1-D Modeling and Inversion of Triaxial Induction Logging Tool in Layered Anisotropic Medium

This dissertation presents a 1-D modeling and inversion algorithm for a triaxial induction logging tool in layered anisotropic formation.;Analytic solutions of the electromagnetic field in layered anisotropic formation generated by a magnetic dipole were derived and a numerical integration method based on Gauss integral algorithm was applied to accelerate those analytical solutions. Those solutions and algorithms were verified with synthetic models and different methods. Applying those developed analytic solutions, we analyzed the effects of dielectric enhancement on triaxial induction logging tool performance in anisotropic formations. This forward model was modified into a propagation forward model for the logging while drilling application.;In order to automatically obtain geophysical parameters (such as horizontal and vertical resistivity, dipping angles and boundary locations) from the logging data, a 1-D inversion was developed. The previous forward model was implemented in the 1-D inversion code. To simplify the solution, the inversion method used a nonlinear least squares model and, in order to make the inversion efficient, line search technology was added to update inverted parameters. Zero-D inversion was conducted at the center of each layer to provide a reliable initial model that will be important for the 1-D inversion as it strongly depends on those initial values. Tested Synthetic data and filed log indicate that the developed inversion algorithm is reliable...