电流波形对航空瞬变电磁法探测能力影响研究  

Study on the influence of current waveform on the detectabilityof airborne transient electromagnetic method

作　　者：毛玉蓉[1,2] 王新宇 周磊[1,2] 李昊锦[1] MAO Yurong;WANG Xinyu;ZHOU Lei;LI Haojin(Key Laboratory of Exploration Technologies for Oil and Gas Resources,Ministry of Education(Yangtze University),Wuhan 430100,Hubei;Cooperative Innovation Center of Unconventional Oil and Gas(Yangtze University),Wuhan 430100,Hubei;School of Geophysics and Geomatics,China University of Geosciences(Wuhan),Wuhan 430074,Hubei)

机构地区：[1]油气资源与勘探技术教育部重点实验室(长江大学),湖北武汉430100 [2]非常规油气省部共建协同创新中心(长江大学),湖北武汉430100 [3]中国地质大学(武汉)地球物理与空间信息学院,湖北武汉430074

出　　处：《长江大学学报（自然科学版）》2023年第3期75-83,共9页Journal of Yangtze University(Natural Science Edition)

基　　金：国家自然科学基金项目“基于井地激电电磁法的储层流体识别方法研究”(42274103);中国石油化工股份有限公司科技项目“全域电磁法储层含油气性检测技术及应用”(P22163)。

摘　　要：航空瞬变电磁法是近年来发展起来的一种快速电磁油气勘探方法,该法具有飞行高度低,探测深度大等特点,广泛应用于森林、山地、戈壁、沼泽、湖区以及浅海等区域的油气勘查。该方法利用发射线圈在空中发射不同波形和功率的电流,接收线圈接收地下地质体感应涡流产生的二次场信息,通过分析和处理二次场信息,进而通过反演或者成像可获取地下地质体的电导率、磁导率的空间分布信息,最终实现对地质目标体的识别和探测。传统的航空瞬变电磁法主要采用单一波形进行供电,极大地影响了航空瞬变电磁法的适用性。通过对比阶跃波、锯齿波、三角波、梯形波和正弦波等5种发射波形激发的电磁响应特征,可知阶跃波和锯齿波的电磁响应最强,梯形波次之,但到了晚期,磁场的衰减均保持一致。在此基础上,提出利用梯形波和锯齿波进行组合发射,可实现航空瞬变电磁法对不同埋深地质目标体探测的目的。研究不同发射电流波形以及组合波的航空瞬变电磁响应特征,对于合理设计和优化航空瞬变系统具有重大意义。Airborne transient electromagnetic(ATEM)is a rapid electromagnetic oil and gas exploration method developed in recent years.It has the characteristics of low flight altitude and large exploration depth,and is widely used in the oil and gas exploration of forests,mountains,Gobi,marshes,lake areas and shallow seas.In the method,the transmitting coil is used to transmit currents of different waveforms and powers in the air,and the receiving coil receives the secondary field information generated by the induced eddy current of underground geological bodies.By analyzing and processing the secondary field information,the spatial distribution information of the conductivity and permeability of underground geological bodies can be obtained through inversion or imaging,and finally the identification and detection of geological target bodies can be realized.The traditional airborne transient electromagnetic method mainly uses a single waveform for power supply,which greatly affects the applicability of airborne transient electromagnetic method.In this paper,by comparing the electromagnetic response characteristics of step wave,sawtooth wave,triangle wave,trapezoidal wave and sine wave,it can be seen that the electromagnetic response of step wave and sawtooth wave is the strongest,followed by trapezoidal wave,but the magnetic field attenuation remains the same in the late stage.On this basis,it is proposed that the combination of trapezoidal wave and sawtooth wave can realize the purpose of airborne transient electromagnetic method to detect geological targets with different burial depths.It is of great significance to study the characteristics of airborne transient electromagnetic response of different transmitting current waveforms and combined waves for the reasonable design and optimization of airborne transient system.

关 键 词：发射电流 组合波形 地质目标体探测 航空瞬变电磁 

分 类 号：P631.325[天文地球—地质矿产勘探] TE132.14[天文地球—地质学]