Interpolation of induction tool response using geometrical factors as basis functions

摘要

A method for estimating the apparent conductivity of a formation comprises the steps of: providing layer conductivity data over a range of points in the formation outside the borehole along a portion of a borehole, calculating an apparent conductivity at a first series of points in the range, calculating a Doll-generated conductivity at each of the first points, calculating a skin effect by calculating a difference value between the Doll-generated conductivity and the apparent conductivity at each of the first points, calculating a Doll- generated conductivity at a second series of points that are different from the first points, calculating an interpolated difference value for each of the second points, and adding to interpolated difference value to the corresponding Doll-generated conductivity at each of the second points. Alternatively, the skin effect can be calculated at each of the first points by calculating the ratio of the apparent conductivity to the Doll- generated conductivity at each of the first points. The interpolation steps can be either linear interpolation or geometric interpolation.