Effectiveness of audio magnetotelluric sounding for detecting gas hydrate in permafrost regions
FANG Hui1, 2, PEI Fa-Gen1, 2, HE Mei-Xing1, 2, BAI Da-Wei1, 2, HU Xiang-Yun3, ZHONG Qing1, 2, DU Bing-Rui1, 2, ZHANG Xiao-Bo1, 2, LU Jing-Qi1, 2
1. Electromagnetic Detection Technology Key Laboratory of Ministry of Land and Resources, Langfang 065000, China; 2. Institute of Geophysical and Geochemical Exploration, CAGS, Langfang 065000, China; 3. Institute of Geophysics and Geomatics, China University of Geosciences, Wuhan 430074, China
Abstract：The permafrost area of the Tibetan Plateau has good gas hydrate ore-forming condition and prospecting vista; nevertheless, the lack of effective exploration techniques has become an serious bottleneck affecting the investigation and evaluation of land gas hydrate resources. In this paper, experimental study of the effectiveness of detection of gas hydrate by the audio magnetotelluric sounding method (AMT) was carried out, and the results show that the audio magnetotelluric sounding (AMT) method is an effective method for detecting the permafrost-associated gas hydrate. Permafrost is well developed in the study area, but the thickness varies greatly, which has a certain control over gas hydrate formation. Gas hydrate orebodies show three characteristics in electrical property. These characteristics can be used as an identification markers for gas hydrate formation. The hydrate accumulation is controlled by reverse thrust fractures (F1 and F2) on the southern margin of the depression. The fault zone is not only a gas migration channel but also a gas hydrate accumulation space. The research results have positive significance for promoting land gas hydrate exploration technology and resources investigation and evaluation in China.
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