Associating Borehole Radar Imaging with Petrophysical Properties for a Mud-Contaminated Reservoir
F. Zhou, I. Giannakis, A. Giannopoulos and E. Slob
Event name: 10th International Workshop on Advanced Ground Penetrating Radar
Session: Imaging and Tomography
Publication date: 11 September 2019
Info: Extended abstract, PDF ( 555.94Kb )
Price: € 20
Logging engineers deem mud invasion a harm and attempt to eliminate its impact on logging data. However, from our point of view, the mud-contaminated parts of the formation do also carry some valuable information, notably with regard to the key hydraulic properties. Therefore, if adequately characterized, the invasion effects, in turn, could be utilized for reservoir estimation. Typically, the invasion depth critically depends of the formation porosity and permeability. To achieve this objective, we propose to use borehole radar to determine the mud invasion depth considering a high spatial resolution of ground-penetrating radar (GPR) compared with the conventional logging tools. We implement numerical investigations on the feasibility of this approach. The simulations imply that a time-lapse radar logging is able to extract EM reflection signals from mud invasion front, and the invasion depth and EM velocity can be estimated by the downhole measurement of one source and two receivers. We find that there exists a positive correlation between the estimated invasion depth and permeability curves, and a negative correlation between the estimated velocity and porosity curves. We suggest that borehole radar has potential to estimate permeability and porosity of oil reservoirs, wherein the mud invasion effect is positively utilized.