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Tropical storms severely affect oil and gas production in the Gulf of Mexico, especially during the storm season from June to December. Offshore well managers often need to shut down operations and evacuate the facility because of storm alerts. Furthermore, if the storms have a more-severe effect, facilities may need to be repaired before production restarts. The purpose of this paper is to determine the effect of storms on production by quantifying metrics such as downtime days and downtime percentage after the storm has passed and whether a facility's platform type affected these metrics. Oil and gas production at offshore facilities (Figure 1) are severely affected, especially in the Gulf of Mexico, by frequent storms.
This paper presents an engineering asset management model for wind turbines that integrates all dimensions impacting the life-cycle of a wind farm. Both technical modules (reliability, supply-chain…) and economic modules (present values of cash-flows, valorization of generation losses) are created and linked together into a global one. The weather module, based on artificial neural networks, used to quantify the accessibility of the turbines for installation or maintenance tasks is described in depth. The paper concludes with test cases demonstrating the importance of integrating such a realistic weather model with the assets models, as well as showing how the global model can be used to support operational decision making. This study is of interest to wind farm operators and service providers seeking to optimize their installation and operational strategies and reduce the overall offshore wind farm costs.
Offshore wind power is a recent electricity generation technology when compared to other renewable energies and if the installed power, around 19GW in 2017, is still largely beneath onshore wind production (about 540GW), it has been growing exponentially since the years 1990 (Sawyer, Liming & Fried 2018). Offshore wind speeds, higher than inland ones, make the offshore energy sector very promising to support the energy transition toward a decarbonized electricity production, although recent strike prices around Europe have put very challenging targets to the offshore wind industry. In order to make sure that those prices are met, the industry needs to reduce its installation and O&M costs, which account for 18 to 23% of the total cost of an offshore wind farms according to (Tavner, 2012). Thus engineering and asset management are useful to optimize the life-cycle management of offshore wind assets (Anastasia, Andrew and Feargal, 2018).
Engineering asset management models have been developed in the industry for decades and have been applied successfully to the energy production for different types of generation (nuclear, fossil, hydropower.). If such models exist for offshore wind turbines and proved to be efficient tools to optimize offshore assets management (Scheu, Matha, Hofmann, Muskulus, 2012 or Douard, Domecq & Lair, 2012), they usually rely on specific assumptions that may differ from one model to the other, making validation and verification difficult as shown in (Dinwoodie et al., 2015). In this paper we will describe a new model that integrates all the dimensions of wind turbine assets, both technical and economic. The main novelty of the presented tool is its flexibility to model any offshore wind farm operations, being agnostic on whether these are installation or maintenance ones. We will focus on the weather model that uses artificial neural networks, to generate weather time series statistically consistent with historical data. Several examples will then highlight the importance of using such models instead of relying on the historical weather data. We will also show how the described integrated model can be used to support life-cycle decision making.
The full-scale measurement system is to necessary to obtain a feedback on the ship powering performance during an operation or a period of ship life. In addition, economical operation with optimized routing is also possible with the use of a ship performance measurement. In this paper, the results of onboard measurements and analysis of powering performance for the dry cargo ship are presented. Onboard measurements had been conducted during a month and a half operating in the southern Atlantic route. Several items related with the powering performance such as the ship position, the speed over ground, the speed through the water, the shaft torque, the propeller speed, the rudder angle, the ship heading, the draughts at the fore and after perpendiculars, the wind direction, the wind speed, and the seawater depth are measured in the real ship. The weather data which are related to the current, wave and swell is obtained from the public weather service. The measured operational data and obtained weather data are combined to analyze the powering performance of the operating ship. Resistance calculation and power correction method of ISO15016:2015 are used to evaluate the powering performance in calm water. Analysis results are compared with model test results to investigate the effects of hull fouling and in-service degradation of ship performance.
In recent years, ship performance has been emphasized due to high fuel costs and environmental regulations. The performance of the ship is assessed by the International Maritime Organization(IMO) with the Energy Efficiency Design Index(EEDI) for new ships and the Energy Efficiency Operational Indicator(EEOI) and the Ship Energy Efficiency Management Plan(SEEMP) for existing ships. Delivery and operation of ships are restricted according to the above criteria and related regulations are gradually tightened. conventionally, the performance evaluation of a new ship is based on the speed trial results in calm sea whether satisfying the requirements of the ship owner. However, since a ship sails in the actual sea with wind, current and wave, a comprehensive performance index that takes into account the influence of the ocean environment is required for the ship performance analysis. To improve the powering performance of ships, the performance analysis based on the actual sailing information is necessary. These results can be widely used for the optimization of the operating condition and the ship design.
A ship weather routing system towards enhancing energy efficiency is briefly introduced firstly. This system is composed of several modules, including ship performance calculation, grids system design, weather routing, ship safety etc. However, when the system was first developed, due to the complicated relationship among these modules and their very huge calculation amount, the working efficiency is very low. Therefore, several methods to improving the working efficiency of this system are designed. Finally, a Bulk Carrier voyage is taken as a case study to prove the validity of these methods. The results show that, with all of these methods, the working efficiency of this ship weather routing system can increase almost 97%.
Ship weather routing is used to determine optimum route (course and speed) between given departure and destination ports based on weather conditions and ship's corresponding performance. It always aims to minimum fuel consumption, suitable ETA (estimated time arrival) or maximum ship safety etc. It has been proved as a very effective tool in shipping field (Simonsen, 2015; Chen, 1998; Buhaug, 2009). People have made great progress on this topic with many weather routing methods developed. The very common methods are: Calculus of variations (Bijlsma, 1975), Isochrone method (James, 1957), Isopone method (Klompstra, 1992, Spaans, 1995), Dijkstra's method (Padhy, 2008; Panigrahi, 2008, Eskild, 2014), Dynamic programming method (De, 1990, Calvert, 1991), 3-dimensional dynamic programming method (Shao, 2013), DIRECT (Dividing RECTangles) method (Finkel, 2003; Larsson, 2015) and some evolutionary algorithms (Hinnenthal, 2010, and J.Szłapczy'nska, 2007) etc. Besides, experts have developed some famous commercial ship weather routing software like OpenCPN, qtVlm, VOSS, VVOS etc. and applied them in the shipping market. All of above make great contribution for the benefits of shipping market.
In this paper, a ship weather routing system for energy efficient shipping is briefly introduced. This system is composed of several modules, including grids system design module, weather routing module, ship safety module, etc. Every module has its own task, and every of them should cooperate with each other so that the whole system can run well towards to a shipping mission. However, the working efficiency of this relatively complicated system is not high enough. For one simple case, it always takes a great of hours to complete calculation, which can not meet the practical demands. Therefore, several methods to improving the working efficiency of this system are designed. These methods include not only system running logistic changing, but also shipping algorithm optimization and programming codes optimization.
Guo, Yongfeng (China Oilfield Services Limited) | Zeng, Huimin (China Oilfield Services Limited) | Qui, Zengwei (China Oilfield Services Limited) | Jin, Fanghong (China Oilfield Services Limited) | Wang, Xiaojuan (China Oilfield Services Limited) | Zhang, Jianzhong (China Oilfield Services Limited) | Wan, Qun (China Oilfield Services Limited)
This paper introduces a process on the metocean survey of a deepwater area in the South China Sea, which is as a basic data for the design and construction of a semi submersible of drilling. The marine environment of the South China Sea is extremely harsh and the semi submersible of drilling will be operated in a very poor condition. So it is necessary to get more metocean data as basic parameters before design a semi-submersible drilling rig. To acquire such data, the engineers carried out a set of surveys and got a lot of in situ metocean data, including not only the weather environment data but also marine environment data, such as the height and frequency of the waves, the current velocity in the difference depth of the sea, and the variational laws of a metocean data with seasons in a year and so on. In addition, engineers also processed theses actual data by related mathematics method and got a set of parameters as basic environmental data to design a new semi submersible of drilling. During surveys in the sea, the engineers found a phenomenon of the soliton that occurred in the South China Sea uniquely. Moreover, this paper involves other special phenomenon in the sea, for example, VIV (Vortex Induced Vibration) when surveys were operating in the South China Sea.
Abstract This paper presents the second version of the Maintenance and Modification Planner (IO-MAP). IO-MAP is a software tool designed to reduce risk in job planning on offshore oil & gas installations in an Integrated Operations (IO) setting. In this situation the planner is likely to have reduced knowledge of the actual installation, and the intention of the IO-MAP is to support the operator in safe job planning through visualization of risks on the actual installation. Risks such as hot work, potentially falling objects, workload and weather data are visualized. The new version is intended to support multiple users planning offshore jobs on a shared large projected display. It is an evolutionary design, based on feedback from exploratory studies on the first version. The studies on the first version identified several improvement areas were parts of the design was too complex and abstract. The new version of the tool described in this paper, has redesigned several objects to be more intuitive and less abstract. The colour scheme has improved consistency for easier comparison of risk factors on the installation. New functionality related to risk factors is also included. The graphical design scheme is inspired from Information Rich Design used in other applications such as large screen displays for oil & gas process monitoring in Norway.
Hashimoto, Noriaki (Hydrodynamics Division, Marine Environment and Engineering Department, Port and Airport Research Institute, Independent Administrative Institution) | Kawaguchi, Koji (Marine Environment and Engineering Department)
In 1989, Amoco Production Company, as part of a worldwide continuous improvement effort by the drilling department, began tracking unscheduled events during drilling operations. It was readily apparent that downtime due to adverse weather conditions was contributing heavily to unscheduled events offshore, especially in the North Sea and Pacific Rim. When the weather downtime percentages were repeated in 1991, after the problem had been identified and publicized internally, drilling management determined that these weather problems were symptomatic of larger problems that encompassed much more than the drilling department and exploratory well schedule.
To study this problem a multi-disciplinary team consisting of two geologists, a geophysicist, a negotiator, three engineers, and a business process facilitator, was formed within the Worldwide Exploration Business Group. One of the team's final products was a Weather Downtime Model. Using detailed weather data and site specific drilling information, the model can predict potential weather downtime problems (Appendix I contains a complete model description). Using hindcasts, in 1992, the team tested the model in a real-time situation (Danish sections Northsea). It also used the model to highlight potential problems as this concession was being developed. This paper describes the work of this multidesciplinary team and its actual use of the Weather Downtime Model.
The Work of the Team
The team examined the entire exploration scheduling process. They were trying to determine if the schedule of physical events (seismic and drilling) were being properly coordinated. The team met for several months to map out the process. They then began by studying the work done by individual disciplinary departments as well as examining the entire system. Their goal was not to change how any discipline chose to do the work required, but rather was to understand the dynamics that drove the system itself, as the requirements of the concession agreement were fulfilled. Three of the main driving factors were communication between disciplines, the annual budgetary process, and the delaying effects of the physical environment, including weather. it was recognized that more effective communication could subdue the effects of budget and environment if the communication was both specific and timely.
`SLIKTRAK` COMPUTER SIMULATION OF SURFACE POLLUTION PROBLEMS ARISING FROM OFFSHORE OIL SPILLS A. W. Glass, B. R. Horton, Shell Internationale Petroleum Maatschappij B. V., Carel van Bylandtlaan 30, PO Box 162, The Hague, The Netherlands. Abstract. The key variables controlling the environmental effects of an offshore oil spill, such as location of the source, flow rate and duration, the weather and current characteristics and the efficiency of the various natural and induced clean-up processes, are subject to considerable uncertainty. In order to evaluate the possible impact of oil weil blow-Outs, either for the purpose of operational decisions or for contingency planning, computer simulation of a large number of fictional incidents has been adopted. The paper will discuss the scenario that is used for the modelling of the slicks, including the assumed patterns of dissipation into the atmosphere and into the seawater. The basic structure of the computer program is presented together with possible application variations. The actual application of the program to various aspects of North Sea development, including the 1977 blow-out of Ekofisk Bravo, is presented. It is concluded that a computer simulator like SLIKTRAK is indispensable for meaningful evaluation of the environmental impact of oil spills in open sea. Résumé. Les variables-clés relatives aux effets sur le milieu d'un déversement de pétrole en mer, telles que lieu de la source, le débit et la durée de l'écoulement, les caractéristiques actuelles de l'état de l'atmosphère et des courants, et l'efficacité des différents processus de nettoyage naturel et provoqué, sont l'objet d'une incertitude considérable. Pour qu'il soit possible d'évaluer l'incidence possible des éruptions de puits de pétrole-soit en vue de la prise de décisions opérationnelles, soit en vue du planning concernant les cas imprévus-n a décidé de procéder à la simulation par ordinateur d'un grand nombre d'incidents fictifs. L'exposé traitera du scénario utilisé pour la mise au point des modèles des nappes, y compris les structures supposées de dissipation dans l'atmosphère et dans la mer. On présente la structure de base du programme d'ordinateur, ainsi que des variations d'application possibles, et l'application effective du programme à différents aspects de l'exploitation en mer du Nord, dont l'éruption de Bravo d'Ekofisk en 1977. On conclut qu'un simulateur pour ordinateur tel que SLIKTRAK est indispensable à l'évaluation rationnelle des conséquences pour le milieu des déversements de pétrole en haute mer. 1.
Offshore drilling for oil carries a risk of pollution of the seas due to uncontrolled well flows, however small the probability of occurrence of such `blow- outs' may be. The oil industry has experienced a limited number of these incidents, at various loca- tions around