[H-SC07] CCUS (Carbon Dioxide Capture, Utilization, and Storage) for Climate Mitigation

[HSC07-P05] Feasibility of Distributed Fiber Optic Vibration Sensing for seismicity monitoring

*Takayuki Miyoshi¹, Takahiro Nakajima¹, Ziqiu Xue¹ (1.Research Institute of Innovative Technology for the Earth)

Keywords:Geological CO2 Storage, Fiber Optic Sensing, Seismicity

Geological CO₂ storage requires long-term monitoring not only for a plume of injected CO₂ but also area of pressure/strain propagation far away from the plume. The Distributed Fiber Optic Sensing (DFOS) is one of the major technologies capable of acquiring spatially continuous recording. The optical fibers for vibration sensing are used as receivers for the 4D VSP (Vertical Seismic Profiles) techniques in order to image the plume of injected CO₂, and also as passive seismometers for natural/induced seismicity. The sensitivity of optical fibers is not as good as typical geophones/seismometers. We conducted the long-term observation for natural earthquakes using the strain-sensing fiber cables installed behind the casing along the vertical wellbore in order to evaluate the sensitivity of the fiber cables.

A single channel record of the fiber optical sensing captured the ground motion of relatively large earthquake events. Whereas, the earthquake events within 20 km epi-distance listed on the JMA website location were all detected using the fiber records along the 880m well. Considering to the area of monitoring in the geological CO₂ storage (~10km), the fiber optic vibration sensing is one of the feasible options for seismicity monitoring.