| 講演要旨(和文) | | 地熱坑井で使用可能な耐熱性能の高い光ファイバを受振器として使用した分布型音響センシングによるVSP（DAS-VSP）実験が木地山地域において実施された。本実験では同時に取得された地表弾性波探査（SSP）との比較を通じ、坑井近傍の断裂系イメージング手法としてDAS-VSPの優れた性能が示されたほか、SSPとの組み合わせることで解析精度が向上する相乗効果が得られることが明らかとなった。 |
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| | 講演要旨(英文) | | Confirming the effectiveness of the distributed acoustic sensing (DAS) as a borehole seismic tool for geothermal wells, we conducted a field test of the vertical seismic profiling using DAS (DAS-VSP) and the surface seismic profiling (SSP) at the Kijiyama geothermal field in 2018. The DAS-VSP data having 26 shots and 215 receivers and the SSP data having 166 shots and 171 receivers were processed in the following steps. First, we applied a 3-D traveltime tomography using both first-arrival data. Second, we created a migration velocity model based on the tomogram. Third, we applied a pre-stack depth migration for each datasets. The results showed not only a notable DAS-VSP's advantage for high-resolution imaging, but a significant synergy between DAS-VSP and SSP for improving each image. |
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