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In structural engineering, offshore structures are undoubtedly among the most exposed to the effects of harsh environmental conditions. The external conditions of these semi-immersed systems involve complex combinations of wave and wind loads. The operating conditions are also unique because oil production platforms are subjected to repeated loading and unloading cycles of the extracted material, which continuously alter their mass. These characteristics make the definition of a structural health monitoring (SHM) protocol highly challenging but necessary to avoid environmental disasters. In this regard, this study discusses an SHM method that can be applied to offshore structures under realistic wave and wind loads. This approach combines anomaly detection, frequency domain decomposition, and a cointegration strategy. Two machine learning regression algorithms were tested to define a cointegration relationship: the support vector machine and the relevance vector machine. The effectiveness of the overall method was evaluated on time-domain signals generated from a finite-element model of a fixed steel platform, on which the Davenport and JONSWAP spectra were used to simulate wind and wave forces. The results show that this damage detection strategy is effective in supervising the health conditions in the analyzed scenario., Geo-engineering

Diverse forms of offshore oil and gas structures are utilized for a wide range of purposes and in varying water depths. They are designed for unique environments and water depths around the world. The applications of these offshore structures require different activities for proper equipment selection, design of platform types, and drilling/production methods. This paper will provide a general overview of these operations as well as the platform classifications. In this paper, a comprehensive review is conducted on different offshore petroleum structures. This study examines the fundamentals of all types of offshore structures (fixed and floating), as well as the applications of these concepts for oil exploration and production. The study also presents various design parameters for state-of-the-art offshore platforms and achievements made in the industry. Finally, suitable types of offshore platforms for various water depths are offered for long-term operations. An extension of this study (Part II) covers sustainable design approaches and project management on these structures; this review helps designers in understanding existing offshore structures, and their uniqueness. Hence, the review also serves as a reference data source for designing new offshore platforms and related structures.

Offshore structures exist in a variety of forms, and they are used for a variety of functions in varied sea depths. These structures are tailored for certain environments and sea depths. Different actions for suitable equipment selection, platform type design, and drilling/production processes are required for the applications of these offshore structures, as given in Part I. This paper is the second part, which outlines various processes, loads, design approaches and project management of offshore platforms. To achieve these, proper planning must be conducted for lifting, transportation, installation, design, fabrication, and commissioning of these offshore platforms. Some historical developments of some offshore structures are presented, and some project planning routines are undertaken in this research. The ultimate goal is to provide a general overview of the many processes of offshore platform design, construction, loadout, transportation, and installation. Some discussions on the design parameters such as water depth and environmental conditions were presented. It also lists various software programs used in engineering designs covering software programs for structural analysis, 3D rendering, computer-aided design (CAD), hydrodynamic design, oceanic flow analysis, offshore structures analysis, mathematical modelling, coding/algorithm development software, and programming software to aid analytical calculations. The review also includes information on cutting-edge offshore platforms and industry advancements. Ultimately, for long-term operations, various types of offshore platforms for specific seawater depths are available.

The average cocaine seizure rate of coast guard operations in the Colombian Pacific can be improved. To enhance this indicator, detection and interdiction must be improved. Therefore, the option of using an offshore platform with better detection means, and several Rapid Reasponse Units (RRUs) stationed offshore, is being analyzed. As a result, offshore platforms are neither feasible nor viable due to the depth of the sea floor (> 2 km), but SWATH platforms can be used. The parametric design of two SWATHs is performed and an operational evaluation is made of the different current units and SWATHs. The operational evaluation of the different current units and the proposed SWATHs is carried out and contrasted with their acquisition and life cycle cost, showing that the SWATHs have a better efficiency/cost ratio. Therefore, they can be considered as an alternative to improve the efficiency of cocaine seizures and other coast guard operations., En las operaciones de guardacostas en el Pacífico colombiano, se tiene un promedio de incautación de la cocaína producida que puede ser mejorado. Para mejorar este indicador, se deben mejorar la detección e interdicción. Por ende, se analiza la opción de utilizar una plataforma costa afuera con mejores medios de detección, y varias Unidades de Reacción Rápida (RRU) destacadas. Como resultado las plataformas costa afuera no son viables ni factibles por la gran profundidad del mar (> 2 km), pero se pueden utilizar plataformas SWATH. Se realiza el diseño paramétrico de dos SWATH y se hace una evaluación operacional a las diferentes unidades actuales y las SWATH propuestas, a la vez que se contrasta con su costo adquisición y de ciclo de vida evidenciando que los SWATH tienen una mejor relación eficiencia/costo. Por ende, se pueden considerar como una alternativa para mejorar la eficiencia de incautaciones de cocaína y demás operaciones de guardacostas.

The average cocaine seizure rate of coast guard operations in the Colombian Pacific can be improved. To enhance this indicator, detection and interdiction must be improved. Therefore, the option of using an offshore platform with better detection means, and several Rapid Reasponse Units (RRUs) stationed offshore, is being analyzed. As a result, offshore platforms are neither feasible nor viable due to the depth of the sea floor (> 2 km), but SWATH platforms can be used. The parametric design of two SWATHs is performed and an operational evaluation is made of the different current units and SWATHs. The operational evaluation of the different current units and the proposed SWATHs is carried out and contrasted with their acquisition and life cycle cost, showing that the SWATHs have a better efficiency/cost ratio. Therefore, they can be considered as an alternative to improve the efficiency of cocaine seizures and other coast guard operations., En las operaciones de guardacostas en el Pacífico colombiano, se tiene un promedio de incautación de la cocaína producida que puede ser mejorado. Para mejorar este indicador, se deben mejorar la detección e interdicción. Por ende, se analiza la opción de utilizar una plataforma costa afuera con mejores medios de detección, y varias Unidades de Reacción Rápida (RRU) destacadas. Como resultado las plataformas costa afuera no son viables ni factibles por la gran profundidad del mar (> 2 km), pero se pueden utilizar plataformas SWATH. Se realiza el diseño paramétrico de dos SWATH y se hace una evaluación operacional a las diferentes unidades actuales y las SWATH propuestas, a la vez que se contrasta con su costo adquisición y de ciclo de vida evidenciando que los SWATH tienen una mejor relación eficiencia/costo. Por ende, se pueden considerar como una alternativa para mejorar la eficiencia de incautaciones de cocaína y demás operaciones de guardacostas.

Due to the demand for oil production in varying water depth regions, the advantage of flexible buoyant conduits has led to an increase in bonded marine hoses for fluid transfer and (un)loading operations. The fluid transfer system for bonded marine hoses is dependent on floating offshore structures (FOS). This paper presents an overview of different systems for sustainable fluid transfer and (un)loading operations via FOS, such as Single Point Mooring (SPM) systems. SPMs are component aspects of the techno-economic design and FOS operation. This review aims to present sustainable fluid transfer technologies while addressing the subject of bonded marine hoses based on application, configuration, test models, hose selection criteria, hose-mooring configurations and operational views. This paper also includes an overview of the hose dynamics, with the loading and unloading (or discharging) techniques for sustainable fluid transfer via marine bonded hoses, based on operational challenges encountered. To dynamically present the hose performance in this review, an overview of the test methods’ guidance as specified in available industry standards was conducted. The pros and cons of marine hose application were also presented. Finally, this study presents different marine hose types and novel design configurations applied in implementing hose-mooring systems. Some concluding remarks with recommended solutions on the technology were presented in this review.

This chapter studies the social acceptance and socio-economic effects associated with the development of multi-use offshore platforms, using a theoretical concept in Taiwan as the relevant casestudy. We use a face-to-face surveys together with in-depth interviews with local people and tourists who are currently or will be potentially affected by offshore developments on Liuqiu Island. A choice experiment is deployed to assess the ecosystem services and non-market effects of the platform. The social costs and benefits analysis are adopted to synthesize both market and non-market effects of the platform. The study finds a generally high support for the platform among tourists. The concern mainly focuses on the uncertain environmental impacts and effects on local fishery industry. Neither locals nor tourists view the energy hub which generates most income and jobs as a very attractive option. The Green & Blue concept shows a high environmental nonmarket benefit which amount to 618 million $NT. However, the high investment cost over weighs the positive GDP and environmental gain when comparing the social benefits with investment costs.

This project is based on 2 issues, the degradation of the ecosystem in North Sea and the decommission of offshore platforms.

Estimation of wave run-up has been of increasing concern for offshore wind structures and a critical aspect for designers. The highly nonlinear phenomenon makes the study difficult. That is the reason for the very few design rules and experimental data available to estimate it. Actual wave run-up is greater than commonly predicted. The goal of this research is to benchmark the theoretical formulations with the results of the physical model tests performed by Deltares in the field of crest elevation, run-up, forces and pressures. The laboratory reproduced in a wave tank (75 m length; 8.7 m width; 1 m depth; and a 1:60 scale, with Froude similarity) an offshore power converter platform located at intermediate water depths (25–43.80 m) in the Southern North Sea, designed by the Norwegian company Aibel. The purpose of this research is to offer a preliminary design guide for wave run–up using theoretical expressions both for cylinders and gravity based structures (GBS), leaning on the cited laboratory tests to validate the results obtained by such theoretical models.

Estimation of wave run-up has been of increasing concern for offshore wind structures and a critical aspect for designers. The highly nonlinear phenomenon makes the study difficult. That is the reason for the very few design rules and experimental data available to estimate it. Actual wave run-up is greater than commonly predicted. The goal of this research is to benchmark the theoretical formulations with the results of the physical model tests performed by Deltares in the field of crest elevation, run-up, forces and pressures. The laboratory reproduced in a wave tank (75 m length; 8.7 m width; 1 m depth; and a 1:60 scale, with Froude similarity) an offshore power converter platform located at intermediate water depths (25–43.80 m) in the Southern North Sea, designed by the Norwegian company Aibel. The purpose of this research is to offer a preliminary design guide for wave run–up using theoretical expressions both for cylinders and gravity based structures (GBS), leaning on the cited laboratory tests to validate the results obtained by such theoretical models.

This project is based on 2 issues, the degradation of the ecosystem in North Sea and the decommission of offshore platforms.

The data were collected through inspection of ROV videos. The data are formatted in a single csv file. It contains 30 columns with 5587 rows, including title row. Each row represents a separate observation of species abundance according to the Braun-Blanquet scale. The dataset contains null values which are indicated with NA. The first 21 columns contain sample information. Columns 22-29 contain information about taxonomic grouping and Column 30 contains the Braun-Blanquet abundance values., The data were collected through inspection of ROV videos by Floor M.F. Driessen [1]. 1.†††††† Bureau Waardenburg, Varkensmarkt 9, Postbus 365, 4100 AJ Culemborg, The Netherlands. EXPLANATION OF DATASET The data are formatted in a single csv file. It contains 30 columns with 5587 rows, including title row. Each row represents a separate observation of species abundance according to the Braun-Blanquet scale. The dataset contains null values which are indicated with NA. The first 21 columns contain sample information. Columns 22-29 contain information about taxonomic grouping and Column 30 contains the Braun-Blanquet abundance values. Explanation per column (1-30): Observation_number: Unique identification code for each observation. Include_YES_NO: indication whether or not the observation was included in data analysis: YES =included, NO= not included. Country: Country of operation of the offshore gas or oil platform: NL = The Netherlands, DK = Denmark Company: Company operating the offshore gas or oil platform: Maersk Oil or Petrogas E&P LLC. Platform_name: name of the offshore gas or oil platform. Latitude: latitudinal coordinate of the location of the platform in decimal degrees, WGS84. Longitude: longitudinal coordinate of the location of the platform in decimal degrees, WGS84. Distance from Dutch shore: shortest distance from platform to the Dutch shoreline as the crow flies (in km) Distance from Danish shore: shortest distance from platform to the Danish shoreline as the crow flies (in km) Year_of_installation: Year of installation of the gas or oil platform (OSPAR production start) Depth_platform: depth of platform at lowest astronomical tide (LAT) in meters Video_Name: unique video name Video_Date: date on which the ROV video was taken Video_quality: video quality as assessed by the video observer and relative to available video material. 0 = no visibility/black screen, 9 = very good visibility, no limitations for video analysis, NA = unknown. Depth_ROVsamp

Grouted connections are frequently used as structural detail of offshore wind turbines and platforms for the load transferring connection between piles and support structure. At latticed substructures this connection is commonly located at mudline. However, a potential influence of the surrounding water on the connection's fatigue behaviour was neglected in earlier tests and consequential design methods. Herein described experimental investigations at small and large-scale fatigue tests in submerged conditions showed a significant reduction of endurable load cycles. In addition, the water impact caused varied damage mechanism in the connection. © 2017 The Author(s).

This data was collected to determine whether the composition and the abundance of species assemblages changes with depth and along a distance from shore gradient. The species assemblage on offshore gas platforms in the Dutch part of the North Sea was inventoried using ROV inspection footage. The dataset contains observations of 11 species on 5 of these platforms.

TNT Equivalency methods are widely used for vapour cloud explosion blast modeling. Presently, however, other types of models are available which do not have the fundamental objections TNT Equivalency models have. TNO Multi-Energy method is increasingly accepted as a more reasonable alternative to be used as a simple and practical method. Computer codes based on computational fluid dynamics (CFD) like AutoReaGas, developed by TNO and Century Dynamics, could be used also in case a more rigorous analysis is required. Application of the Multi-Energy method requires knowledge of two parameters describing the explosion: a charge size and a charge strength. During the last years, research has led to an improved determination of the charge strength (i.e., the class number or source overpressure) to be chosen to apply the blast charts. A correlation has been derived relating the charge strength to a set of parameters describing the boundary conditions of the flammable cloud and the fuel in the cloud. A simple approach may not be satisfactory in all situations. The overpressure distribution inside a vapour cloud explosion is generally not homogeneous and the presence of obstructions causes directional blast propagation in the near field. A CFD approach, in which the actual situation is modeled, supplies case-specific results. An overview of the key aspects relevant to the application of the Multi-Energy method and CFD modeling is provided. Then the application of the two methods is demonstrated for an example problem involving the calculation of the explosion blast load on a structure at some distance from the explosion in an offshore platform complex. Copyright (C) 2000 Elsevier Science B.V.

Part I: The computer program INTRA models the collapse behavior of trusswork offshore structures with the aid of two types of elements: 'Beam-column' elements, designed to simulate bending dominated failure of structural members, and 'strut' elements, that can represent normal force dominated failure. The behavior of both types of INTRA elements has been investigated by comparison with the results of analytical solutions and of the MARC finite element program. A satisfying performance has been found for the beam-column element BEMC and the strut element ISTR. A Fortran routine has been established to generate the required input parameters for INTRA strut elements, resulting in more exact input values than can be derived with the aid of the default property generation. A parameter study has been carried out to the behavior of strut elements under conditions that may occur in the modelling of a large North Sea platform. It appears that lateral loads and imposed end rotations each may result in a maximum reduction of buckling strength of 15%, but that, however, the average reduction is much lower. Also the post-buckling strength is only modestly influenced. A plane frame pushover analysis has been performed with both the INTRA and the MARC programs. The influence of schematizations in INTRA strut elements on the overall structural beahavior appears to be acceptably small. However, serious numerical problems occurred during the INTRA analysis, resulting in a too low prediction of the ultimate load of the platform. Part II: As a preparation to pushover analysis of a complete fixed steel offshore structure, failure of the foundation has been analyzed in a qualitative way. Structure-foundation interaction is considered and some methods are treated to describe load-deformation behavior of piles loaded up to failure. Main attention is paid to methods in conjunction with the computer program INTRA. Computational rules to achieve load settlement curves for pile groups under ex, Steel Structures / Structural Mechanics, Structural Engineering, Civil Engineering and Geosciences

Part I: The computer program INTRA models the collapse behavior of trusswork offshore structures with the aid of two types of elements: 'Beam-column' elements, designed to simulate bending dominated failure of structural members, and 'strut' elements, that can represent normal force dominated failure. The behavior of both types of INTRA elements has been investigated by comparison with the results of analytical solutions and of the MARC finite element program. A satisfying performance has been found for the beam-column element BEMC and the strut element ISTR. A Fortran routine has been established to generate the required input parameters for INTRA strut elements, resulting in more exact input values than can be derived with the aid of the default property generation. A parameter study has been carried out to the behavior of strut elements under conditions that may occur in the modelling of a large North Sea platform. It appears that lateral loads and imposed end rotations each may result in a maximum reduction of buckling strength of 15%, but that, however, the average reduction is much lower. Also the post-buckling strength is only modestly influenced. A plane frame pushover analysis has been performed with both the INTRA and the MARC programs. The influence of schematizations in INTRA strut elements on the overall structural beahavior appears to be acceptably small. However, serious numerical problems occurred during the INTRA analysis, resulting in a too low prediction of the ultimate load of the platform. Part II: As a preparation to pushover analysis of a complete fixed steel offshore structure, failure of the foundation has been analyzed in a qualitative way. Structure-foundation interaction is considered and some methods are treated to describe load-deformation behavior of piles loaded up to failure. Main attention is paid to methods in conjunction with the computer program INTRA. Computational rules to achieve load settlement curves for pile groups under ex, Steel Structures / Structural Mechanics, Structural Engineering, Civil Engineering and Geosciences