Resistivity and relative permittivity imaging for oil-based mud: A method and numerical simulation

Abstract

In this study, a brief review of development of electrical microresistivity imaging in well logging has been made. Based on the existing problems, a new imaging method has been presented abstractly. In this method, oil-based mud resistivity, relative oil-based mud permittivity, oil-based mudcake thickness, supply frequency, formation resistivity and relative formation permittivity are all considered synthetically. Different from the conventional imaging method, not only apparent formation resistivity but also apparent formation relative permittivity is derived out. With 3D numerical simulation, the tool sensitivity, calculation and imaging for both apparent resistivity and apparent relative permittivity have been analyzed and discussed. The imaging tool sensitivity is affected complicatedly by all parameters. Compared with the blurry results from the conventional method, qualitative and quantitative calculation and high clear imaging of formation resistivity and relative permittivity are both presented simultaneously, which have verified the accuracy of the method presented in this paper.