Hcable for Time-Lapse Seismic Monitoring of Marine Carbon Capture and Storage

To ensure project safety and secure public support, an integrated and comprehensive monitoring program is needed within a carbon capture and storage (CCS) project. Monitoring can be done using many well-established techniques from various fields, and the seismic method proves to be the crucial one. This method is widely used to determine the CO₂ distribution, image the plume development, and quantitatively estimate the concentration. Because both the CO₂ distribution and the potential migration pathway can be spatially small scale, high resolution for seismic imaging is demanded. However, obtaining a high-resolution image of a subsurface structure in marine settings is difficult. Herein, we introduce the novel Hcable (Harrow-like cable system) technique, which may be applied to offshore CCS monitoring. This technique uses a high-frequency source (the dominant frequency>100 Hz) to generate seismic waves and a combination of a long cable and several short streamers to receive seismic waves. Ultrahigh-frequency seismic images are achieved through the processing of Hcable seismic data. Hcable is then applied in a case study to demonstrate its detailed characterization for small-scale structures. This work reveals that Hcable is a promising tool for time-lapse seismic monitoring of oceanic CCS.