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    06 January 2024, Volume 10 Issue 4 Previous Issue   
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    Research Progress and Challenges of Ship Ballast Water Treatment
    ZHANG Weidong, DU Bin, QU Huifang, LI Tao
    2023, 10 (4):  1. 
    Abstract ( 295 )   PDF (3948KB) ( 451 )  
    Ship ballast water is one of the main ways for the alien invasion. It is considered as one of the four threats to the marine environment. The ballast water convention established to solve this problem has stipulated the standards for ballast water treatment, which has entered into force on September 6,2019. This paper reviews the background and social needs of the research on ballast water treatment technology, analyzes the characteristics of different ballast water treatment technologies, introduces the latest achievements of the research on ballast water treatment technology in the academic community, and the efforts of the industrial community in the research and development of ballast water treatment systems, and discusses the challenges faced by ballast water treatment at different levels of standards, economy, technology, testing and law.
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    Commissioning of Subsea Production System based on a Gas Field in the South China Sea
    JIANG Bingbing, CHEN Juan, HONG Longfei, DENG Chiyu, LONG Xiaopin, CAO Juhang, HU Yunhai
    2023, 10 (4):  11. 
    Abstract ( 148 )   PDF (870KB) ( 230 )  
    The subsea production system is the key equipment for the deepwater oil and gas development, which comprises of surface control equipment and subseainstalled production equipment. In order to ensure that the surface control equipment is able to monitor and control the subseainstalled production system during normal production and shut down, the production system where required after the subsea production system is installed offshore, the commissioning work needs to be completed prior to putting into production. Based on the subsea production system of a gas field in the South China Sea, this paper briefly addresses the subsea production control system, discusses the purpose, content and procedure of the subsea production system commissioning in detail. The research will help to break technological monopoly of American and European countries in the commissioning of subsea production system and independently develop the offshore oil and gas in our country.
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    Study on Ideal Superstructure Design of Ship
    LIAO Shiyang, LIU Jun, ZENG Wenyuan
    2023, 10 (4):  16. 
    Abstract ( 122 )   PDF (6248KB) ( 191 )  
    The ideal superstructure means that the superstructure does not bend when the hull is bent, and the normal stress of the superstructure is consistent in the direction of height. Different from the strong superstructure and the light superstructure, the stress level of the ideal superstructure is close to the main deck, which can maximize the utilization of material strength. In this paper, a typical oil tanker is taken as the research object. Based on the composite beam method, considering the influence of shear hysteresis effect, the design method of ideal superstructure is discussed. According to the section characteristics of superstructure, the length of ideal superstructure is explored. Based on the theoretical formula of the ideal superstructure, the design length of the ideal superstructure is obtained according to the parameters of the transverse section of the ship. After the theoretical design scheme of the ideal superstructure is obtained, the stress distribution law of the deck of the ideal superstructure is verified by the finite element method. The verification results show that the normal stress level of the superstructure is close to the main deck, which can provide reference for the design of the early ideal superstructure. Finally, the deck thickness of the superstructure is adjusted to save materials and reduce the center of gravity.
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    Application of Underwater Reinforcement Repair Technique with Wrap Composite Materials of External Corrosion for Submarine Pipeline
    LIU Jun, , , , ZHANG Chuanxu, , , QU Jie, ,
    2023, 10 (4):  24. 
    Abstract ( 124 )   PDF (2356KB) ( 116 )  
    The safe service of submarine pipelines in oil, gas and water transportation is very important, and the long standing corrosion problem also affects the service life of submarine pipelines. The composite material reinforcement and repair technology has been widely used in onshore pipelines, but it has not been applied in the repair of submarine pipelines. A submarine pipeline adopts the composite material underwater winding reinforcement and repair technology to carry out practical application. The practical application proves that the composite material underwater winding reinforcement and repair technology is a safe and reliable reinforcement and repair technology. This paper will introduce the repair material properties of the composite underwater winding reinforcement repair technology, the application design of the repair system, and the construction technology of the repair system.
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    Analysis of the Reason of Corrosion and Prevention Measures for 316L Stainless Steel Pipeline
    BI Hangming
    2023, 10 (4):  30. 
    Abstract ( 152 )   PDF (5312KB) ( 129 )  
    The corrosion of stainless steel piping for a precommissioning offshore platform in the South China Sea is sampled and analyzed. The conclusion obtained from the test is that the chloride ion content exceeds the standard leading to serious corrosion of stainless steel pipelines. This paper explores the basic principles of damage caused by chloride ions to 316L stainless steel pipeline. From the perspective of offshore platform pipeline construction, for how to effectively prevent corrosion of stainless steel pipelines, we put forward relevant recommendations, and provide reference for subsequent offshore platform construction projects.
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    Research on Product Standard and Test Scheme of High Pressure Underwater Valve
    YAN Jiayu, HONG Yi, LIU Boying, ZHOU Xuejun, CHEN Di, HE Xiaoyong
    2023, 10 (4):  36. 
    Abstract ( 79 )   PDF (689KB) ( 150 )  
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    Model Test and Effect Analysis of Submarine Jet Trencher
    LI Zhenwang, ZHAO Huaibin, YU Zongbing, ZOU Li, WANG Kai, CAO Lin
    2023, 10 (4):  44. 
    Abstract ( 76 )   PDF (10732KB) ( 45 )  
    Many measures have been used to ensure the safety and stability of submarine pipelines and cables. One of the most cost effective methods is to use trenchers and other related equipment to bury the pipeline or cable into the seafloor. In this paper, a light weight, autonomously propelled underwater jet trencher has been designed and conducted underwater trenching tests on the machined prototype model to verify that the designed trencher can trench under submerged condition, and complete the autonomous propulsion work to destroy sand with shear strength of 8kPa when the pipeline flow reaches 50m3/h. The maximum ditch depth can reach 0.41m. This work provides the theory and basis for subsequent model optimization and pipeline burial.
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    Float over Method Application for 2.5WM Wind Turbine Integral Removal in Guanting Reservoir
    YU Lei, GAO Zhizhao
    2023, 10 (4):  52. 
    Abstract ( 89 )   PDF (4469KB) ( 41 )  
    In inland reservoirs and lakes, the integral removal technology of wind turbines is currently blank in China, As the conventional technology and equipment used for offshore wind turbine disassembly cannot be used. in order to solve the problem of Goldwind Technology produced 2.5WM wind turbine removal in Guanting Reservoir, a float platform assembled by some pontoons at temporary wharf, the temporary wharf built by dredging on the shore, the single pontoon is prefabricated in the factory and the transport to wharf where assembled one by one to form a floating platform. The floatover integral removal technology applied in extremely shallow water depth, which improves construction safety, saves materials and construction time, and is convenient for demolition. This paper introduces the design idea and engineering practice of integral removal of wind turbine by floatover method, hopes can provide reference for similar projects.
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    Passive Fire Protection Design for Offshore Oil and Gas Production Facility
    LI Yanhua, XU Xiaoli, QIN Liusha, JIA Qinli, HUO Youli
    2023, 10 (4):  59. 
    Abstract ( 75 )   PDF (884KB) ( 81 )  
    Fire risk is one of the major risk on offshore oil and gas production facility due to the congest layout of hydrocarbon related process equipment. Passive fire protection is the last barrier to protect people on the facility during emergency situation; it plays a very important role on safety protection of people. Passive fire protection design principles, design methods and some special issues related passive fire protection design, such as fire division design, passive fire protection scope, the critical temperature of steel structure as well as the feasible of fire water system replace of passive fire protection have been discussed and recommend solution for these issues have been raised. A project passive fire design example has been given. Some issues about the passive fire protection design on offshore production facility need further research have been discussed. It is suggests that passive fire protection design codes and standards should be establishment as soon as possible as well as the establishment of equipment and facility failure criteria.
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    A Simplified Calculation of Doubler Plate Reinforced Tubular T Joints
    HUANG Huaizhou, WANG Hailong, YUAN Yujie, HOU Tao, SHI Rui, YE Maosheng
    2023, 10 (4):  64. 
    Abstract ( 78 )   PDF (993KB) ( 51 )  
    Doubler plate has been widely used in marine engineering structures, due to its complex force characteristics, and there is no quantifiable calculation method for its mechanical properties. The finite element method is used to study the bearing capacity of doubler plate reinforced tubular T joints under axial compression, axial tension and bending conditions. Based on the formula of the ultimate bearing capacity of the wideamplitude doubler plate, combined with the calculation method of the simple joint in API RP2A, a quantifiable formula for the narrow amplitude doubler plate reinforced tubular T joints for engineering practice is given. Also, the method of selecting the fillet weld is present. The analysis results show that the simplified calculation method can effectively reflect the influence of various parameters of the doubler plate on the bearing capacity, and play a guiding role in the design of the doubler plate, which can effectively simplify the calculation design process.
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    Study on Underwater Twodimensional Exhaust Vent Mode Based on Distribution of Fixed Orifice Spacing and Variable Orifice Area
    SUO Jun, XU Fei, TANG Simi, WANG Hongbin
    2023, 10 (4):  70. 
    Abstract ( 50 )   PDF (10961KB) ( 24 )  
    The scale parameters of bubbles produced by underwater exhaust influence the effect of the acoustic insulation. According to the dynamic characteristics in the process of underwater gas exhaust and the design criteria of equal flow per unit area, the two dimensional exhaust equation of underwater gas is established. The analytical expressions of the opening position and geometric parameters of the two dimensional exhaust device of underwater gas are obtained. The finite element models are established to compare the two vent patterns of uniform distribution and constant pitch/variable size distribution. The exhaust effect is verified by circulating flume test. The simulation and experimental results show that the distribution mode of fixed orifice spacing and variable orifice area can effectively control the distribution of bubbles scale parameters, and enhance the acoustic insulation effect of bubbles.
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    Several Applications of Vibration Monitoring in Structural Safety Assurance of Jacket Platform
    WANG Huoping, WANG Deyang, PENG YiJin, WANG Weiwei
    2023, 10 (4):  78. 
    Abstract ( 75 )   PDF (8291KB) ( 52 )  
    A large number of platforms in my country's waters have entered the middle and late stages. The management of these aging platforms, especially structural safety, has become the focus of the current operator's relationship. Vibration monitoring is used. The safety assurance of the jacket platform structure is a new type of means, which provides early warning through fundamental frequency changes and displacement changes. The fundamental frequency change is realized by shorttime Fourier transform and wavelet spectrum analysis methods. In addition, a method of correcting the evaluation model through vibration measurement and then performing post evaluation is proposed.
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    Evaluation of Operation Capability of Ultra-Deep Water Well Completion and Workover Vessel
    DONG Lu, ZU Wei
    2023, 10 (4):  84. 
    Abstract ( 62 )   PDF (16317KB) ( 57 )  
    Taking an ultra deep water well completion and workover ship as the research object, a method of its operation probability around main offshore oil and gas regions is studied based on hydrodynamic analysis in frequency and coupled analysis in time domain. The sea state in several offshore regions is studied and analyzed based on rules and codes recommendations. The analysis results show that the ultradeep water well completion workover ship can meet the operation requirements in mild sea areas, and has a relative high probability of operation in the sea areas of southern South China Sea, West Africa and Brazil. Its operation ability in severe sea areas should be studied based on detail technical analysis and metocean data, to ensure a sufficient operation weather window for well completion and workover operation. The analysis method in this paper can be used to evaluate the operation capacity of the same type and other offshore engineering vessels.
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    Current Status and Prospects of External Security Technology for Offshore Platforms
    ZHANG Qingguo, LIU Chunyue, LUO Song, WANG Shuili, LIU Qing
    2023, 10 (4):  92. 
    Abstract ( 95 )   PDF (63262KB) ( 121 )  
    In response to the current issues of unclear classification, unclear definition, and low universality of external security systems for offshore platforms, a definition of offshore platform security to prevent external human interference and damage is proposed. A universal offshore platform external security system is constructed, and industry standardization system construction ideas are proposed. We review the technical solutions, composition structures, and performance indicators of relevant offshore platform security equipment and systems in major foreign countries, with a focus on the security capabilities of ports, islands, and offshore oil and gas platforms to respond to external threats of human destruction. We provide an overview and explanation of the research progress and typical applications in the field of domestic offshore platform security, and combine actual needs with the current development of new technologies and equipment to prospect offshore platform security technology and equipment. We provide future construction ideas and suggestions, which can provide reference for further research and system construction of offshore platform external security technology.
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    Life Prediction of Glass Fiber Reinforced Vinyl Ester Composites Under Seawater Corrosive Environment
    LI Xiang, LIU Xiao, LI Sen, LIU Chengcheng, LIU Xiaobin, GAO Shuang
    2023, 10 (4):  107. 
    Abstract ( 136 )   PDF (1277KB) ( 78 )  
    Fiber reinforced plastics shields are used in the development of offshore oil and gas fields in the South China Sea to protect critical facilities in underwater production systems. Fiberglass (FRP) is the most commonly used composite material, widely used in Marine and ocean engineering fields. By establishing the seawater corrosion resistance life model and defining the bending strength retention rate, the general equation of seawater corrosion resistance life and the seawater corrosion resistance life formula under deepsea low temperature conditions are obtained. Based on the flexural strength test results of longterm immersion in seawater at room temperature and high temperature, from the point of view of bending strength, corrosion resistance is short. it is predicted that the corrosion resistance life of glass fiber reinforced vinyl ester composites in the seawater temperature range of 0-4℃ is about 12.28-16.55 years for applications subject to low bending loads.
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     Current Situation and Development Trend of Unmanned Platform Technology in Offshore Oilfield
    SUI Xianfu, QIU Hao, ZHANG Fu, ZHOU Chao, WANG Juanyan
    2023, 10 (4):  111. 
    Abstract ( 178 )   PDF (2530KB) ( 102 )  
    With the development of offshore oil field, the cost of production and operation is increasing rapidly.Unmanned platform technology has been widely concerned in recent years because of its simple structure, less equipment and low production and operation cost. However, the unmanned platform mode also exposes the problems of high cost of workover operation, difficulty of boarding the platform and difficulty of equipment monitoring in the process of production and operation. The author systematically summarizes the experience of unmanned platform development by investigating the advanced technologies and excellent practices in the current unmanned platform development process, which aims to provide a reference for the further promotion and application of unmanned platform technology.
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    Evaluation of Lamellar Tearing Resistance of Extra High Strength Steel for Deepwater Jacket
    ZENG Jingbo, WANG Huopin, LUN Yuguo
    2023, 10 (4):  117. 
    Abstract ( 85 )   PDF (2717KB) ( 88 )  
    All main structure of jacket platforms that have been built and put into operation in China use high strength steel of 355MPa at present. In order to reduce weight to meet the capacity of launching barge, some deepwater jacket under constrcution uses more than 20000t extra-high strength steel of 420MPa, which is produced in domestic. To ensure the securely construction of the jacket, the lamellar tearing performance and susceptibility of domestic extra-high strength steel API 2Y-60 for deepwater jacket are evaluated in this paper through chemical composition analysis, Z-direction tensile test and Z-type window test. The test results mean that the domestic API 2Y-60 steel has good lamellar tearing resistance, which is the basic condition of steels used in jacket tubular joints. The research results can ensure the safety of jacket platform, and also provide a reference for the first application demonstration of similar structural steel.
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    Research on Vibration Suppression of New Barge Floating Wind Turbine by TMD in the Platform
    JIANG Kun, CAI Qingqing, LI Sunwei
    2023, 10 (4):  122. 
    Abstract ( 146 )   PDF (1461KB) ( 93 )  
    Barge-type floating wind turbine is an important equipment for the development of offshore wind power, and its motion response can be effectively suppressed by a passive control device tuned mass damper (tuned mass damper, TMD). Based on the ITI Energy Barge wind turbine, this study designs a new Barge floating wind turbine foundation, establishes a wind turbine dynamic model configured with TMD in the platform, configures TMDs with different positions, masses, and damping parameters in the floating platform, and studies the change of the motion response of the floating wind turbine before and after the TMD with optimal parameters configured on the wind turbine platform under the action of wind and wave loads. The results show that after the TMD with a mass ratio of 3% and a damping ratio of 6% is configured on the top of the buoy in the new wind turbine platform, the front and rear and left and right displacements of the top of the wind turbine tower are reduced by 15.56% and 44.93% respectively. The pitch and roll suppression rate of the platform reaches 22.97% and 62.79%. The front and rear and left and right bending moments of the fan tower base are reduced by 15.62% and 39.8% respectively. At this time, the control effect of TMD is the best, and the overall stability of the wind turbine is greatly improved.
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    Research and Application of Fine Imaging Processing Technology of Buried Hill in the Overlapping Area of Multiple Working Areas in Bohai Sea
    XI Zibin
    2023, 10 (4):  130. 
    Abstract ( 63 )   PDF (4624KB) ( 61 )  
    At present, the Bohai Sea working area has achieved full coverage of 3D acquisition, but the construction time span of different working areas is large. There are a variety of acquisition methods, so different working areas have great differences in acquisition direction, offset range, amplitude difference, frequency characteristics, signaltonoise ratio and other aspects, which brings arduous challenges to buried hill imaging in the overlapping area of multiworking areas. In order to improve the imaging quality of buried hill structural area, this paper focuses on three aspects: fine key processing technology, fine splicing technology and high precision 3D prestack depth migration. Through the actual data verification, the imaging effect of the proposed method on buried hill of old data in the overlapping area of multiple working areas in Bohai Sea is significantly improved, which better verifies the effectiveness of the proposed method.
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    Influence of Submarine Bedforms on the Determination of Length Redundancy for Optical Communication Cable Laying
    ZHOU Yeqi, WANG Rui
    2023, 10 (4):  135. 
    Abstract ( 88 )   PDF (4402KB) ( 51 )  
    Submarine optical communication cables are the main infrastructure for modern international communication. Due to the presence of underwater bedforms, the difficulty to lay optical cables on the seabed is increased. If the amount of cable laid is less than required, it would cause the cable to hang between the two peaks of the bedforms. Under the actions of ocean currents and internal waves, the suspended section of the optical cable would generate vortex vibrations and even wear due to oscillatory motions with the seabed, so that the safe life of the optical cable would be shorten. Therefore, to determine reasonable length of cable laying is a very important task in the design of submarine optical cable engineering. This article explores the causes of submarine bedforms, the mechanism of cable damage on the bedform seabed, and analyzes the calculation method of cable laying length redundancy in order to provide references for the design of submarine optical cable engineering.
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     The Application of RBI Integrity Management to Deepwater Oil and Gas Exploitation
    LU Jin, ZHU Liyun, CHEN Miaomou, ZHANG Lin
    2023, 10 (4):  140. 
    Abstract ( 118 )   PDF (1449KB) ( 56 )  
    Compared to traditional timebased and conditionbased inspection methods, Riskbased Inspection (RBI), recently, is a new integrity management inspection technique which has been rapidly developed and applied to large offshore facilities. RBI is an advanced method for developing an optimum inspection plan and strategy which has coupled with techniques of database management, material damage and deterioration mechanism analysis, structural strength FEA, fracture mechanics for crack assessment, risk analysis and ranking, digital computer management system, etc. The RBI approach can guarantee that structures or equipment with higher risk could warrant more focused inspection than those with lower risk, which can effectively reduce inspection cost. This article will systematically discuss how to apply RBI technique for integrity management of large offshore facilities, while focusing on the application of RBI to the hull, mooring and riser systems of large deepwater offshore installations. Besides, a detailed case study on how to perform quantitative risk analysis on SN curve based offshore structures fatigue analysis.
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