Table of Content

    25 April 2015, Volume 2 Issue 2 Previous Issue    Next Issue
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    Orginal Article
    CO2 Storage Scenario for Dongfang Gas Field Terminal
    Zhi-jun LI, Xi-chong YU, Yu-xing LI, Qing WANG, Bing CHENG
    2015, 2 (2):  105-110. 
    Abstract ( 173 )   HTML ( 0 )   PDF (3704KB) ( 225 )  

    The available CO2 volume in Dongfang gas reservoir is rather abundant, which brings an important problem, that is, how to bury the CO2 to realize CO2 emission reduction. According to the specific situation of Dongfang gas field terminal, four schemes to recycle CO2 are proposed, including burying on site onshore or offshore and injecting in Weizhou oil field or Bohai oil field for enhancing oil recovery (EOR). On that basis, four utilization programs, all of which include treatment, liquefaction, transportation and burying of CO2, are put forward. Finally, process calculation, apparatus selection and economic analysis are developed for every scheme. Results show that the first scheme (onshore local storage near Dongfang gas field terminal) possesses the least investment, but no profit. The fourth scheme [EOR/enhancing gas recovery (EOR/EGR) in Bohai Gulf] takes the largest investment. The investment of the second scheme (EGR in Dongfang 1-1 gas field) is less than that of the third scheme (EGR/EOR in Weizhou 12-1 platform). EGR/EOR can always get profit. The optimum scheme should be determined by economic evaluation.

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    Global Response Analysis for the Deep-Sea Umbilical
    Xi-qia CHEN, Lei-jian SONG, Xia-ying DU, Jun WAN, Shi-xiao FU
    2015, 2 (2):  111-117. 
    Abstract ( 234 )   HTML ( 0 )   PDF (3900KB) ( 360 )  

    We present the global analysis for the deep-sea umbilical. The design and analysis of the umbilical has become the research focus in the offshore engineering field. Global response analysis is the key issue in the research of umbilical. We present the theoretical models of the free hanging catenary shape and the lazy-wave shape at first. Based on the theoretical models, the umbilical models of the free hanging catenary shape and lazy-wave shape are then developed in OrcaFlex. The distribution characteristics of effective tension and bending curvature are calculated and compared. The results show that the shape of the lazy-wave is more complex than that of the free hanging catenary. However, the lazy-wave shape can reduce the effective tension at the top hanging points and dynamic response at the touchdown point, which makes it more applicable in the deep sea. Meanwhile, the sensitivity analysis of the generalized configuration parameters, including the length of the buoyancy catenary, the buoyancy factor and the starting location of the buoyancy catenary, is performed and the effect of the configuration parameters on the static characteristics of the umbilical is studied. The research results may provide a reference for the configuration design of the deep-sea umbilical.

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    Thermal Load Analysis on 6S50ME-B Piston Crown
    Jian TIAN
    2015, 2 (2):  118-123. 
    Abstract ( 163 )   HTML ( 0 )   PDF (2714KB) ( 289 )  

    The low speed two-stroke marine diesel engine is developing continuously towards long stroke, high pressure, high automation, high intelligence, low consumption and low emission. MAN Company designs new ME-B type diesel engine to meet these requirements. Piston crown are one of the most important components of the engine and thermal load analysis is always the focus of research. ME-B piston crown is modified significantly in structure and dimension compared with old design. Finite element analysis is carried out for piston crown of the latest 6S50ME-B diesel engine by using ANSYS software. The three-dimensional model of piston crown is established and the temperature field is obtained. Using the temperature field as the boundary conditions, the thermal stress field and the weak point on the piston crown are found, which may offer theoretical support for further optimization.

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    Optimization of Liquid Seal Device for Drain Systems Containing Sand on Offshore Platforms
    Zhi-sheng DU, Jin-jin XU, Chao MA, Fa ZHANG, Fu-qiang LIU
    2015, 2 (2):  124-127. 
    Abstract ( 234 )   HTML ( 0 )   PDF (1311KB) ( 197 )  

    Drain system is one of the most important systems on offshore platforms. In order to prevent the turbulent flow of combustible gas which comes from different regions, U-tube liquid seal device is often used in open drain pipes. When the drain system contains sand, the U-tube will get clogged frequently and is difficult to clean. To solve this problem, the optimization of U-tube liquid seal device is performed according to the principle of liquid seal. Moreover, a new Y-tube liquid seal device is designed, which is more suitable for drain systems which contain sand on offshore platforms. The Y-tube liquid seal device, with the function of sealing and settling, can easily be cleaned, and provides more advantages than U-tube liquid seal device.

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    Deluge System Optimization Design for Offshore Oil and Gas Production Facility
    Jin-hong XIE, Jin LI, Yan-hua LI, Jiao-lin ZHU
    2015, 2 (2):  128-132. 
    Abstract ( 162 )   HTML ( 1 )   PDF (2023KB) ( 304 )  

    Deluge system is an important system on offshore oil and gas production facility. The design of deluge system is related with other offshore system design such as electric system and general layout design. Nozzle type selection and deluge distribution piping routing have much more impact on the fire water system design. We put forward an optimization method from the theoretical to the actual engineering design aspects. This method can decrease the water demand as much as possible and save the engineering cost on the premise of meeting the requirements of safety and standards.

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    Design of Low-Power Platform for Deepwater Riser Underwater Monitoring
    Hao BAI, Meng-na ZHANG, Xiao-hong SHEN, Hai-yan WANG
    2015, 2 (2):  133-137. 
    Abstract ( 245 )   HTML ( 0 )   PDF (2950KB) ( 239 )  

    Underwater information processing platform is the nerve center of the riser fatigue monitoring device. It controls fatigue parameters detection, signal processing, data transmission, dormancy and initiation of the monitoring equipment and a series of processes. The hardware system of the low-power-consumption underwater information processing platform consists of low-power microprocessor, high-speed digital signal processor (DSP), a variety of sensors, signal modulation and transmission circuit, power supply and other accessories and so on. In order to improve the service period of the monitoring equipment, we optimize the design of the low-power underwater information processing platform during the "Eleventh Five-Year" period. We add storage modules and optimize spatial layout and program flow to greatly reduce the circuit board area. After optimization, the reliability of the underwater information processing platform is enhanced further. And then the volume and weight of the riser monitoring system are reduced and its convenience and applicability are improved.

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    Research on Materials Management Digital System of Offshore Platform
    Shu-min LI, Tai-an HUANG, Bao-rui YIN, Xiao-gang ZHANG, Jia WANG, Xiao-fang LIU, Yu-ming LI
    2015, 2 (2):  138-144. 
    Abstract ( 195 )   HTML ( 0 )   PDF (4526KB) ( 242 )  

    Considering the low materials management efficiency and a serious shortage of informatization level in domestic offshore engineering enterprises, the significance of materials management is emphasized through the analysis of domestic and foreign advanced materials management theory. Taking the actual project of a company as the background, business demand for materials management is drawn through field investigation, and the structure of the management system is figured out based on the demand analysis. The structural modelling of the system is thus accomplished. Using Java language, combined with MyEclipse development environment and Oracle database, we develop a prototype system. The feasibility and validity of the system are testified through the demonstration of the actual project material management process.

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    Multiaxial Fatigue Assessment of Pile Leg Joint under Complex Stress State
    Ying-fang LIU, Hong-feng LIU, Fu-hong JIANG, Li-zhong SAN, Yan-feng WANG, Wan-xiong XU
    2015, 2 (2):  75-79. 
    Abstract ( 224 )   HTML ( 0 )   PDF (2388KB) ( 271 )  

    A new multiaxial fatigue criterion is introduced. In combination with the hot spot stress method, it is used to estimate the fatigue life of about 250 test specimens published in international open literature, through which the accuracy of the new method is verified. Finally we use the new method to do a successful fatigue life assessment of the pile leg joint. This research provides an available reference to improve the accuracy of the fatigue life prediction of pile leg joint.

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    Analysis of Main Factors Affecting Fracturing Effect in Low Permeability Reservoir of Xihu Oil and Gas Field
    Shun-shui LI, San-xi LI
    2015, 2 (2):  80-83. 
    Abstract ( 159 )   HTML ( 0 )   PDF (755KB) ( 221 )  

    Hydraulic fracturing has found more and more applications in low permeability reservoir of Xihu oil and gas field in recent years. It is of great guiding significance to the selection of well and layer for fracturing and fracturing design to study the main factors affecting the fracturing result in low permeability reservoir in offshore oil field. We analyze such factors through gray correlation method and fuzzy curve method. The results show that the main factors affecting the fracturing result in the test areas are well testing permeability, skin factor, geological reserves, sanding strength, porosity, and effective thickness. The two analysis methods lead to slightly different ranking results of the affecting factors, but with the same overall trend. Therefore, the main factors affecting the fracturing effect can be identified in this way.

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    Interference Analysis of Top Tensioned Risers for Tension Leg Platform under Wave and Current
    Yun SHI, Xiao-dong ZHOU, Jing CAO, Xiao-yan LIU
    2015, 2 (2):  84-87. 
    Abstract ( 290 )   HTML ( 0 )   PDF (998KB) ( 247 )  

    Tension leg platform (TLP) has been widely used in deepwater oil field development in recent years. The risk of top tensioned riser (TTR) interference increases with the increase of water depth. If the collision force or collision energy caused by riser interference is large enough, it is possible to endanger the integrity of riser systems, and even the safety of the platform. TTR interference assessment becomes increasingly important and a design challenge for deepwater TLP. Reasonable well-bay spacing should be selected to avoid TTR collision and also minimize the impact on TLP topsides. Based on an oil field development plan, well-bay spacing and riser interference are investigated. The key parameters such as drag coefficient and top tension factor are discussed, and sensitivity analysis is carried out on those factors. The results may provide references for the research and design of TTRs.

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    Global Performance Analysis for Deepwater Flexible Riser
    Cheng-lin LU, Lan LI, Ping-na SONG, Jing CAO, Yong SHA, Wei-wei ZHOU
    2015, 2 (2):  88-92. 
    Abstract ( 336 )   HTML ( 0 )   PDF (1466KB) ( 163 )  

    Ocean flexible pipe is of great importance in ocean oil resource exploitation. Due to its outstanding capability of erosion resistance, terrain adaptability, long continuous length and convenient installation, flexible pipe is gradually replacing traditional steel pipe. Flexible riser has been widely used among foreign countries to connect the floating structures to underwater production system of deepwater oil/gas field. However, there is no design and manufacturing technology in China for deepwater flexible pipe. Here we focus on the introduction of analysis method on the global performance of flexible pipe in-place condition. Taking riser parameters, environmental conditions, parameters of the floating production, storage and offloading system, and the riser shape as input parameters, static analysis, dynamic analysis, regular wave analysis and irregular wave analysis can be performed using certain software. Based on the analysis results, one can easily judge whether the designed riser can meet the application requirements.

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    Subsea Pipeline Appendage Finite Element Analysis and Comparison of Different Checking Criteria
    Jie ZHANG, Guo-min SUW, Hong-qi MA, Guo-yang LAN
    2015, 2 (2):  93-98. 
    Abstract ( 422 )   HTML ( 0 )   PDF (2594KB) ( 273 )  

    Subsea pipeline system consists of pipelines, risers, spools and appendages. For pipelines and risers, special softwares is used for analysis and design; for the appendages, common finite element analysis (FEA) software is used. We use the ANSYS software to do the analysis for appendages. Considering the real load of the appendages, FEA model is built, and the stress distribution is obtained. According to DNV-OS-F101 code and ASME Ⅷ Div2 code, stress checking is carried out to estimate if the appendages can meet the requirements and ensure the safe operation. Besides, the comparison between the two checking criteria can provide a reference for future projects.

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    Study on Failure Mechanism and Countermeasures of Two-Way Shock Absorber in Ocean Drilling
    Jia-lin TIAN, Chuan-hong FU, Ming-jian DONG, Zheng-lian LIU, Xiao-kang LONG, Jian FANG, Chun-ming WU
    2015, 2 (2):  99-104. 
    Abstract ( 147 )   HTML ( 0 )   PDF (2270KB) ( 220 )  

    In view of the deficiencies in the study of two-way shock absorber in marine oil and gas drilling and its abnormal failure, the failure mechanism is analyzed based on the structural principle of two-way shock absorber and field use. On the basis of the analysis, a series of feasible measures are established. The results show that the main causes leading to two-way shock absorber's failure include seal failure, thread failure, loosening between spindle and outer cylinder, and the design defects of nine-thread. Accordingly, avoiding artificial damage, preventing seal failure, strengthening supervision of all positions and improving the nine-thread structure are reasonable choices to avoid shock absorber failure. The conclusions are helpful to effectively reduce the risk of shock absorber failure and the failure probability, which are of great significance to improving production speed and drilling safety.

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