海上CCS井固井关键技术探讨

Discussion on Key Cementing Technology of Offshore CCS Well

碳捕集与封存(CCS)技术是减少温室气体排放、延缓气候变暖的有力手段。通过注入井将CO_(2)注入至地下储层是海上CCS项目的重要环节。固井水泥环作为井筒与CO_(2)储层间的第一级屏障,在注入井的井筒完整性中发挥着重要作用。因此,良好固井作业及水泥体系设计是CCS项目可持续运行的重要保障。从固井水泥体系性能及固井工艺方面论述了海上CCS项目中注入井固井工程关键技术;分析了硅酸盐水泥及非硅酸盐水泥在CCS井环空密封中的适用性;指出了在典型CCS井工况下,水泥石力学性能的设计要求及改进思路;最后针对海上CCS井提出了相关的固井工艺措施。研究成果有助于指导海上CCS井固井工作、提高固井质量,从而有效保障碳封存井的井筒完整性。

Carbon capture and storage(CCS)technology is a powerful means to reduce greenhouse gas emissions and slow down climate warming.It is an important step in offshore CCS projects by injecting CO2 into underground reservoirs through injection wells.As the primary protection between the wellbore and the CO2 reservoir,cement plays an important role in the integrity of the injection well.Therefore,better cementing operation and cement slurry design is an important assurance for sustainable operation of CCS projects.This paper discusses the key technologies of injection well cementing engineering in offshore CCS project from the aspects of cement system performance and cementing process,analyzes the applicability of Portland cement and non-Portland cement in the annulus seal of CCS well,points out the design requirements and improvement ideas of mechanical properties of cement-sheath under typical CCS well working conditions,and proposes well cementing process for offshore CCS wells.The results can help guide the filed cementing process of offshore CCS wells and improve the quality of well cementing,so as to effectively ensuring the integrity of carbon sequestration wells.