Abstract：There are the issues of how to divide the near-field from the far-fields when using manual field source for electro-magnetic prospecting. Taking the azimuth-anisotropic and half-infinite earth as a model,the paper yielded the far-field distance (FFD) of ground horizontal electric dipole (HED) by computation,presented taking relative variation η≤5%as the judge condition of dividing the near-field from the far-field.The influence of azimuth-anisotropy on division of the near-field from the far-field has been studied by numeric tests,that resuited in following conclusions:the linear relation between the far-field distance (FFD) and skin effect existed when the anisotropic parameters are certain;the affect of anisotropy on FFD in formation strike is larger than that in its orthonormal direction,the same is true for its value.
岳瑞永, 徐义贤. 可控源频率域电方位各向异性与近场效应研究[J]. 石油地球物理勘探, 2004, 39(3): 342-347.
Yue Rui-yong, Xu Yi-xian. Study on Electric Azimuth Anisotropy of Controlled Source in Frequency Domain and Near-Field Effects. OGP, 2004, 39(3): 342-347.
