Installation of a Submerged Buoy for Supporting Risers (BSR) System in Campos Basin Site

2011 ◽  
Author(s):  
Jairo Bastos de Arau´jo ◽  
Jose´ Carlos Lima de Almeida ◽  
Antonio Carlos Fernandes
Keyword(s):  
Numerical Analysis ◽  
Model Test ◽  
Water Depth ◽  
Water Model ◽  
Floating Platform ◽  
Mooring Lines ◽  
Sea Bottom ◽  
Campos Basin ◽  
Steel Catenary Risers ◽  
Field Location

The BSR (Buoy for Supporting Risers) concept is composed by a submerged buoy anchored to the sea bottom by tethers and intended to support risers coming from the bottom (probably SCRs — Steel Catenary Risers) and going to the floating platform (probably with flexible jumpers). For the case under analysis here, the main dimensions of the BSR prototype are 27.2 m length × 27.2 m width × 5.0 m depth. The paper describes all final full scale installation step so that the BSR may be considered a suitable technology. The installation indeed was the great challenge of this design due the size of the hull. The present work also evaluates numerically and experimentally a specific new manner to install the BSR with the support of auxiliary mooring lines among with the four tethers connected to it. One of the installation premises was to make use of Anchor Handling Supply Vessels instead of Crane Vessels. After this numerical analysis, the work went on by performing model tests that simulates the operation in a deep water model basin using 1:40 scale. The model test anticipated several problems such as the chain stopper weakness in the operation and others as discussed in this paper. As a conclusion the work was devised the most important parameters during the system installation and suggested ways to improve the methodology. In November 2009 the BSR was installed in 500 m of water depth at Congro field location, Campos Basin, offshore Brazil. The tethers were adjusted in January 2010 and in March 2010 two risers were installed. Thenceforward the last edge of this knowledge was considered over passed.

Alternative Method of Buoy Supporting Riser (BSR) Installation

2011 ◽  
Author(s):  
Ricardo Franciss ◽  
Enrique Casaprima Gonzales ◽  
Jose´ Carlos Lima de Almeida ◽  
Jairo Bastos de Arau´jo ◽  
Antonio Carlos Fernandes
Keyword(s):  
Fatigue Life ◽  
Field Test ◽  
Water Depth ◽  
Monitoring Systems ◽  
Deep Waters ◽  
Alternative Method ◽  
Sea Bottom ◽  
Campos Basin ◽  
Steel Catenary Risers ◽  
Flexible Risers

Due to the 2200m water depth and harsher environmental conditions, one option that Petrobras is considering for the production of the Pre-Salt fields is the use of a subsurface buoy known as a Buoy Supporting Riser (BSR). It is composed of a subsurface tethered buoy, flexible jumpers connecting the Floating Production Unit (FPU) to the BSR and Steel Catenary Risers (SCRs) connecting the BSR to the flowlines on the sea bottom. The main advantages of this system are that it decouples the FPU motions from the SCRs, reducing fatigue damage in the touch down zone. It may also be installed independently of the FPU, except for the flexible jumpers, which would reduce the risers load on the FPU. Petrobras has been studying this concept since 1997 and has established, as a final stage of the study, a field test with the actual installation of the BSR. This was performed through an alternative method using only Petrobras AHTS boats, in order to avoid critical and expensive resources such as lift barges. With the purpose of validating this new installation procedure, Petrobras performed the referred installation of a 27.2m × 27.2m square ring shaped buoy in Congro Field in the Campos Basin over a water depth of 500m. The buoy was positioned at 80m depth, where the incidence of loads caused by waves is negligible, thus increasing the fatigue life of risers. After the BSR installation, the riser pull-in procedure was also conduced. This paper describes why this technology is necessary for these fields and the model tests made to validate the installation procedures. It also discusses how Petrobras tested the pull-in operations for two flexible risers after the actual buoy was installed. Monitoring systems were designed to check all forces and displacements during the referred installation. These actions will consolidate the BSR technology for Petrobras leading to another riser system option for production in ultra deep waters.

The Research of Moonpool Size Effect on the Hydrodynamic Performance of FDPSO

2011 ◽  
Author(s):  
Yuefeng Wei ◽  
Jianmin Yang ◽  
Gang Chen ◽  
Zhiqiang Hu
Keyword(s):  
Numerical Analysis ◽  
Size Effect ◽  
White Noise ◽  
Natural Frequency ◽  
Model Test ◽  
Hydrodynamic Performance ◽  
Ocean Engineering ◽  
Floating Platform ◽  
Paper Making ◽  
Reliable Model

FDPSO is a multifunction floating platform, which has the combined function of drilling, production, storage and offloading oil. The moonpool is necessary for drilling operation and the moonpool size effect will play a role on the hydrodynamic performance of FDPSO. A study of the moonpool size effect on such performance of FDPSO hull is presented in this paper, making use of numerical analysis and model tests techniques. The code WADAM is used for the hydrodynamic performance analysis. A model test aiming to validate the accuracy of the numerical analysis results was conducted in the Ocean Engineering basin in the State Key Laboratory of Ocean Engineering in the Shanghai Jiao Tong University. The model test included decaying test and white noise test. The decaying tests are performed in still water for heave, roll and pitch. White noise tests were carried out to obtain the RAO of FDPSO, with the wave incoming direction of 180° and 135°. The numerical results show a good agreement with the model test results, indicating a reliable model. The “piston” motion of the water inside the moonpool is significant, affecting the hydrodynamic performance of the FDPSO. The effect of moonpool size on the hydrodynamic performance of the FDPSO is analyzed through a numerical method. The relationship between the piston natural frequency of the water column inside the moonpool and its diameter and draft, are studied. An empirical formula of the “piston” natural frequency is proposed, and its validity is assessed.

Ultra-Deepwater Floating Platforms Simulation on SPAR Realistic Marine Virtual Environment System

2003 ◽  
Author(s):  
Gerson Gomes Cunha ◽  
Luis Augusto Petrus Levy ◽  
Maria Ce´lia Santos Lopes ◽  
Luiz Landau
Keyword(s):  
Environmental Conditions ◽  
Large Scale ◽  
Scientific Data ◽  
Design System ◽  
Floating Platform ◽  
Visual Effects ◽  
Mooring Lines ◽  
Campos Basin ◽  
Scale Design ◽  
Floating Platforms

This paper presents a new system for offshore floating petroleum platforms design and simulation using virtual reality technology. Environmental conditions and visual effects were introduced together the analysis results to build a realistic experience. The system integrates the capabilities of a large scale design system PROSIM, for design and evaluation of floating structures, mooring lines and rigid or flexible risers under wave, wind and current effect; and SPAR system, for realistic visual effects and environmental conditions representation to enhance the visual perception and phenomenon understanding. It will be presented a real case usage of the system in the project of new floating platform with wave, wind and terrain data of the Campos Basin (Brazilian biggest reservoir). The real-time simulation of floating systems is not new, but until today only scientific aspects were considered besides visual appeal. The association of artistic elements only used on movies and games are introduced in real engineering simulation creating a new way of understanding and interacting with this scientific data.

Hydrodynamic Performance Effect of Steel Catenary Risers on Wave Frequency Motions of a Semi Submersible

2016 ◽  
Author(s):  
Chen Gang ◽  
Zhao Nan ◽  
Zhang Wei ◽  
Yuan Hongtao ◽  
Li Chunhui ◽  
...  
Keyword(s):  
Time Domain ◽  
Wave Frequency ◽  
Hydrodynamic Performance ◽  
Coupled Analysis ◽  
Phase Lag ◽  
Floating Platform ◽  
Mooring Lines ◽  
Performance Effect ◽  
Steel Catenary Risers ◽  
Depth Increase

The analysis of the influence of risers on the motions of a floating platform is often conducted and simplified by uncoupled method. As the number of risers and water depth increase, this method would not predict system motion accurately. Coupled analysis method in time domain becomes a very convenient approach in response calculation since it automatically includes the interaction among platform, mooring lines and risers. This paper introduces a full coupled approach by AQWA-NAUT to include viscous damping of the semi submersible and effects of steel catenary risers on the wave frequency response of platform in time domain motion analysis. The main conclusion of this paper is that full coupled method can accruately predict semi submersible Response Amplitude Operator (RAOs) comparing to the case without risers. Other conclusions are that risers have an important effect on the wave frequency motion of semi submersible and also lead to a phase lag with respect to platform motions.

Subsurface Buoy Configuration for Rigid Risers in Ultra Deepwater

2005 ◽  
Author(s):  
Ricardo Franciss
Keyword(s):  
Model Test ◽  
Water Depth ◽  
Production System ◽  
Field Trial ◽  
Production Department ◽  
Campos Basin ◽  
Production Platform ◽  
Exploration And Production

The Exploration and Production Department of Petrobras asked the R&D Center the development of a production system for 1800 m water depth, in Campos Basin, which would allow the installation of Steel Caterany Risers (SCR) in the starboard side of a production platform. The subsurface buoy concept was chosen as one of the alternatives. This concept has being developed since the preliminary studies conducted in the first phase of JIP Deepstar. This concept has an advantage of uncoupling the movements of the platform from the risers, reducing the loads due to the risers in the platform and allowing the installation of this system before the installation of the production vessel, anticipating the production of the field. This article shows the main characteristics of the buoy, its sizes, results of structural analyses and installation procedures for a buoy which sustains 14 SCR and 5 umbilicals in one side and 14 flexible jumpers and the same 5 umblicals in the opposite side. This concept was tested in two model test tanks, where it was verified that this concept is feasible. Also, information related to a field trial with a prototype installed in Brazilian waters will be presented.

scholarly journals Transient Responses Evaluation of FPSO with Different Failure Scenarios of Mooring Lines

2021 ◽  
Vol 9 (2) ◽  
pp. 103
Author(s):  
Dongsheng Qiao ◽  
Binbin Li ◽  
Jun Yan ◽  
Yu Qin ◽  
Haizhi Liang ◽  
...  
Keyword(s):  
Service Condition ◽  
Mooring Line ◽  
Mooring System ◽  
Transient Effects ◽  
Floating Platform ◽  
Transient Responses ◽  
Mooring Lines ◽  
Performance Deterioration ◽  
Steady State Responses ◽  
Influence Process

During the long-term service condition, the mooring line of the deep-water floating platform may fail due to various reasons, such as overloading caused by an accidental condition or performance deterioration. Therefore, the safety performance under the transient responses process should be evaluated in advance, during the design phase. A series of time-domain numerical simulations for evaluating the performance changes of a Floating Production Storage and Offloading (FPSO) with different broken modes of mooring lines was carried out. The broken conditions include the single mooring line or two mooring lines failure under ipsilateral, opposite, and adjacent sides. The resulting transient and following steady-state responses of the vessel and the mooring line tensions were analyzed, and the corresponding influence mechanism was investigated. The accidental failure of a single or two mooring lines changes the watch circle of the vessel and the tension redistribution of the remaining mooring lines. The results indicated that the failure of mooring lines mainly influences the responses of sway, surge, and yaw, and the change rule is closely related to the stiffness and symmetry of the mooring system. The simulation results could give a profound understanding of the transient-effects influence process of mooring line failure, and the suggestions are given to account for the transient effects in the design of the mooring system.

Submarine Pipeline Installation JIP: Strength and Deformation Capacity of Pipes Passing Over the S-Lay Vessel Stinger

2006 ◽  
Author(s):  
Enrico Torselletti ◽  
Luigino Vitali ◽  
Erik Levold ◽  
Kim J. Mo̸rk
Keyword(s):  
Water Depth ◽  
Failure Modes ◽  
Bending Moment ◽  
External Pressure ◽  
Submarine Pipeline ◽  
Design Guideline ◽  
Moment Capacity ◽  
Sea Bottom ◽  
Major Vessel ◽  
Gas Fields

The development of deep water gas fields using trunklines to carry the gas to the markets is sometime limited by the feasibility/economics of the construction phase. In particular there is a market for using S-lay vessels in water depth larger than 1000m. The S-lay feasibility depends on the applicable tension at the tensioner which is a function of water depth, stinger length and stinger curvature (for given stinger length by its curvature). This means that, without major vessel up-grading and to avoid too long stingers that are prone to damages caused by environmental loads, the application of larger stinger curvatures than presently allowed by current regulations/state of the art is needed. The work presented in this paper is a result of the project “Development of a Design Guideline for Submarine Pipeline Installation” sponsored by STATOIL and HYDRO. The technical activities are performed in co-operation by DNV, STATOIL and SNAMPROGETTI. The scope of the project is to produce a LRFD (Load Resistant Factor Design) design guideline to be used in the definition and application of design criteria for the laying phase e.g. to S and J-lay methods/equipment. The guideline covers D/t from 15 to 45 and applied strains over the overbend in excess of 0.5%. This paper addresses the failure modes relevant for combined high curvatures/strains, axial, external pressure and local forces due to roller over the stinger of an S-lay vessel and to sea bottom contacts, particularly: • Residual pipe ovality after laying, • Maximum strain and bending moment capacity. Analytical equations are proposed in accordance with DNV OS F101 philosophy and design format.

Qualification and Certification of Polyester Rope for Seabed Contact

2017 ◽  
Author(s):  
Øystein Gabrielsen ◽  
Kjell Larsen
Keyword(s):  
Water Flow ◽  
Water Depth ◽  
Test Method ◽  
Mooring System ◽  
Qualification Test ◽  
Mooring Lines ◽  
Norwegian Sea ◽  
Flow Through ◽  
Full Scale Tests ◽  
Certification Requirements

The Aasta Hansteen spar in the Norwegian Sea is designed to be moored with a taut polyester rope mooring system. The water depth at the field is 1300 meters, and due to the short installation season the most efficient hookup is with pre-installed mooring lines, which require the mooring lines to be laid down on the seabed. DNV certification does not allow seabed contact for polyester ropes unless proven that no soil ingress and damage takes place. To be able to certify the ropes Statoil developed a test method including contact with soil, rope movement and forced water flow through the filter construction. Full scale tests were performed with actual rope and Aasta Hansteen soil, both in laboratory and at site. This paper discusses the certification requirements and presents adequate qualification test together with results from testing.

A Joint-Industry Effort to Develop and Verify CFD Modeling Practice for Vortex-Induced Motion of a Deep-Draft Semi-Submersible

2021 ◽  
Author(s):  
Hyunchul Jang ◽  
Dae-Hyun Kim ◽  
Madhusuden Agrawal ◽  
Sebastien Loubeyre ◽  
Dongwhan Lee ◽  
...  
Keyword(s):  
Test Data ◽  
Model Test ◽  
Working Group ◽  
Cfd Modeling ◽  
Physical Model Test ◽  
Mooring Lines ◽  
Cfd Models ◽  
Induced Motion ◽  
Modeling Practice ◽  
Decay Tests

Abstract Platform Vortex Induced Motion (VIM) is an important cause of fatigue damage on risers and mooring lines connected to deep-draft semi-submersible floating platforms. The VIM design criteria have been typically obtained from towing tank model testing. Recently, computational fluid dynamics (CFD) analysis has been used to assess the VIM response and to augment the understanding of physical model test results. A joint industry effort has been conducted for developing and verifying a CFD modeling practice for the semi-submersible VIM through a working group of the Reproducible Offshore CFD JIP. The objectives of the working group are to write a CFD modeling practice document based on existing practices validated for model test data, and to verify the written practice by blind calculations with five CFD practitioners acting as verifiers. This paper presents the working group’s verification process, consisting of two stages. In the initial verification stage, the verifiers independently performed free-decay tests for 3-DOF motions (surge, sway, yaw) to check if the mechanical system in the CFD model is the same as in the benchmark test. Additionally, VIM simulations were conducted at two current headings with a reduced velocity within the lock-in range, where large sway motion responses are expected,. In the final verification stage, the verifiers performed a complete set of test cases with small revisions of their CFD models based on the results from the initial verification. The VIM responses from these blind calculations are presented, showing close agreement with the model test data.

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