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.

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.

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).

scholarly journals Validating management simulation models and implications for communicating results to stakeholders

2007 ◽  
Vol 64 (4) ◽  
pp. 818-824 ◽  
Author(s):  
Martin A. Pastoors ◽  
Jan Jaap Poos ◽  
Sarah B. M. Kraak ◽  
Marcel A. M. Machiels
Keyword(s):  
North Sea ◽  
Simulation Models ◽  
Management Plan ◽  
Level Of Detail ◽  
Advisory Council ◽  
The North ◽  
Management Procedure ◽  
Management Plans ◽  
The North Sea ◽  
Fleet Dynamics

Abstract Pastoors, M. A., Poos, J. J., Kraak, S. B. M., and Machiels, M. A. M. 2007. Validating management simulation models and implications for communicating results to stakeholders. – ICES Journal of Marine Science, 64: 818–824. Simulations of management plans generally aim to demonstrate the robustness of the plans to assumptions about population dynamics and fleet dynamics. Such modelling is characterized by specification of an operating model (OM) representing the underlying truth and a management procedure that mimics the process of acquiring knowledge, formulating management decisions, and implementing those decisions. We employ such a model to evaluate a management plan for North Sea flatfish proposed by the North Sea Regional Advisory Council in May 2005. Focus is on the construction and conditioning of OMs, key requirements for such simulations. We describe the process of setting up and validating OMs along with its effects on the ability to communicate the results to the stakeholders. We conclude that there is tension between the level of detail required by stakeholders and the level of detail that can be provided. In communicating the results of simulations, it is necessary to make very clear how OMs depend on past perceptions of stock dynamics.

XVI.—The Macrofauna of the Intertidal Sand of Kames Bay, Millport, Buteshire

1942 ◽  
Vol 60 (2) ◽  
pp. 543-561 ◽  
Author(s):  
E. Emrys Watkin
Keyword(s):  
North Sea ◽  
Soil Fauna ◽  
Point Of View ◽  
Intertidal Sand ◽  
Number Of Species ◽  
The North ◽  
Intertidal Species ◽  
South Wales ◽  
Ecological Problems ◽  
The North Sea

During the last few years the distribution of the macrofauna, and to a less extent the microfauna, of the intertidal soils of the shores of Britain has received considerable attention and the principle that the species show a zonation with maximum densities at certain levels is now well established. The extensive studies of Elmhirst (1931) and of Stephen (1928, 1929, and 1930) on the fauna of the sandy and muddy areas of numerous Scottish bays has laid the foundation for much further work in this area. Pirrie, Bruce, and Moore (1932) have described the zonation of the fauna in the intertidal sand of Port Erin bay. Alexander, Southgate, and Bassindale (1935) refer to the fauna of the sand at the mouth of the River Tees, but mainly from the point of view of comparison with the fauna of the estuary. Crawford (1937 a and b) gives notes on the distribution and habits of certain intertidal species in sandy bays and estuaries in west England and south Wales. Rees (1939) has surveyed in outline, as part of a study of the interstitial sand copepods, the macrofauna of some sandy bays in north Donegal. Spooner and Moore (1940) have given a detailed description of the zonation of the species in the estuarine muds of the Tamar. Apart from the above, reference must be made to two intensive studies on the soil fauna of the eastern shores of the North Sea, namely, that of Thamdrup (1935) on Danish shores and of Wohlenberg (1937) on certain bays on the island of Sylt. A general discussion of the ecological problems of sand, mud, and algal environments is given by Remane (1933), based on the macrofauna and microfauna of Kiel bay. He reaches the conclusion, based on the number of species which occur in each environment, that the macrofauna of sand is comparatively poor compared with mud.

scholarly journals Effects of global ship emissions on European air pollution levels

2020 ◽  
Vol 20 (19) ◽  
pp. 11399-11422
Author(s):  
Jan Eiof Jonson ◽  
Michael Gauss ◽  
Michael Schulz ◽  
Jukka-Pekka Jalkanen ◽  
Hilde Fagerli
Keyword(s):  
Air Pollution ◽  
North Sea ◽  
Ozone Formation ◽  
Ship Emissions ◽  
Pollution Levels ◽  
The North ◽  
The North Sea ◽  
Sensitivity Studies ◽  
Oxidised Nitrogen ◽  
Sulfur Emissions

Abstract. Ship emissions constitute a large, and so far poorly regulated, source of air pollution. Emissions are mainly clustered along major ship routes both in open seas and close to densely populated shorelines. Major air pollutants emitted include sulfur dioxide, NOx, and primary particles. Sulfur and NOx are both major contributors to the formation of secondary fine particles (PM2.5) and to acidification and eutrophication. In addition, NOx is a major precursor for ground-level ozone. In this paper, we quantify the contributions from international shipping to European air pollution levels and depositions. This study is based on global and regional model calculations. The model runs are made with meteorology and emission data representative of the year 2017 after the tightening of the SECA (sulfur emission control area) regulations in 2015 but before the global sulfur cap that came into force in 2020. The ship emissions have been derived using ship positioning data. We have also made model runs reducing sulfur emissions by 80 % corresponding to the 2020 requirements. This study is based on model sensitivity studies perturbing emissions from different sea areas: the northern European SECA in the North Sea and the Baltic Sea, the Mediterranean Sea and the Black Sea, the Atlantic Ocean close to Europe, shipping in the rest of the world, and finally all global ship emissions together. Sensitivity studies have also been made setting lower bounds on the effects of ship plumes on ozone formation. Both global- and regional-scale calculations show that for PM2.5 and depositions of oxidised nitrogen and sulfur, the effects of ship emissions are much larger when emissions occur close to the shore than at open seas. In many coastal countries, calculations show that shipping is responsible for 10 % or more of the controllable PM2.5 concentrations and depositions of oxidised nitrogen and sulfur. With few exceptions, the results from the global and regional calculations are similar. Our calculations show that substantial reductions in the contributions from ship emissions to PM2.5 concentrations and to depositions of sulfur can be expected in European coastal regions as a result of the implementation of a 0.5 % worldwide limit of the sulfur content in marine fuels from 2020. For countries bordering the North Sea and Baltic Sea SECA, low sulfur emissions have already resulted in marked reductions in PM2.5 from shipping before 2020. For ozone, the lifetime in the atmosphere is much longer than for PM2.5, and the potential for ozone formation is much larger in otherwise pristine environments. We calculate considerable contributions from open sea shipping. As a result, we find that the largest contributions to ozone in several regions and countries in Europe are from sea areas well outside European waters.

XVI.—The Macrofauna of the Intertidal Sand of Kames Bay, Millport, Buteshire

1942 ◽  
Vol 50 (2) ◽  
pp. 543-561
Author(s):  
E. Emrys Watkin
Keyword(s):  
North Sea ◽  
Soil Fauna ◽  
Point Of View ◽  
Intertidal Sand ◽  
Number Of Species ◽  
The North ◽  
Intertidal Species ◽  
South Wales ◽  
Ecological Problems ◽  
The North Sea

During the last few years the distribution of the macrofauna, and to a less extent the microfauna, of the intertidal soils of the shores of Britain has received considerable attention and the principle that the species show a zonation with maximum densities at certain levels is now well established. The extensive studies of Elmhirst (1931) and of Stephen (1928, 1929, and 1930) on the fauna of the sandy and muddy areas of numerous Scottish bays has laid the foundation for much further work in this area. Pirrie, Bruce, and Moore (1932) have described the zonation of the fauna in the intertidal sand of Port Erin bay. Alexander, Southgate, and Bassindale (1935) refer to the fauna of the sand at the mouth of the River Tees, but mainly from the point of view of comparison with the fauna of the estuary. Crawford (1937 a and b)gives notes on the distribution and habits of certain intertidal species in sandy bays and estuaries in west England and south Wales. Rees (1939) has surveyed in outline, as part of a study of the interstitial sand copepods, the macrofauna of some sandy bays in north Donegal. Spooner and Moore (1940) have given a detailed description of the zonation of the species in the estuarine muds of the Tamar. A part from the above, reference must be made to two intensive studies on the soil fauna of the eastern shores of the North Sea, namely, that of Thamdrup (1935) on Danish shores and of Wohlenberg (1937) on certain bays on the island of Sylt. A general discussion of the ecological problems of sand, mud, and algal environments is given by Eemane (1933), based on the macrofauna and microfauna of Kiel bay. He reaches the conclusion, based on the number of species which occur in each environment, that the macrofauna of sand is comparatively poor compared with mud.

I—North Sea Oil

1974 ◽  
Vol 27 (2) ◽  
pp. 206-212
Author(s):  
T. F. Gaskell
Keyword(s):  
North Sea ◽  
Point Of View ◽  
Good Prospect ◽  
Severe Storms ◽  
New Developments ◽  
The North ◽  
Exploration And Production ◽  
The North Sea ◽  
Tidal Streams ◽  
Gas Fields

There have been many new developments in the North Sea during the last seven years since gas was first discovered in the B.P. West Sole field. First, half a dozen other gas-fields have been found and a large quantity of methane has already been piped to Britain. Secondly, oil has been discovered in the northern part of the North Sea between Scotland and Scandinavia. One may well ask why this large source of energy was not discovered many years ago. The reasons are much the same as applied to the gas discovery; the North Sea 10 years ago was not a very good prospect from a geological point of view, and in any case the techniques of exploration and production in offshore areas were not adequate until recently, especially in a place such as the North Sea wher severe storms and tidal streams make operations difficult and hazardous.

RESULTS OF THE 1987 FORTIES CRUDE OIL TRIAL IN THE NORTH SEA

1989 ◽  
Vol 1989 (1) ◽  
pp. 525-532 ◽  
Author(s):  
N. Hurford ◽  
I. Buchanan
Keyword(s):  
Physical Properties ◽  
Crude Oil ◽  
North Sea ◽  
Oil Spill ◽  
Simulation Models ◽  
The North ◽  
Surface Samples ◽  
The North Sea

ABSTRACT This report presents the results of a trial to study the behavior of Forties crude oil spilled at sea. The trial involved the release of approximately 20 metric tons (t) of Forties crude oil and monitoring the movement, spreading, and dispersion of the slick over a four-day period. Surface samples were collected at regular intervals to determine changes in the physical properties of the oil. The implications of the results for the development of oil spill simulation models are discussed.

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