The Sapinhoá and Lula North-East fields were developed through pilot systems composed of satellite wells connected to spread moored FPSOs. Each of these developments needed to connect up to 45 lines coming from the wells to a single balcony at FPSO portside, not including gas export riser and its ESDV umbilical. It was expected variable levels of CO 2 and H 2 S, posing the challenge to find a suitable solution that endure the 27 years life of the fields in 2140m water depth in the harsher Santos Basin. To cope with these challenges, Petrobras and partners (BG E&P Brazil and Repsol Sinopec Brazil, in Sapinhoá field, BG E&P Brazil and Petrogral Brazil, in Lula Field) decided to pursue a decoupled risers' system solution and launch a "design competition process" which ended up selecting the Buoy Supporting Risers (BSR) concept solution developed by Subsea 7. This paper describes the BSR System and the needed careful physical and numerical modelling and massive analysis of a largely complex new system, backed up by prototype tank testing, all of them tackled to capture the in-place behaviour to generate the design input envelopes for all system components.

This paper presents the technical solutions adopted and implemented to develop the Brazilian pre-salt reservoirs, covering the main aspects of the subsea production systems already installed and in operation, that allowed overcome the challenges and turn the ultra deepwater pre-salt production into a reality that currently produces more than seven hundred thousand barrels per day. The characteristics related to this particular ultra deepwater scenario are presented, highlighting the ones that demanded to push the envelope of the available technological solutions, considering the conditions are more severe than typical ones from the previous experience with Campos Basin development projects: presence of CO2 and H2S contaminants in the produced fluids; higher internal pressure; high CO2 content gas injection; deeper waters and more severe metocean conditions. The aspects related to subsea trees, control systems, subsea manifolds, diverless connection systems, subsea flowlines, umbilicals and risers for the production systems are presented, as well as the flow assurance issues. The risers and pipelines for produced gas flow to shore are also covered. Considering the large number of projects that would be required to develop the Brazilian pre-salt province, different riser system solutions were developed and applied, being now field proven and available for the industry. Several firsts and records were established and are presented. The effort related to subsea equipment standardization, to cope with the large number of systems to be installed, is also part of this paper. Similarly to the situation of Campos Basin in the 80's, playing the role of a big laboratory for technology development towards deep water production, Brazilian pre-salt scenario, and specially Santos Basin pre-salt province, is nowadays the site where technology development is taking place for ultra deepwater production of high GOR oil with variable CO2 content. Subsea systems are enabling such production and this technology enhancement will contribute for the future development of other areas with similar characteristics.

Objectives/Scope: The successful installation of the four BSR (Buoy Supporting Risers) systems in Brazil's Sapinhoá and Lula NE fields provides the final breakthrough for this new riser design concept, in which SCR's motions are uncoupled from FPSO motions by providing an intermediary support through a vertically tethered submerged buoy at 250m below the sea surface.The installation of the systems' foundations (16 suction anchors & 64 counterweights), tethers (32 spiral strand wires complete with top and bottom connectors, chain, chain tensioners and other special links) and the four buoys (2800T steel weight, 10000T gross buoyancy each) did not happen without overcoming serious challenges in operational constraints and events.Methods, Procedures, Process: Considerable installation engineering efforts led to solutions for the logistical problems associated with the sheer quantity, volume, size and weight of the foundations and top connector structures as well as for the actual installation in waters of 2140m depth and in seas often characterised by bi-directional swells.In buoy design, solutions were found for the conflicting requirements for permanent and temporary weight-buoyancy distribution and pressure differentials, further complicated by the need to accommodate a considerable amount of temporary ballasting, pressurisation, survey and other equipment with associated ROV access envelopes in an area already congested with the structural provisions for the permanent SCRs, flexibles, umbilicals and general monitoring equipment. Results, Observations, Conclusions:The required ballast configurations and detailed installation procedures for buoy tow-out and lowering and tether hook-up to the foundations were determined following the development of a buoy/tether numerical analysis model addressing weight, stability, ballast distribution, internal pressure and hydrodynamic issues. This was backed-up by model tests and thorough sensitivity analysis on all relevant parameters to ensure the system's integrity in the most rigorous risk and contingency scenarios would not be compromised.During the offshore phase, the robustness of the installation concept, the ballasting, pressurisation, chain tensioning, bottom connector and other equipment, in conjunction with the developed installation analysis tool, provided sufficient flexibility to resolve the operational set-backs related to equipment damage caused by extensive weather exposure.Other operational improvements were made continuously, taking advantage of the repetitive nature of the installation scope for foundations, tethers and buoys by evaluating all installation steps systematically and applying the assimilated lessons learned rapidly after thorough Management-of-Change risk assessments.Novel/Additive information: Numerical modelling for dynamic analysis, prototype tank tests and step-by-step 3D simulation methods were applied to ensure reliable multi-vessel operations offshore. The field results obtained during the first time installation of such a large system ...

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Petrobras has operated offshore production units on the Brazilian coast for over 25 years. Over time, its facilities are expected to degrade due to the variety of mechanisms of damage that the offshore environment provides. Mooring systems are among the assets that present degradation throughout the operation and understanding the integrity behavior of this system throughout its lifetime is extremely important for operational safety. Mooring lines installed in floating production units of Petrobras have a wide range of operating ages (2 to 30 years) and a diversity of mooring systems (Spread mooring semisubmersible, single point mooring FPSO and spread mooring FPSO). To optimize integrity management, a reliability-centered strategy was developed using available field data of mooring lines installed in floating production units of Petrobras. The database created for this study covered failure data, maintenance, and operational parameters of mooring line components installed between 1992 and 2021. Life data analysis was used to evaluate how the failure probability evolved with the lifetime. Therefore, the Weibull parameters of each mooring line component were estimated. The strategy aims to improve reliability and optimize life cycle cost, reducing corrective maintenance and avoiding production loss as a result. The results show that different mooring line components have different failure rate behaviors during their lifetime. Also, parameters such as mooring system type (single point mooring or spread mooring), the position of mooring lines (due to environmental conditions), and the presence of cathodic protection are important to predict the level of degradation of the components. Through the scenarios evaluated, it was possible to define critical systems where preventive maintenance should be done and the optimal time, to improve life cycle cost and reliability.