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API code is introduced at first, and then a comparison of seismic character and seismic hazard between Bohai and Southern California is carried out. The analysis indicates both the seismic frequency and intensity and the seismic hazard of Bohai are much weaker than that of Southern California. API code states the strength level and deformation level of permanent structures in Southern California takes 200 a and several hundred to a few thousand years respectively. But in the reference codes in China, the seismic levels take 500 a and 10 000 a for strength design and deformation design, and it seems too conservative. In China, the deformation level of class A structure takes 2%–3% probabilities of exceedance in reference period 100 a, and that of class B and C often takes 2%–3% in 50 a. Now that offshore platforms may cause server subsequent risk, it is safe to take 1% in 30 a as its deformation design level. On the basis of the above analyses and social economic level and the consistency with present codes, the strength design level and deformation design level of Chinese offshore platforms is suggested to take 200 a and 3 000 a respectively. [ABSTRACT FROM AUTHOR]

Lectotype optimization of offshore platforms is of particular importance in the concept design process. Lectotype optimization involves multiple objectives with uncertainty and so is a problem of multiple attribute decision making. To date, there have been few published works on this topic in the context of offshore engineering. This paper develops a framework and methodology for evaluation of offshore platform alternatives, where a fuzzy optimum model is proposed to integrate the influence of each objective in the criteria set, and a new weight-assessing method is developed to mimic the decision maker’s experience and preference based on complementary pairwise comparisons. A case study shows that the new framework and methodology is scientific, reasonable and easy to use in practice. [Copyright &y& Elsevier]

In this paper, the propagation characteristics of vibration waves in periodic pipelines were studied based on the band theory of phononic crystals, and we analyzed the influence of the geometrical structure parameters on the band gap characteristics of pipelines. The results show that, by increasing the number of layers of local resonant structure, both the initial frequency and the cutoff frequency of the band gap moved towards the lower frequency, while the width of the system band gap increased by 35 Hz, and the damping effect increased by 18.3 dB. By changing the thickness of the wall of the pipeline system, the width of the system band gap increased by 20 Hz, and the damping effect increased by 9.1 dB. The maximum vibration isolation of the offshore platform truss based on the periodic structure can be up to 7.93 dB. Therefore, it is feasible to apply the local resonant periodic structure to the vibration control of a practical offshore platform.

Multi-purpose offshore structures are very complex systems to be designed as many different requirements have to be taken into account simultaneously. Experimental tests on scaled models can be very useful to verify structural behavior and to validate numerical models. The definition of the scale can play a key role in performing tests as high scales, closer to full-scale, are generally related to more reliable results. The present paper concerns the design of a wind turbine model for a large-scale model of a Multi-purpose offshore Platform developed within the EU project H2020 Blue Growth Farm. This project aims at developing an offshore farm, based on a modular floating structure that integrates wave energy converters and a wind turbine with aquaculture. The scale model of the complete structure will be deployed at the Natural Ocean Engineering Laboratory (NOEL). The paper will focus on the strategies adopted to scale 1:15 the DTU 10 MW wind turbine in order to represent both the main aeroelastic features and all the functionalities of a real machine. The complete design of the machine and its control will be also provided. • The present work was developed within the EU H2020 project 'The Blue Growth Farm'. • The aim of the project is the design of a multi-purpose platform for offshore applications, equipped with a wind turbine. • A large outdoor scaled model of a wind turbine is completely designed. • Typical scaling procedure were adopted to obtain an aeroelastic model for a natural laboratory. • The outdoor scaled model was verified from structural and mechatronic point of view. • Control strategies for the outdoor scaled model were provided. [ABSTRACT FROM AUTHOR]

Li, F., 2019. Offshore platform actuator fault optimal anti-interference self-repair fault-tolerant control. In: Gong, D.; Zhu, H., and Liu, R. (eds.), Selected Topics in Coastal Research: Engineering, Industry, Economy, and Sustainable Development. Journal of Coastal Research, Special Issue No. 94, pp. 153–156. Coconut Creek (Florida), ISSN 0749-0208. A fault-tolerant control method based on extended fault diagnostics is proposed for the actuator failure of offshore platforms under the influence of ocean waves. Firstly, a self-repairing fault-tolerant control law is designed for actuator failure. Then an optimal anti-interference self-repairing fault-tolerant controller is designed according to Riccati and Sylvester matrix equations to ensure that the offshore platform system is optimal under fault and wave interference. In order to solve the physical unrealizable problem that the system state and faults in fault-tolerant control cannot be directly measured, an extended fault diagnostic device is designed. Finally, numerical simulation results verify the feasibility and effectiveness of this scheme. [ABSTRACT FROM AUTHOR]

• A non-integration method on reconstruction of dynamic displacements and velocities from measured structural accelerations is proposed. • The velocity and displacement can be accurately reconstructed from the noise-free acceleration signal with an obvious baseline offset. • A four degree-of-freedom system is employed to demonstrate the approach. • Experimental data from a steel cantilever beam fixed on a shaking table and a four-leg offshore platform are used to make comparisons with traditional methods. For offshore structures in service such as offshore platforms and offshore wind turbines, their displacements are expected but can be difficult to measure directly due to the lacking of fixed reference points in ocean. Aiming at obtaining displacements of offshore structures from accelerations which can be easily measured by accelerometers, a new non-integration displacement reconstruction method is proposed in this paper. The complex exponential series is adopted to establish a relationship between the measured acceleration and the targeted displacement. Compared to direct-integral or high-pass filtering methods, one theoretical development in the present approach is that the reconstructed displacement is derived from the estimated complex exponential parameters of measured acceleration signal with a form of fraction, and the components that cause the drift could be identified and removed, thus significantly reducing the drift issue typically experienced by traditional methods. Additionally, a challenging problem involving the estimation of velocity and displacement at the measured starting moment is solved, which implies that the noises contained in the measured acceleration signal will not be amplified during the conversion from acceleration to velocity and displacement. To investigate the performance of the proposed method, one numerical example and two physical experiments are carried out sequentially. The selected numerical example is a 4-dof system, which aims at verifying the correctness and investigating the robustness of the proposed method. Numerical results show: (1) velocities and displacements can be accurately reconstructed from noise-free acceleration signals with an obvious baseline offset; (2) even when the acceleration signals are contaminated with 15 % Gaussian noise, a good estimation of velocities and displacements can still be obtained. Subsequently, a steel beam fixed on a shaking table is tested, and two accelerometers and two laser displacement sensors are used to measure the dynamic responses of the table as well as the top of the beam, respectively. The experimental results show a good agreement between the reconstructed displacements and the measured data from the laser displacement sensors. Finally, a four-leg offshore platform is investigated experimentally to assess the potential application of the present method in ocean engineering. It is observed from the experimental results that the maximum absolute difference in the amplitude between the reconstructed and measured displacements is 0.47 mm with the computed peak displacement error of 0.3166, which further confirms the feasibility and correctness of the proposed method. [ABSTRACT FROM AUTHOR]

• A motor starting study in the time domain contributes better information than the static study. • A study of motor starting for an offshore platform should be carried out in the time domain. • This work reveals the need that selection criterias between the two methodologies must be defined in the IEEE 3002.7–2018 standard. This paper presents a comparison between static (Snapshot) and dynamic (Time Study) motor starting study methodologies in terms of buses voltage drop and power flow, using a case study of an offshore platform. For this purpose, the Power Tools for Windows (PTW) software and the real-time digital simulator (RTDS) were used to performing the analysis of the Snapshot and Time-Domain methodologies, respectively. The investigation has focused on differences in the parameter requirements necessary for each methodology, with a special application in a complex isolated system, such as the case of an offshore platform typical composed of synchronous generators and the large induction motors. The advantages and disadvantages of each methodology will be analyzed according to the strict operating and handling requirements of an actual offshore platform. Simulation results demonstrated that a motor starting study in the time domain contributes better information than the static one, even more for this type of particular system. This work reveals the need that selection criterias between the two methodologies must be defined in the IEEE 3002.7–2018 standard and for isolated systems is highly recommended to perform an analysis in the time domain. [ABSTRACT FROM AUTHOR]

Motivated by soial and environmental reasons, water scarcity has become a global top agenda item. Egypt is one of the countries suffering from an acute shortage of freshwater. A promising novel and efficient solution to overcome Egypt's freshwater shortage, especially in remote coastal areas far from the national grid of freshwater and electricity, is a mobile floating desalination plant (FDP) powered by offshore renewable energy. The proposed new FDP concept powered by an offshore wind turbine needs a special floating platform to provide enough buoyancy to support the weight of the desalination plant and to restrain the six degrees of freedom motions within an acceptable operational limit for a wind turbine. Based on hydrodynamics, the main objective of this study is to select the suitable offshore platform that can meet the novel FDP concept operation's requirements at a specific deployment location in Egypt. Determining the safe natural frequencies zone necessitates taking into account the new FDP concept operation constraints and the Egyptian environmental loads to select platform far from the dynamic amplifications responses in the structure. Numerical modelling results show that the cylindrical platform with a heave plate configuration demonstrated the best dynamic and static performance for Egypt. • A novel mobile Floating Desalination Plant (FDP) is proposed for Egypt. • FPD is powered by offshore renewable energy. • The most suitable offshore platform is selected by performing numerical analysis. • The cylindrical platform with heave plate configuration demonstrated the best performance. [ABSTRACT FROM AUTHOR]

This paper describes and illustrates the architecture of computer-based Dynamic Risk Management Systems (DRMS) designed to assist real-time risk management decisions for complex physical systems, for example, engineered systems such as offshore platforms or medical systems such as patient treatment in Intensive Care Units. A key characteristic of the DRMSs that we describe is that they are hybrid, combining the powers of Probabilistic Risk Analysis methods and heuristic Artificial Intelligence techniques. A control module determines whether the situation corresponds to a specific rule or regulation, and is clear enough or urgent enough for an expert system to make an immediate recommendation without further analysis of the risks involved. Alternatively, if time permits and if the uncertainties justify it, a risk anddecision analysis module formulates and evaluates options, includingthat of gathering further information. This feature is particularly critical since, most of the time, the physical system is only partially observable, i.e., the signals observed may not permit unambiguous characterization of its state. The DRMS structure is also dynamic in that, for a given time window (e.g., 1 day or 1 hour), it anticipatesthe physical system's state (and, when appropriate, performs a risk analysis) accounting for its evolution, its mode of operations, the predicted external loads and problems, and the possible changes in theset of available options. Therefore, we specifically address the issue of dynamic information gathering for decisionmaking purposes. The concepts are illustrated focusing on the risk and decision analysis modules for a particular case of real-time risk management on board offshore oil platforms, namely of two types of gas compressor leaks, one progressive and one catastrophic. We describe briefly the DRMS proof-of-concept produced at Stanford, and the prototype (ARMS) that is being constructed by Bureau Veritas (Paris) based on these concepts. [ABSTRACT FROM AUTHOR]

The urgency of climate change, while the world economy is projected to depend on fossil fuels for some time, requires substantial reduction of greenhouse gas emissions in the oil and gas industry. This study proposes a methodology for the decarbonisation of offshore natural gas production networks through progressive electrification, either by connecting offshore platforms with nearby renewable energy sources, e.g. offshore wind farms, or by sharing resources so as to improve their energy generation efficiency. In this context, a novel multi-objective mixed-integer linear programming model is proposed to simultaneously minimise greenhouse gas emissions and associated costs from a determined offshore platform network, considering technical constraints, such as maintaining the energy balance of the network, ensuring that cables are installed to enable energy flows, and respecting the maximum generation capacities and minimum operating loads of turbines. For demonstration purposes, the proposed methodology was applied to a UK Southern North Sea network and optimised using the augmented ε -constraint method. The Pareto front approximation obtained suggests that the studied network's cumulative greenhouse gas emissions can be reduced by 25% over the next 10 years at an average cost of US$370.9 per tonne CO 2 e. This study also explores the impact that uncertainties and postponing investment decisions may have in the set context. [Display omitted] • Offshore natural gas production GHG emissions can be reduced via electrification. • Energy generation options were analysed using a multi-objective optimisation model. • Sharing power production reduces GHG emissions in mature offshore fields in the UK. • GHG emissions reduction (25%) is achieved at average cost of US$370.9/tonneCO 2 e. • Integration with offshore wind farms provided the greatest benefits in the optima. [ABSTRACT FROM AUTHOR]

This paper presents a strategy specialized for modal energy (ME) based methods, including modal strain energy (MSE) and modal kinetic energy (MKE), to select the best mode subset prior to damage identification. The damages due to the changes in stiffness and mass of structural members are both considered. In order to apply the proposed scheme to a more general situation, the cross modal energy (CME) sensitivity instead of the usual ME sensitivity is derived and designated as a sensitivity index. According to this index, the mode combinations (MCs) that are more sensitive to stiffness and mass changes are retained, while the remaining MCs that complicate the process of damage detection are eliminated. One of the important applications of the proposed mode subset selection strategy (MSSS) is to optimize the Cross-model cross-mode (CMCM) system by eliminating some redundant equations, thereby improving the performance of the CMCM method and reducing the computational burden. Numerical and experimental studies are carried out to prove the effectiveness of the proposed scheme. The results show that the performance of the CMCM method has been significantly improved after adopting the MSSS. • A pretest strategy is proposed to select damage-sensitive mode subsets for structural damage identification. • The sensitivities of cross modal energy with respect to both stiffness and mass changes are derived. • The strategy can improve the performance of the modal energy-based damage identification methods. • Experimental and numerical results are presented. [ABSTRACT FROM AUTHOR]

The offshore plant, due to its characteristics, is subject to many restrictions on the material and design of the pipes. Because the design of the firefighting piping depends on the pre-set fire protection design, it is possible to reduce the cost of the piping design by optimizing the arrangement of the firefighting equipment. Existing studies have low accuracy in obtaining service areas under these conditions. In addition, the arrangement optimization problem is generally modeled as a set cover problem (SCP). However, except for the traditional greedy approximation, this problem is not well researched for general solutions. In this paper, first, a modified iterative-deepening search (MIDS), which accurately obtains a service area according to the travel distance in the grid space, is proposed before optimization. Additionally, this paper seeks to define a set cover problem by combining the subsets obtained by MIDS. Second, by using the traditional greedy algorithm, we obtained the initial arrangement of the firefighting equipment. Then, we proposed a method to obtain an approximate optimization solution using a modified greedy method including rearrangement. The validity of the proposed coverage area acquisition and arrangement optimization method is verified by comparing the performance with other algorithms. Finally, this study was applied to the drawings of an actual offshore platform. [ABSTRACT FROM AUTHOR]

A neural network-based fuzzy controller is proposed to attenuate the irregular wave-induced vibration of a steel-jacket offshore platform. Firstly, the offshore platform is modeled as a system with time-varying control delay under random wave forces. Secondly, disturbance rejection measures are taken in designing an optimal controller containing delayed states. Thirdly, neural networks are adopted to observe and restore the controlled system, in order to learn the delayed control law using instant state. Finally, fuzzy models are constructed for reducing the complexity in data collecting and neural network training. Trained with sample data from fuzzy models, the neuro-fuzzy observation system is able to reconstruct the control system, and the generalized neural network-based controller works efficiently in different delayed cases. It achieves better vibration-attenuating performance under uncertain control delay and random waves, when compared to existed optimal control laws and fuzzy controllers without neural networks. The main contributions of this paper are: 1) obtaining a neural network-based observer in state approximation; 2) designing a neural network-based controller based on fuzzy rules to cope with random control delay. • We design neural network observers to appropriate the system states containing uncertainty. • We propose fuzzy rules in model approximation to deal with time-varying control delay. • We develop observer-based controllers, using the neuro-fuzzy observation system to reconstruct the control system by extracting neural networks out of the designed controllers [ABSTRACT FROM AUTHOR]

• A deployable tensegrity structure is developed as solution for sea accessibility. • Structural modules are foldable and reconfigurable through specific mechanical design. • Self-stress level and support conditions are optimized using a numerical model. • Experimental work demonstrates the modularity and feasibility of this solution. Tensegrity systems are a class of reticulated space structures composed of compressed bars maintained in equilibrium by a network of tensioned cables. Their stiffness depends both on elements' mechanical properties and their internal self-stress state. Taking advantage of their structural properties, we respond to the challenge of accessibility for everybody to the sea with a new concept of modular lightweight and deployable platforms. Variable configurations are developed to fit ecologically into the marine environment thanks to the transparency of double layer tensegrity structures. Moreover, allowing practical assembly and disassembly is considered in the design to respect the coastal law. Through a numerical study, we demonstrate in this paper the capability of this solution under various representative load cases and support conditions. After the structural and design optimization of elements constrained by weight and stiffness, we detail the design of the nodes, which are the key components ensuring geometry and foldability of the structure. Finally, on-site setting and interfacing with ground supports is experimented in marine conditions to proof the feasibility of this concept. [ABSTRACT FROM AUTHOR]

For the vibration of long-served offshore platforms induced by working equipment, it is very difficult to determine the relevant parameters such as structural stiffness, mass and exciting loads accurately. In order to determine the parameters reasonably, a comprehensive vibration testing was carried out to learn the general vibrating features on the offshore platform by a total of 51 measured points distributed on different decks of a 15-year platform. The measurement showed that the induced vibration covers multiple modes with a range of frequencies because of the complexity of the platform structure. Therefore we introduced average amplitude of vibrating displacement at each measurement point to define its vibrating strength. With the measured results of the vibration, a finite element model of the platform with explicit solution was set up to simulate the vibration of the platform. The natural frequencies and average amplitudes at different locations were set as the target values to determine the unknown mass and exciting load in an updating procedure. The results of the modified model have a good agreement with the target values, which indicated that the modified model is reliable and the updating method for determining unknown parameters in a complex structure is feasible. • Carry out comprehensive in-situ measurementand simulation of vibration response on along-served offshore platform. • Determine the vibration source of a complicatedstructure in a complex environment based onin-situ vibration response. • Propose a new updating method for FE model toderive the unknown structural parameters and the excited load for the long-serviced offshoreplatform. [ABSTRACT FROM AUTHOR]

The offshore platform serves as the infrastructure for offshore mining. In order to guarantee safe operation of the platform and the development of the platform in the direction of intelligence, a natural gas leakage intelligent detection system with fast response is necessary to prevent potential accident when leakage occurs. In this work, a method to locate leaked natural gas is proposed based on the particle swarm optimization algorithm for the multi-robots to achieve. First, the advection diffusion equation is calculated to simulate the leakage gas transmission using finite difference method in different scene layouts. At the same time，a multi-robot collaborative detection strategy for gas detection, gas tracking, and gas source localization is proposed using an improved particle swarm optimization algorithm. After that, the process of multi robots search for leak sources was simulated. In addition, the control algorithm is analyzed, and the results show that the strategy has a high detection rate. Further analysis shows that the number of robots has increased from 2 to 7, the time it takes for the multi-robot system to successfully locate the leak source decreased; when the number of robots is constant, the time it takes for the multi-robot to successfully locate two leak sources is longer than the time to locate a single leak. Finally, search strategies based on particle swarm optimization, ant colony algorithm and cuckoo search algorithm are used to simulate in a single leak source environment. When the number of robots is changed from 3 to 7, compared with the other two algorithms, the accuracy of the search strategy search based on particle swarm is increased by 2%–28%, and the search time is accelerated by 27s–92s.the particle swarm optimization is superior than two others for control of multi-robot system in leakage source location. • Simulating gas diffusion based on advection diffusion equation. • Based on particle swarm optimization, a strategy for multi robot to locate natural gas leakage is proposed. • Through numerical simulation, the feasibility and effectiveness of the method are verified. • This method has great positioning effects in different environments. [ABSTRACT FROM AUTHOR]

The study of evacuation on offshore platforms under fire is significant but has received little attention by previous researchers. The evacuation process from offshore platforms under three distinct visibilities (>10 m, 1 m–10 m, <1 m) is investigated by a group of experiments and questionnaires with 120 participants. The group evacuation activities of the participants regarding the evacuation time, movement speed, typical behavior and route choice were recorded and studied by 48 cameras and wristbands with Bluetooth positioning function. We ignited smoke bombs often used in the fire drill to generate the smoke, which had a little irritating smell but is safe for people. We investigated the speed in running mode and walking fast mode, and the speed of participants with walking fast without smoke we obtained fits well with the data that IMO recommend. In addition, we found the speed of participants does not always decrease in the smoke environment, sometimes it increases when people are well aware of the surroundings. Finally, we study the relationship between personnel characteristics and evacuation behavior with the help of hypothesis testing. The study will be helpful to the guidelines of IMO to be revised in the future and develop efficient evacuation strategy to guide the evacuation under fire in offshore platforms. • A full-scale evacuation experiment was carried out in a real platform in winter in China. • Smoke evacuation performance of the platform with three different visibilities was assessed by experiments and questionnaires. • The relationship between personnel characteristics and evacuation behavior is studied with quantitative analysis. [ABSTRACT FROM AUTHOR]

• Facture failure analysis of bolt on offshore platform has been performed. • The failure of bolt is caused by stress corrosion cracking of metal materials. • Chloride ions on bolt fracture are derived from seawater droplets. • Poor corrosion resistance of bolt materials is the main cause of the failure. Gas turbine generator unit is the most important equipment on the offshore platform, the reliability of pressure gauge on its fuel gas system affects the operation of the entire platform equipment. In this paper, an abnormal fracture failure of pressure gauge bolt on fuel gas system of offshore platform was investigated. Series experiments of visual examination, chemical analysis, fractography analysis, metallographic analysis, and hardness analysis were conducted on the pressure gauge bolts. Thereafter, the failure mechanism of the pressure gauge bolt was discussed based on the experimental results and bolt service environment. It was concluded that the bolt was fractured due to the stress corrosion cracking, and the poor corrosion resistance of bolt materials is the main cause. Finally, countermeasures were proposed to address similar problems. [ABSTRACT FROM AUTHOR]

Wu, X.; Zhang, J.; Chen, Y., and Tang, Z., 2020. A system methodology and its application in developing an emergency response plan for natural gas leakage on an offshore platform. In: Liu, X. and Zhao, L. (eds.), Today's Modern Coastal Society: Technical and Sociological Aspects of Coastal Research. Journal of Coastal Research, Special Issue No. 111, pp. 89–92. Coconut Creek (Florida), ISSN 0749-0208. To meet the needs of systematic analysis in emergency response plan for natural gas leakage on an offshore platform, a six-dimensional system methodology is presented by integrating Hall three-dimensional morphology and the Wu, Shi, and Ren approach (Arthur, 1969). On the basis of synthesizing the content and thinking of the two system methodologies, content and its thinking redundancy between the methodologies are eliminated, part of original dimensions is retained, and new dimensions and relationships among dimensions are extended. Natural gas leakage on an offshore platform is a high-risk and strong chain-reaction accident, greatly affected by marine meteorological factors, so there needs to be good coordination and dynamic adjustment in the disposal process. The research framework and thinking for developing the emergency response plan are proposed by using the integrated methodology. [ABSTRACT FROM AUTHOR]

Increasing water demand in remote coastal areas in Egypt has shifted attention to the role of floating desalination plants to alleviate water shortages. A novel mobile floating desalination plant is proposed for Ras Ghareb city in Egypt. The compatibility between floater natural periods and the energy excitation range of waves in deployment area can lead to resonance responses. Therefore, understanding the motions behaviour among waves of such floaters at a particular location is important for its safety, performance and operation. The goal of the present study is to investigate the suitability of proposed concept for Egyptian environment conditions by characterising the behaviour of the plant motion responses during its entire deployment conditions. Based on full scale design of the proposed plant, experimental study over a range of wave heights and frequencies was performed in the present study using a 1:100 scale model test. In order to identify the plant natural frequency and damping ratio, free decay and swinging tests were performed for different load conditions. Different wave heights were tested during the experiments in order to investigate the effect of wave height on the heave and pitch responses at plant natural frequencies. The experimental test results were compared with numerical results from frequency domain program HydroD implemented in Sesam DNV GL software package. Results show that heave and pitch motion responses give the closest agreement between the measurements and numerical predictions over the whole range of wave periods except the peak spike. The proposed cylindrical FDP is compared against a conventional ship FPSO concept widely used for offshore freshwater production and it was concluded that new cylindrical FDP shows better motion responses compared to conventional ship FPSO concept in same wave bands in Egypt. • A novel mobile floating desalination plant is proposed for Egypt. • Experimental study over a range of wave heights and frequencies was performed. • Free decay and swinging tests were performed for different load conditions. • The effect of wave height on the heave and pitch responses at plant natural frequencies was investigated. [ABSTRACT FROM AUTHOR]

• The low-rate collection method based on posture sensors saves computing resources compared with the high-rate collection method based on acceleration sensors, which is beneficial to the health monitoring of offshore platform structure. • The collection method based on low-rate attitude can solve the problems of limited space resources and long-term continuous monitoring of offshore platforms. • We verified by nonlinear system simulation that the system characteristic identification effects based on low rate posture data are not lower than that based on high rate acceleration data. • We verified by model experiment that the damage identification effects of the tilt data based on low rate posture are not lower than the damage identification effects of the acceleration data based on high rate. • We use the tilt data of the FPSO soft york single-point mooring system to verify the damage identification. In vibration-based structural health monitoring (SHM), if the data are collected at a higher sampling rate from sensors, a large amount of computing resources and space resources will be consumed. For offshore platforms with limited space resources, there are many difficulties in long-term continuous monitoring. Aiming at this problem, the influence of sampling rate on structural damage identification is studied by comparing and analyzing the acceleration and posture sensors commonly used in offshore platform monitoring. In the simulation of parameter change of nonlinear system, random decrements and their spectrum characteristics are extracted from acceleration and displacement data respectively under different sampling rates, and the characteristics are classified by support vector machine (SVM) to identify the rule of change. The research of model experiment data also shows that the low sampling rate data can realize the identification of the damage, and the recognition degree of the low sampling rate data based on posture is not lower than that of the acceleration. The method is applied to the monitoring data analysis of FPSO soft york single-point mooring system and the damage situation is identical with the actual situation. The results show that the structural damage can be reflected from the low sampling rate posture monitoring data. [ABSTRACT FROM AUTHOR]

On conventional offshore petroleum platforms, the combined heat and power production (CHP) currently depends on simple cycle gas turbine systems (SCGT) that operate at lower efficiency and increased environmental impact compared to modern onshore thermoelectric plants. Additionally, the reduced space and the limited weight budget on offshore platforms have discouraged operators from integrating more efficient, but also bulkier cogeneration cycles (e.g. combined cycles). In spite of these circumstances, more stringent environmental regulations of offshore oil and gas activities have progressively led to a renewed interest in the integration of advanced cogeneration systems, together with either customary or unconventional carbon capture approaches, to maintain both higher power generation efficiencies and reduced CO 2 emissions. Thus, in this paper, it is evidenced how advanced gas turbine concepts are promising technologies for maintaining or even increasing efficiency, while facilitating the capture rate of CO 2 produced, either for geological storage or enhanced oil recovery. Despite the profuse research works on onshore applications, advanced cogeneration and carbon capture systems have been barely studied in the context of supplying power to offshore petroleum platforms. Accordingly, the performance of a conventional offshore petroleum production platform (without carbon capture system) is compared to other configurations, based on either an amine-based chemical absorption system or oxyfuel combustion concepts (S-Graz and Allam cycles) for CO 2 capture purposes. Since the original power and heat requirements of the processing platform must remain satisfied, an energy integration analysis is performed to determine the waste heat recovery opportunities. Additionally, the exergy method helps quantifying the most critical components that lead to the largest irreversibility and identifying the thermodynamic potential for enhanced cogeneration plants. As a result, oxyfuel equipped platforms provide a diversified set of advantages, while keeping competitive efficiencies. For instance, advanced systems allow for cutting down ostensibly the atmospheric CO 2 emissions compared to the conventional and amine-based power plant configurations of the FPSO. • The Allam configuration has a power efficiency of 42.63%, followed by the S-Graz with 27.10%. • S-Graz-cycle powered configuration presents the best CO 2 mitigation potential with only 0.014 kg CO 2 /t oil. • Despite oxyfuel cycles' good performance, conventional configuration still upholds the highest separation efficiency. • CO 2 emissions costs for oil and gas increase by nearly two to tenfold for the conventional configuration. • The amine-based configuration has the largest fuel consumption and exergy destruction rate among all the four utility plants. [ABSTRACT FROM AUTHOR]

Ding, N., 2020. Vibration analysis of offshore oil and gas platform mechanical equipment. In: Gong, D.; Zhang, M., and Liu, R. (eds.), Advances in Coastal Research: Engineering, Industry, Economy, and Sustainable Development. Journal of Coastal Research, Special Issue No. 106, pp. 633–637. Coconut Creek (Florida), ISSN 0749-0208. Based on the case of a shallow-water drilling platform, this article focuses on the vibration principle and vibration-control strategy for oil and gas platforms. Through the analysis of ANSYS and field-measured data, this research obtained several causes for violent vibrations of platforms and puts forward countermeasures to prevent platform accidents from vibration. Drilling platforms belong to offshore operation, which have great theoretical risks. In the work of substations, railways, and mines on land, the design of the operation sheet and dispatching instruction are strictly evaluated, and there should be similar attention to dispatching work of drilling platform. [ABSTRACT FROM AUTHOR]

Dai, W. and Yu, Y., 2020. Data analysis of safety assessment and early warning for offshore platform. In: Gong, D.; Zhang, M., and Liu, R. (eds.), Advances in Coastal Research: Engineering, Industry, Economy, and Sustainable Development. Journal of Coastal Research, Special Issue No. 106, pp. 536–539. Coconut Creek (Florida), ISSN 0749-0208. Offshore platform is a very complex system and is affected by wind, wave, currents, and other loads for a long time. When a safety problem occurs in the offshore platform, catastrophic accidents can cause incalculable loss of life and property and can also damage the vulnerable marine ecological environment. However, the research on the safety of early warning of offshore platforms in China is still in its infancy. Therefore, by performing safety assessment and early-warning work, this paper can obtain the health status of the offshore platform timely and accurately. By studying the safety assessment and early-warning system of the offshore platform, a theoretical basis for the safe operation of offshore platform can be provided. Through the technology of safety monitoring and safety evaluation, this paper constructs the safety early-warning model of the offshore platform, which realizes the monitoring, diagnosis, control, correction, and other functions of the production activities of the offshore platform. [ABSTRACT FROM AUTHOR]