03 November 2023, Volume 10 Issue 3 Previous Issue   

Numerical Analysis and Risk Study of Large Offshore Converter Station Transportation and Floatover Installation

Xiong Gen, Liang Fusheng, Li Xin, Sun Zhenzhou, Xu Xin, Tian Xinliang,
2023, 10 (3):  1-12. 
Abstract ( 35 )   PDF (8344KB) ( 35 )  
With the development trend of large-scale and ocean-going offshore wind farms, the demand for large-scale offshore converter stations will continue to increase, and their installation problems will gradually receive attention. In this paper, taking the SanXia Rudong offshore converter station as an example, a multi-body dynamic model is established by OrcaFlex software to numerically calculate the transportation and floatover installation process of the converter station, and the motion, acceleration and mooring line force of the barge and converter station in some stages are analyzed. The results show that during the transportation stage, when the significant wave height is the same, the motion amplitude and acceleration of the barge-converter station system increase correspondingly with the increase of the spectral peak period Tp (6~9s), but they are basically within the limit value. During the installation stage, the spectral peak period Tp = 8s at the same wave height will cause greater surge, sway, and yaw motion amplitudes than Tp = 6s and 10s, and more attention should be paid to such working conditions. In addition, head sea conditions are more conducive to the floatover operation. Besides, the risk research of the converter station transportation stage is carried out, and effective risk control measures are proposed to provide a certain reference for the actual large-scale offshore converter station installation operation.

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Overview of deepwater umbilical pre-commissioning
JIANG Bingbing, CAO JuHang, ZHANG Jie, GAO Lei, LONG Xiaopin, TANG Yu, LUO Jie, Li Jian, CHEN Juan, ZHANG Jie
2023, 10 (3):  13-23. 
Abstract ( 19 )   PDF (11950KB) ( 13 )  

Umbilical is an important link between the upper control system and the subsea production facility. This paper systematically summarizes the conventional pre-commissioning technology of umbilical and key testing equipment & instruments, which is helpful to promote the research & development of relevant supporting equipment and improve the domestic technical service capacity of deepwater umbilical pre-commissioning. Based on the practice of a gas field in the South China Sea, a simple, integrated and flexible umbilical testing process is proposed, which provides technical support for the subsequent deepwater umbilical pre-commissioning. Two different types of subsea precommissioning equipment for deepwater umbilical are compared and analyzed: the deck testing equipment represented by intervention, workover and control system and the subsea testing equipment represented by the subsea booster module. The limitation of the deepwater umbilical pre-commissioning technology based on the test system of subsea booster module is analyzed, and the future development direction of its is proposed. Finally, its broad application prospect is pointed out.

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Application of Ship 3D-modeling based on NURBS surface

ZHANG Dapeng, YAN Jin, ZHAO Bowen, HOU Ling, ZHU Keqiang
2023, 10 (3):  24-32. 
Abstract ( 25 )   PDF (7786KB) ( 24 )  

NUBRS surface modeling technology is specially designed for the reconstruction of 3D models of complex surface objects. It can accurately and precisely express the contour and shape of the 3D model of target objects based on the form of curves and surfaces. This paper introduces Maxsurf Modeler, a 3D modeling program of hull based on NURBS surface, and gives the process of applying this program to 3D modeling of hull. At the same time, the reliability and applicability of the 3D model are verified by CFD. In the calculation of hydrostatic resistance, the maximum error under 6 working conditions is 2.29%. In seakeeping calculation, the calculation error of pitch motion is the largest, which is 19.32%. The results show that the 3D model completed by Maxsurf Modeler has certain reliability.

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Overview of the Development of Expendable Conductivity Temperature and Depth
DU Libin, CUI Yongchao, LIU Jie, ZHANG Xiaobo
2023, 10 (3):  33-40. 
Abstract ( 41 )   PDF (1757KB) ( 36 )  

Expendable Conductivity Temperature and Depth (XCTD) is an advanced marine dynamic environmental element measuring instrument, which can be used on various civil and military vessels, aircraft or submarines to quickly obtain underwater environmental information data. It is a standing instrument for marine survey and an important supplement to traditional measuring instruments such as marine environmental monitoring buoy, submarine buoy and shipborne CTD because of its flexibility, economy and simplicity. At present, the Expendable Conductivity Temperature and Depth is widely used in the field of ocean profile observation because of its characteristics of simple measurement, high measurement efficiency and low hardware cost. In order to understand the development gap at home and abroad and clarify the future development direction of this field, this paper expounds the development status of the expendable marine exploration instruments at home and abroad through comparative analysis and summary starting from its classification, at the same time, compares the main gap between domestic and foreign products, and focuses on the working principle and key technology of the Submarine-launched Expendable Conductivity Temperature and Depth (SSXCTD), meanwhile, the research summarized the future research directions in this field.

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Strength Design Criterion on Hydrogen Offshore Pipeline

WANG Meng, LIANG Guangqiang
2023, 10 (3):  41-47. 
Abstract ( 18 )   PDF (1547KB) ( 20 )  
The design criterions of strength, fracture toughness and hydrogen fatigue crack growth rate of hydrogen offshore pipeline have been studied, and the sensitivity of the FCGR’s model was also studied. This paper can provides a guidance for the engineering design of hydrogen submarine pipeline.
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Discussion on the Procedure of Oil Flushing in Complex Pipelines

Dong Lei, Liang Tengfei
2023, 10 (3):  48-51. 
Abstract ( 28 )   PDF (3136KB) ( 22 )  
Oil flushing, also known as oil cleaning, is a common process in the construction of offshore platforms. In particular, the hydraulic system has a high requirement for pipeline cleanliness, and usually the pipeline has many branches. So it is difficult to divide the oil flushing package into single line circuits, and the oil flushing quality of each branch cannot be guaranteed. This paper builds models according to parameters of the pipeline system, proposes to analyze the feasibility of the procedure using fluid software simulation before oil flushing operation. Adjusts the oil temperature, kinematic viscosity, flow control and other aspects, and then optimizes the oil flushing procedure to ensure the quality and improve efficiency.
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Key techniques and applications of high-speed drilling in Huangyan District Y1 oil and gas field

Xu Jia, Yuan Zeming, Zhang Haishan, Zuo Honggang, Wang Xijie
2023, 10 (3):  52-56. 
Abstract ( 13 )   PDF (1394KB) ( 9 )  
The target layer of the Y1 oil and gas field  is deeply buried, with a large dip angle and a typical low porosity and permeability reservoir, there are some difficult problems, such as difficult to release Rop in surface layer, prominent problem of borehole instability in middle and upper layer, poor drill ability in deep layer, low local formation loss pressure and high risk of loss during cementing in long open hole section, etc. , the drilling speed and efficiency of the gas field are restricted. To this end, the corresponding comprehensive technical research, through the analysis of the gas field during the operation of the technical difficulties encountered, and the East China Sea has a mature drilling technology system, key Technologies, such as casing program simplification, oil-based mud system, personalized PDC bit design, and optimized BHA, have been developed to speed up drilling operations in deep and ultra-deep wells in the Y1 oil and gas field, the technical problems which restrict drilling speed and efficiency are solved, and the technical guidance is provided for the scale development of the gas field.
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Research on integration lifting technology of J-tube of offshore booster station jacket

FENG Yinglei
2023, 10 (3):  57-64. 
Abstract ( 25 )   PDF (11685KB) ( 24 )  

As offshore wind power gradually moves towards the deep sea, the size and weight of offshore booster station jackets are also getting larger. The number of cable protectors of the offshore booster station jackets is large, making installation difficult. If use the installation method of traditional oil and gas jacket’s J-tube, the project duration and cranes will be greatly affected. This paper discusses an integration lifting technology of J-tube and structural piece,which lifts the J-tube and structure in place at the same time, and checks the structural strength and local strength of lifting points under different working conditions. Provide technical basis for construction of wind power technology to break through in deep sea areas.

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The Design and Application for External-Addition Well Slots on Platform
SHI Xiaoqing
2023, 10 (3):  65-71. 
Abstract ( 19 )   PDF (15058KB) ( 10 )  

The platform adding well slot can make full use of the old platform workover rig and other equipment resources, the construction period is short, the investment cost is low. In recent years, it has been widely used in engineering. Taking the PL9-3WHPB platform external-addition well slot project as an example, this paper introduces in detail the location scheme comparison and selection of the external well slot, the design of the wellhead piece, the overall safety evaluation of the platform and the installation and maintenance of the wellhead, analyzes and summarizes the problems encountered in the external well slot and the solutions, and provides reference and ideas for similar adding well slot projects.

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Analysis on anticorrosion structure of narrow and long inner hole tube body

Xu Youliang, Qi Lin, Meng Hua, Li Zhijie
2023, 10 (3):  72-75. 
Abstract ( 16 )   PDF (2722KB) ( 10 )  

Based on a deep-sea long-distance pipeline solid transmission device project, combined with the deep-sea long-distance solid transmission device tube structure, characteristics, manufacturing technology and working conditions, the paper analyzes and compares the advantages and disadvantages of corrosion resistance between different structures, and provides solutions for the subsequent design of deep-sea pipelines and narrow-long inner-bore tubes.

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Processing of Beidou Positioning Error in the Integrated Navigation for Use At Sea

Wang Yafeng, Huang Peishuo, , Yu Xiaqiong, Song Lei, Yu Wenbin
2023, 10 (3):  76-82. 
Abstract ( 21 )   PDF (1558KB) ( 14 )  

Taking the SINS/Beidou loose integrated navigation as the object, the processing method of Beidou positioning error at sea is studied. By analyzing the source of Beidou positioning error, it is pointed out that there is a constant deviation of Beidou positioning error in local areas within a short time. This constant deviation can be compensated by the differential data released by the ground differential stations. However, at this stage, the ground differential stations of Beidou system are mainly concentrated in the key areas of China. For overseas areas, especially marine areas, where there is no ground differential station, the common method is to treat the Beidou positioning error as noise, but this method will sacrifice the accuracy of integrated navigation. In this paper, the constant deviation of Beidou positioning is incorporated into the filter state. And the Kalman filter state expansion method is proposed to estimate this constant deviation to improve the integrated navigation accuracy. Finally, the simulation examples show that the method can effectively improve the positioning accuracy.

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Lifting Methods for Vertical Construction of Offshore Wind Turbine Jacket
CHEN Shiwei
2023, 10 (3):  83-89. 
Abstract ( 16 )   PDF (11405KB) ( 11 )  
The offshore wind turbine jacket is relatively small and needs to be built in batches, therefore, it mostly adopts vertical construction process. However, due to the particularity of this type of jacket structure, offshore wind turbine jacket will faces a lot of hard lifting operations during its vertical construction process. Currently, there is no relevant lifting experience and engineering case for reference. Hereto, this paper based on a 2000T class large offshore wind turbine jacket project, introduced the general assembly process of this jacket, analyzed the technical difficulties of its assembly in different process, provides a lifting method for TP and upper jacket integrated lifting and lower jacket turn over lifting. Practice has proved that the method can effectively solve a series of lifting problems, such as difficult arrangement of lifting points, high difficulty of assembly and high requires of crane performance. This paper could help realize the batch construction of offshore wind turbine jacket and provide technical support for other similar projects.
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Technical status of subsea pressure and temperature integrated transmitter
Han Yunfeng Yue Yuanlong Wei Juan Zuo Xin Sun Hanxuan
2023, 10 (3):  90-98. 
Abstract ( 20 )   PDF (2290KB) ( 26 )  

Subsea production system is widely used in the development of offshore oil and gas resources, and always runs at the position of subsea mud line for a long period. In order to ensure safe operation and reduce the structural complexity as well as the maintenance cost of equipment, it is necessary to equip a highly reliable subsea pressure and temperature transmitter (PTT). So far, the design and manufacture technology of subsea PTT has not been developed in China. On the basis of fully realizing the localization of subsea production system, and planning the industrial distribution of subsea key equipment from technical commanding point, this paper analyzes the technical status of PTT comprehensively. Firstly, the engineering background, the installation position of PTT and its key role in subsea production system are introduced. The working principle of PTT is described as well. Afterwards, the function and technical requirement of the relevant standards for PTT are illuminated. The mechanical structure, component material, power supply, communication, pressure-temperature transmitter precision, resolution and other data parameters are compared and analyzed as well. Finally, the technical difficulties, the problems faced by international procurement, along with the urgency and necessity of localization of  PTT are presented with summary and prospect.

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The Current State of Chemical Injection Metering Valve Technology

Wu Lu, Sun Qin, An Weizheng, Zuo Xin, Bai Xiaobo, Yue Yuanlong
2023, 10 (3):  99-108. 
Abstract ( 27 )   PDF (10473KB) ( 35 )  
Subsea chemical injection metering valve is the core chemical injection equipment to ensure the long-term safe operation of the subsea production system and realize the functions of accurate injection and flow metering. In this paper relevant standards for the function and technical requirements of subsea chemical injection are introduced, Then, the subsea chemical injection process is proposed, the installation position and function of subsea chemical injection metering valve are pointed out. Finally, considering the international mainstream subsea chemical injection metering valves, operation principle, power supply and communication, mechanical structure and subsea installation are analyzed. This research can provide somewhat significance for the independent development of our subsea chemical injection metering valve. 
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Application of Big Platform Twin hole-in-Monobore Technology in Offshore Bohai Oilfield

QI Hengzhi
2023, 10 (3):  109-112. 
Abstract ( 14 )   PDF (5244KB) ( 5 )  

Design and development of Penglai oilfield two period 40 slots (16 dual bore slots) wellhead platform can drill 56 wells. By far, it is the most number of Bohai offshore drilling platform. On the basis of slots and Christmas tree surface layout, considering the design of directional well and the anti-collision problem, this paper describes the installation of the surface casing and cementing procedure. The 56 wells slots drilled from a 40 slot WHP reduces the number and cost of the platform while providing additional wells to meet the reservoir development plan. Thus it plays a guiding role of the development of subsequent oilfield.

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Marine lifting optimization of separated lifting topsides of eight legs central production platform #br#

LAN Guoyang, YUAN Yujie, HU Xingtao, SUN Huafeng
2023, 10 (3):  113-117. 
Abstract ( 18 )   PDF (2903KB) ( 13 )  
This article has a successfully put into operation example of a separated lifting topsides of eight legs central production platform in Bohai sea。 According to the idea of integrated design, in the detailed design phase through the marine lifting optimization of separated lifting topsides of eight legs central production platform, it not only reduces the occupation of key production resources such as large floating cranes and the input of labor costs, but also by shortening the offshore construction time to reduce the uncertainty risk of offshore construction. In addition, the redundancy of the structure can be effectively used to achieve the optimization of the structure and achieve the purpose of reducing cost and increasing efficiency. Through the analysis and demonstration of professional computing technology, this article proves the feasibility of this optimization scheme
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Analysis of the Installation and Test Scheme of Marine Environment Monitoring System for Semi-Submersible Platform
JIA Chuang, HE Xiaoyong, HUANG Jun, WANG Tingting
2023, 10 (3):  118-124. 
Abstract ( 14 )   PDF (7169KB) ( 9 )  

With the development of offshore oil and gas resources moving towards the deep sea, there are more and more floating production facilities being used. In order to be able to monitor the production facilities under complex marine environmental conditions, the integrated marine monitoring system is adopted by most floating production facilities. This system can monitor the location and attitude of facilities, structural stress, mooring system, etc., which are essential for platform structure status conduction, safety assessment and response and remaining life prediction. The marine environment monitoring system is an important component of the whole system, which can monitor the marine environmental conditions around the floating facilities in real time and provide data support for ballast adjustment and mooring adjustment of floating facilities. The installation and test of the monitoring system is a prerequisite for the realization of the system functions. Through the detailed analysis of the application conditions and functions of the system, this paper gives the layout and installation scheme of hardware equipment, as well as the test scheme of software and hardware, which can be a useful reference for the installation and test of the marine environment monitoring system of the floating production facilities.

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Finite Element Analysis of Soil Heave during Settlement of Suction Foundation
Xu Fan, Deng Yucong, Chen Rumu, Ren Guanglu, Lu Jiaqi
2023, 10 (3):  125-131. 
Abstract ( 18 )   PDF (1362KB) ( 19 )  
Suction foundation is widely used in the installation and fixation of large offshore engineering structures. In this paper, the finite element analysis software ABAQUS is used to establish a three-dimensional large deformation finite element analysis model based on the coupled Euler Lagrange method (CEL). The finite element numerical simulation of the soil plug uplift process during the installation and settlement of suction foundation is carried out. The finite element simulation results and theoretical calculation are comprehensively analyzed, and the mechanism of soil plug uplift and its weakening the ultimate bearing capacity of suction foundation is obtained.
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Multi-objective particle swarm optimization analysis on static configuration of steel lazy wave catenary riser

JIA Lusheng , WEI Jiayao, AI Shangmao
2023, 10 (3):  132-137. 
Abstract ( 19 )   PDF (2110KB) ( 9 )  
The steel lazy wave catenary riser has many design parameters, which is cheerful due to its cheap price, and it is necessary to find the optimal design configuration with minimum stress among various parameters. The riser configuration influences of the horizontal span, suspension length, float length and float diameter are discussed at first. The full factorial design of experiment is used to determine the sample points, and then the static stress response surface model of a lazy wave steel catenary riser is established by using the catenary theory. Finally, the multi-objective particle swarm optimization algorithm is used to solve the pareto optimal solution set, which can be chosen for the optimal riser design in engineering. Comparing with single optimization object, the multi-objective particle swarm optimization algorithm can effectively deal with the minimization optimization for both the hang-off point and the touch-down zone of the riser, and the optimization results show that the force of the riser in the optimal scheme is significantly reduced at hang-off point and touch-down point.
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Collision analysis of subsea connector seal ring based on the explicit algorithm
WANG Wei, LI Wei, ZHAO Xiaolei, LI Nan, ZHANG Tengyue
2023, 10 (3):  138-143. 
Abstract ( 15 )   PDF (4583KB) ( 9 )  
In this paper, the significance and method of subsea connector sealing ring collision analysis was introduced. Based on explicit algorithm and finite element theory, the analysis and calculation method of the subsea connector sealing ring collision critical velocity was researched. In the process of analysis, the 3D model establishment, material properties set, meshing, boundary conditions set and collision parameters set were introduced. The calculated results were analyzed in detail, and the critical velocity was obtained, the necessary theory basis for clamp subsea connector connection velocity selection was provided.
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