• Geophysics and Geophysical Exploration
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• v.26 no.2
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• pp.52-61
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• 2023

The use of ultra-high-resolution (UHR) seismic surveys to preceisly characterize coastal and shallow structures have increased recently. UHR surveys derive a spatial resolution of 3.125 m using a high-frequency source (80 Hz to 1 kHz). A digital streamer system is an essential module for acquiring high-quality UHR seismic data. Localization studies have focused on reducing purchase costs and decreasing maintenance periods. Basic performance verification and application tests of the developed streamer have been successfully carried out; however, a comparative analysis with the existing benchmark model was not conducted. In this study, we characterized data obtained by using a developed streamer and a benchmark model simultaneously. Tamhae 2 and auxiliary equipment of the Korea Institute of Geoscience and Mineral Resources were used to acquire 2D seismic data, which were analyzed from different perspectives. The data obtained using the developed streamer differed in sensitivity from that obtained using benchmark model by frequency band.However, both type of data had a very high level of similarity in the range corresponding to the central frequency band of the seismic source. However, in the low frequency band below 60 Hz, data obtained using the developed streamer showed a lower signal-to-noise ratio than that obtained using the benchmark model.This lower ratio can hinder the quality in data acquisition using low-frequency sound sources such as cluster air guns. Three causes for this difference were, and streamers developed in future will attempt to reflect on these improvements.

• Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
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• 2010.06a
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• pp.105-109
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• 2010

전 세계적으로 육상자원의 고갈로 해양광물을 개발하고 이를 경제적으로 활용하려는 움직임이 점점 증가하고 있다. 이에 우리나라도 한반도 주변 해역의 해양광물자원을 확보하기 위한 탐사와 연구가 진행 중에 있다. 특히 우리나라는 삼면이 바다로 둘러싸인 지형학적 특정으로 주변국과의 자원경쟁이 불가피하여 전략적 체계적 탐사자료의 관리와 이를 활용하기 위한 방안이 필요하다. 하지만 탐사 분야가 다양하고 그에 따른 데이터가 상이하여 관리에 어려움이 있다. 현재 국내에서 해양자원에 대한 정밀탐사가 이루어지고 과학적인 정보제공이 요구됨에 따라 해양광물자원정보시스템이 구축 운영되고 있지만 몇 가지 제약점이 존재한다. 따라서 본 연구에서는 이를 보완하기 위해 특히 시추 퇴적물 탐사 분야에 있어 GIS기반의 표출 가능한 대상항목을 분류하였고, 데이터베이스 구축을 위한 모델링을 진행하였다. 이는 위치기반의 분석결과 자료를 제시할 수 있도록 하였다 본 연구는 해저 퇴적층에 분야의 과학적 정보 제공을 위한 기반을 마련하였다는데 의의가 있다. 또한, 한반도 주변에 해양광물자원의 부존 가능 지역을 파악하는데 있어 과학적 정보를 지원하고 나아가 광물자원의 매장량 추정이나 경제성 평가를 위한 정보제공의 기반이 될 것으로 사료된다. 향후 연구에서는 시추퇴적물의 깊이에 따른 데이터베이스 관리 방안과 더불어 3차원 정보 제공에 대한 연구와 모델링 결과를 통해 실제 데이터에이스 구축이 진행되어야 할 것이다.

• Economic and Environmental Geology
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• v.38 no.4 s.173
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• pp.395-409
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• 2005

To explore submarine groundwater discharge (SGD) into the coastal zone of Jeju Island, the water quality analysis with seasonal remotely sensed data was carried out. If the groundwater is directly discharged into the ocean, the water quality of coastal zone is influenced. Therefore sea surface temperature (SST), the transparency, and Chlorophyll-a's concentration were analyzed for extracting the anomaly zone related with SGD using Landsat Thematic Mapper (TM) data acquired on April, August, and December. Then the spatial characteristics of springs, which located along the coastal area, were analyzed by CIS data integration based on Fuzzy logic. The integration results were compared with the anomaly zone extracted from Landsat TM data, and it is considered that springs has close relationship with SGD.

• 한국신재생에너지학회:학술대회논문집
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• 2005.06a
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• pp.626-629
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• 2005

새로운 에너지 자원으로 활용 가능성을 포함하고 있는 가스 하이드레이트를 조사하기 위해 한국지질자원연구원에서는 동해일원에서 탄성파탐사를 실시하고 있다. 탄성파 반사자료로부터 가스 하이드레이트 부존여부를 확인하는 방법은 해저면과 평행하면서 위상이 반대로 나타나는 고진폭 반사파 BSR (Bottom Simulating Reflect ion)과 BSR 상부에서의 진폭감소, 하부에서 진폭증가와 구간속도 감소 등을 들 수 있다. 그러나 고진폭 반사파는 free gas 또는 실리카를 포함하는 퇴적층에서도 발생하므로 이를 구별할 수 있는 방법이 필요하다. 여기에서는 가스 하이드레이트 탐사자료에 대한 일반자료처리와 함께 가스층 존재 유무를 확인하는 방법으로 많이 이용되는 탄성파 복소분석법을 적응하였다. 가스 하이드레이트 부존 유망지역에 대해 순간진폭, 순간진폭에 대한 1차, 2차 미분, 순간위상, 순간주파수 단면도를 제작하여 중합단면도와 비교하였으며 그 결과 순간진폭단면도의 경우 강한 BSR이 나타나는 지층경계면에서 순간진폭변화 차이를 강하게 보였으며, 순간주파수 단면도의 경우 BSR지역에서 고주파에서 저주파수로 변화함을 확인할 수 있었다.

• Economic and Environmental Geology
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• v.47 no.6
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• pp.673-681
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• 2014

Recently, many countries in the world try to develop alternative energy sources, however, traditional hydrocarbon resources are still occupying most of the energy resources. Exploration demands for high technologies are increasing in the development of limited oil & gas resources field owing to the exhaustion of hydrocarbon resources for access area. Therefore, an effort for the development and the application of new technologies such as azimuth seismic survey, ocean-bottom seismic survey and marine controlled-source electromagnetic survey is necessary as well as an understanding of the existing technologies such as 2D/3D seismic survey. This dissertation is designed with the purpose of introducing marine hydrocarbon exploration technologies and analyzing their internalexternal researches, development and science information. In this study, we analised total 616 dissertations for the marine petroleum exploration released in the Sci-expanded DB of 'web of science' during the 2001~2014 periods.

• Geophysics and Geophysical Exploration
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• v.2 no.4
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• pp.184-190
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• 1999

A study of gas hydrate is a worldwide popular interesting subject as a potential energy source. A seismic survey for gas hydrate have performed over the East sea by the KIGAM since 1997. General indicators of natural submarine gas hydrates in seismic data is commonly inferred from the BSR (Bottom Simulating Reflection) that occurred parallel to the see floor, amplitude decrease at the top of the BSR, amplitude Blanking at the bottom of the BSR, decrease of the interval velocity, and the reflection phase reversal at the BSR. So the seismic data processing for detecting gas hydrates indicators is required the true amplitude recovery processing, a accurate velocity analysis and the AVO (Amplitude Variation with Offset) analysis. In this paper, we had processed the field data to detect the gas hydrate indicators, which had been acquired over the East sea in 1998. Applied processing modules are spherical divergence, band pass filtering, CDP sorting and accurate velocity analysis. The AVO analysis was excluded, since this field data had too short offset to apply the AVO analysis. The accurate velocity analysis was performed by XVA (X-window based Velocity Analysis). This is the method which calculate the velocity spectrum by iterative and interactive. With XVA, we could determine accurate stacking velocity. Geobit 2.9.5 developed by the KIGAM was used for processing data. Processing results say that the BSR occurred parallel to the sea floor were shown at $367\~477m$ depths (two way travel time about 1800 ms) from the sea floor through shot point 1650-1900, the interval velocity decrease around BSR and the reflection phase reversal corresponding to the reflection at the sea floor.

• Geophysics and Geophysical Exploration
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• v.22 no.2
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• pp.62-71
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• 2019

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.

• Geophysics and Geophysical Exploration
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• v.26 no.4
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• pp.199-210
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• 2023

The physical properties of rocks in reservoirs change after CO₂ injection, we modeled a reservoir with a transition zone within which the physical properties change linearly. The function of the Wolf reflection coefficient consists of the velocity ratio of the upper and lower layers, the frequency, and the thickness of the transition zone. This function can be used to estimate the thickness of a reservoir or seafloor transition zone. In this study, we propose a method for predicting the thickness of the transition zone using deep learning. To apply deep learning, we modeled the thickness-dependent Wolf reflection coefficient on an artificial transition zone formation model consisting of sandstone reservoir and shale cap rock and generated time-frequency spectral images using the continuous wavelet transform. Although thickness estimation performed by comparing spectral images according to different thicknesses and a spectral image from a trace of the seismic stack did not always provide accurate thicknesses, it can be applied to field data by obtaining training data in various environments and thus improving its accuracy.

• The Science & Technology
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• v.9 no.8 s.87
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• pp.23-27
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• 1976

우리나라에서 본격적으로 물리탐사를 시도한것은 1958~1960년에 실시한 항공자력탐사로서 그후 현재까지 불과 20년이 지나지 않았다. 그간 물리탐사의 기술발전으로 자원탐사분야에 많은 공헌이 있었다. 현재까지 주로 적용된 분야는 철자원탐사를 위한 자력탐사, 지하수조사를 위한 전기비저항탐사동, 연등의 통화금속광물탐사를 위한 각종 전기탐사, 제3기층 지질구조와 땜공사, 공업단지조성등의 기반암조사, 그리고 광산의 갱내 출수조사등을 위한 탄성파탐사, 우라늄자원을 위한 방사능탐사, 그리고 해저지질 및 자원조사를 위한 해상물리탐사등이다. 이와 동시에 석탄층조사를 위한 전기탐사 및 Model연구자력탐사의 전산처리 적용, 그리고 광물 및 암석의 물리적 성질등 학술분야에 대한 기초연구도 계속하여 왔다. 우리나라에 있어 물리탐사의 적용조건은 비교적 험악한 지형, 복잡한 지질구조, 광상의 불규칙 또는 소규모의 발달과 산재등이다. 이와 같은 특징은 탐사해석의 정도를 높이기 위하여 보다 고도의 과학기술문제의 해결을 요구하고 있으며 이와 동시에 현대적 탐사방법과 연구개발로 대상자원의 탐사지역확대와 지하심부 탐사등이 당면과제이다. 기술과제로서는 석탄 및 기타자원에 대한 물리검층탐사, 경상계 지질구조구명을 위한 탄성파탐사 및 동력탐사의 적용, 항공자력, 전자 및 방사능탐사 및 해양의 각종물리탐사의 기술개발이 있으며 그외 탐사자료의 전산처리기술 및 지구과학의 기초연구등이 있다.

• Journal of the Korean Geophysical Society
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• v.9 no.4
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• pp.311-320
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• 2006

Digital filters designed using wavelet theory are applied to bathymetry data acquired from KR5 area of Korea Deepsea Mining Area. The filters used in this study are the linear B-spline wavelet filter and derivative of a Cubic B-spline filter. With proper tuning of the digital filters, we can identify the location and orientation of the abyssal hill and abyssal trough in bathymetry. These features obtained from the digital filters are well correlated with bathymetric image. This quantitative information, which can be used to understand the underlying geophysical processes, can be further processed to obtain the spacing, orientation and distribution of the abyssal hill. This wavelet analysis of bathymetry provides good data to select the mining site.