A novel array laterolog method

Abstract

The dual laterolog tool has been used widely and traditionally to investigate the resistivity profile of formations. In this paper, we point out some weaknesses of the traditional method and introduce a new tool design - the Array Laterolog tool. The finite element method is used to simulate the apparent resistivity curves for both the dual laterolog and Array Laterolog tools for various formation models. Numerical results show the Array Laterolog tool has both higher vertical resolution and more flexible radial investigation than the dual laterolog tool. With its unique new electrode configuration, the Array Laterolog tool can theoretically measure an unlimited number of shallow apparent resistivity curves. While having approximately the same high vertical resolution as the deep Array Laterolog (ALD) measurement, each of these curves has a different investigation depth. These shallow Array Laterolog (ALS) curves, combined with the ALD curve, can provide a full formation radial resistivity profile.