CO2封存井筒密封性及强化方法
CO2 Sequestration Wellbore Sealing and Enhancement Method
王典 1李军 2连威 3刘献博 1张俊成 1郭少坤1
作者信息
- 1. 中国石油大学(北京)石油工程学院,北京 102200
- 2. 中国石油大学(北京)石油工程学院,北京 102200;中国石油大学(北京)克拉玛依校区石油学院,克拉玛依 834000
- 3. 中国石油大学(北京)克拉玛依校区石油学院,克拉玛依 834000
- 折叠
摘要
考虑CO2封存井筒的实际服役环境,基于有限元方法建立了含水泥腐蚀层的井筒屏障模型,模拟了水泥塞-地层界面微环隙发育过程,厘清了流体驱动下微环隙扩展机制及主控因素,提出了井筒密封性强化方法.模拟结果表明:超临界CO2聚积会引起水泥胶结面应力改变,当界面处应力由压应力转为拉应力,且应力值高于界面胶结强度时,井筒便会产生微环隙;若水泥腐蚀后腐蚀层刚度、界面胶结强度下降,则井筒密封能力下降;膨胀性添加剂可提高胶结面初始压应力,进而增强井筒密封性.当水泥塞膨胀率为0.5‰时,微环隙扩展压力上升43.7％,微环隙长度下降了 42.7％,井筒密封性得到显著增强.
Abstract
Considering the service environment of the CO2 sequestration wellbore,a wellbore model containing a cement corrosion layer was developed.Based on the finite element method,the development process of micro-annu-lus at the cement plug-formation interface was simulated,the mechanism of micro-annulus expansion and the main controlling factors under the fluid drive were clarified,and the method of wellbore sealing enhancement was pro-posed.The simulation results show that the supercritical CO2 accumulation will cause a change in the stress at the cement bonding surface.When the stress at the interface changes from compressive to tensile,and the stress value is higher than the bonding strength,micro-annulus will be generated in the wellbore.If the cement stiffness and bonding strength decrease after corrosion,the wellbore sealing decreases;the expansive additive can increase the initial compressive stress of the bonding surface and then enhance the wellbore sealing.When the expansion rate is 0.5‰,the micro-annulus propagation pressure rises by 43.7％,the micro-annulus length decreases by 42.7％,and the wellbore sealing is significantly enhanced.
关键词
CO2封存井筒/密封性/微环隙/水泥塞/强化方法Key words
CO2 sequestration wellbore/sealing/micro-annulus/cement plug/enhancement method引用本文复制引用
基金项目
国家自然科学基金联合基金项目(U23B2081)
中石油科技创新基金项目(2022DQ02-0605)
出版年
2024
NETL
NSTL
万方数据