Patent ID: 7894989
Filing Date: 2011-02-22
Classification: G01V

Abstract:
1. A computer-implemented method for determining earth vertical electrical anisotropy from an electromagnetic survey of a subsurface region located below the water bottom in an offshore environment, said survey using an electromagnetic source and a plurality of electromagnetic receivers, said method comprising: (a) obtaining electromagnetic field data from the survey's results at a plurality of online and offline receiver locations and corresponding to selected ones, but fewer than all, of the six electromagnetic field components E (b) solving Maxwell's electromagnetic field equations for horizontal resistivity and vertical resistivity at an (x,y,z) position in the subsurface region, using survey acquisition parameters and the selected components of measured electromagnetic field data, said solving being performed on a computer by either inversion or forward modeling techniques; and (c) obtaining a measure of vertical electrical anisotropy at location (x,y,z) from the calculated horizontal and vertical resistivities.