Wang Chenguang, Li Tianyang, Yu Tao, Feng Xiao, Liu Hanghang, Du Bingrui, Yang Yichun, Yang Linjun, Luo Yaxuan
School of Resources and Safety Engineering, Chongqing University, Chongqing 400044, China.
State Key Laboratory of Coal Mine Disaster Dynamics and Control, Chongqing University, Chongqing 400044, China.
Sensors (Basel). 2025 Mar 14;25(6):1796. doi: 10.3390/s25061796.
This study establishes a homogeneous half-space and a horizontally layered two-layer background stratigraphy model using cross-borehole electrical resistivity tomography (ERT) based on an incomplete Gauss-Newton (IGN) method to investigate the resistivity inversion characteristics of CO storage zones. The effects of storage zone volume (VCO2), storage zone resistivity (ρCO2), background formation resistivity (ρf), and CO diffusion on inversion results were systematically analyzed, and the mechanisms underlying the influence of different parameters on inversion imaging were explored. The results indicate that an increase in the VCO2 significantly affects the inverted resistivity. The ρCO2 can be well inverted within a certain range, but inversion accuracy decreases once the resistivity exceeds a threshold. The ρf is a critical factor influencing inversion results; as the ρf increases, the inverted resistivity values rise markedly, although this effect exhibits an upper limit. The study also uncovers the exponential nature of CO diffusion in the storage zone, where diffusion leads to exponential changes in resistivity and the delineation of the diffusion zone is enhanced by comparing pre- and post-injection resistivity differences. These findings offer valuable insights for CO storage monitoring, contributing to both safety assessments and the evaluation of storage stability in geological sequestration.
本研究基于不完全高斯 - 牛顿（IGN）方法，利用跨孔电阻率层析成像（ERT）建立了均匀半空间和水平分层的两层背景地层模型，以研究二氧化碳（CO₂）储存区的电阻率反演特征。系统分析了储存区体积（VCO₂）、储存区电阻率（ρCO₂）、背景地层电阻率（ρf）以及CO₂扩散对反演结果的影响，并探讨了不同参数对反演成像影响的机制。结果表明，VCO₂的增加对反演电阻率有显著影响。ρCO₂在一定范围内可以很好地反演，但一旦电阻率超过阈值，反演精度就会降低。ρf是影响反演结果的关键因素；随着ρf的增加，反演电阻率值显著上升，不过这种影响存在上限。该研究还揭示了CO₂在储存区扩散的指数性质，即扩散导致电阻率呈指数变化，并且通过比较注入前后的电阻率差异增强了扩散区的 delineation。这些发现为CO₂储存监测提供了有价值的见解，有助于地质封存中的安全评估和储存稳定性评价。
