Detection and imaging of subsurface high impedance contrast objects

Patent metadata

Field	Value
Publication number	US-2016178781-A1
Application number	US-201514971218-A
Country	US
Kind code	A1
Filing date	Dec 16, 2015
Priority date	Dec 19, 2014
Publication date	Jun 23, 2016
Grant date	—

Abstract

A system for detecting an object in a subsurface environment includes a first recorder of a vertical electromagnetic component, including first pair of polarization orientation components, of an electromagnetic field in a region of interest, a second recorder of an orthogonal electromagnetic component, including second pair of polarization orientation components, of the electromagnetic field in the region of interest, at least one processor configured to derive a pair of transfer functions that relates the vertical electromagnetic component and the orthogonal electromagnetic component of the electromagnetic field for each of the polarization orientation components, at least one processor configured to determine a simulation of the pair of transfer functions for a given impedance distribution, and at least one processor configured to infer a subsurface impedance map using the pair of transfer functions of the recorded data and the simulation of the pair of transfer functions.

First claim

1 . A system for detecting an object in a subsurface environment comprises:
a first recorder of a vertical electromagnetic component of an electromagnetic field in a region of interest, wherein the vertical electromagnetic component includes first pair polarization orientation components; a second recorder of an orthogonal electromagnetic component of the electromagnetic field in the region of interest, wherein the orthogonal electromagnetic component includes second pair polarization orientation components; at least one processor configured to derive a pair of transfer functions that relates the vertical electromagnetic component and the orthogonal electromagnetic component of the electromagnetic field for each of the polarization orientation components; at least one processor configured to determine a simulation of the pair of transfer functions for a given impedance distribution; and at least one processor configured to infer a subsurface impedance map using the pair of transfer functions of the recorded data and the simulation of the pair of transfer functions.

2 . The system of claim 1 , wherein the first recorder is a passive recorder.

3 . The system of claim 1 , wherein the first recorder is an airborne sensor.

4 . The system of claim 1 , wherein the second recorder is a passive recorder.

5 . The system of claim 1 , wherein the second recorder is one of a ground based sensor and an airborne sensor.

6 . The system of claim 1 , wherein the at least one processor configured to infer the subsurface impedance map recovers a background field and a secondary field including data indicative of the object.

7 . A method for detecting an object in a subsurface environment comprising:
collecting data indicative of an orthogonal component of an electromagnetic field; collecting data indicative of a vertical component of an electromagnetic field; deriving a pair of actual transfer functions using the data indicative of the orthogonal component and the data indicative of the vertical component of the electromagnetic field; deriving a pair of simulated transfer functions using a simulation of a background primary field; performing an inversion to update model parameters reducing a discrepancy between the pair of actual transfer functions and the pair of simulated transfer functions using a-priori information; and simulating a secondary field for a set of model parameters using the inversion and the pair of simulated transfer functions to resolve a subsurface impedance map including the object.

8 . The method of claim 7 , wherein the pair of simulated transfer functions correspond to the pair of actual transfers.

9 . The method of claim 7 , wherein collecting the data indicative of the orthogonal component includes collecting data indicative of both polarizations of the orthogonal component.

10 . The method of claim 7 , wherein collecting the data indicative of the vertical component includes collecting data indicative of both polarizations of the vertical component.

11 . The method of claim 7 , further comprising regularizing and stabilizing the subsurface impedance map using the a-priori information.

12 . The method of claim 7 , further comprising enforcing, using the a-priori information, an edge preserving total variation function.

13 . The method of claim 7 , further comprising enforcing, using the a-priori information, the subsurface impedance map to have tabular structures using a parametric level set function.

14 . The method of claim 7 , further comprising generating the model parameter update by performing a non-linear constraint optimization.

15 . The method of claim 14 , further comprising generating the model parameter update by performing the non-linear constraint optimization using a noise model.

16 . The method of claim 14 , further comprising generating the model parameter update by performing the non-linear constraint optimization using a motion compensation model.

17 . A computer program product for detecting an object in a subsurface environment, the computer program product comprising a computer readable storage medium having program instructions embodied therewith, the program instructions executable by a processor to cause the processor to:
collect data indicative of an orthogonal component of an electromagnetic field; collect data indicative of a vertical component of an electromagnetic field; derive a pair of actual transfer functions using the data indicative of the orthogonal component and the data indicative of the vertical component of the electromagnetic field; derive a pair of simulated transfer functions using a simulation of a background primary field; perform an inversion to update model parameters reducing a discrepancy between the pair of actual transfer functions and the pair of simulated transfer function using a-priori information; and simulate a secondary field for a set of model parameters using the inversion and the pair of simulated transfer functions to resolve a subsurface impedance map including the object.

18 . The computer program product of claim 17 , wherein the pair of simulated transfer functions correspond to the pair of actual transfers.

19 . The computer program product of claim 17 , wherein collecting the data indicative of the orthogonal component includes collecting data indicative of both polarizations of the orthogonal component.

20 . The computer program product of claim 17 , wherein collecting the data indicative of the vertical component includes collecting data indicative of both polarizations of the vertical component.

Assignees

• IBM

Inventors

• Haber Eldad
• Horesh Lior

Classifications

• G01V3/081 Primary

  the magnetic field is produced by the objects or geological structures (characterised by the method of magnetic field measurement G01R33/00) · CPC title

• G01V3/165

  operating with magnetic or electric fields produced or modified by the object or by the detecting device (with electromagnetic waves G01V3/17) · CPC title

• G01V3/082

  operating with fields produced by spontaneous potentials, e.g. electrochemical or produced by telluric currents (G01V3/26 takes precedence) · CPC title

• G01V3/16 Primary

  specially adapted for use from aircraft (G01V3/165 - G01V3/175 take precedence) · CPC title