Theory of induction sonde in dipping beds

Abstract

The analysis necessary for the computation of the response of an induction sonde in dipping beds is developed. The boundary‐value problem solved is for a bed of uniform thickness surrounded by two infinitely thick shoulder beds. The source is a magnetic dipole oriented in an arbitrary direction and located in any of the three media. The resulting electromagnetic fields in all three media are obtained. From these fields, induction logs are calculated for a focused induction sonde (6FF40) passing through a dipping bed. Under the assumptions of negligible borehole effect and no invasion, the analysis is also used to obtain correction charts for dipping beds.