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根据线圈系半径和金属套管半径之间的关系，分3种情况讨论了均质地层和非均质地层中金属套管对电磁测井响应的影响，给出了在均质地层中扣除套管影响的图版。在非均质地层中，当发射线圈和接收线圈均在套管内时，不能由含套管测井信号得到不含套管地层信号。当发射线圈在套管外而接收线圈在套管内时，对于低电导率对比的非均质地层，可根据含套管测井信号得到不含套管地层信号，从而将套管的影响消除；当地层电导率对比度大时，上述结论只适用于低频情况。当发射线圈和接收线圈均在套管外时，在频率100～10kHz之间，可以由合套管非均质地层信号得到不含套管地层的信号，套管的影响能够消除。
According to the relationship between the radius of the coil and the radius of the metal casing, the influence of the metal casing on the electromagnetic logging response in homogeneous and heterogeneous formations is discussed in three cases. Tube affected plate. In heterogeneous formations, a casing-free formation signal can not be derived from casing-containing logging signals when both the transmitting and receiving coils are within the casing. When the transmitting coil is out of the casing and the receiving coil is in the casing, the influence of the casing can be eliminated for the non-homogeneous formation with low conductivity comparing with the casing-free formation signal based on the casing logging signal. When the conductivity of the formation is high contrast, the above conclusion applies only to low frequencies. When the transmitting coil and the receiving coil are outside the casing, the signals without casing casing can be obtained from the casing non-homogeneous formation signal at the frequency of 100-10 kHz, and the influence of casing can be eliminated.