Study on borehole radar for well logging

Borehole radar becomes useful tool for high resolution probing of both deep oil reservoir and shallow subsurface. To improve understanding of the electromagnetic wave propagation associated with borehole radar, this paper introduces a 2-D pseudospectral time-domain (PSTD) algorithm that allows us to model the full EM wavefield for rotationally symmetric structure. This technique uses the fast Fourier transform (FFT) algorithm for spatial derivatives and the exponential attenuation absorbing boundary condition to eliminate the wraparound effect due to the spatial periodicity introdued by FFT. The effects of the borehole mud and the responses of several types of formation are simulated. The simulated borehole radar responses can be used to delineate the formation structure around the wellbore and found to be helpful in obtaining petrophysical parameters.