Analysis and simulation of metal casing effect on induction logging

Induction logging is an effective method of measuring formation conductivity in open hole. However, when the metallic pipes are inserted into the borehole, the standard induction logging is found to be invalild. In this paper, a system of single-well through-casing induction logging is modeled. The influences of the casing parameters (conductivity, permeability and thickness) and the current frequency on magnetic field are studied. Meanwhile, the optimum receiver location is analyzed. Simulation results show that: under the same conditions, the value of the magnetic field is 3-5 orders of magnitude higher in cased hole than that in open hole, the formation conductivity can be distinguished by detecting the effective magnetic field in cased hole. The optimun receiver location has a variation when the casing parameters and the current frequency are changed.