As an emerging seismic acquisition technology, distributed acoustic sensing (DAS) has drawn significant attention in earth science for long-term and cost-effective monitoring of underground activities. Field seismic experiments with optical fibers in a vertical seismic profile (VSP) configuration were conducted at the Newell County Facility of Carbon Management Canada in Alberta, Canada, for \({\text{CO}}_2\) injection and storage monitoring. Seismic full-waveform inversion (FWI) represents one promising approach for high-resolution imaging of subsurface model properties. In this study, anisotropic FWI with variable density is applied to the DAS-recorded walk-away VSP data for characterizing the subsurface velocity, anisotropy, and density structures, serving as baseline models for future time-lapse studies at the pilot site. Synthetic inversion experiments suggest that, without accounting for anisotropy, the inverted density structures by isotropic FWI are damaged by strong trade-off artifacts. Anisotropic FWI can provide more accurate P-wave velocity, density, and valuable anisotropy models. Field data applications are then performed to validate the effectiveness and superiority of the proposed methods. Compared to the inversion outputs of isotropic FWI, the inverted P-wave velocity by anisotropic FWI matches trend variation of the well log more closely. In the inverted density model, the \({\text{CO}}_2\) injection formation can be clearly resolved. The inverted anisotropy parameters provide informative references to interpret the structures and lithology around the target \({\text{CO}}_2\) injection zone.

作为一种新兴的地震采集技术，分布式声学传感（DAS）在对地下活动进行长期且经济有效的监测方面引起了地球科学界的广泛关注。在加拿大艾伯塔省的加拿大碳管理纽厄尔县设施中，采用垂直地震剖面 (VSP) 配置中的光纤进行现场地震实验，用于\({\text{CO}}_2\)注入和储存监测。地震全波形反演（FWI）代表了一种有前景的地下模型特性高分辨率成像方法。在本研究中，将可变密度的各向异性 FWI 应用于 DAS 记录的无人值守 VSP 数据，以表征地下速度、各向异性和密度结构，作为试点现场未来延时研究的基线模型。综合反演实验表明，在不考虑各向异性的情况下，各向同性 FWI 反演的密度结构会受到强烈的权衡伪影的破坏。各向异性 FWI 可以提供更准确的 P 波速度、密度和有价值的各向异性模型。然后进行现场数据应用以验证所提出方法的有效性和优越性。与各向同性FWI反演输出相比，各向异性FWI反演的纵波速度与测井曲线趋势变化更加吻合。在反演密度模型中，可以清楚地解析\({\text{CO}}_2\)注入地层。反演的各向异性参数为解释目标注入区\({\text{CO}}_2\)周围的结构和岩性提供了信息参考。