Case study on amplitude and phase response comparison between DAS and 3C geophone VSP surveys at a test site in Japan
Distributed acoustic sensing (DAS) is an effective tool for seismic surveys and is widely used as the preferred sensor for acquiring dense Vertical Seismic Profile (VSP). However, DAS has some disadvantages compared to conventional geophone acquisition, such as single-component data, sensor directiv...
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| Format: | Article |
| Language: | English |
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Frontiers Media S.A.
2022-10-01
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| Series: | Frontiers in Earth Science |
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| Online Access: | https://www.frontiersin.org/articles/10.3389/feart.2022.991964/full |
| _version_ | 1818024495375450112 |
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| author | Takahiro Nakajima Takahiro Nakajima Takayuki Miyoshi Takayuki Miyoshi Tsutomu Hashimoto Tsutomu Hashimoto Ziqiu Xue Ziqiu Xue |
| author_facet | Takahiro Nakajima Takahiro Nakajima Takayuki Miyoshi Takayuki Miyoshi Tsutomu Hashimoto Tsutomu Hashimoto Ziqiu Xue Ziqiu Xue |
| author_sort | Takahiro Nakajima |
| collection | DOAJ |
| description | Distributed acoustic sensing (DAS) is an effective tool for seismic surveys and is widely used as the preferred sensor for acquiring dense Vertical Seismic Profile (VSP). However, DAS has some disadvantages compared to conventional geophone acquisition, such as single-component data, sensor directivity pattern, low S/N, etc. To apply DAS data to VSP processing, it is important to understand the characteristics of DAS measurements. This study first examined DAS and geophone responses for a VSP survey in a 1D earth model. The relationship of signal amplitude as a function of incident angle and phase shift between wavelets was confirmed. Next, we validated this relationship in a walk-away VSP survey, which was conventionally applied to monitor geological CO2 storage. The survey was carried out at a test site in Japan. We obtained both three-component (3C) geophone and DAS data using a single-mode fiber installed behind a casing. The observed amplitudes of the first P-waves by DAS and geophone showed very good agreement with the theoretical expectations. Finally, we performed imaging using acquired DAS data following the workflow for conventional VSP processing. These basic behaviors of DAS are useful for designing further analyses, such as VSP in deviated wells and full waveform inversion. |
| first_indexed | 2024-12-10T04:01:07Z |
| format | Article |
| id | doaj.art-5848cc0dfcc749a0ab4a41dbcaf68e49 |
| institution | Directory Open Access Journal |
| issn | 2296-6463 |
| language | English |
| last_indexed | 2024-12-10T04:01:07Z |
| publishDate | 2022-10-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Earth Science |
| spelling | doaj.art-5848cc0dfcc749a0ab4a41dbcaf68e492022-12-22T02:02:59ZengFrontiers Media S.A.Frontiers in Earth Science2296-64632022-10-011010.3389/feart.2022.991964991964Case study on amplitude and phase response comparison between DAS and 3C geophone VSP surveys at a test site in JapanTakahiro Nakajima0Takahiro Nakajima1Takayuki Miyoshi2Takayuki Miyoshi3Tsutomu Hashimoto4Tsutomu Hashimoto5Ziqiu Xue6Ziqiu Xue7Geological Carbon Dioxide Storage Technology Research Association, Kyoto, JapanResearch Institute of Innovative Technology for the Earth (RITE), Kyoto, JapanGeological Carbon Dioxide Storage Technology Research Association, Kyoto, JapanResearch Institute of Innovative Technology for the Earth (RITE), Kyoto, JapanGeological Carbon Dioxide Storage Technology Research Association, Kyoto, JapanResearch Institute of Innovative Technology for the Earth (RITE), Kyoto, JapanGeological Carbon Dioxide Storage Technology Research Association, Kyoto, JapanResearch Institute of Innovative Technology for the Earth (RITE), Kyoto, JapanDistributed acoustic sensing (DAS) is an effective tool for seismic surveys and is widely used as the preferred sensor for acquiring dense Vertical Seismic Profile (VSP). However, DAS has some disadvantages compared to conventional geophone acquisition, such as single-component data, sensor directivity pattern, low S/N, etc. To apply DAS data to VSP processing, it is important to understand the characteristics of DAS measurements. This study first examined DAS and geophone responses for a VSP survey in a 1D earth model. The relationship of signal amplitude as a function of incident angle and phase shift between wavelets was confirmed. Next, we validated this relationship in a walk-away VSP survey, which was conventionally applied to monitor geological CO2 storage. The survey was carried out at a test site in Japan. We obtained both three-component (3C) geophone and DAS data using a single-mode fiber installed behind a casing. The observed amplitudes of the first P-waves by DAS and geophone showed very good agreement with the theoretical expectations. Finally, we performed imaging using acquired DAS data following the workflow for conventional VSP processing. These basic behaviors of DAS are useful for designing further analyses, such as VSP in deviated wells and full waveform inversion.https://www.frontiersin.org/articles/10.3389/feart.2022.991964/fulldistributed acoustic sensing (DAS)DAS sensitivityrelationship between DAS and geophonewalk-away VSPmonitoring by DAS |
| spellingShingle | Takahiro Nakajima Takahiro Nakajima Takayuki Miyoshi Takayuki Miyoshi Tsutomu Hashimoto Tsutomu Hashimoto Ziqiu Xue Ziqiu Xue Case study on amplitude and phase response comparison between DAS and 3C geophone VSP surveys at a test site in Japan Frontiers in Earth Science distributed acoustic sensing (DAS) DAS sensitivity relationship between DAS and geophone walk-away VSP monitoring by DAS |
| title | Case study on amplitude and phase response comparison between DAS and 3C geophone VSP surveys at a test site in Japan |
| title_full | Case study on amplitude and phase response comparison between DAS and 3C geophone VSP surveys at a test site in Japan |
| title_fullStr | Case study on amplitude and phase response comparison between DAS and 3C geophone VSP surveys at a test site in Japan |
| title_full_unstemmed | Case study on amplitude and phase response comparison between DAS and 3C geophone VSP surveys at a test site in Japan |
| title_short | Case study on amplitude and phase response comparison between DAS and 3C geophone VSP surveys at a test site in Japan |
| title_sort | case study on amplitude and phase response comparison between das and 3c geophone vsp surveys at a test site in japan |
| topic | distributed acoustic sensing (DAS) DAS sensitivity relationship between DAS and geophone walk-away VSP monitoring by DAS |
| url | https://www.frontiersin.org/articles/10.3389/feart.2022.991964/full |
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