Method and apparatus for balancing the electrical output of the receiver coils of an induction logging tool by use of a slidable magnetic rod for eliminating direct coupling

摘要

In an induction logger, a method for nulling the output signal from a pair of series-coupled receiver coils by altering the magnetic flux distribution within the coils by use of one or more magnetic equalization bodies. The shape and aspect ratio of the equalization body are chosen to minimize temperature dependence of the initial permeability. Alternatively, a highly conductive equalization body may be used.