Calculation of apparent resistivity in large fixed loop TEM by simulated annealing algorithm
Li Jian-hui1, Zhu Zi-qiang1, Liu Shu-cai3, Zeng Si-hong1, Zhao Yun-wei1
1. School of Geophysics and Info-Physics,Central South University,Changsha City,Hunan Province,410083,China;
2. School of Resource and Geoscience,China University of Mining and Technology,Xuzhou City,Jiangsu Province,221116,China
Abstract：The apparent resistivity of measured point inside rectangular transmitting loop in large fixed loop TEM can be calculated by using simulated annealing algorithm to fit theoretical induction electromotive force and measured induction electromotive force.The precision and stability of algorithm is verified by using the homogeneous half-space and 3-layerd geoelectric models in the paper.The algorithm is run for twenty times with different initial model in verification using homogeneous half space geoelectric model.The calculated results showed the most errors between apparent resistivity and true resistivity are within 0.5% and part errors which meet the random distribution are between 1.5～6.0%.It only requires about forty times of calculation in each iteration procedure,and then the high precision apparent resistivity can be obtained.When using 3-layered geoelectric model in verification,the comparison with Weng Ai-hua's apparent resistivity calculated using dichotomy further proved the correctness of the algorithm presented in this paper.
