Table of Content

    25 June 2018, Volume 5 Issue 3 Previous Issue    Next Issue
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    Study on Hydrate Prevention and Control in Deepwater High Water Production Gas Field
    LIU Yong-fei, QIN Rui, LI Qing-ping, YAO Hai-yuan
    2018, 5 (3):  149-153.  DOI: 10.12087/oeet.2095-7297.2018.03.01
    Abstract ( 306 )   PDF (1994KB) ( 43 )  
    We analyze the high water production problem of deepwater gas field and the harm of this problem. Aiming at the hydrate formation problem, the solutions which include hydrate inhibitor application, subsea pipeline insulation, subsea separation and boosting are described. By analyzing the principle, technical progress and application situation of each solution, we summarize the technical features, availability, main influencing factors and main application conditions of these solutions. The results show that the water content, the length of the pipeline and the temperature and pressure of flow are the main factors affecting the selection of the scheme.
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    Trends of Pipeline Free Spanning Evaluation and Their Applications in In-Service Evaluation
    XIA Qiu-ling, FENG Xian-hong
    2018, 5 (3):  154-159.  DOI: 10.12087/oeet.2095-7297.2018.03.02
    Abstract ( 338 )   PDF (946KB) ( 63 )  
    The development trends of free spanning evaluation and related criteria in the pipeline industry from the 1980s are presented. An example is given to calculate the maximum allowable span length by different codes. Then, the differences in the criteria and critical cases are compared and the reasons for these differences are analyzed. Finally, based on the engineering experience and the in-service evaluation results, suggestions on the code selection for submarine pipeline design and in-service evaluation are given.
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    Study on Piping Layout Design of CALM
    JI Zhi-yuan, CHENG Jiu-huan, DONG Bao-hui, WANG Chun-xia, HAO Wen-xi, DONG Xiao-man
    2018, 5 (3):  160-164.  DOI: 10.12087/oeet.2095-7297.2018.03.03
    Abstract ( 328 )   PDF (7226KB) ( 26 )  
    Catenary anchor leg mooring (CALM), as one of the terminal stations for offshore oil exploitation and transportation, has been widely used in recent years. CALM will bring considerable economic benefits to China's offshore oil industry after successful promotion. Based on the buoy design of an offshore CALM, the piping design principles, basis, layout requirements and layout design optimization are introduced. This research could provide engineering references for CALM buoy piping layout design.
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    Design Research of Subsea Hose with Chinese Lantern Configuration Used in CALM System
    YANG Wei, ZHANG Yong-hui, SUN Guo-min
    2018, 5 (3):  165-173.  DOI: 10.12087/oeet.2095-7297.2018.03.04
    Abstract ( 340 )   PDF (2292KB) ( 51 )  
    Subsea hose is an important part of catenary anchor leg mooring (CALM) system. The technical requirements, design conditions and analysis methods of subsea hose with Chinese lantern configuration in the CALM system are introduced. It is confirmed that the key of subsea hose design is the reasonable determination of hose section, float arrangement and buoy offset. In addition, the dynamic response of the subsea hose and the fatigue of key parts are analyzed with an example, which provides a reference for practical engineering design.
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    Key Technologies for Deep Large Extended Reach Wells Drilling in the East China Sea
    YAN Wei-feng, YUAN Ze-ming, HE Peng-fei, MU Zhe-lin, ZHU Sheng, SHI Wen-zhuan
    2018, 5 (3):  174-180.  DOI: 10.12087/oeet.2095-7297.2018.03.05
    Abstract ( 227 )   PDF (3862KB) ( 46 )  
    To prolong the economic life of an oil and gas field in the East China Sea, it was considered to drill an extended reach well through existing well, relying on the existing facilities. In this way, we could develop the reservoir of the midmountain pavilion in the southwest of the oil and gas field. By optimizing the casing fishing technology, successful completion of large-size long-distance casing fishing operation was successfully implemented, which laid the foundation of the subsequent lateral drilling of the ultra-deep extended reach well. With the further optimization of technologies including oil-based drilling fluid system, friction and torque control, hole cleaning, equivalent circulation density (ECD) control, and casing cementing, the drilling operation of the first ultra-deep extended reach well in the East China Sea was successfully completed.
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    Study of Vortex-Induced Vibration of SCRs for a Spar Platform with the Application in South China Sea
    CHEN Gang, CHENG Yong-ming, XU Ai-jin, WANG Yu-han
    2018, 5 (3):  181-185.  DOI: 10.12087/oeet.2095-7297.2018.03.06
    Abstract ( 294 )   PDF (6590KB) ( 43 )  
    Spar platform is a new type of floating platform for deep and ultra-deep water applications. It is suitable for the exploration, development and production of oil and gas in the South China Sea. Steel catenary risers (SCRs) are widely used allover the world due to its structure simplicity, high reliability and economy. SCR's fatigue damage caused by vortex-induced vibration (VIV) is vital to the safety of SCRs and the entire platform. We consider the environmental conditions in the South China Sea and study the VIV of SCRs for a Spar platform. The layout and configuration of SCRs are introduced at first. Then the VIV fatigue of 18-inch SCR is analyzed. Furthermore, the sensitivity of key parameters is investigated. This research will provide a good reference for deepwater riser design.
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    VIV Fatigue Damage Analysis for Tendons of Tension Leg Platform under In-Place Condition
    LIU Yu-xi, HUANG Huai-zhou, LIU Zhao
    2018, 5 (3):  186-190.  DOI: 10.12087/oeet.2095-7297.2018.03.07
    Abstract ( 328 )   PDF (4658KB) ( 53 )  
    The vortex-induced vibration (VIV) caused by current directly affects the fatigue of tendon of tension leg platform (TLP). Proper VIV fatigue analysis is very important for tendon fatigue life prediction. Firstly, the mathematical model for tendon VIV and stress-life (S-N) curve method are studied. Secondly, for tendons under TLP in-place condition, the procedure of VIV fatigue analysis using Flexcom and SHEAR7 is presented. Finally, detailed VIV fatigue analysis is performed for a specified TLP.
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    Study on Calculation Method for Jacket Docking with Subsea Template Guide
    XU Feng, RUAN Sheng-fu, HU Yong-ming, JIN Bao-wang, TIAN Wei-xing
    2018, 5 (3):  191-196.  DOI: 10.12087/oeet.2095-7297.2018.03.08
    Abstract ( 273 )   PDF (2120KB) ( 54 )  
    For offshore installation of jackets, subsea template guide pre-installed on seabed and sleeves designed on the jacket are beneficial to the rapid and accurate positioning of the jacket. Subsea wellheads can be pre-drilled and the development period of oil and gas field can be shortened by adopting this installation method. To investigate the interaction between jacket and guide pile during docking, MOSES software is used for the analysis of motion and impact load in time domain. The analysis results are compared with the results according to the relevant standards. The conclusions of this research have a certain reference value for the projects using subsea docking installation method.
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    Winch Design of Catenary Anchor Leg Mooring System
    TIAN Feng, DONG Xiao-man, ZHANG Jia-ping, Lyu Jin-bo, ZHOU Yan
    2018, 5 (3):  197-201.  DOI: 10.12087/oeet.2095-7297.2018.03.09
    Abstract ( 387 )   PDF (4385KB) ( 38 )  
    Key contents to be considered in the winch design of catenary anchor leg mooring (CALM) single point mooring system are introduced and concluded, including environment condition to be satisfied, selection of drive mode, steel wire rope selection, spooling gear configuration, winch installation, etc. In an actual design project, the design results meet the functional requirements and save the equipment costs. Some references are provided for the type selection design of winch in similar facilities.
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    Equipment Selection for the Air-Conditioning System of Deepwater Semi-Submersible Drilling Rig
    HE Yang
    2018, 5 (3):  202-207.  DOI: 10.12087/oeet.2095-7297.2018.03.10
    Abstract ( 280 )   PDF (4106KB) ( 19 )  
    The air-conditioning system of deepwater semi-submersible drilling rig directly affects the health of employees and the operation safety of electrical equipment on the platform. For the air-conditioning system equipment selection of a semi-submersible drilling rig in the South China Sea, comparison of the same type of semi-submersible drilling rigs is carried out, and the environmental conditions of the South China Sea are investigated and analyzed. Considering the spatial arrangement of deepwater semi-submersible drilling rig, the environmental conditions and the requirements on vibration, noise and comfortableness in NORSOK standards, the air-conditioning system equipment selection of this platform is accomplished.
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    Comparative Analysis on Three Move Methods of Deepwater Drilling Platform
    DONG Tie-jun, XIANG Kai, ZHOU Xin-bao
    2018, 5 (3):  208-213.  DOI: 10.12087/oeet.2095-7297.2018.03.11
    Abstract ( 349 )   PDF (1279KB) ( 136 )  
    Deepwater semi-submersible drilling units normally move between well locations by sailing using self-propulsion, towing by tug boat, or combination of self-propulsion and towing. Comparison and analysis of these three approaches are carried out in the aspects of risk tolerance and economic efficiency using HYSY981 as an example. The results show that: self-propulsion is the most economical way of the three, combination towing is the second, but the combination towing could save a lot of time, and the time of moving the platform by self-propulsion and that by towing are almost the same to each other.
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    Suppression Methods of Transformer Inrush Current in Offshore Platform
    ZHANG Xiao-yu
    2018, 5 (3):  214-217.  DOI: 10.12087/oeet.2095-7297.2018.03.12
    Abstract ( 359 )   PDF (980KB) ( 31 )  
    Transformer no-load closing may cause large inrush current. This large current may cause the fail of transformer closing and the malfunction of generator vacuum circuit breaker (VCB). In order to improve the success rate of transformer closing, and thus to ensure the safe operation of offshore platform, it is essential to suppress inrush current. The cause of inrush current is introduced, and three common suppression methods including phase control, soft start and pre-magnetizing technology are described. The advantages and disadvantages of these methods, as well as their applications in offshore platforms, are compared briefly.
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    Failure Analysis and Maintenance of Flameproof Surface Shafts for Medium-Sized High-Voltage Flameproof Motor
    SUN Jun, LIU Lei, LIU Xin-wei, JIA Dong-hui, HUANG Lei
    2018, 5 (3):  218-222.  DOI: 10.12087/oeet.2095-7297.2018.03.13
    Abstract ( 359 )   PDF (2321KB) ( 36 )  
    Flameproof three-phase asynchronous motor is widely used in dangerous areas of offshore platforms. For this kind of motor, failure mostly occurs in bearings or bearing shells. On an offshore platform in Bohai, a medium-sized high-voltage flameproof motor was shut down normally and then restarted. In the restart process, the motor vibrated, showing a suddenly increasing current and abnormal noise. Inspection showed that there was no problem in the motor bearing, so plane shaft failure was considered. The reasons for the failure of the flameproof surface and shaft of the bearing chamber of the medium-sized high-pressure flameproof motor are analyzed, and the method of repairing the damaged motor's flameproof surface and rotor shaft is described.
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    Contents of Vol.5, No.3, 2018
    OEET Editorial Office
    2018, 5 (3):  3001-3002. 
    Abstract ( 60 )   PDF (180KB) ( 68 )  
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