我国深地资源电磁探测新技术研究进展

New development of the Electromagnetic(EM)methods for deep exploration

诸多研究表明我国深部资源潜力巨大,但目前的开发开采深度普遍停留在500m以浅,开展"攻深探盲"是构建国家资源安全体系的有效途径.应用最先进的科学技术手段,提取深部地质信息,已成为我国当前地球物理科学研究的发展方向.作为地球物理学的重要分支,电磁法是矿产资源探查的主体手段之一.在分析我国现阶段航空、地面及海洋电磁探测技术进展的基础上,本文重点说明了极低频电磁法(简称WEM法),多通道瞬变电磁法(简称MTEM)和电性源短偏移瞬变电磁法(简称SOTEM)等电磁探测新技术.WEM法建立一套包括岩石层、大气层和电离层在内的全空间电磁传播理论,通过新研制的观测系统,获取地下10km的地电信息;MTEM方法是地下埋深4km目标体精细勘查的有效手段;SOTEM实现地下1.5km深度范围内目标体的精细探测.通过多种电磁探测技术组合,可实现地下10km深度范围内多尺度探测,达到"望远镜+放大镜+显微镜"探测效果.同时,本文指出进一步研发与新方法配套的装备、资料处理技术和大数据人工智能识别等将是我国电磁法未来的发展方向.

Many studies have been carried out to demonstrate the huge potential of mineral resources greater than 500m.Therefore,it is of crucial importance to design an instrument locally for deep seated targets.Electromagnetic (EM) method is an important means for mineral exploration.With the development of airborne,surface and marine EM detection technology in China,Wire-less Electromagnetic Method (WEM),Multi-channel Transient Electromagnetic Method (MTEM),as well as Short-offset Transient Electromagnetic method (SOTEM) are focused on in this paper.The WEM wave propagates through lithosphere,atmosphere and ionosphere to probe 10 km-depth geo-electric structures underground;MTEM method is proven as an effective means for burying the target body;SOTEM reaches a depth of 1.5 km with accurate detection.The combination of various electromagnetic technologies can achieve multi-scale detection within a depth of 10 km and realize the effect of "telescope-magnifier-microscope".It also pointed that the future direction of electromagnetic method is in terms of equipment,data processing and big data information.