Study on the Two‐Dimension Full‐Parameter Inverse Method of the Electromagnetic Propagation Resistivity Logging

Abstract

AbstractThe multiple propagation resistivity (MPR) tool of the Baker‐Hughes INTEQ is the widely used electromagnetic propagation resistivity logging tool. It has four phase difference curves and four amplitude ratio curves. With it as an example, the application of the two‐dimension inverse method to the electromagnetic propagation resistivity logging data in vertical well is presented. Because the sensitivity of logging response to layer's boundary is much higher than that to other formation parameters, so how to accurately pick up layer's boundary is important. With the method described in this paper, we begin by picking the layer's boundaries from the highest resolution curve with the characteristic recognition method, and perform vertical one‐dimension inversion for the shallow and deep detection phase difference curves. Utilizing this result to construct the initial model for two‐dimension inversion, we carried out the full‐parameter inversion of MPR data by using an improved damping regularized Gauss‐Newton optimization algorithm. The satisfying inversion result is obtained for the two typical 23‐layer models. The inversion result can significantly improve the quality of MPR interpretation. In addition, it is found that the inversion results from only five curves are nearly the same to the results from eight curves.