高温含CO_2气井的井筒完整性设计

Wellbore integrity design of high-temperature gas wells containing CO_2

高温含CO2气井(特别是海洋及深水油气井)的井筒完整性备受关注,因它涉及太多的具体技术、材料和工具及装备。为此,在深入研究挪威石油工业协会和美国石油学会最新发布的井筒完整性技术标准的基础上,结合已经取得的经验和大量的实验评价成果,重点对投产期的井筒完整性设计框架进行了研究。提出了井筒完整性设计理念,推荐了井筒腐蚀完整性管理方法及技术流程,给出了井筒安全屏障系统划分方法,从实体屏障、水力屏障、操作屏障3个方面讨论了井筒安全屏障分类和功能,以及油管柱设计及完整性管理。同时,给出了固井水泥屏障设计要求及方法,强化了井筒水力屏障对井筒完整性的作用,重点阐述了井筒的腐蚀完整性评价和管理的"适用性"理念和方法。针对海洋气井,还提出了适合的油套环空保护液,将环空保护液和水泥面之上滞留流体按水力屏障对待。

The wellbore integrity of high temperature gas wells containing CO2 （especially subsea or deepwater oil-gas wells） receives great attention since it involves various specific technologies, materials, tools and equipment. Based on an intensive study of the lat est Norwegian Oil Industry Association （OLF） and American Petroleum Institute （API） technical standards related to wellbore integrity, combined with the experiences and various experimental evaluations, a research was conducted focusing on the design frame work for wellbore integrity during production. On this basis, the concept of wellbore integrity design was first put forward, and the wellbore corrosion and integrity management method as well as technical process were then recommended. Second, the wellbore safety was classified into physical, hydraulic and operating barriers, the functions of which were also compared as well as the design and integrity management for tube strings. Third, the requirements and method were presented for designing the cementing barrier to enhance the effect of hydraulic barrier on the wellbore integrity. Moreover, the concept and method of ＂fitness-for-service＂ are particu larly discussed for assessment and management of wellbore corrosion and integrity. Finally, for subsea gas wells, a proper tubing annulus protecting fluid was introduced, and the retained fluid on the cement sheath and annulus protecting fluid are treated as the by draulic barrier. To sum up, those mentioned multiple terms or requirements can be referenced for establishing the recommended practices or a conceptual design for wellbore integrity management.