Principles of tensor induction well logging in a deviated well in an anisotropic medium

Abstract

In this paper we develop an interpretation method for the characterization of conductivity anisotropy in an earth formation, based on the tensor induction well logging (TIWL) technique. The method is based on examining the response of a tri-axial electromagnetic induction logging instrument in a deviated well penetrating a transversely isotropic medium. The foundations of the TIWL method were developed in Zhdanov et al. (2001), where the low frequency approximations for the quadrature components of the induction tensor were derived. In this paper we further examine the basic principles of tensor induction logging in two-, three-, and multi-layer anisotropic formations in vertical and deviated wells using numerical simulation of tensor induction logs. We introduce a technique for correct reconstruction of the apparent conductivities of the anisotropic formations, based on application of a regularized Newton method. The method is fast and provides a "real time" interpretation. The practical effectiveness of this technique for tensor induction log interpretation is illustrated using results of numerical experiments.