Geophysics and Geophysical Exploration (지구물리와물리탐사)

Korean Society of Earth and Exploration Geophysicists (한국지구물리·물리탐사학회)
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A Study on the Resistivity Structure in Central Myanmar Basin using DC Resistivity and Magnetotellurics

전기비저항 탐사와 자기지전류 탐사 자료를 이용한 미얀마 중앙분지 전기비저항 구조 연구

  • Noh, Myounggun (GEOLUX, Co. Ltd.) ;
  • Lee, Heuisoon (GEOLUX, Co. Ltd.) ;
  • Ahn, Taegyu (GEOLUX, Co. Ltd.) ;
  • Jang, Seonghyung (Korea Institute of Geoscience and Mineral Resources, Petroleum and Marine Division) ;
  • Hwang, InGul (Korea Institute of Geoscience and Mineral Resources, Petroleum and Marine Division) ;
  • Lee, Donghoon (Korea Institute of Geoscience and Mineral Resources, Petroleum and Marine Division) ;
  • Hwang, Seho (Korea Institute of Geoscience and Mineral Resources, Geologic Environment Division)
  • 노명근 ((주)지오룩스) ;
  • 이희순 ((주)지오룩스) ;
  • 안태규 ((주)지오룩스) ;
  • 장성형 (한국지질자원연구원 석유해저연구본부) ;
  • 황인걸 (한국지질자원연구원 석유해저연구본부) ;
  • 이동훈 (한국지질자원연구원 석유해저연구본부) ;
  • 황세호 (한국지질자원연구원 지질환경연구본부)
  • Received : 2019.02.22
  • Accepted : 2019.04.29
  • Published : 2019.05.31
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Abstract

We conducted DC resistivity and MT survey to obtain the resistivity structure of the central Myanmar basin. We tried to analyze the underground structure through the resistivity variation of Myanmar by performing representative geophysical survey methods because researches on the electrical resistivity structure are insufficient in Myanmar. The electrical resistivity is expected to be low considering the marine sedimentary rocks composed of shale and sandstone in this area. The DC resistivity and MT survey were carried out using SmartRho of Geolux Co., Ltd. and MTU-5A of Phoenix geophysics Ltd., respectively, to visualize the electrical resistivity structure of study area. DC resistivity and MT survey showed an electrical resistivity less than dozens of ohm-m within the depth of 100 m. In particular, MT survey data were almost similar to TM and TE modes in the frequency range above 1 Hz. The two-dimensional inversion of MT data showed a subsurface structure with low resistivity below 150 ohm-m divided into east-west direction. We confirmed that the inversions of DC resisitivity and MT data along an overlapped survey line represented similar results. In the future, considering the high electrical conductivity, it would be effective to perform DC resistivity and MT survey simultaneously to study the electrical resistivity structure of the central Myanmar basin.

이 연구에서는 전기비저항 탐사와 자기지전류(magnetotellurics, MT) 탐사를 이용하여 미얀마 중앙분지에 대한 탐사를 수행하였다. 미얀마에서는 지하구조의 전기비저항 구조로 해석한 연구가 미흡하여 심부까지 전기비저항을 제공해 주는 대표적인 탐사를 활용하여 지하구조를 분석하였다. 연구지역 지질은 셰일층과 사암층으로 구성된 해성퇴적층으로 지하의 전기비저항 값이 낮을 것으로 예상되었다. 이 연구는 (주)지오룩스에서 자체 개발한 전기비저항 탐사 장비(SmartRho)와 Phoenix사의 MTU-5A를 사용하여 연구지역에 대한 전기비저항 구조를 영상화하였다. 전기비저항 탐사와 MT 탐사는 지하 100 m까지는 수십ohm-m 미만의 전기비저항 구조를 보였다. 특히 MT 탐사 자료에서는 1 Hz 까지 TM, TE 모드가 거의 유사한 양상을 보인다. MT 탐사 2차원 역산 결과 150 ohm-m 이하의 낮은 전기비저항 구조를 나타냈고, 동서방향으로 전기비저항 구조가 나뉘는 것을 확인할 수 있었다. MT 탐사를 전기비저항 탐사와 인접한 위치에서 수행한 결과, 2차원 역산 결과가 유사한 전기비저항 값을 나타내는 것을 확인하였다. 향후 미얀마 중앙분지의 전기비저항 구조 연구를 위해서는 높은 전기전도도를 고려하여 전기비저항 탐사와 MT 탐사를 동시 수행하는 것이 효과적일 것으로 생각된다.

Keywords

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Fig. 1. Tectonic structure of central basin (Rangin, 2017) and DC resistivity measurement line (white dotted line) and MT measurement station(yellow circle). Red dotted box shows the study area.

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Fig. 2. Pictures of study area. (a) view of MT survey site (b) picture of DC resistivity site (c) view of non-polarizable electrode installed (d) view of sucker rod pump installed.

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Fig. 3. Electrode elevation measured by GPS.

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Fig. 4. Inversion result of DC resistivity survey.

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Fig. 5. Inversion result of DC resistivity survey considering topographic effect.

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Fig. 6. Result of data editing and coherency analysis using P8 data. (a) Data editing and (b) coherency.

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Fig. 7. Polar diagrams of principal direction estimated with MT and AMT data at P7 according to frequency intervals. (a) 0.1 ~ 1 Hz, (b)1 ~ 10 Hz, (c) 10 ~ 100 Hz and (d) 100 ~ 1000 Hz.

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Fig. 8. Results of MT survey. (a) Apparent resistivity of P6, (b) phase of P6, (c) apparent resistivity of P11 and (d) phase of P11.

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Fig. 9. Two-dimensional inversion result of MT survey. White dotted line indicates a fault.

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Fig. 10. Comparison of 2D inversion results of DC resistivity and MT survey.

Table 1. Location and length of electrode field of MT stations.

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References

  1. Chhibber, H. L., 1934, The Geology of Burma. MacMillan, London, 320p.
  2. Cho, K., 2015, Energy Status and Policy in Myanmar, WORLD ENERGY MARKET Insight Weekly, 15(2), 17-24.
  3. Go, S., 2013, Current Status of Energy Resources in Myanmar and Strategies for the Advance, Kotra news https://news.kotra.or.kr/user/globalBbs/kotranews/6/globalBbsDataView.do?setIdx=322&dataIdx=120018. (January 18, 2019 Accessed).
  4. IEA, 2014, Energy Statistics of Non-Oecd Countries (2014 edition), International Energy Agency. 764p.
  5. Ir, S. P., Kyaw, L. Z., and Kyaw, Z. L., 2010, Report on Regional Geology of Myanmar. Department of Geological Engineering Faculty of Engineeing, Gadjah Mada University, 20p.
  6. Khin, J. A., 1991, Hydrocarbon-Producing Formations of Salin, Irrawaddy, and Martaban basins, Myanmar (Burma), Society of Petroleum Engineers Asia Pacific Conference, Proceedings, 245-258.
  7. Kim, J., 1996, Dipro for windows version 4.0 manual, HeeSong-Geotech. 21-40.
  8. Lee, D., Jang, S., Hawng, S., and Chung, H., 2017, A Case Study on the Quality Management of Data Acquisition Using Cable-free Seismic Acquisition System, KSEG 2017 Spring Conference, Expanded Abstracts, 53.
  9. Lee, S., Lee, T., Uchida, T., Park, I., Song, Y., and Cull, J., 2008, Analysis of MT Data Acquired in Victoria, Australia, Muli-Tamsa, 11(3), 184-196.
  10. Lee, T., Lee, S., and Song, Y., 2006, Magnetotelluric surveys from mid-mountain area of Jeju Island for evaluating possible structures for deep-seated geothermal energy. The Korean Society for New and Renewable Energy, Proceedings, 434-437 (in Korean with English abstract).
  11. Nyein, K., Nyunt, U., Hlaing, U. S., Lyen, U. S., Maw, U. W., Lwin, S., Thein, U. O., Myint, U. L., Kyaw, U. M. M., and Win, U. M., 1996, Myanmar petrloleum geology and hydrocarbon potential, Myanmar Oil & Gas Summit, 1-26.
  12. Park, G. and Heo, C., 2014, Magnetic Data Analysis of the Chromium Mineralized Belt in Bophi Vum area, Northwestern Myanmar, Geophys. and Geophys. Explor., 17(3), 147-154 (in Korean with English abstract). https://doi.org/10.7582/GGE.2014.17.3.147
  13. Thein, M., 1993, Tectonic province of Myanmar. Monograph, Geology Department, Yangon University, Myanmar. 312p.
  14. Rangin, C., 2017, Active and recent tectonics of the Burma Platelet in Myanmar, Geological Society, London, Memoirs, 48, 53-64, https://doi.org/10.1144/M48.3
  15. Pivnik, D. A., Nahm, J., Tucker, R. S., Smith, G. O., Nyein, K., Nyunt, M., and Maung, P. H., 1998, Polyphase Deformation in a Fore-Arc/Back-Arc Basin, Salin Subbasin, Myanmar (Burma), AAPG Bulletin, 82(10), 1837-1856.
  16. Yi, M., Kim, J., and Chung, S., 2003, Enhancing the resolving power of least-squares inversion with active constraint balancing, Geophysics, 68(3), 931-941. https://doi.org/10.1190/1.1581045