The Mero 1 subsea system comprises six production wells and seven injection wells connected to FPSO Guanabara. Rigid and flexible production, gas-lift, water-and-gas-injection lines and electro-hydraulic control umbilicals link the subsea trees to the vessel. The mooring and riser arrangement provides positions for 56 flexible risers and umbilicals, including nine oil-production risers, nine gas-lift risers, multiple convertible water, gas and production risers, fourteen water-or-gas injection risers, seventeen control umbilicals and one fibre-optic cable. Eighteen production or gas-injection connections can alternatively use steel risers. Onboard facilities separate and treat the produced oil, gas and water and store stabilised crude in tanks with approximately 1.4 million barrels capacity. After meeting onboard fuel demand, the processed associated gas is compressed and reinjected rather than exported. Gas injection alternates with water injection through the same reservoir-support strategy, known as WAG. The vessel also carries high-pressure gas handling, water-treatment and injection systems and a refrigeration package used for high-pressure-gas hydrocarbon-dew-point control. Guanabara is a converted, approximately 332-metre-long tanker hull. Its permanent spread mooring comprises four groups of six chain-and-polyester lines secured through pile chains to torpedo piles. This 24-line arrangement holds the vessel on station in ultra-deep water while the risers descend from hull-side porches. Stabilised crude is stored onboard and transferred through the offloading system to shuttle tankers.