topsides accommodates all processing facilities for oil, gas and produced water, as well as seawater treatment for water injection.
Fabrication of topsides began in January 2005 and are comprised of 12 equipment modules. There are two power generation modules as well as modules containing the equipment for well fluids reception, HP and LP separation, crude oil metering, the high pressure flare and KO drum, three modules for low, medium and high pressure gas compression and three modules for seawater treatment and injection. In January 2006 the completed hull was moved to the HHI offshore yard for topsides integration and the start of hook-up and commissioning activities. Seawater is treated for injection into the reservoirs in the Sulphare Reduction Plant (SRP) where membrane elements are contained within an array of 612 vessels. The SRP can produce up to 400mbd of low sulphate seawater.