Patent ID: 6615139
Filing Date: 2003-09-02
Classification: G01V

Abstract:
A digitally implemented method for determining depth values of a subterranean 3-dimensional density interface based on which a parabolic density-depth function models the decrease in density contrast of sedimentary rocks with depth, said method comprising the steps of:(a) measuring gravity field values at a plurality of locations over a region covering a sedimentary basin therein said plurality of locations coincides with a plurality of grid nodes of rectangular/square mesh; (b) approximating the sedimentary sequence above a density interface by an array of 3-dimensional rectangular/square blocks wherein their epicenters coincide with said grid nodes of said mesh; (c) calculating initial depth estimates of a density interface for said array of 3-dimensional blocks at said plurality of grid nodes; (d) calculating predicted gravity fields of said 3-dimensional rectangular/square blocks at said plurality of grid nodes of said mesh; (e) calculating a misfit function between said measured and predicted gravity fields; (f) improving depth extents of said 3-dimensional rectangular/square mesh at said plurality of grid nodes; (g) repeating steps (d)-(f), iteratively, until said number of iterations are complete or said misfit function falls below a predefined error; and (h) importing said generated grid files to a software application for viewing said interpreted results in the form of respective contour maps.