HSE Consequences of FPSO Mooring Lines Pretension Uncertainty in Deep Waters Applications

2020 ◽  
Author(s):  
Jairo B. Araújo ◽  
Joel S. Sales ◽  
Antonio C. Fernandes ◽  
Ana C. S. Thurler
Keyword(s):  
Mooring Lines ◽  
Indirect Measurements ◽  
Extreme Loads ◽  
Deep Waters ◽  
Integrity Management ◽  
Precision System ◽  
Anchor Points ◽  
Design Requirements ◽  
Safety And Environment

Abstract The purpose of FPSO (Floating Production Storage and Offloading) mooring system is to keep the unit operating in site in order to attend the Health, Safety and Environment (HSE) requirements and to meet the production risers design requirements. The pretension specification is a design task and it is a key activity due to its influence on extreme loads and fatigue life for both the mooring lines and risers. It is surprising that the project pretension specifications are not always actually implemented in practice and followed during all the unit life. Some inaccurate methods are used to get the actual pretension and may cause significant errors, and this may cause pretensions values outside design allowable tolerances. A contemporary uncertainty analysis method that uses numerical simulations to estimate the consequences and propagation of the uncertainties in pretensions is applied. A case study is presented for the case of an operating FPSO moored by a spread system, offshore Brazil. A second investigation compares the uncertainty of pretensions measured by means of sensors with the uncertainties that arise from indirect measurements by top angles and as built data for mooring segments and anchor points. The paper finally shows the need of a Mooring Integrity Management (MIM) implementation of at least annual pretension measurements with a robust and higher precision system.

Optimization of Mooring Systems for Floating Offshore Platforms Considering Seabed Obstacles

2017 ◽  
Author(s):  
Bruno da Fonseca Monteiro ◽  
Carl Horst Albrecht ◽  
Beatriz Souza L. Pires de Lima ◽  
Breno Pinheiro Jacob
Keyword(s):  
Production Systems ◽  
Element Model ◽  
Optimization Methods ◽  
Offshore Platforms ◽  
Mooring Lines ◽  
Oil Reserves ◽  
Offshore Production ◽  
Deep Waters ◽  
Candidate Solution

With the constant increase of known oil reserves in deep and ultra-deep waters, floating production systems (FPS) have been established as the main option for offshore production activities. This work presents recent advances regarding an innovative application of evolutionary optimization methods to the design of mooring systems for FPS. Here the focus in in the consideration of actual scenarios with seabed obstacles and other restricted areas where anchors cannot be positioned. The optimization tool employs the Particle Swarm Optimization (PSO) method. The constraints are treated by specialized constraint-handling techniques, and each candidate solution is evaluated through nonlinear analyses coupling the hydrodynamic model of the platform hull with a Finite Element model of the mooring lines and risers. A case study illustrates the application of the optimization for a real-world scenario.

Exploring Effective Change Propagation in a Product Family Design

2017 ◽  
Vol 139 (12) ◽  
Author(s):  
Inayat Ullah ◽  
Dunbing Tang ◽  
Qi Wang ◽  
Leilei Yin
Keyword(s):  
Product Family ◽  
Design Structure Matrix ◽  
Change Propagation ◽  
Effective Change ◽  
Design Structure ◽  
Design Changes ◽  
Requirements Change ◽  
Change Impact ◽  
Design Requirements

Product family (PF) design is a widely used strategy in the industry, as it allows meeting diverse design requirements. Change propagation in any PF is difficult to predict. Consequently, while numerous design change management methodologies presently exist, their application is restricted to a single artifact. This issue is overcome in the present study. The proposed framework explores effective change propagation paths (CPPs) by considering the risks associated with design changes in the PF with the aim of minimizing the overall redesign cost. The propagated risk, which would result in rework, is quantified in terms of change impact and propagation likelihood. Moreover, a design structure matrix (DSM) based mathematical model and an algorithm for its implementation are proposed to investigate the change propagation across the PF. Finally, to demonstrate their effectiveness, a PF of electric kettles is examined in a case study. The study findings confirm that the proposed technique is appropriate for evaluating different CPPs in PF.

Dynamic Analysis for the Design of CALM System in Shallow and Deep Waters

1997 ◽  
Vol 119 (3) ◽  
pp. 151-157 ◽  
Author(s):  
Y.-L. Hwang
Keyword(s):  
Mathematical Model ◽  
Dynamic Analysis ◽  
Model Test ◽  
Time Domain ◽  
Time Domain Analysis ◽  
Mooring Lines ◽  
Deep Waters ◽  
Wave Drift ◽  
The Mathematical Model ◽  
Survival Condition

This paper presents a time domain analysis approach to evaluate the dynamic behavior of the catenary anchor leg mooring (CALM) system under the maximum operational condition when a tanker is moored to the terminal, and in the survival condition when the terminal is not occupied by a tanker. An analytical model, integrating tanker, hawser, buoy, and mooring lines, is developed to dynamically predict the extreme mooring loads and buoy orbital motions, when responding to the effect of wind, current, wave frequency, and wave drift response. Numerical results describing the dynamic behaviors of the CALM system in both shallow and deepwater situations are presented and discussed. The importance of the line dynamics and hawser coupled buoy-tanker dynamics is demonstrated by comparing the present dynamic analysis with catenary calculation approach. Results of the analysis are compared with model test data to validate the mathematical model presented.

scholarly journals Case study: successful disconnection of a traditional floating production storage and off-loading unit

2018 ◽  
Vol 58 (1) ◽  
pp. 72
Author(s):  
Sashi Gajula ◽  
Bertrand Peuchot
Keyword(s):  
Feasibility Studies ◽  
Oil Price ◽  
Mooring Lines ◽  
Project Costs ◽  
Innovative Solutions ◽  
Lost Time ◽  
Two Phases ◽  
Early Departure

Decommissioning a producing asset within a low oil-price market scenario with a possibility of resuming production at a later stage is becoming a frequent task. The main objective of the offshore campaign is to release the floating production storage and off-loading unit (FPSO) at the earliest time by disconnecting all production risers, umbilical and mooring chains, and ensuring integrity of the subsea assets for future use. The entire project for the disconnection of this FPSO was managed in four phases. The first two phases were related to shutdown of production and FPSO clean-up. The FPSO readiness for disconnection was required before the final two phases: disconnection of risers and mooring lines. Detailed engineering was carried out in consultation with various stakeholders involved in the project: the regulator, the company, the FPSO owner and the installation contractor. Through feasibility studies, the best option was selected, which included innovative solutions to reduce overall offshore duration and project costs. The project was successfully completed by meeting the key objective of early departure of the FPSO without lost time injury or any significant environmental incidents.

Smoke Flow Control in Tunnels Using Natural Ventilation

2018 ◽  
Author(s):  
Mark P. Colino ◽  
Elena B. Rosenstein
Keyword(s):  
Natural Ventilation ◽  
Smoke Control ◽  
Smoke Movement ◽  
Design Elements ◽  
Industry Standards ◽  
Emergency Ventilation ◽  
Design Requirements ◽  
Smoke Control System ◽  
Ventilation Systems

This paper provides an overview of the design of natural ventilation systems to control smoke movement in rail tunnels. The paper discusses the current industry standards and design requirements for tunnel emergency ventilation systems, and then addresses the various technical elements that are used to design such systems. These technical elements include parameters in the direct control of the designer, as well as those that are beyond the control of the designer. The paper also presents a case study where various physical design elements are utilized to create a working natural ventilation smoke control system for a short rail tunnel.

Lightweight Materials for Mooring Lines of Deepwater Tension Leg Platforms

1984 ◽  
Vol 21 (03) ◽  
pp. 234-241
Author(s):  
Mamdouh M. Salama
Keyword(s):  
Carbon Fiber ◽  
Water Depth ◽  
Hybrid Composites ◽  
Medium Size ◽  
Mooring System ◽  
Basic Design ◽  
High Modulus ◽  
Mooring Lines ◽  
Lightweight Materials ◽  
Design Requirements

The design of a mooring system for tension leg platforms (TLPs) becomes more complicated as water depth increases. The use of steel mooring lines requires complicated tensioning, handling, and flotation systems. This paper discusses the basic design requirements for the TLP mooring system and identifies several advanced fiber-reinforced lightweight materials as alternatives to steel. High-modulus carbon fiber/KevlarcircleR fiber hybrid composites and Kevlar ropes appear to offer the optimum mooring systems for TLPs used in the development of large and medium-size reservoirs, respectively.

Informed consent in de etnografische veldwerkpraktijk

KWALON ◽  
2014 ◽  
Vol 19 (2) ◽  
Author(s):  
Petra Heyse
Keyword(s):  
Informed Consent ◽  
Empirical Evidence ◽  
Macro Level ◽  
Ethical Review ◽  
Ethnographic Research ◽  
Research Practice ◽  
Saint Petersburg ◽  
Ethnographic Fieldwork ◽  
Deep Waters

Informed consent in ethnographic research practice. Deep waters between macro ethical regulation and micro ethical fieldwork dilemmas Informed consent in ethnographic research practice. Deep waters between macro ethical regulation and micro ethical fieldwork dilemmas Drawing on my experiences of nine months of ethnographical fieldwork in an international matchmaking agency in Saint-Petersburg (Russia), I show how the negotiation of ‘informed consent’ in practice differs from ‘informed consent’ procedures of universities’ and research funds’ ethical review boards. Evidence in my case study contributes to existing debates that question the applicability in ethnography of consent rituals that are common in (bio)medical and psychological sciences. These ‘informed consent’ protocols have been criticized to be insufficiently empirically grounded in the ethnographical fieldwork practice. My tale from the field offers empirical evidence for a further conceptual refinement of a process-based approach to consent negotiations. I both provide recommendations for an adaptation of ethical regulations on a macro level and for a more reflexive consent negotiation in the situated ethnographic fieldwork practice.

A Concept for Floating Offshore Wind Mooring System Integrity Management Based on Monitoring, Digital Twin and Control Technologies

2021 ◽  
Author(s):  
Alberto Puras Trueba ◽  
Jonathan Fernández ◽  
Carlos A. Garrido-Mendoza ◽  
Alessandro La Grotta ◽  
Jon Basurko ◽  
...  
Keyword(s):  
Control Strategies ◽  
Offshore Wind ◽  
Motion Sensor ◽  
Mooring System ◽  
Mooring Lines ◽  
Efficient Operation ◽  
Digital Twin ◽  
System Integrity ◽  
Integrity Management ◽  
And Control

Abstract Efficient operation of mooring systems is of paramount importance to reduce floating offshore wind (FOW) energy costs. MooringSense is an R&D project which explores digitization to enable the implementation of more efficient integrity management strategies (IMS) for FOW mooring systems. In this work, the MooringSense concept is presented. It includes the development of several enablers such as a mooring system digital twin, a smart motion sensor, a structural health monitoring (SHM) system and control strategies at the individual turbine and farm levels. The core of the digital twin (DT) is a high-fidelity fully coupled numerical model which integrates simulation tools to allow predictive operation and maintenance (O&M). Relevant parameters of the coupled model are updated as physical properties evolve due to damages or degradation. The DT assimilates information coming from the physical asset and environmental sensors. Besides, a smart motion sensor provides feedback of the attitude, position, and velocity of the floater to allow the computation of virtual loads in the mooring lines, the detection of damages by the SHM system and the implementation of closed-loop control strategies. Finally, the IMS takes advantage of the mooring system updated condition information to optimize O&M, reduce costs and increase energy production.

H∞ loop Shaping Robust Postprandial Glucose Control for Type 1 Diabetes

2021 ◽  
Vol 39 (2A) ◽  
pp. 268-279
Author(s):  
Safa F. Fadhel ◽  
Safanah M. Raafat
Keyword(s):  
Blood Glucose Concentration ◽  
Artificial Pancreas ◽  
Postprandial Glucose ◽  
Robust Controller ◽  
Control Effort ◽  
Loop Shaping ◽  
Design Requirements ◽  
And Performance

The Bergman model is one of the most commonly used models applied to the representation of the artificial pancreas (AP). It is important to study the effects of the insulin infusion on blood glucose concentration. This work includes a case study for the design of a robust controller for an AP. Robustness is a structured control that improves a system's ability to keep its stability and performance under various conditions. The proposed H∞ loop shaping HLS method will fulfill the design requirements of robust control and performance. The results of the simulation prove the superiority of the intended approach in terms of simple structure, robust performance, and stability with the least control effort

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