The effect of conductive borehole water on borehole radar

A wire dipole was modeled, without resistive loading. Even without loading, the modeled results correspond to the experimental results. Modeling suggests that the conductive water forms an extension to the arm of the antenna, dramatically altering the time domain response of the antenna. While conductive water does have some screening effect on the radar antenna, lowering the signal strength of the transmitted pulse, its main effect is to change the coupling between the antenna and the surrounding rock. Unexpected wave modes can then be set up causing anomalous responses in early time. Modeling suggests that minimal isolation between the antenna and the borehole can remove the anomalous response.