Claims
- 1. A method of simulating the signal of an electromagnetic source, comprising the steps of
a) locating a dipole source at a first excitation location, said first excitation location corresponding to a first segment of said electromagnetic source; b) energizing the dipole source; c) measuring an electromagnetic signal at one or more receiver locations; d) repeating steps a, b, and c for one or more additional excitation locations, each said additional excitation location corresponding to an additional segment of said electromagnetic source; and e) using the measured electromagnetic signals to simulate the signal of the electromagnetic source.
- 2. The method of claim 1, wherein said segments cumulatively encompass substantially the entire length of said electromagnetic source.
- 3. The method of claim 1, wherein the electromagnetic source to be simulated is a radial bipole source.
- 4. The method of claim 1, wherein the electromagnetic source to be simulated is a concentric ring source.
- 5. The method of claim 4, wherein said concentric ring source is simulated from six or more simulated radial bipole sources.
- 6. The method of claim 1, wherein said simulation derives from a Green's function integration of the measured electromagnetic signals.
- 7. The method of claim 6, wherein said integration is performed in the time domain.
- 8. The method of claim 6, wherein said integration is performed in the frequency domain.
- 9. The method of claim 1, wherein the measured electromagnetic signals are normalized to a corresponding source signal.
- 10. A method of simulating the signal of a grounded concentric ring source, comprising the steps of
a) locating a dipole source at a first excitation location, said first excitation location corresponding to a first segment of a first radial bipole source; b) energizing the dipole source; c) measuring an electromagnetic signal at one or more receiver locations; d) repeating steps a, b, and c for one or more additional excitation locations, each said additional excitation location corresponding to an additional segment of said first radial bipole source; e) using the measured electromagnetic signals to simulate the signal of said first radial bipole source; f) repeating steps a, b, c, d, and e for at least five additional radial bipole sources; and g) using the simulated signals for the radial bipole sources to simulate the signal of said grounded concentric ring source.
- 11. A method of imaging a subsurface formation, comprising the steps of:
a) computing the inner and outer radii of a grounded electromagnetic concentric ring source focused on the formation; b) using the radii to compute the length of a radial electric bipole corresponding to the ring source; c) using the length of the radial electric bipole to determine the length of a radial dipole source; d) positioning the radial dipole source at a first position along a radius of the ring source; e) energizing the radial dipole source; f) measuring an electromagnetic signal at one or more receiver locations; g) repeating steps d, e, and f for one or more additional positions of the radial dipole source along the radius; h) using the measured electromagnetic signals to compute the signal of a virtual radial bipole corresponding to the radius; i) repeating steps d, e, f, g, and h for at least five additional radii of the ring source; and j) using the signals of the virtual radial bipoles to image the formation.
- 12. The method of claim 11, wherein the image of the formation is created using virtual source configurations created from use of Green's function reciprocity conditions.
- 13. The method of claim 11, wherein said formation is imaged at two or more depths, each said depth corresponding to a specific set of virtual concentric ring sources, wherein signals of virtual radial bipoles corresponding to each said set of virtual concentric ring sources are used to image said formation at the depth corresponding to said virtual concentric ring sources.
- 14. A method of varying the central focusing zone of a bipole source, comprising the steps of:
a) Using a dipole source sequentially along substantially the entire length of a linear bipole source to acquire electromagnetic data to simulate said linear bipole source; b) Using a first combination of said data to image the subsurface for a first central focusing zone, and c) Repeating step b) one or more times to image the subsurface for additional central focusing zones.
Parent Case Info
[0001] This application claims the benefit of U.S. Provisional Application No. 60/318,082 filed on Sep. 7, 2001.
Provisional Applications (1)
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Number |
Date |
Country |
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60318082 |
Sep 2001 |
US |