Field demonstration experiment of MIMO type 3D directional borehole radar for geothermal exploration

• Project/Area Number: 18K05019
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 31020:Earth resource engineering, Energy sciences-related
• Research Institution: Osaka Electro-Communication University
• Principal Investigator: EBIHARA Satoshi 大阪電気通信大学, 工学部, 教授 (20301046)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Project Status: Completed (Fiscal Year 2020)
• Budget Amount: ¥4,420,000 (Direct Cost: ¥3,400,000、Indirect Cost: ¥1,020,000); Fiscal Year 2020: ¥780,000 (Direct Cost: ¥600,000、Indirect Cost: ¥180,000); Fiscal Year 2019: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000); Fiscal Year 2018: ¥2,600,000 (Direct Cost: ¥2,000,000、Indirect Cost: ¥600,000)
• Keywords: ボアホールレーダ / 地中レーダ / 指向性

Outline of Final Research Achievements

We developed a borehole radar system for the estimation of fractures and faults in 3-D space. First, we designed and developed a prototype of multiple-input and multiple-output type 3D directional borehole radar. Our field experiments with the radar ensured the estimation of the objects in the subsurface. Also, we researched critical phenomena about radar and invented some signal processing methods.

Academic Significance and Societal Importance of the Research Achievements

本研究は30～300 MHz の電磁波によって１本の坑井から離れた物体を３次元的に位置・形状推定を可能にする研究である。この技術は、地熱開発における貯留層評価、放射性廃棄物地層処分場の健全性評価や建造物建て替えの際の基礎杭調査などで活躍できる可能性がある。このような応用において、本研究により、物体からの反射波の伝搬方向推定を深度区間２０ｍ程度で、短時間で多数に配列したアンテナでレーダ計測できるシステムが実現する可能性が示唆された。これにより、地熱貯留層で坑井から20 m 程度離れた断裂の3次元イメージングの可能性が示唆された。

Research Products

• [Journal Article] 送受信ダイポールアレーを用いたボアホールレーダによる波の到来方向推定実験 (2021)
  • Author(s): 辻川裕貴, 海老原 聡, 小山幸輝, 加古智也, 山本久也
  • Journal Title: 2021年電子情報通信学会総合大会,講演論文集 Volume: 1 Pages: 193-193
• [Journal Article] 坑井内ダイポール・ループによる斜め導体円柱からの反射波測定 (2021)
  • Author(s): 小山幸輝, 海老原 聡, 山本久也, 辻川裕貴, 加古智也
  • Journal Title: 2021年電子情報通信学会総合大会講演論文集 Volume: 1 Pages: 194-194
• [Journal Article] Borehole effects on direction finding of a planar interface with an array-type directional borehole radar (2020)
  • Author(s): S. Ebihara, S. Kotani, K. Fujiwara, Y. Kimura, T. Shimomura, and R. Uchimura
  • Journal Title: 18th International Conference on Ground Penetrating Radar Volume: 1 Pages: 344-347
• [Journal Article] S11 Measurement of Dipole Antenna in a Borehole (2020)
  • Author(s): S. Ebihara, K. Okamoto, and S. Kobayashi
  • Journal Title: 18th International Conference on Ground Penetrating Radar Volume: 1 Pages: 348-351
• [Journal Article] Consideration of Oblique Incidence in 3-D Imaging of a Planar Interface with a Circular Dipole Array in an Air-filled Borehole (2020)
  • Author(s): S. Ebihara, S. Kotani, K. Fujiwara, Y. Kimura, T. Shimomura, and R. Uchimura
  • Journal Title: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing Volume: 13 Pages: 3711-3722
  • DOI: 10.1109/jstars.2020.3004479
  • Peer Reviewed / Open Access
• [Journal Article] Field Experiments to Investigate Cross-polarization Characteristics of a Dipole Array Antenna in a Water-filled Borehole (2019)
  • Author(s): S. Ebihara, K. Toyozawa and T. Hasegawa
  • Journal Title: Proceedings of the 10th edition of the biennial series of the International Workshop on Advanced Ground Penetrating Radar Volume: 2019 Pages: 1-6
  • DOI: 10.3997/2214-4609.201902583
  • Peer Reviewed
• [Journal Article] Arrival Times of Plane Waves Obliquely Incident on a Dipole Array Antenna in a Borehole (2019)
  • Author(s): S. Ebihara, S. Kotani and K. Fujiwara
  • Journal Title: IEEE Transaction on Geoscience and Remote Sensing Volume: 58 Issue: 5 Pages: 3273-3286
  • DOI: 10.1109/tgrs.2019.2951823
  • Peer Reviewed
• [Journal Article] 3-D IMAGING OF A PLANAR INTERFACE CLOSE TO A BOREHOLE WITH AN ARRAY-TYPE DIRECTIONAL BOREHOLE RADAR (2019)
  • Author(s): S. Ebihara, S. Kotani, and K. Fujiwara
  • Journal Title: Proceedings of the International Geoscience and Remote Sensing Symposium 2019 (IGARSS 2019) Volume: 印刷中
  • Peer Reviewed
• [Journal Article] Consideration of Oblique Incidence in Planar Interface Measurement with a Dipole Array Antenna of Directional Borehole Radar (2018)
  • Author(s): S. Ebihara, S. Kotani, and K. Fujiwara
  • Journal Title: Proceedings of the 13th SEGJ International Symposium Volume: 1 Pages: 1-4
  • Peer Reviewed