广域电磁法异常分离技术探索研究  

Exploration of anomaly separation technology of wide-fi eld electromagnetic method

作　　者：田红军 古志文 张广大 赵东东 周昊 张剑 郭冰 王雨辰 Tian Hong-Jun;Gu Zhi-Wen;Zhang Guang-Da;Zhao Dong-Dong;Zhou Hao;Zhang Jian;Guo Bing;Wang Yu-Chen(Sichuan Zhongcheng Coal Field Geophysical Engineering,Research Institute Co.,Ltd.,Chengdu 610072,China;Sichuan Changning Natural Gas Development Co.,Ltd.,Yibin,Sichuan 610056,China;Nanjing center,China Geological Survey,Nanjing 210016,China)

机构地区：[1]四川中成煤田物探工程院有限公司,成都610072 [2]四川长宁天然气开发有限责任公司,成都610056 [3]中国地质调查局南京地质调查中心,南京210016

出　　处：《Applied Geophysics》2024年第2期343-357,421,共16页应用地球物理（英文版）

摘　　要：如何有效地压制区域背景场,提取局部异常场加以分析,是广域电磁法提升资料处理和解释准确度亟待解决的问题之一。本文借鉴重磁勘探区域场分离的基本思想提出一种基于残差法的异常分离技术,既能有效地压制区域背景场,又能很好地突出反演成像中的断层、薄层等局部异常的有效信息,有效弥补了传统解释方法的不足。该方法以插值切割法为理论基础,提出了动态改进型插值切割算子,得到区域背景场,实现局部异常场与区域背景场的分离。设计了一维、二维复杂地电模型进行正演计算、反演成像和异常分离,证明了采用异常分离技术提取的局部异常信息对地层、构造和断裂的刻画更加精细,明显优于传统处理成果。使用该方法对川南长宁地区广域电磁法反演成像进行异常分离,进一步验证了异常分离成果反映的构造、薄层及断层等局部信息与地震剖面吻合度较高,表明本文提出的异常分离技术有效、可靠,能有效提升传统广域电磁法的反演成像精度和解释可靠度,具有重要的应用价值。To improve the accuracy of data processing and interpretation,eff ective suppression of the regional background fi eld and extraction of the local anomaly fi eld for further analyses represent urgent issues that need to be solved in the wide-fi eld electromagnetic methods.The present study proposes an anomaly separation technique based on the residual method to develop the basic idea of regional fi eld separation in gravity and magnetic exploration.The proposed technique can eff ectively suppress the regional background fi eld and highlight local anomalies,such as faults and thin layers in inversion imaging,overcoming the shortcomings of traditional interpretation methods.Based on the interpolation-cutting method,a dynamically improved interpolation-cutting operator is proposed to obtain the regional background fi eld by separating it from the local anomaly fi eld.Furthermore,one-and two-dimensional complex geoelectric models are designed to perform calculations,inverse imaging,and anomaly separation.It has been demonstrated that the local anomaly information extracted by the anomaly separation technology describes accurate strata,structures,and faults,obviously superior to the traditional processing results.The proposed method is used to separate the anomalies from the wide-field electromagnetic inversion imaging in the Changning area of the southern Sichuan Province.The local information of the structures,thin layers,and faults obtained by the anomaly separation results is highly consistent with the seismic profi le,indicating that the proposed anomaly separation technology is eff ective and reliable.Further,the proposed technology can eff ectively improve the inversion imaging accuracy and the interpretation reliability of traditional wide-field electromagnetic methods;thus,it has important application value.

关 键 词：广域电磁法 插值切割法 异常分离技术 区域场 局部异常 

分 类 号：P631.325[天文地球—地质矿产勘探]