Multicomponent borehole radar systems and methods

Patent metadata

Field	Value
Publication number	US-9562987-B2
Application number	US-201114111963-A
Country	US
Kind code	B2
Filing date	Apr 18, 2011
Priority date	Apr 18, 2011
Publication date	Feb 7, 2017
Grant date	Feb 7, 2017

Abstract

Disclosed herein are multicomponent borehole radar tools and methods. At least some tool embodiments employ at least two antennas that receive reflections of electromagnetic pulses transmitted from the tool. A processor processes the receive signals to identify reflection signals and to determine a direction and/or distance to the sources of the reflection signals. Possible sources include formation boundaries, fluid boundaries, cased wells, and other features that cause contrasts in electromagnetic properties. In addition to reflection signals, the measured responses may include direct signal measurements that are useful for determining formation resistivity and permittivity. Each of the antennas may transmit and receive, and they may be collocated to reduce tool size and reduce processing complexity. Disclosed logging tool examples employ both electric and magnetic dipole antennas.

First claim

What is claimed is:

1. A borehole logging tool that comprises:
at least two antennas to receive reflections of one or more electromagnetic pulses transmitted from the tool; and
a processor that processes receive signals from the at least two antennas as a function of tool position to provide at least one formation image that plots reflected electromagnetic signals or associated values as a function of depth and of distance from a borehole to represent one or more formation anomalies, wherein the formation image is selected from a set consisting of: a reflected self-component electromagnetic signal image; a reflected cross-component electromagnetic signal image; an anomaly azimuth angle image; and an anomaly elevation angle image.

2. The tool of claim 1 , wherein the processor processes said receive signals to determine a direction or distance of the one or more anomalies.

3. The tool of claim 2 , wherein the one or more anomalies comprise a cased well or a boundary between formation regions having different resistivity.

4. The tool of claim 1 , wherein the two antennas are part of an antenna triad, and wherein each antenna in the triad transmits selected ones of said electromagnetic pulses from the tool.

5. The tool of claim 4 , wherein the antennas in the antenna triad are substantially collocated.

6. The tool of claim 1 , wherein said antennas are of a type in a set consisting of separated electrodes, wires, toroids, and horns.

7. The tool of claim 1 , wherein said antennas are of a type in a set consisting of coils, tilted coils, magnetometers, and solenoids.

8. The tool of claim 1 , wherein said electromagnetic pulses have widths below 100 ns.

9. The tool of claim 1 , wherein the reflected electromagnetic signals comprise a plurality of reflected self-component electromagnetic signals plotted as a function of depth and of distance from a borehole, or a plurality of reflected cross-component electromagnetic signals plotted as a function of depth and of distance from a borehole.

10. The tool of claim 1 , wherein the associated values comprise a plurality of anomaly azimuth angle values plotted as a function of depth and of distance from a borehole, or a plurality of anomaly elevation angle values plotted as a function of depth and of distance from a borehole.

11. A borehole logging method that comprises:
transmitting electromagnetic pulses from a tool in a borehole;
measuring, by at least two antennas of the tool, self-component and cross-component responses to the electromagnetic pulses, said responses including one or more reflection signals;
processing, by a processor, said responses as a function of tool position to provide at least one formation image that plots reflected electromagnetic signals or associated values as a function of depth and of distance from a borehole to represent one or more formation anomalies, wherein the formation image is selected, wherein the formation image is selected from a set consisting of: a reflected self-component electromagnetic signal image; a reflected cross-component electromagnetic signal image; an anomaly azimuth angle image; and an anomaly elevation angle image;
determining a formation anomaly direction or distance based on the formation image; and
communicating a representation of said direction or distance to a user.

12. The method of claim 11 , wherein said one or more anomalies are in a set consisting of a cased well, a formation bed boundary, and a fluid boundary.

13. The method of claim 11 , wherein said tool comprises a triad of differently oriented antennas that each transmit and receive.

14. The method of claim 13 , wherein said antennas at least approximate electric dipoles or magnetic dipoles.

15. The method of claim 11 , wherein said electromagnetic pulses have widths below 100 ns.

16. The method of claim 11 , wherein said responses further include a direct signal.

17. The method of claim 16 , further comprising determining a formation resistivity or a relative permittivity of the formation from said direct signal.

18. The method of claim 11 , wherein said determining includes finding an eigenvector expansion of an orthogonal dipole signal data tensor.

19. The method of claim 11 , wherein the reflected electromagnetic signals comprise a plurality of reflected self-component electromagnetic signals plotted as a function of depth and of distance from a borehole, or a plurality of reflected cross-component electromagnetic signals plotted as a function of depth and of distance from a borehole.

20. The method of claim 11 , wherein the associated values comprise a plurality of anomaly azimuth angle values plotted as a function of depth and of distance from a borehole, or a plurality of anomaly elevation angle values plotted as a function of depth and of distance from a borehole.

Assignees

• Guner Baris
• Donderici Burkay
• Bittar Michael S
• San Martin Luis E
• Halliburton Energy Services Inc

Inventors

• Guner Baris
• Donderici Burkay
• Bittar Michael S
• San Martin Luis E

Classifications

• G01V3/28

  using induction coils · CPC title

• G01V3/30 Primary

  operating with electromagnetic waves · CPC title