Method and apparatus for determining resistivity and dielectric anisotropy parameters of earth formations by using multifrequency and/or multispacing measurements

摘要

An apparatus and a method for determining the conductivity and dielectric constants of an anisotropic formation uses a redundant set of electromagnetic measurements in combination with anisotropic formation models that relate the anisotropic conductivity and dielectric constant of the formation to measurements of a propagating electromagnetic wave in the formation. A conjugate gradient scheme or a Newton-Raphson algorithm is used to obtain solutions to the nonlinear equations of propagation. The solutions to the equations are usually non-unique and are also susceptible to measurement errors. Use of redundant measurements makes it possible to resolve the non-uniqueness. The redundancy is obtained by using multiple frequency and/or multiple spacing tools. The use of redundant measurements also makes it possible to reduce the error in the solution of the wave propagation equation.