石油学报 ›› 2019, Vol. 40 ›› Issue (4): 482-492.DOI: 10.7623/syxb201904010

• 石油工程 • 上一篇    下一篇

考虑温度影响的水下井口疲劳损伤计算方法

畅元江1, 王健1, 李家仪1, 聂振宇1, 张伟国2, 许亮斌3, 刘秀全1, 陈国明1   

  1. 1. 中国石油大学(华东)海洋油气装备与安全技术研究中心 山东青岛 266580;
    2. 中海石油深海开发有限公司 广东深圳 518067;
    3. 中海油研究总院有限责任公司 北京 100028
  • 收稿日期:2018-08-29 修回日期:2019-01-29 出版日期:2019-04-25 发布日期:2019-05-07
  • 通讯作者: 畅元江,男,1974年10月生,1995年获石油大学(华东)学士学位,2008年获中国石油大学(华东)博士学位,现为中国石油大学(华东)机电工程学院副教授、硕士生导师,主要从事海洋石油装备及其安全可靠性研究。Email:changyj@upc.edu.cn
  • 作者简介:畅元江,男,1974年10月生,1995年获石油大学(华东)学士学位,2008年获中国石油大学(华东)博士学位,现为中国石油大学(华东)机电工程学院副教授、硕士生导师,主要从事海洋石油装备及其安全可靠性研究。Email:changyj@upc.edu.cn
  • 基金资助:

    国家重点基础研究发展计划(973)"深水海底井口-隔水管-平台动力学耦合机理与安全控制"(2015CB251203)和国家科技重大专项"深水隔水管-水下井口全寿命完整性技术及工程应用"(2016ZX05028-001-05)资助。

Calculation method of subsea wellhead fatigue damage considering thermal effect

Chang Yuanjiang1, Wang Jian1, Li Jiayi1, Nie Zhenyu1, Zhang Weiguo2, Xu Liangbin3, Liu Xiuquan1, Chen Guoming1   

  1. 1. Centre for Offshore Engineering and Safety Technology, China University of Petroleum, Shandong Qingdao 266580, China;
    2. CNOOC Deep Sea Development Co., Ltd., Guangdong Shenzhen 518067, China;
    3. CNOOC Research Institute Company Limited, Beijing 100028, China
  • Received:2018-08-29 Revised:2019-01-29 Online:2019-04-25 Published:2019-05-07

摘要:

水下井口系统与隔水管系统共同构成连接平台与地下油藏的通道。钻井、完井、修井作业过程中泥浆循环导致井筒温度发生变化,并且平台运动、波浪等产生的循环动载荷通过隔水管作用于水下井口,造成水下井口疲劳损伤。首先建立深水井筒温度场计算模型,将温度场计算得到的井筒温度分布施加于水下井口精细有限元模型,采用局部等效方法得到水下井口的等效梁模型,把等效梁模型作为子模型代入隔水管-井口耦合模型中进行水下井口动态响应和疲劳损伤计算,研究泥浆循环作业过程中井筒温度对水下井口疲劳热点处疲劳损伤的影响,并研究不同水泥环返高对水下井口疲劳损伤的影响。结果表明,对于水泥环返高无缺陷的水下井口,50 h内不考虑温度影响时最大疲劳损伤发生在导管接头处,其值为1.00×10-2;考虑温度影响时最大疲劳损伤发生在套管接头处,其值为3.59×10-2。当水泥环返高缺陷分别为-2 m和-5 m时,与水泥环返高无缺陷相比,套管(接头和焊缝)的疲劳损伤减小,而导管(接头和焊缝)的疲劳损伤增加,最大损伤均发生在套管接头处,其值分别为3.55×10-2和3.48×10-2

关键词: 水下井口系统, 井筒温度场, 局部等效模型, 疲劳损伤, 水泥环返高

Abstract:

The subsea wellhead and drilling riser system form a channel connecting the floating platform and underground reservoir resources. Mud circulation during the drilling, completion and workover operations results in the variation of wellbore temperature. The subsea wellhead is subjected to circulation dynamic loading caused by platform movement and waves and currents loads through the risers, leading to fatigue damage in it. Firstly, the calculation model of deep-water wellbore temperature field is established to obtain the wellbore temperature which is applied to the fine finite element model of the subsea wellhead. Secondly, the equivalent beam model of subsea wellhead is achieved by using local equivalent method, and is then substituted into the riser-wellhead coupling model for dynamic response analysis and fatigue damage calculation as a sub-model. Finally, the influence of wellbore temperature on the fatigue damage of subsea wellhead at fatigue hotspot during mud circulation operation process is researched, and also the influence of different cement level on fatigue damage of subsea wellhead is investigated. The results show that, for the subsea wellhead without cement defect, the maximal fatigue damage will be 1.00×10-2 in 50 h when the temperature effect is not taken into account, which occurs at the conductor connector of the subsea wellhead. While the maximal fatigue damage will be 3.59×10-2 in the same time duration, which occurs at casing connector when temperature effect is considered. When the defect of cement top is -2 m and -5 m, respectively, compared with cement defect, the fatigue damage at the casing (connector and weld)will decrease, while that of the conductor (connector and weld)will increase. The maximal damage of the subsea wellhead will be 3.55×10-2 and 3.48×10-2, which both occur at the casing connector.

Key words: underwater wellbore system, wellbore temperature field, local equivalence model, fatigue damage, cement level

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