[H-RE20] 地球温暖化防止と地学（CO2地中貯留・有効利用,地球工学）

[HRE20-08] 分布式光ファイバーを用いた遮蔽層や坑井健全性監視技術開発

*薛 自求¹、橋本 努¹ (1.公益財団法人　地球環境産業技術研究機構)

キーワード：二酸化炭素地中貯留、光ファイバー、健全性監視

We have been developing a new technology to monitor the caprock and wellbore integrity at CO₂ injection sites by utilizing the Distributed Fiber Optic Sensing (DFOS). DFOS has an advantage to measure temperature and strain at any point in an unprocessed optical fiber, contrary to the conventional Fiber Bragg Grating (FBG) sensing which measures temperature and strain at a limited number of discrete points along the processed fiber cable. To put the DFOS technique into the practical use at the CCS sites, we measured the frequency shifts of the Rayleigh and Brillouin scattering in an optical fiber attached to sandstone samples under hydrostatic pressure, and also measured strain of the samples by conventional strain gages simultaneously. Strains measured by optical fiber are estimated based on the frequency shifts and those strains agreed well with the strains by conventional strain gages. The experimental results demonstrated the potential use of DFOS as a promising technology for monitoring the geomechanical deformation of geological formation at the CO₂ injection site.