AMT acquisition experimental study of gas hydrate exploration in the permafrost region of the Tibetan Plateau
PEI Fa-Gen1, 2, 3, HE Mei-Xing1, 2, 3, QIU Gen-Gen1, 2, 3, DU Bing-Rui1, 2, 3, BAI Da-Wei1, 2, 3
1.Electromagnetic Detection Technology Key Laboratory of the Ministry of Land and Resources,Langfang 065000,China; 2.National Modern Geological Exploration Technology Research Center,Langfang 065000,China; 3.Institute of Geophysical and Geochemical Exploration,CAGS,Langfang 065000,China
Abstract：Obtaining high-quality original data is a key step. Especially in the "dead band" (500 ~ 5000 Hz), the signal of the AMT field source which is the natural electromagnetic field is weak and the apparent resistivity and phase curve are distorted in the dead band. To obtain high-quality data in the permafrost region of the Tibetan Plateau, the authors carried out AMT acquisition experiments of the natural gas hydrate exploration. These experiments included five acquisition parameters, i.e., the acquisition range of time, the acquisition time length, the weather, the electrode length and the density of measuring points. The experiments show that, for the purpose of obtaining high-quality AMT data, the acquisition time range should be selected from the afternoon to the evening, the acquisition time length should be more than 40 minutes, a smaller electrode length (eg. 50~100 m) should be chosen, and the cloudy days are favorable. In addition, the use of high density of measuring points is helpful to building an accurate electrical model.
裴发根, 何梅兴, 仇根根, 杜炳锐, 白大为. 青藏高原冻土区AMT探测天然气水合物采集试验[J]. 物探与化探, 2017, 41(6): 1113-1120.
PEI Fa-Gen, HE Mei-Xing, QIU Gen-Gen, DU Bing-Rui, BAI Da-Wei. AMT acquisition experimental study of gas hydrate exploration in the permafrost region of the Tibetan Plateau. Geophysical and Geochemical Exploration, 2017, 41(6): 1113-1120.
[1] 李斌,赵虎,钟邱平,等.公路深埋隧道勘察中的数据采集及常见干扰解决方法[J].西南公路, 2016(3): 199-206. [2] 汤井田,任政勇,周聪,等.浅部频率域电磁勘探方法综述[J].地球物理学报, 2015, 58(8): 2681-2705. [3] 汤井田,胡双贵,肖晓. 接地电阻稳定性对音频大地电磁法测量的影响[J].物探化探计算技术, 2015, 37(5): 547-551. [4] 乔宝强,程纪星,刘祜,等.AMT野外最佳观测时间及人工源信号作用的探讨[J].铀矿地质, 2014, 30(3): 180-186. [5] 杜炳锐,何梅兴,裴发根,等.关于音频大地电磁测深在冻土区“跳点”现象研究[J].中国西部科技, 2014, 13(10): 15-17. [6] 杨承志,邓居智,陈辉,等.采集参数对音频大地电磁法二维非线性共轭梯度反演结果的影响研究[J].地球物理学进展, 2013, 28(3): 1346-1354. [7] Garcia X, Jones A G. Atmospheric sources for Audio-Magnetotelluric(AMT) sounding [J]. Geophysics, 2002, 67(2): 448-458. [8] Sternberg B K. The variability of naturally occurring magnetic field levels: 10Hz to 8kHz [J]. Geophysics, 2010, 75(6):F187-F197. [9] Schennen S, Ritter O. High frequency MT data: understanding the “dead band” between 1 and 4 kHz[C]// 22nd EM Induction Workshop. Weimar, Germany, 2014. [10] Tuncer V, Unsworth M J, Siripunvaraporn W, et al. Exploration for unconformity-type uranium deposits with audiomagnetotelluric data: A case study from the McArthur River mine, Saskatchewan, Canada [J]. Geophysics, 2006, 71(6): B201-B209. [11] Jones A G, Garcia X. Okak Bay AMT data-set case study: Lessons in demensionality and scale [J]. Geophysics, 2003, 68(1): 70-91. [12] Monteiro Santos F A, Trota A, Soares A, et al. An audio-magnetotelluric investigation in Terceira Island(Azores) [J]. Journal of Applied Geophysics, 2006, 59(4): 314-323. [13] 周聪, 汤井田, 任政勇,等. 音频大地电磁法“死频带”畸变数据的Rhoplus校正[J]. 地球物理学报, 2015, 58(12): 4648-4660. [14] 方胜. 如何保证大地电磁测深原始资料的质量[J]. 地球科学,1990(S1):12-78.
