To: “Radius of Investigation in dc resistivity well logging” by A. Roy and R. L. Dhar, GEOPHYSICS, v. 36, no. 4, p. 754–760.

Abstract

Due to inadequate precision in computation with small values of radius r, the radial investigation characteristic (RIC) curves in the above paper are incorrect for values of r less than about 0.15. Fortunately, this has not affected the positions of the maxima which determined the radii of investigation in that paper.