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02 July 2023, Volume 10 Issue 2 Previous Issue   

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A Brief Summary of Key Points for The Installation of Offshore Wind Turbine Monopile Foundation FAN Changhui 2023, 10 (2):  1-7.  Abstract ( 340 )   PDF (6154KB) ( 1532 )   The installation of offshore wind turbine monopile foundation requires a variety of ship machinery and lifting equipment, etc. If the suitabe selection of those above matters could make the completion of the construction objectives be achieved. In order to select suitable ship machinery lifting equipment, using project as example the compare between domestic and foreign monopile installation, the selection consideration of the main floating crane ship and the drivability of the hydraulic hammer are specifically analyzed through the verification analysis of the monopile stabilizing platform and the description of other additional installation points, which shows that the main considerations for the selection of marine machinery and lifting equipment for offshore wind turbine monopile installation in China and the verification analysis methods are useful. These can provide serve as for the selection of marine floating machine for monopile installation, for the design and verification of monopile stabilizing platform, and for the preparation of construction organization and scheme. Related Articles | Metrics

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The Hull Structure Design and Practice of the Condensate Storage Tank of Semi-Submersible Platform LIU Xiaoyan, FENGJiaguo, LI Da 2023, 10 (2):  8-13.  Abstract ( 198 )   PDF (5185KB) ( 948 )   There is little industrial experience and projects for semi-submersible platform with large volume condensate storage tanks. The hull structure design of condensate storage tanks were provided. Firstly, the column was designed with the double-wall voids (cofferdams ) around the condensate tanks and connected with flats with manholes for maintenance access. Secondly, the pressure head of condensate tank was increased by 10 m compared to the ballast tank after optimizing the reduction of 20 m. Thirdly, the bulkheads of condensate tank are non-watertight and continuous, but with the upper and lower 2 m height gaps for the flowing of condensate and gas. Fourth, the additional corrosion margin of 2 mm was added to the boundary of frequently ballast and de-ballast tanks in the nodes and columns. It is a successful practice for other similar design in the future. Related Articles | Metrics

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Design and Analysis of the Pressure Test Facilities of Subsea Wellhead and Supporting Tools GENG Yanan, WANG Mingchun, SUN Chong, ZHANG Huizeng, ZHAO Weiqing, ZHAO Suwen, LIJian, HU Xiaoyu 2023, 10 (2):  14-21.  Abstract ( 126 )   PDF (5040KB) ( 733 )   Subsea wellheads subjected to complex internal pressure and external loads is the key equipment for deepwater oil and gas development. Currently, stability of subsea wellhead and corresponding supporting tools are mainly assessed by theoretical analysis and numerical simulation. Due to lack of pressure test tools, the actual structure responses of subsea wellhead and corresponding supporting tools could not be reflected. In this work, specialized tools aiming attesting the internal pressure of subsea wellhead and corresponding supporting tools are designed with consideration of different operation conditions and loads. Additionally, for guaranteeing the security of test tools during test experiments, mechanical strength analysis is carried out by establishing related finite element model. Simulation results show that bearing capacity test could be implemented in safety using the designed test tools, and the stress are lower than the yielding strength of test tools. The research could provide technical support for the structural design and optimization analysis of the subsea wellhead test tool. Related Articles | Metrics

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Technical Status and Developing Trend of Vertical Lay System for Flexible Pipe Laying CHEN Xiaodong, SUN Kun, ZHANG Xiwei, PENG Yong, YANG Sheng, LIU Wen 2023, 10 (2):  22-29.  Abstract ( 203 )   PDF (3941KB) ( 721 )   Flexible pipes are important facility for offshore oil and gas development. Vertical laying technology is a high-speed and efficient method for flexible pipes laying operation, which has been widely used in deepwater development projects in the world. The advantages o fvertical laying in deepwater is analyzed by comparing the two typical laying methods for flexible pipes. The type and system components, structural and layout characteristics, and suppliers for designing and manufacturing vertical laying system are summarized. The future development trend and localization suggestions of vertical laying system is analyzed, which can provide a useful reference for the independent development of vertical laying system equipment in China. Related Articles | Metrics

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Research on the Connection between Tiller and Rudder of a Large Container Ship JIN Cai, WU Jinxing, LIU Jinhua 2023, 10 (2):  30-36.  Abstract ( 280 )   PDF (5690KB) ( 594 )   Ship construction is tending to large-scale development, the size of the supporting tiller of large ships also increases, the procurement cost and construction difficulty will also increases correspondingly. At present, the tiller and the rudder of the ship mainly adopt two connection ways: hydraulic-keyed connection and dry-keyed connection. By analyzing and studying the connection modes between tiller and rudder, this paper obtains the optimal connection mode which meets the requirements,is convenient for construction. The parts are lightweight, which has important engineering significance. Combined with the requirements of classification Society, this paper takes a large container ship as an example, and on the basis of the two traditional connection methods, puts forward the third connection method of hydraulic-keyed connection method. The three connection methods are compared in the paper, and the finite element method is used to check the strength, and the conclusions of push up load, push-up and material yield strength are obtained. In the end, an optimal connection mode which meets the requirements of real ship is obtained, which is convenient for ship yard construction. The designed tiller is lightweight. Related Articles | Metrics

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Study on Interface Principal for Topside of General FPSO LIU Yanming, HU Rong, GUO Guosheng, YE Yongkun, WU Zhikun 2023, 10 (2):  37-42.  Abstract ( 155 )   PDF (5538KB) ( 1077 )   Firstly, the purpose of study on interface principle for topside of FPSO is introduced; Secondly, the typical main process scheme, general arrangement, structure scheme are illustrated; Thirdly, the interface between FPSO topside and Hull/Subsea are analyzed and demonstrated, including the interface about process, general area, structure, EIT. Finally, it is prospected how to proceed the interface principal study in the future. Related Articles | Metrics

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Analysis and Practice on the Risk of Deep water Semi-Submersible Production Platform with Condensate Oil Storage LIU Xiaoyan, FENGJiaguo, LI Da 2023, 10 (2):  43-50.  Abstract ( 121 )   PDF (2560KB) ( 579 )   Deepwater gas field development is characterized by large investment and high risk. However, there is little experience in deepwater gas field development in China. Combined HAZOP, HAZID, SIL and improved expert statistical analysis method, storage platform is established from two aspects of conventional risk and specific risk. On the basis of drawing lessons on the experience of foreign experts, the research focuses on the analysis of specific risks caused by such factors as fire and explosion, column storage of large-capacity condensate oil, construction based on domestic resources, first polyester cable, first large-diameter SCR, lack of deep-water experience, etc. The potential risks of the platform are fully identified in the aspects of project management, hull structure, riser, mooring system, hull system and platform. Commissioning, and the main risk countermeasures are given to effectively implement risk management. The research provides the guidance for engineering design and implementation, and provides the reference for risk management of deepwater gas field development projects in the future. Related Articles | Metrics

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Noise Characteristics and Its Reduction Measures of Air Duct on Offshore Platform Blocks LIU Xinfu, CHENG Hui, LI Hui, LI Bo, GAO Peng, ZHANG Shousen, LIU Bilong 2023, 10 (2):  51-56.  Abstract ( 161 )   PDF (2173KB) ( 435 )   Various noises are generated during the operation of air ducts and equipment in block rooms of offshore platforms, which will result in variable effects on the operators and even the lives underwater. Therefore, it is necessary to put forward higher requirements for block noise control of offshore platforms. Considering the coupling effect of turbulence pulsation and fan air excitation, in the paper, the calculation model of the air duct noise of the platform block is established, and the FW-H method is used to analyze the influence of the air duct noise in the ventilation system on the sound pressure level of the platform room; Based on the statistical energy method, we further build the SEA model of the platform modular room, analyze the loss factor in the SEA subsystem and the coupling loss factor between subsystems, predict the dynamic distribution of the noise in the modular room, determine the noise propagation path and dominant component under typical working conditions, and take noise reduction measures for rooms exceeding the standard to achieve the purpose of noise control. The results show that the air duct noise of offshore platform modules is mostly in the middle and low frequency band, and has little effect on the total sound pressure level of the module room. At the same time, low-frequency noise spreads far and high frequency noise attenuates quickly. The remote rooms are mainly affected by low-frequency air noise and structural noise. Therefore, sound insulation and vibration isolation measures are designed respectively for air noise and structural noise. Our platform module rooms meet the requirements of national standards. Related Articles | Metrics

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Research on Tensile Fatigue of Glass Fiber Reinforced Composites GAO Shuang, LI Zebang, LI Sen, CHU Xingpeng, LIU Xiaobin, LI Xiang 2023, 10 (2):  57-60.  Abstract ( 132 )   PDF (1751KB) ( 484 )   Through the tensile-fatigue test of glass fiber reinforced vinyl resin matrix composite laminates at different stress levels, the test data are fitted in logarithmic form to obtain the S-N curve. With the decrease of stress amplitude, the number of endurance limit cycles of glass fiber reinforced composites increases significantly, showing a significant increasing trend. At the same time, it is inferred from the curve that when the stress amplitude decreases again, the number of endurance limit cycles will increase more. The failure process is generally degumming at the interface between glass fiber and matrix, glass fiber fracture and matrix crack; stress concentration will occur in this area, and the resin matrix crack continues to expand until the glass fiber is completely separated from the resin matrix, forming layered glass fiber fracture. Related Articles | Metrics

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Key Testing Technologies and Application of Gate Valve and Connector Used in Subsea Christmas Tree LIU Xiao, ZHANG Ning, ZHU Wei, LI Sen 2023, 10 (2):  61-66.  Abstract ( 180 )   PDF (4263KB) ( 519 )   As the key components of the subsea Christmas tree system, underwater valves and wellhead connectors are faced with extremely complex marine service environment, and must be tested to verify that they can meet the performance requirements of relevant standards and specifications for opening, closing, locking, unlocking, sealing, pressure bearing, load bearing, etc. In order to fully simulate the working conditions of underwater low temperature and high pressure as well as the rated water depth under combined loading, the key testing technologies of underwater gate valves and hydraulic wellhead connectors based on API Spec 17D and API Spec 6A standards were studied; a set of combined testing methods, procedures and testing systems were proposed; and the laboratory testing application of domestic equipment was successfully completed. Related Articles | Metrics

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Research and Experimental Verification on Key Technologies of Remote Frequency Conversion Drive for Offshore Oil and Gas WANG Shanfen, GUO Hong, LIU Ying, ZHANG Rong, LUJingjian, ZHOU Zhonghao, GUOJiangyan 2023, 10 (2):  67-71.  Abstract ( 119 )   PDF (5532KB) ( 218 )   With the gradual consumption of energy in the world, the exploitation of deep-sea oil and gas fields has gained significant importance as a research topic. At present, the deep-sea underwater production technology has started to develop and put to practice, and the underwater power supply has always been an important factor that restricts the innovation of Chinese underwater production technology. It is very important to carry out the long-distance conversion drive experimental platform analysis simulation and construction. This paper leverages the experimental platform to carry out system resonance analysis, motor start-up and other research, and verifies the test ability of the long-distance frequency conversion drive experimental platform. It shows that the system can effectively simulate the operation state of the actual engineering, and provide further technical support for the research of underwater power supply system. Related Articles | Metrics

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Research on Key Technologies of Dynamic Analysis and Numerical Simulation for the Floating Offshore Wind Turbine QU Xiaoqi, LI Hongtao, TANG Guangyin, DU Haiyue, YANG Linlin 2023, 10 (2):  72-78.  Abstract ( 244 )   PDF (8230KB) ( 1045 )   With the development of floating offshore wind turbine technology, engineering projects of large scale floating offshore wind turbine has begun to emerge. Because manufacturers keep the parameters of wind turbine confidential, there are many challenges in numerical simulation analysis of floating offshore wind turbines in practical engineering projects. In this paper, the key technologies on numerical simulation of floating wind turbine in the practical engineering project was studied. Through the equivalent thrust model, a numerical model of real floating wind turbine was established and the dynamics responses under a typical load case was analyzed. Based on the research results of this study, the difficulties in establishing the numerical model of floating wind turbine in practical engineering projects can be well solved. This is of great significance to promote the technical development and accelerate the commercialization of China's floating wind turbine industry. Related Articles | Metrics

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Engineering Exploration and Practice of Key Technology for Floating Offshore Wind Turbine Equipment LI Hongtao, YANG Linlin, QU Xiaoqi, SUN Tao 2023, 10 (2):  79-88.  Abstract ( 354 )   PDF (12983KB) ( 150 )   Floating offshore wind turbine equipment has gradually become a hot topic in the development of deep-sea renewable energy. However, there are still a series of technical difficulties and challenges in the commercialization of floating offshore wind turbine. This study systematically combs the key technologies for design and analysis of floating offshore wind turbine equipment. The solutions and analysis methods are put forward regarding six aspects including overall performance analysis, structural global strength, mooring system design, fatigue strength analysis, stability check and dynamic cable design. A set of useful conclusions and suggestions are given through the introduction of actual domestic floating offshore wind turbine engineering project. Engineering exploration and practice are performed on the development of floating offshore wind turbine equipment in China, and it is expected to provide useful reference for the development and expansion of China's floating offshore wind turbine technology. Related Articles | Metrics

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Key Technologies and Breakthrough Path of Hydrogen Production by Offshore Wind Power GAO Chang, LI Hongtao 2023, 10 (2):  89-94.  Abstract ( 416 )   PDF (2904KB) ( 1485 )   Marine renewable energy is abundant but difficult to store. The generation of green hydrogen from offshore renewable energy can provide a new idea for the storage of green energy. This paper mainly analyzes the key technologies of hydrogen production from offshore wind power, focusing on the four aspects of offshore water electrolysis hydrogen production technology, offshore hydrogen energy storage and transportation technology, offshore hydrogen production and storage equipment design, as well as offshore hydrogen production and storage scheme. This paper compares and summarizes the key technologies of offshore wind power hydrogen production in China, and puts forward relevant countermeasures and suggestions on this basis. It provides reference for the innovative development of offshore wind power hydrogen production technology and equipment in China. Related Articles | Metrics

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Structural Emergency Response Analysis and Application for Deep-water Column Stabilised Units GAO Chang 2023, 10 (2):  95-100.  Abstract ( 122 )   PDF (1592KB) ( 343 )   Aiming at the typical structural safety accidents and emergencies of deep-water column stabilised units, in this paper the main safety risks of platform structure are expounded. A closed-loop structural emergency response system is established，which includes dynamic data management before the emergency response, emergency response mechanism, and accident tracking after emergency response, etc. For typical accidents, the contents and recommended methods of structural risk emergency response analysis of deep-water column stabilised units are put forward. The proposed methods can provide useful guidance to the platform operators. Related Articles | Metrics

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Research on the Applicability of Standards for Offshore Facility Structure Monitoring Systems KANG Yongtian, LING Aijun, JIN Xinyue, LIANG Yuanhua, TANG Aipan 2023, 10 (2):  101-105.  Abstract ( 171 )   PDF (4469KB) ( 1369 )   With the increasing technical requirements for the structural safety of offshore facilities and the rapid development of digital technology, structural health monitoring technology is becoming more widely used in offshore facility structures for monitoring the safety of the structure and ensuring the safety of the facilities. At present, the application of digital twins technology on offshore facilities is emerging, and  the offshore facility structure monitoring system has not formed a mature technical standard so far. This paper studied the standards  of offshore facility structure monitoring system, analyze d the applicability of monitoring system design, manufacturing, installation, commissioning and inspection standards, and provided  technical support for the engineering application of offshore facility structure monitoring systems. Related Articles | Metrics

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Research on Digital and Intelligent Transformation of Discrete Offshore Oil and Gas Equipment Manufacturing Industry HE Chen, LUO Chao, LIU Shicong, KANG Dongchun, WANG Liang 2023, 10 (2):  106-111.  Abstract ( 268 )   PDF (4845KB) ( 201 )   This paper firstly expounds the impact of the application of digital technology and intelligent on the manufacturing industry technology in the field of information technology. The cutting-edge technologies related to intelligent manufacturing are then introduced in detail, and the latest industry status quo is briefly analyzed. Then, in conjuction with the unique characteristics of equipment construction in the current offshore petroleum engineering industry, it conducts an in-depth analysis, and clarifies the pain points brought to offshore petroleum engineering by the characteristics of discrete equipment manufacturing. Finally, according to the current status of discrete manufacturing, combined with the field practice accumulated over the years, through 3D model design, intelligent robots and other multi-dimensional exploration the digital and intelligent transformation are studied in this paper. Related Articles | Metrics

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Time-frequency Method Comparison for Wave-induced Fatigue Prediction of Deepwater SCRs HUANG Jun, KANG Zhuang, ZHANG Yansong, AI Shangmao 2023, 10 (2):  112-118.  Abstract ( 408 )   PDF (5975KB) ( 267 )   Wave-induced fatigue damage is an important component of deep-water steel catenary riser (SCR) fatigue damage. In this paper, the fatigue damage caused by SCR wave in the South China Sea caused by storm state is predicted through time domain and frequency domain respectively. The difference of platform motion response and riser dynamic response obtained by time domain method and frequency domain method is also analyzed. The prediction results of fatigue damage risk position and damage extreme value are then compared. The applicability of the methods in prediction of deep-ocean risers’ wave-induced fatigue was evaluated. The result show that there is a huge gap between the time domain method and the frequency domain method, and that the damage risk position calculated by the frequency domain method is lagging behind. With the frequency domain method, the wave-induced fatigue cumulative damage is amplified, while the order of magnitude is consistent. Related Articles | Metrics

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Design of China National Scientific Seafloor Observatory Buoy Platform LI Qing, LU Hai, HAN Rui, WANGJianjun 2023, 10 (2):  119-125.  Abstract ( 120 )   PDF (3430KB) ( 1542 )   China National Scientific Seafloor Observatory (CNSSO) is a major science and technology infrastructure project approved by the National Development and Reform Commission (NDRC), which aims to observe the ocean via various aspects and fields. Unlike the buoy network operated by the government, CNSSO requires smart data acquisition and control system, underwater acoustic communication, system protection and domestic instrument experiment platform. In response to the realization of these scientific goals, improvements needs to be made for the buoy platform to meet the requirement of CNSSO. Related Articles | Metrics

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Overview of Subsea Well Intervention Technology and Equipment Development WANG Di, HUANG Congcong, CHANG Shuangli 2023, 10 (2):  126-130.  Abstract ( 222 )   PDF (2963KB) ( 1040 )   As the continuous expansion of the resources development of offshore oil and gas, more subsea well will be used at domestic offshore oil and gas fields, yet there is still no supporting technology and equipment for subsea well intervention in China. This paper compare the technology of well intervention and workover, introduce two kinds of light well intervention systems, compare their advantages and disadvantages, and then analyze the development and operation of subsea well intervention systems in the world. The development gap and countermeasures of related technologies in China will be summarized, at the end.  Related Articles | Metrics

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Research and Application of Heave Compensation Technology in Deep-Sea Mining Engineering YU Dequan, JI Jiangang, XIA Kui, XIA Haihong, HUANG Tianzhong, TAO Jun 2023, 10 (2):  131-139.  Abstract ( 266 )   PDF (16741KB) ( 109 )   In this paper, the significance of the research on heave compensation technology in deep-sea mining engineering is described, and the overall plan, working principle as well as workflow of the heave compensator are studied that ensures that the lifting pipe can obtain the supporting force and compensation force during operation, maintain a stationary position relative to the seabed and work steadily. Through the simulation analysis method, the dynamic comprehensive performance of the heave compensation system is studied. The influence law of vibration period, load size, hydraulic line flow resistance, friction and other factors of the mining ships on the compensation effect is also summarized. In addition, the speed-limited safety technology is analyzed, while the functional principle, structural composition and test plan of the speed-limited shut off valve are studied. The safety guarantee effect is verified by the shipment applications. As a result, a more comprehensive research result on the heave compensation technology in deep-sea mining is obtained. Related Articles | Metrics

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Research on the Mechanical Performance of Polyester Rope Based on the Dynamic Stiffness Model KANG Zhuang, SUI Haibo, HuangJun, AI Shangmao 2023, 10 (2):  140-144.  Abstract ( 441 )   PDF (6034KB) ( 637 )   The taut mooring system using polyester rope as the mooring lines overcomes the heavy weight of the traditional chain mooring material and provides better mooring performance for the floating structures, which attracts much attention in the field of deep-water mooring. The nonlinear mechanical properties of the polyester make it more difficult to predict the tension response of the material. Therefore, it is essential to model this nonlinear relationship accurately. In this paper, based on the absolute nodal coordinate formulation under the condition of large axial tension and combined with the dynamic stiffness model of 8-strand braided polyester rope, the tension response of the polyester line is accurately calculated and analyzed, and the results are compared with the approximate method. The simulation shows that the axial tension of the polyester cable obtained by the accurate model is larger than that of the approximate method. The nonlinear constitutive relationship of the polyester cable displays the phenomenon that the larger stretch, the larger sitffness is. Besides, the approximate method will distort the tension prediction. Therefore, it is necessary to adopt an accurate dynamic stiffness model in calculating the tension response of mooring systems using polyester material.  Related Articles | Metrics

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Analysis of J-Lay Laying of Large Diameter Submarine Pipeline Huang Jun, LI Shaojie, KANG Zhuang 2023, 10 (2):  145-151.  Abstract ( 280 )   PDF (10242KB) ( 54 )   J-Lay system has been the most suitable laying method for large diameter subsea pipeline at present because of its advantageous pipeline laying form. In the process of laying large diameter submarine pipeline with J-Lay system, the effect of laying angle and water depth on the pipeline is of critical importance. Therefore, based on the catenary theory, the static analysis considering the factors above has been carried out in order to determine the suitable laying angle of large diameter submarine pipeline under different water depths. In addition, the time domain dynamic analysis has been conducted to study the influence of ship motion, current incidence angle and existing pipeline damage on the dynamic stress of pipeline, and the results can server as reference for engineering practice. Related Articles | Metrics