The Búzios 4 subsea system was developed with 17 wells connected to P-77: nine production wells and eight injection wells. Subsea trees and manifolds gather the wellstreams, while production, injection and service flowlines, flexible risers and electro-hydraulic umbilicals connect the seabed system to the FPSO. The topsides include oil separation and treatment, crude stabilisation, produced-water handling, seawater treatment and high-pressure injection, gas treatment, carbon-dioxide compression, export-gas compression and injection-gas facilities. Process gas is also used for onboard fuel and gas lift. P-77 was converted from a very large crude carrier and fitted with modular topsides and a permanent 16-line spread-mooring arrangement. The storage hull accommodates approximately 1.4 million barrels of crude. Stabilised oil is held in cargo tanks and transferred to shuttle or relief tankers through the offshore offloading system, avoiding a fixed oil pipeline to shore. Gas is routed through the field’s subsea gathering and export infrastructure. The wider network includes Rota 3, which delivers pre-salt gas to the Boaventura Energy Complex at Itaboraí. Permanent utility and safety systems include electrical generation and distribution, production and export metering, chemical injection, seawater lift, flare and pressure-relief equipment, integrated control and safety systems, subsea controls, emergency shutdown, fire-and-gas detection, firewater, cargo management, marine services and accommodation. The vessel is a standalone host and is not physically bridge-linked to another offshore platform.