Improved FPSO Offloading Strategy Based on Analysis Including DP System

2018 ◽  
Author(s):  
Gerhard Gundersen ◽  
Petter Stuberg ◽  
Timothy Edward Kendon ◽  
Svein-Arne Reinholdtsen
Keyword(s):  
Wind Waves ◽  
Time Domain Analysis ◽  
Analysis Model ◽  
Real Time System ◽  
The North ◽  
Increased Risk ◽  
Probability Of Collision ◽  
The North Sea ◽  
Operation Control ◽  
Tandem Offloading

Direct offloading operations from turret moored FPSOs are traditionally performed with dynamic positioned (DP) shuttle tankers with a bow loading hose and hawser line connected to the stern of the production facility. The hawser line restricts the mobility of the shuttle tanker which is often forced to point towards the FPSO. The inherent increased risk of collision in case of a forward drive-off incident has motivated a study for a hawser-less tandem offloading operation. The structural limits of the flexible loading hose allows for larger operational sector and heading flexibility which enables the shuttle tanker to point away from the FPSO and hence reduces the probability of collision. An analysis model with two representative vessels for offloading operations in the North Sea has been developed in order to investigate the new concept. The model includes a compiled version of the DP system core algorithm, extracted from the real time system of both vessels. The new offloading strategy, with heading offset away from the FPSO, has been implemented in an updated control algorithm for the shuttle tanker. Time-domain analysis of the complete tandem offloading system has been simulated with measured wind, waves and current from a HindCast data base. Heading and relative motion between FPSO and shuttle tanker has been extracted and statistically evaluated in order to determine the time for which the shuttle tanker is directed towards the FPSO. The paper demonstrates how a marine simulation model, including core algorithm of the actual DP system and numerous simulations based on historical measured environment, can be used to document the feasibility of a new offloading operation control strategy.

scholarly journals The North Sea Bicycle Race ECG Project: Time-Domain Analysis

2018 ◽  
Vol 12 (1) ◽  
pp. 23-32
Author(s):  
Dominika Długosz ◽  
Trygve Eftestø ◽  
Aleksandra Królak ◽  
Tomasz Wiktorski ◽  
Stein Ørn
Keyword(s):  
North Sea ◽  
Time Domain ◽  
Time Domain Analysis ◽  
Domain Analysis ◽  
The North ◽  
The North Sea

Prediction of Relative Motion and Probability of Contact Between FPSO and Shuttle Tanker in Tandem Offloading Operation

2002 ◽  
Author(s):  
Haibo Chen ◽  
Torgeir Moan ◽  
Sverre Haver ◽  
Kjell Larsen
Keyword(s):  
North Sea ◽  
Extreme Values ◽  
Simulation Models ◽  
Point Of View ◽  
Simulation Code ◽  
The North ◽  
Simulation Based ◽  
The North Sea ◽  
Sensitivity Studies ◽  
Tandem Offloading

Tandem offloading safety between FPSO and shuttle tanker is under concern. A few collisions between the two vessels have happened in the North Sea in recent years. In these incidents, excessive relative motions (termed as surging and yawing in this paper) between FPSO and tanker are identified as “failure prone situations” which have contributed to the initiation of most collision incidents. To quantitatively assess the probability of surging and yawing events, and more importantly, to effectively reduce their occurrence in tandem offloading operation, we present a simulation-based approach in this paper, which is carried out by a state-of-the-art time-domain simulation code SIMO. The SIMO simulation models are setup and calibrated for a typical North Sea purpose-built FPSO and a DP shuttle tanker. This 2-vessel system motion in tandem offloading is simulated. The simulated relative distance and relative heading between FPSO and tanker are analyzed by fitting their extreme values into statistical models. This gives out probabilities of surging and yawing events. Sensitivity studies are performed to analyze contributions from various technical and operational factors. Measures to minimize the occurrence of surging and yawing from design and operational point of view are proposed.

Danish–German–Dutch Wadden Environments

2005 ◽  
Author(s):  
Jacobus Hofstede
Keyword(s):  
Present State ◽  
North Sea ◽  
Energy Input ◽  
Wadden Sea ◽  
Wind Waves ◽  
Tidal Energy ◽  
Point Of View ◽  
Energy Impact ◽  
The North ◽  
The North Sea

The Wadden Sea environment is a coastal tidal environment situated between the North Sea and the northwestern European Lowlands. It stretches over a distance of about 450 km from Den Helder in The Netherlands to the peninsula of Skallingen in Denmark. The approximately 10,000 km2 large Wadden Sea is a coastal sediment sink that developed in the course of the Holocene transgression. It resulted from a specific combination of sediment availability (mainly from the North Sea) and a hydrodynamic regime of tides and waves. In its present state, the Wadden Sea environment consists of extensive tidal flats (the wadden), tidal gullies and inlets, salt marshes, and about twenty-four sandy barrier islands. Further, four estuaries exist that discharge into the Wadden Sea. The Wadden Sea may best be characterized by the words ‘dynamic’ and ‘extreme’; dynamic from a geo-morphological point of view, extreme in its biology. According to Spiegel (1997), with each flood phase a tidal energy input in the order of 2.2 thousand MW occurs in the Wadden Sea of Schleswig-Holstein (Germany). This energy input, combined with the energy impact of wind, waves, and storm surges, results in strong morphological processes. Flora and fauna in the Wadden Sea have to adapt to these intense morphodynamics. Further, they have to endure the permanent change of flood and ebb and fluctuations in salinity, as well as high water temperatures during summer and occasional ice cover during winter. As a result of these extreme environmental conditions, a highly specialized biosystem with about 4,800 species has developed (Heydemann 1998). In its present state the Wadden Sea is one of the last remaining near-natural large-scale ecosystems in central Europe. Its ecological significance is underlined by the fact that 250 animal species live exclusively here (Heydemann 1998). Furthermore, nowhere else in Europe is an ecosystem of this size visited by more birds per surface area for the purpose of feeding. However, the Wadden Sea is subjected to considerable human influences, e.g. the input of nutrients and pollutants, fisheries, dredging, boat traffic, and tourism (de Jong et al. 1999).

Prediction of Relative Motion and Probability of Contact Between FPSO and Shuttle Tanker in Tandem Offloading Operation

2003 ◽  
Vol 126 (3) ◽  
pp. 235-242 ◽  
Author(s):  
Haibo Chen ◽  
Torgeir Moan ◽  
Sverre Haver ◽  
Kjell Larsen
Keyword(s):  
North Sea ◽  
Extreme Values ◽  
Simulation Models ◽  
Time Domain Simulation ◽  
Simulation Code ◽  
The North ◽  
Simulation Based ◽  
The North Sea ◽  
Sensitivity Studies ◽  
Tandem Offloading

Excessive relative motions between Floating Production Storage Offloading Unit (FPSO), and tanker, which are termed as excessive surging and yawing events, are identified as the “failure prone situation” in tandem offloading. These events have contributed to the initiation of tanker drive-off in most collision incidents that happened in the North Sea in recent years. To estimate and reduce the probability of excessive surging and yawing events in tandem offloading, a simulation-based approach, which is based on a state-of-the-art time-domain simulation code SIMO, is presented in this paper. A typical North Sea FPSO and a DP shuttle tanker simulation models are setup in SIMO and calibrated by full-scale measurements. The simulated relative distance and relative heading between FPSO and tanker are analyzed by fitting their extreme values into statistical models which give out probabilities of excessive surging and yawing events. Sensitivity studies are performed to pinpoint contributions from various technical and operational factors. Measures to minimize the occurrence of excessive surging and yawing events are identified in design and operational perspectives.

scholarly journals BEACH AND DUKE EROSION TESTS

1968 ◽  
Vol 1 (11) ◽  
pp. 44
Author(s):  
T. Van der Meulen ◽  
M.R. Gourlay
Keyword(s):  
The Netherlands ◽  
Sea Level ◽  
Surf Zone ◽  
Scale Effects ◽  
Wind Waves ◽  
Sand Dunes ◽  
Public Works ◽  
The North ◽  
The North Sea ◽  
Hydraulics Laboratory

In the Netherlands a large part of the country lying below sea level is protected by sand dunes. The erosion of sand dunes during storms at the North Sea, by which the strong wave action is attended with a high sea level, is therefore of extreme importance in the Netherlands. It is almost impossible to do adequate measurements along the coast during storms. Accordingly the Delft Hydraulics Laboratory was requested by the Public Works Department of the Dutch government to investigate in a model a number of matters related to both the maintenance of existing dunes and the design of artificial sand dunes as sea defence works. The investigations reported in this paper are concerned with the following problems a) the influence of the height of sand dunes upon the amount of coastal recession during storm conditions. b) the influence of the wave characteristics upon the amount of coastal recession. c) the differences in coastal recession and profiles obtained with regular waves and those obtained with wind waves. The reproduction on scale of the phenomena m the surf zone is a difficult matter. Many investigators have come to the conclusion that there are several scale effects. Till now our knowledge is not sufficient to determine the magnitude of the scale effects. Owing to this the described tests can give only qualitative information.

scholarly journals The North Sea Bicycle Race ECG Project: Time-Domain Analysis

2017 ◽  
Author(s):  
Dominika Długosz ◽  
Trygve Eftestøl ◽  
Stein Ørn ◽  
Tomasz Wiktorski ◽  
Aleksandra Królak
Keyword(s):  
North Sea ◽  
Time Domain ◽  
Time Domain Analysis ◽  
Domain Analysis ◽  
The North ◽  
The North Sea

Added Resistance and Speed Loss of a Ship Found Using Onboard Monitoring Data

2020 ◽  
Vol 64 (02) ◽  
pp. 99-117
Author(s):  
Øyvind Øksnes Dalheim ◽  
Sverre Steen
Keyword(s):  
Nonlinear Effects ◽  
Model Tests ◽  
Monitoring Data ◽  
Radius Of Gyration ◽  
Added Resistance ◽  
The North ◽  
Planning Optimization ◽  
The North Sea ◽  
Operation Control ◽  
Improved Methods

Prediction of the added resistance or corresponding speed loss in real sea conditions is essential to evaluate the performance of a ship. Assessment of the environmental impact on vessel performance is essential for route and cargo planning, optimization of fuel consumption and design, and configuration of engines and the main propulsion system. In the present study, added resistance and speed loss in real sea conditions are evaluated from1 year of onboard monitoring data of a platform supply vessel (PSV) operating in the North Sea. The true sea margin is shown on an annual basis. Relative contributions from environmental conditions and vessel operation control are presented. Results are compared with model experiments and existing numerical methods for prediction of added resistance and speed loss in waves. The study shows that added resistance due to waves for this PSV is significantly larger than predicted by conventional frequency-domain calculations or model tests. No reason for the deviation is found, but it is anticipated that a combination of effects of longitudinal mass radius of gyration, differences in wavelength and steepness in model tests and reality, and nonlinear effects (not accounted for in the numerical calculations) is partly responsible for the deviations. For ships having similar main dimensions, the conventional ways of predicting added resistance or speed loss in waves is nonconservative, and improved methods should be sought.

scholarly journals All at Sea

2009 ◽  
Vol 131 (06) ◽  
pp. 52-53
Author(s):  
Jeffrey Winters
Keyword(s):  
Oil And Gas ◽  
Wind Waves ◽  
Oil Production ◽  
Management Service ◽  
The North ◽  
Use Of Data ◽  
The North Sea ◽  
Waves And Tides ◽  
Wind Resource ◽  
Recoverable Energy

This article explores oil production options in the American waters. Survey shows that there is significant oil production in the waters of the North Sea and the Bight of Bonny in Nigeria, as well as the Gulf of Mexico. However, the figure published for proved reserves is generally far lower than what geologists believe is available. Proved reserves are restricted to oil and gas that can be commercially recovered from known fields using existing methods under prevailing government regulations. The Minerals Management Service tries to estimate the amount of recoverable energy found in the wind, waves, and tides. The Department of the Interior report makes use of data from the Department of Energy's National Renewable Energy Laboratory, which has estimated the wind resource both on land and at sea, as well as other recent studies. The Department of the Interior's report suggests that the biggest offshore energy source is wind, not oil. It remains to be seen whether calls to exploit that resource will be catchy.

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