Acta Petrolei Sinica ›› 2025, Vol. 46 ›› Issue (5): 977-993.DOI: 10.7623/syxb202505010

• PETROLEUM ENGINEERING • Previous Articles    

Fatigue damage law of cement sheath based on continuum damage mechanics

Yang Huanqiang1,2, Wang Kai1,2, Cai Meng3, Wang Peng3, Zhang Nan3, Li Junliang3, Ma Wenhai3, Huang Weiming3, Li Yong1,2   

  1. 1. National Engineering Research Center for Oil & Gas Drilling and Completion Technology, Yangtze University, Hubei Wuhan 430100, China;
    2. State Key Laboratory of Low Carbon Catalysis and Carbon Dioxide Utilization (Yangtze University), Hubei Wuhan 430100, China;
    3. Oil Production Engineering Research Institute, Daqing Oilfield Limited Company, Heilongjiang Daqing 163453, China
  • Received:2024-01-11 Revised:2025-02-26 Published:2025-06-10

基于连续损伤力学的水泥环疲劳损伤规律

杨焕强1,2, 王凯1,2, 蔡萌3, 王鹏3, 张楠3, 李俊亮3, 马文海3, 黄伟明3, 李勇1,2   

  1. 1. 长江大学油气钻完井技术国家工程研究中心 湖北武汉 430100;
    2. 低碳催化与二氧化碳利用全国重点实验室(长江大学) 湖北武汉 430100;
    3. 大庆油田有限责任公司采油工艺研究院 黑龙江大庆 163453
  • 通讯作者: 杨焕强,男,1985年2月生,2015年获中国石油大学(华东)博士学位,现为长江大学石油工程学院副教授、硕士生导师,主要从事固井工程理论与技术、水泥环完整性评价与保障等方向研究。Email:yanghuanqiang@yangtzeu.edu.cn
  • 基金资助:
    中国石油天然气股份有限公司科技重大专项"二氧化碳规模化捕集、驱油与埋存全产业链关键技术研究及示范"(2021ZZ01)资助。

Abstract: Under complex pressure and temperature conditions, the fatigue damage in cement sheaths and the resulting annular pressure pose significant threats to wellbore safety. A continuous fatigue damage mechanical model of the cement sheath was constructed based on the continuum damage mechanics theories, in combination with the damage-plasticity constitutive model comprehensively considering both compression and tension states. Then a comprehensive damage factor was introduced to quantitatively evaluate the degree of fatigue damage. Focusing on the wellbore configuration and injection-production parameters of CCUS wells in Daqing oilfield, a cement bonding logging test was performed under alternating temperature and pressure conditions inside the casing by using a full-scale wellbore integrity evaluation system and an eight-sector cement bonding logging tool, thus verifying the accuracy of the model. Moreover, an investigation was conducted on the fatigue damage law of the cement sheath under CO2 cyclic injection conditions. The results show that during CO2 cyclic injection, the cement sheath damage initially increases linearly and then tends to be mitigated. At an injection-production frequency of 4 cycles per year, operation thresholds for ensuring 20-year safe operation in Daqing oilfield CCUS wells are established as below:casing internal alternating pressure and temperature fluctuation amplitude below 30 MPa and 70 ℃, respectively. Due to the coupled effects of temperature and pressure, the decrease in wellbore temperature during CO2 injection helps mitigate the fatigue damage of the cement sheath caused by an increase in casing internal pressure.

Key words: continuum damage mechanics, cement sheath, fatigue damage, CO2 cyclic injection, full-scale test, comprehensive damage factor

摘要: 水泥环在复杂压力及温度条件下发生疲劳损伤以及由此引起的环空带压,严重影响井筒安全。基于连续损伤力学理论,综合考虑水泥环压缩和拉伸两种状态的损伤塑性本构模型,构建了水泥环连续疲劳损伤力学模型,引入综合损伤因子对疲劳损伤程度进行定量评价;针对大庆油田应用二氧化碳的捕集、利用与封存(CCUS)的井筒结构及注采参数,利用全尺寸井筒完整性评价系统及八扇区水泥胶结测井仪,开展了套管内温度、压力交变的水泥胶结测井试验,以验证模型的准确性;研究了CO2循环注入工况下的水泥环疲劳损伤规律。研究结果表明,CO2循环注入时水泥环损伤初期线性增加后趋势变缓;在4次/年的注采频率下,套管内压力交变幅值小于30 MPa、套管内温度交变幅值小于70℃为大庆油田CCUS井安全生产20年的运行界限;受温度和压力的耦合作用,CO2注入时,井筒温度降低有助于减小套管内压力增大而造成的水泥环疲劳损伤。

关键词: 连续损伤力学, 水泥环, 疲劳损伤, CO2循环注入, 全尺寸试验, 综合损伤因子

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