Methodology to Obtain the Life Cycle Mooring Loads on a Semisubmersible Wind Platform

2014 ◽  
Author(s):  
Raúl Guanche ◽  
Lucía Meneses ◽  
Javier Sarmiento ◽  
César Vidal ◽  
Íñigo Losada
Keyword(s):  
Life Cycle ◽  
Numerical Model ◽  
Data Base ◽  
Oil And Gas ◽  
Oil And Gas Industry ◽  
Offshore Wind ◽  
Mooring System ◽  
Gas Industry ◽  
Wave Basin ◽  
The Moment

Nowadays there are few methodologies related with the design of mooring systems for floating offshore wind platforms. The ones used until the moment are inherited from the oil and gas industry. Because of that, mooring loads may be incorrectly estimated. This study presents a validated methodology in order to estimate the loads of the moorings of offshore floating platforms along the life cycle of the structure. The methodology is based on an extensive laboratory test data base carried out in a wave basin of the University of Cantabria. The proposed methodology has been applied to a floating semisubmersible platform (similar to the one in Agucadoira by Principle Power). The methodology is composed by a few steps. The first step consist on the selection of the most representative sea states of a long term met-ocean data base through a selection technique named MDA (Maximum dissimilitude algorithm). Afterwards, mooring system loads and platform motion are numerically simulated. SESAM (DNV) numerical model has been used in this particular application. SESAM numerical model was previously calibrated based on the laboratory tests. Finally, based on a multidimensional interpolation technique named Radial Basis Function life cycle mooring system loads were reconstructed. A sensitivity analysis of the methodology were carried out. Based on it, it can be concluded that selecting 1000 sea states with the MaxDiss technique, life cycle mooring loads can be accurately predicted.

Demonstration of the Intelligent Mooring System for Floating Offshore Wind Turbines

2019 ◽  
Author(s):  
Magnus J. Harrold ◽  
Philipp R. Thies ◽  
Peter Halswell ◽  
Lars Johanning ◽  
David Newsam ◽  
...  
Keyword(s):  
Wind Turbines ◽  
Oil And Gas ◽  
Oil And Gas Industry ◽  
Offshore Wind ◽  
Mooring System ◽  
Gas Industry ◽  
Offshore Wind Turbines ◽  
Floating Offshore Wind Turbines ◽  
Physical Testing ◽  
Line Loads

Abstract Existing mooring systems for floating offshore wind turbines are largely based on designs from the oil and gas industry. Even though these can ensure the safe station keeping of the floating wind platform, the design of the mooring system is currently largely conservative, leading to additional expense in an industry striving to achieve cost reduction. Recent interest in the usage of mooring materials with non-linear stiffness has shown that they have the potential to reduce peak line loads, ultimately reducing cost. This paper reports on the combined physical testing and numerical modeling of a hydraulic-based mooring component with these characteristics. The results suggest that the inclusion of the component as part of the OC4 semi-submersible platform can reduce the peak line loads by 10%. The paper also discusses a number of challenges associated with modeling and testing dynamic mooring materials.

Validation of a Simplified LiDAR-Buoy Model Using Open Sea Measurements

2018 ◽  
Author(s):  
Wei Yu ◽  
Oliver Bischoff ◽  
Po Wen Cheng ◽  
Gerrit Wolken-Moehlmann ◽  
Julia Gottschall
Keyword(s):  
Numerical Model ◽  
Oil And Gas ◽  
State Of The Art ◽  
Oil And Gas Industry ◽  
Offshore Wind ◽  
Gas Industry ◽  
Open Sea ◽  
Induced Motion ◽  
Wind Measurements ◽  
Wind Resource

This work validates a numerical model of the Fraunhofer IWES LiDAR-Buoy by using open sea measurements. Such floating LiDAR systems (FLS) have been deployed for almost twenty years, aiming at exploring the offshore wind resource with lower cost. However, the uncertainty of wind measurements from a moving LiDAR are not clear, particularly due to the wave- and current-induced motion of the buoy. Therefore a numerical model with state-of-the-art approaches in conventional oil and gas industry was developed to quantify uncertainty and understand the effect of environmental conditions on the buoy. The model was validated against data from a measurement campaign at the offshore research platform FINO 3. The results show the challenges and limitations when transferring the experience from the oil and gas industry directly because of the different geometries and the much smaller buoys used for FLS. It has been found that the position of the LiDAR is dominated by the current, which is however commonly simplified in the state-of-the-art approach; the rotational motions are significantly influenced by the wave and can be reproduced up to a certain limit.

Simulation of proppant transport and fracture plugging in the framework of a radial hydraulic fracturing model

2020 ◽  
Vol 35 (6) ◽  
pp. 325-339
Author(s):  
Vasily N. Lapin ◽  
Denis V. Esipov
Keyword(s):  
Numerical Model ◽  
Hydraulic Fracturing ◽  
Oil And Gas ◽  
Oil And Gas Industry ◽  
Injection Rate ◽  
Fluid Injection ◽  
Subtraction Technique ◽  
Gas Industry ◽  
Proppant Transport ◽  
Hydraulic Fracture Propagation

AbstractHydraulic fracturing technology is widely used in the oil and gas industry. A part of the technology consists in injecting a mixture of proppant and fluid into the fracture. Proppant significantly increases the viscosity of the injected mixture and can cause plugging of the fracture. In this paper we propose a numerical model of hydraulic fracture propagation within the framework of the radial geometry taking into account the proppant transport and possible plugging. The finite difference method and the singularity subtraction technique near the fracture tip are used in the numerical model. Based on the simulation results it was found that depending on the parameters of the rock, fluid, and fluid injection rate, the plugging can be caused by two reasons. A parameter was introduced to separate these two cases. If this parameter is large enough, then the plugging occurs due to reaching the maximum possible concentration of proppant far from the fracture tip. If its value is small, then the plugging is caused by the proppant reaching a narrow part of the fracture near its tip. The numerical experiments give an estimate of the radius of the filled with proppant part of the fracture for various injection rates and leakages into the rock.

scholarly journals Stochastic Simplex Approximate Gradient for Robust Life-Cycle Production Optimization: Applied to Brugge Field

2019 ◽  
Vol 141 (9) ◽  
Author(s):  
Bailian Chen ◽  
Jianchun Xu
Keyword(s):  
Life Cycle ◽  
Net Present Value ◽  
Oil And Gas ◽  
Oil And Gas Industry ◽  
Optimization Techniques ◽  
Production Optimization ◽  
Operating Conditions ◽  
Optimization Under Uncertainty ◽  
Theoretical Argument ◽  
Gas Industry

In oil and gas industry, production optimization is a viable technique to maximize the recovery or the net present value (NPV). Robust optimization is one type of production optimization techniques where the geological uncertainty of reservoir is considered. When well operating conditions, e.g., well flow rates settings of inflow control valves and bottom-hole pressures, are the optimization variables, ensemble-based optimization (EnOpt) is the most popular ensemble-based algorithm for the robust life-cycle production optimization. Recently, a superior algorithm, stochastic simplex approximate gradient (StoSAG), was proposed. Fonseca and co-workers (2016, A Stochastic Simplex Approximate Gradient (StoSAG) for Optimization Under Uncertainty, Int. J. Numer. Methods Eng., 109(13), pp. 1756–1776) provided a theoretical argument on the superiority of StoSAG over EnOpt. However, it has not drawn significant attention in the reservoir optimization community. The purpose of this study is to provide a refined theoretical discussion on why StoSAG is generally superior to EnOpt and to provide a reasonable example (Brugge field) where StoSAG generates estimates of optimal well operating conditions that give a life-cycle NPV significantly higher than the NPV obtained from EnOpt.

scholarly journals Theoretical and practical aspects of assessment of innovative activity in oil and gas enterprises

2020 ◽  
Vol 13 (4) ◽  
pp. 531-540
Author(s):  
M. V. Rybin ◽  
D. S. Lobov
Keyword(s):  
Life Cycle ◽  
Oil And Gas ◽  
Oil And Gas Industry ◽  
Innovative Activity ◽  
Gas Industry ◽  
The Innovative Management ◽  
And Performance ◽  
Key Indicators ◽  
Oil And Gas Companies ◽  
Oil And Gas Enterprises

Analysis of theoretical and practical aspects of assessment of innovative activity at national and foreign oil and gas enterprises revealed the necessity of improvement of the existing tools which include the lists of key indicators of efficiency and performance applied within the innovative development programs of the Russian companies. Thereby the authors analyzed national and foreign research paying the most serious attention to theoretical aspects of innovative activity assessment. Among them of greatest interest is the complex approach to application of metrics in scientific and technical development of a company. The authors have also studied the conceptual apparatus and the main terms for the problems under consideration. As a result, the research confirmed the idea that the practice of applying the lists of key indicators of innovative activity in oil and gas industry does not coincide with the results of academic works and the innovative management theory: the current methods are primarily aimed at assessment of the results of innovative activity, several stages of the life cycle of creation of innovation are not subject to monitoring. At the same time lists of key indicators of innovative activity make it possible for the company’s management to estimate economic and resource effects of innovations which corresponds to strategic interests of oil and gas companies.Lists of indicators of efficiency and performance of innovative activity can be improved by means of national and foreign research. It is important to involve more metrics which make it possible to monitor all the life cycle of creation and implementation of innovative solutions.The results of the study can be used as the basis for further research on improvement and development of the lists of key indicators of innovative activity of oil and gas companies.

The Experiences From the First Rounds of Offshore Wind Farm Installation in the German EEZ (Both Baltic and North Sea) and Lessons Learnt to Achieve Serial Production Status: A Consultant’s Perspective

2014 ◽  
Author(s):  
Ekkehard Stade
Keyword(s):  
Wind Farm ◽  
Oil And Gas ◽  
Wind Farms ◽  
Oil And Gas Industry ◽  
Offshore Wind ◽  
Offshore Wind Farm ◽  
Gas Industry ◽  
Offshore Wind Farms ◽  
Near Misses ◽  
Construction Operation

Offshore wind farms present a lesser safety risk to operators and contractors than traditional oil and gas installations. In the post Macondo world this does not come as a surprise since the risks involved in construction, operation and maintenance of an offshore wind farm are by far lower. Even with higher probability of incidents and near misses (due to serial construction) the severity/ impact of those is considerably lower. On the other hand projects are complex, profit margins are what they are called: marginal. Hence there is no room for errors, perhaps in form of delays. If, for example, the installation completion of the turbines and the inner array cabling/ export cables are not perfectly in tune, the little commercial success that can be achieved is rapidly diminishing by costly compensation activities. The paper will try to present solutions to the most pressing challenges and elaborate on the effect those would have had, had they been implemented at the beginning of the projects. How can a sustainable new industry evolve by learning from established industries? Presently, there is a view that offshore wind is a short-lived business. Particularly representatives of the oil and gas industry raise such concern. Apart from the obvious bias of those voices, this controversy is also caused by the fact that offshore wind seems to have a tendency to try and re-invent the wheel rather than using established procedures. Even with a relatively stable commitment to the offshore wind development regardless of the respective government focus within European coastal states the industry suffers from financing issues, subsidies, over-regulation due to lack of expertise within authorities and other challenges. The avoidance of those is key to a successful development for this industry in other areas of the planet. In conjunction with a stable commitment this is essential in order to attract the long lead-time projects and to establish the complex supply chains to achieve above goals. The paper will look at the short but intensive history of the industry and establish mitigation to some of the involved risks of offshore wind farm EPCI.

Numerical Simulation of Spudcan Penetration Into Silica Sand and Prediction of Bearing Behaviour

2012 ◽  
Author(s):  
Tim Pucker ◽  
Britta Bienen ◽  
Sascha Henke
Keyword(s):  
Bearing Capacity ◽  
Oil And Gas ◽  
Cone Angle ◽  
Oil And Gas Industry ◽  
Friction Angle ◽  
Offshore Wind ◽  
Silica Sand ◽  
Gas Industry ◽  
Jack Up ◽  
Bearing Behavior

Prediction of the bearing behavior of vertical loaded shallow foundations is typically done using the classical bearing capacity approach. This approach is very sensitive to the friction angle assumed in the calculation. A conservative estimate of the bearing capacity is required for most applications, hence uncertainties in the friction angle may be absorbed by the safety factor applied. Spudcans are used to found mobile jack-up platforms in the oil and gas industry as well as in the offshore wind energy industry. Contrary to the classical approach, the bearing capacity of spudcans has to be predicted accurately. Spudcans are penetrated into the seabed and a continuous bearing failure proceeds until the target capacity is met. A Coupled Eulerian-Lagrangian (CEL) approach is used to simulate the penetration process of spudcans into silica sand. The sand is modeled using a hypoplastic constitutive model to capture the influence of the void ratio and stress state for example. A parametric study of foundation diameter and enclosed cone angle is presented. The numerical model is validated against results from centrifuge experiments of flat and conical circular footings penetrating into silica sand. A first empirical approach to estimate the bearing capacity depending on the diameter and enclosed cone angle is given for silica sand.

Revision of DNV Design Standard for Offshore Wind Turbine Structures

2007 ◽  
Author(s):  
Jakob Wedel-Heinen ◽  
Knut O. Ronold ◽  
Peter Hauge Madsen
Keyword(s):  
Wind Turbine ◽  
Oil And Gas ◽  
Oil And Gas Industry ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Wave Loads ◽  
Gas Industry ◽  
Standard Design ◽  
Practical Guidelines ◽  
Offshore Oil And Gas

The first DNV-OS-J101 standard “Design of Offshore Wind Turbine Structures” [1] was issued in June 2004. The standard represented a condensation of all relevant requirements in DNV standards for the offshore oil and gas industry which were considered relevant also for offshore wind turbine structures, supplemented by necessary adaptation to the wind turbine application. Det Norske Veritas (DNV) plans to issue the next revision of DNV-OS-J101 [2] in 2007. The DNV revised standard now implements the requirements of the coming IEC 61400-3 standard [11], which was presented as a committee draft in 2006. Numerous practical guidelines have been included to help designers of offshore wind turbine structures to develop cost optimal designs. The present paper summarises the proposed revisions of DNV-OS-J101 [2]. The most important revisions cover new formulations for design load cases, modified partial safety factors, exclusion of transformer platforms, more information on wave loads in shallow water and a revised chapter for design of concrete structures.

scholarly journals On Disaster Risk Reduction in Norwegian Oil and Gas Industry Through Life-Cycle Perspective

2019 ◽  
Author(s):  
Michaela Ibrion ◽  
Nicola Paltrinieri ◽  
Amir R. Nejad
Keyword(s):  
Life Cycle ◽  
Risk Reduction ◽  
Oil And Gas ◽  
Oil And Gas Industry ◽  
Learning And Development ◽  
Gas Industry ◽  
Life Cycle Perspective ◽  
Offshore Field ◽  
Perspective Analysis ◽  
Reduction Of Uncertainty

Abstract This paper presents the risk reduction in Norwegian oil & gas industry over the time (1975–2016) through a life cycle perspective analysis with the aim to identify the critical stage(s) both in terms of accident occurrence and cause of the accident. Fifteen accidents, major accidents and disasters for example Ecofisk 2/4 Alpha 1975, Alexander L. Kielland 1980, Songa Endurance 2016 were studied. Cases from outside of the Norwegian offshore field — the Piper Alpha 1988, the Bourbon Dolphin 2007, and the Deep Water Horizon 2010 — were also considered as comparison. For each accident and through the life cycle analysis, the occurrence stage of the accident and its main technical causes were identified and compared. It was found that a high risk is concentrated in the Operation (In-Service) stage and associated Marine Operations. Furthermore, it was observed that a high number of accidents in oil and gas industry are associated with mobile structures. All the investigated accidents have acted as powerful reminders to the oil and gas industry that a continuous improvement of risk management and reduction of uncertainty are of paramount importance in order to ensure safe operations and risk reduction for accidents, major accidents and disasters. However, a reactive learning from major accidents and disasters needs to be supported by a proactive learning and development of a dynamic risk culture in the oil and gas industry.

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