Patent ID: 6442488
Filing Date: 2002-08-27
Classification: G01V

Abstract:
A method of using an induction logging tool in a borehole within earth formations for determining conductivities thereof, the borehole axis having an inclination angle to a symmetry axis of said earth formations, the method comprising:(a) estimating an anisotropic background formation model from borehole corrected data, said anisotropic background model comprising horizontal and vertical resistivities; (b) determining asymptotic conductivities of the anisotropic background model relative to the borehole axis using an assumed value for said inclination angle; (c) obtaining a modeled response for said anisotropic background model with said asymptotic conductivities; (c) making skin-effect corrections to said modeled response giving a skin-effect corrected response; (d) calculating a response residual as a difference between the skin-effect corrected response and the borehole corrected data; (e) focusing said residual giving a focused residual; (f) calculating an idealized focused result for said background model; and (g) combining the results of said focusing of said residual with said ideal focused results.