CO2 Injection Deformation Monitoring Based on UAV and InSAR Technology: A Case Study of Shizhuang Town, Shanxi Province, China

Abstract

Carbon Capture, Utilization and Storage, also referred to as Carbon Capture, Utilization and Sequestration (CCUS), is one of the novel climate mitigation technologies by which CO2 emissions are captured from sources, such as fossil power generation and industrial processes, and further either reused or stored with more attention being paid on the utilization of captured CO2. In the whole CCUS process, the dominant migration pathway of CO2 after being injected underground becomes very important information to judge the possible storage status as well as one of the essential references for evaluating possible environmental affects. Interferometric Synthetic Aperture Radar (InSAR) technology, with its advantages of extensive coverage in surface deformation monitoring and all-weather traceability of the injection processes, has become one of the promising technologies frequently adopted in worldwide CCUS projects. In this study, taking the CCUS sequestration area in Shizhuang Town, Shanxi Province, China, as an example, unmanned aerial vehicle (UAV) photography measurement technology with a 3D surface model at a resolution of 5.3 cm was applied to extract the high-resolution digital elevation model (DEM) of the study site in coordination with InSAR technology to more clearly display the results of surface deformation monitoring of the CO2 injection area. A 2 km surface heaving dynamic processes before and after injection from June 2020 to July 2021 was obtained, and a CO2 migration pathway northeastward was observed, which was rather consistent with the monitoring results by logging and micro-seismic studies. Additionally, an integrated monitoring scheme, which will be the trend of monitoring in the future, is proposed in the discussion.

Review of the Monitoring Applications Involved in the Underground Storage of Natural Gas and CO2

“…The Jingbian (China) EOR site is recalled in two journal articles [38,91], while the CCS applications carried out in Shanxi province (China) with the case study of Shizhuang Town are represented with only one journal article [39], for a total of three Chinese contributions.…”

“…However, there is no mature evaluation system to determine whether InSAR technology is suitable for each UGS or CCS site. Zhang et al [39] propose eight factors that may affect gas storage monitoring using the InSAR technique: (i) vegetation coverage; (ii) topographic factor; (iii) reservoir location; (iv) land use/land cover; (v) injection/withdrawal rate; (vi) injection/withdrawal quantity; (vii) reservoir depth (theoretically, the shallower the reservoir, the better the surface deformation effect); and (viii) monitoring duration. InSAR technology is a potential monitoring method for UGS and CCS sites, but it still has limitations, especially in heavily vegetated and complex mountainous areas, e.g., [39].…”

“…InSAR and seismic data are two measurement approaches that can be analyzed for obtaining a more specific result about reservoir displacement and subsidence investigation [38]. Other useful techniques can be implemented for the integration of these analyses, e.g., unmanned aerial vehicles (UAV), e.g., [39], and global navigation satellite systems (GNSS), e.g., [35,37], allowing more specific studies of the area of interest.…”

“…Just few monitoring contributions focus on other techniques, such as seismic reflection and ambient seismic noise (9.4%), mainly used to monitor the pilot site of Ketzin located in Germany, e.g., [21,50], and the Aquistore CCS project of Weyburn (Canada), e.g., [52][53][54][55], and GPS/GNSS (6.9%), e.g., [60]. UGS activities can be dangerous because of the potential for gas leaks from pipelines, which could provoke fires or flammable clouds (flash fires) [101] and ground deformation caused by a high rate of gas injection or gas pressure [39]. In fact, methane is highly flammable when mixed with air at certain concentrations, making gas leakage at the ground surface a severe safety hazard and threat to surface infrastructure [102].…”

“…The technical contributions (14.0%) focus on (i) monitoring fault activity in the proximity of UGS facilities, e.g., the Vienna basin [40], where the tectonic fault structure of this area caused special behavior, (ii) InSAR data interpretation and impact assessment for monitoring the evolution of CCS activities though time and the detection of surface deformation induced by reservoir exploitation, e.g., [64,70], (iii) the combination of different monitoring traditional and remote-sensed data, e.g., that used to analyze In Salah CCS activities, e.g., [48], and (iv) approaches for assessing the most suitable areas to be monitored by remote-sensing data [39]. The Vienna basin [40] is particularly interesting because the area adjacent to the underground gas storage activities shows exactly the opposite phase of typical UGS vertical movements, i.e., the terrain above the underground reservoirs subsides with the injection of natural gas.…”