Development of azimuthal resistivity survey data processing program with graphical user interface for anisotropic coefficient quantification

Abstract

The physical properties of underground material are anisotropic. This applies to all physical properties including resistivity. Anisotropic property is quantified by the anisotropic coefficient. The anisotropy of physical properties can be shown by 2D and or 3D modeling, but it is not always economically efficient for small-scale studies, while 1D modeling is not capable of showing the anisotropy effect. One of the many geophysical methods developed to learn about anisotropic properties under the earth is the azimuthal resistivity survey (ARS) which is the improvement of the vertical electrical sounding (VES) method. Measurement is carried out in one dimension with various electrode spacing and azimuth of electrode lines. The result of this measurement is VES data for various azimuths. ARS data is then plotted with a polar plot to show the anisotropy of physical properties below the surface. The anisotropic coefficient calculation is carried out by performing the one-dimension inversion of the measurement data for every azimuth, for a user-defined number and constant thickness of the layer. The result is then used to calculate the variation of the anisotropic coefficient value against depth. The algorithm used to create the polar plot and VES data inversion are then combined into one program based on Python programming language. This program is equipped with a graphical user interface (GUI) to make the program more user-friendly. The program is tested with synthetic data and successfully imaged the anisotropic coefficient variation against depth for the synthetic data.