Abstract: [Purposes] In order to monitor and analyze the characteristics and responses of surface deformation during CO₂ injection at a carbon storage area in Tangshan,Hebei,and to ensure the safe operation of the CCS project.[Methods] This study utilizes 113 descending orbit Sentinel-1A time-series SAR images to extract surface deformation information based on the SBAS-InSAR technique,and analyzes the spatiotemporal characteristics of the deformation in conjunction with engineering background data.Quantification of the surface deformation impact induced by CO₂ injection is conducted using LOWESS trend separation and the Mann-Whitney U test.[Findings] The results show that subsidence was the dominant deformation pattern in the study area,with both its rate and cumulative magnitude within safe limits.CO₂ injection induced a diffuse spreading deformation pattern without significant impact on overall stability,although a marked negative step-change occurred around the injection well surrounding the CO₂ leakage.[Conclusions] This methodology provides a long-term and continuous deformation monitoring solution for carbon storage areas,addressing the spatiotemporal limitations of traditional measurement techniques,and offers technical support for engineering safety assessments.

Key words: carbon capture and storage, SBAS-InSAR technology, time-series analysis, LOWESS trend separation, Mann-Whitney U test