SINGLE WELL RESERVOIR IMAGING APPARATUS AND METHODS

• US 20110227577A1
• Filed: 03/19/2010
• Published: 09/22/2011
• Est. Priority Date: 03/19/2010
• Status: Active Grant

• Current Assignee: Schlumberger Technology Corporation (Schlumberger NV)
• Original Assignee: Schlumberger Technology Corporation (Schlumberger NV)
• Inventors: Badri, Mohammed, Zhang, Tianhua, Ligneul, Patrice, Akbar, Mahmood
• Granted Patent: US 8,680,865 B2
• Time in Patent Office: Days
• US Class Current: 324/338
• CPC Class Codes: E21B 47/047 Liquid level measuring depth or liquid level using radioactive markers E21B47/053
• CPC Class Codes: E21B 47/12 Means for transmitting measuring-signals or control signals from the well to the surface, or from the surface to the well, e.g. for logging while drilling
• CPC Class Codes: G01B 3/30 Bars, blocks, or strips in which the distance between a pair of faces is fixed, although it may be preadjustable, e.g. end measure, feeler strip
• CPC Class Codes: G01V 3/26 operating with magnetic or electric fields produced or modified either by the surrounding earth formation or by the detecting device with electromagnetic waves G01V3/30
• CPC Class Codes: G01V 3/28 using induction coils
• CPC Class Codes: G01V 3/30 operating with electromagnetic waves

Abstract

An apparatus and related methods are described for detecting features of a reservoir surrounding a borehole, the apparatus being capable of emitting an electromagnetic wave signal and receiving a signal representing a response of the reservoir to the electromagnetic wave signal, wherein the emitted signal is a broadband signal selected from within the range of 1 Hz to 1000 Ghz and the received signal includes a directional characteristic to provide an azimuthal determination of the direction of a discontinuity within the formation as the discontinuity reflects or scatters at least part of the broadband signal; azimuthally scanning the surrounding formation; and inverting the received signal for deriving at least a distance of the reflecting discontinuity from the borehole using simultaneous inversion of the reflected or scattered wavefield at multiple frequencies.

Claims

1. An apparatus for detecting features of a subterranean formation surrounding a borehole, said apparatus comprising:

at least one transmitter to emit an electromagnetic wave signal and at least one receiver to receive a signal representing a response of said formation to said electromagnetic wave signal, wherein said at least one transmitter emits a broadband signal from within the range of 1 Hz to 1000 Ghz and said at least one transmitter and said at least one receiver combined have a directional characteristic to provide an azimuthal determination of the direction of a discontinuity within said formation as said discontinuity reflects or scatters at least part of said broadband signal and wherein said at least one transmitter and said at least one receiver are mounted on a tool body to allow an azimuthally resolved scanning of said surrounding formation; and

further comprising output feeds for connecting said at least one transmitter and said at least one receiver to an inversion calculator for deriving at least a distance of said reflecting discontinuity from the borehole from a simultaneous inversion of a reflected wavefield at multiple frequencies.

2. The apparatus of claim 1, wherein the inversion calculator is adapted to include a non-linear frequency response of the formation to the electromagnetic wave signal.

3. The apparatus of claim 1, having the ability to modulate and demodulate higher frequency electromagnetic waves into lower frequency carrier waves to ensure length of penetration.

4. The apparatus of claim 1, having a transmitter and/or receiver arrangement rotatable mounted on the tool body.

5. The apparatus of claim 1, having a plurality of transmitter and/or receiver arrangements arranged around the circumference of the tool body.

6. The apparatus of claim 1, wherein the emitted signals has significant output at frequencies spread across at least 4 orders of magnitude within the electromagnetic frequency spectrum.

7. The apparatus of claim 1, wherein the multi-frequency inversion is inverting frequencies spread across at least 4 orders of magnitude within the electromagnetic frequency spectrum.

8. The apparatus of claim 1, wherein the inversion calculator is designed to perform a waveform inversion.

9. The apparatus of claim 1, wherein the inversion calculator provides any or all of azimuthal direction, radial distance from the borehole and aperture of a fracture.

10. The apparatus of claim 1, wherein the inversion calculator provides any or all of azimuthal direction, radial distance from the borehole of a body of water.

11. The apparatus of claim 1, wherein the inversion calculator provides control signals to geo-steer a drilling tool relative to the discontinuities.

12. The apparatus of claim 1, wherein the inversion calculator provides azimuthally resolved water saturations at a distance from the well.

13. A method for detecting features of a reservoir surrounding a borehole, said method comprising the steps of:

emitting an electromagnetic wave signal and receiving a signal representing a response of said reservoir to said electromagnetic wave signal, wherein said emitted signal is a broadband signal from within the range of 1 Hz to 1000 Ghz and the received signal includes a directional characteristic to provide an azimuthal determination of the direction of a discontinuity within the formation as said discontinuity reflects at least part of said broadband signal;

scanning azimuthally the surrounding formation; and

inverting the received signal for deriving at least a distance of said reflecting discontinuity from the borehole using simultaneous inversion of a reflected wavefield at multiple frequencies.

14. The method of claim 13, wherein the inversion includes a possible non-linear frequency response of the formation to the electromagnetic wave signal.

15. The method of claim 13, including the further step of modulating and demodulating higher frequency electromagnetic waves into lower frequency carrier waves to ensure of length of penetration.

16. The method of claim 13, including the step of rotating in the borehole a transmitter and/or receiver arrangement for the electromagnetic signals.

17. The method of claim 13, wherein the emitted signals has significant output at frequencies spread across at least 4 orders of magnitude within the electromagnetic frequency spectrum.

18. The method of claim 13, wherein the multi-frequency inversion is inverting frequencies spread across at least 4 orders of magnitude within the electromagnetic frequency spectrum.

19. The method of claim 14, wherein the inversion is designed to a full waveform inversion.

20. The method of claim 13, further comprising the step of performing the inversion to provide any or all of azimuthal direction, radial distance from the borehole and aperture of a fracture.

21. The method of claim 13, further comprising the step of performing the inversion to provide any or all of azimuthal direction, radial distance from the borehole and aperture of a fracture not crossing the borehole.

22. The method of claim 13, further comprising the step of performing the inversion to provide any or all of azimuthal direction, radial distance from the borehole of a body of water.

23. The method of claim 13, further comprising the step of performing the inversion to provide control signals to geo-steer a drilling tool relative to the discontinuities.

24. The method of claim 13, further comprising the step of performing the inversion to provide azimuthally resolved water saturations at a distance from the well.