Spatial estimates of surface deformation and topsoil moisture in operating CO2-EOR project: Pilot environmental monitoring using SAR technique

Abstract

Abstract Environmental sustainability is a mandatory consideration for Carbon Capture and Storage (CCS) project, thereby making environmental monitoring more essential. This paper aims at demonstrating the feasibility and superiority of Synthetic Aperture Radar (SAR) technique for environmental monitoring of enhanced oil recovery (EOR) project. Surface deformation and topsoil moisture are considered as the monitoring factors due to their importance to the public security and sustainability. Taking Jingbian CO 2 -EOR project as a case study, Interferometric SAR (InSAR) and Advanced Integral Equation Model (AIEM) were used for spatial estimates of surface deformation and topsoil moisture from Sentinel-1A images. The results showed that the distribution of surface deformation and topsoil moisture both manifested as spatial heterogeneity. No significantly regular uplift or subsidence trend was observed within the storage fields. The average deformation velocity of 5.63 mm yr −1 from 537 measuring points was probably determined by the trade-off between soil erosion and eolian dust deposit. Topsoil moisture was observed to associate with natural conditions, and its spatial distribution was mainly ruled by topographic factors. Areas with soil moisture below 20% covered about 3.98 km 2 , totally accounting for 77.14%. Areas with soil moisture over 20% were mostly distributed in the gully regions. In conclusion, currently, there was no large deformation trend or abnormal topsoil moisture distribution as public concerns, but long-term monitoring program is still needed for ensuring environmental sustainability. This study demonstrates that SAR technique can improve the spatial knowledge of surface deformation and topsoil moisture, which is useful for sustainability assessment of operating CO 2 -EOR project.