A 3D Near-Wellbore Imaging Algorithm for Triaxial Induction Data

We present a rigorous nonlinear inversion method for the three-dimensional (3D) imaging of the near-wellbore region employing multi-array triaxial induction data. The method used is the so-called Multiplicative-Regularized Contrast Source Inversion<br>(MR-CSI) method. There are two main features of this method. The first is that the method does not require the explicit solution of the full forward problem at each iteration step. The second is that the regularizer is included as a multiplicative constraint that allows the automatic and adaptive determination of the regularization parameter. These two features enable us to robustly solve an inverse problem with 65,536 unknowns using a single-processor present-day computer power.