A New Approach to Fracture Network Modeling Using Impedivity and Permittivity-Dominated Imaging

The challenge of generating high resolution images in oil based muds have been solved through the use of multi-frequency pad based electrical imaging tools. To gain an image in oil-based mud, high frequencies and short current paths allow capacitive coupling of the formation to the buttons. The signal received is measured by two components, the phase and amplitude. These are affected by resistivity, permittivity, and stand-off. By dealing with the phase and amplitude as complex numbers, we can generate a resistivity dominated impedivity image and a permittivity dominated "Imaginary" image. The results have also led us to question the traditional assumption that open fractures would exhibit a "Bright" response due to be filled with a resistive drilling fluid; the results show this not to be true and further require an understanding of the mud behavior. By combining an understanding of the mud, the resistivity and permittivity responses we can understand more of the nature of the fractures and their potential to be fluid conductive. This paper provides examples from Kuwait to support our theories and to help interpreters to get the most from these images.