Claims
- 1. A method of determining a parameter of interest of an earth formation using a tool conveyed in a borehole in the earth formation, the method comprising:
(a) obtaining measurements indicative of said parameter of interest with a first resistivity measuring instrument responsive to a property of the earth formation proximate to the borehole (near zone); (b) determining from said measurements a first model comprising a property of said near zone, (c) obtaining multicomponent measurements indicative of a vertical resistivity of said earth formation; and (d) determining from said first model and said multicomponent measurements said parameter of interest.
- 2. The method of claim 1 wherein said property of said first model comprises at least one of (i) a thicknesses of a plurality of layers, (ii) a length and resistivity of an invaded zone corresponding to said plurality of layers, and, (iii) horizontal resistivities of said earth formation outside said invaded zone.
- 3. The method of claim 1 wherein said parameter of interest comprises at least one of (i) a vertical resistivity of said earth formation, and, (ii) an anisotropy factor for said earth formation.
- 4. The method of claim 1 wherein said first resistivity measuring instrument comprises a galvanic instrument.
- 5. The method of claim 4 wherein said galvanic instrument comprises at least one of (i) a Dual Laterolog/Microlaterolog (DLL/MLL), and, (ii) a High-Definition Lateral Log/Microlaterolog (HDLL/MLL).
- 6. The method of claim 1 wherein determining said first model comprises performing an inversion of measurements made by said first instrument.
- 7. The method of claim 1 wherein determining said parameter of interest further comprises performing an inversion of said multicomponent measurements wherein said thicknesses of said layers, and said length and resistivity corresponding to each of said plurality of layers are fixed in said inversion.
- 8. The method of claim 7 wherein performing said inversion further comprises defining a global objective function that is the sum of a data objective function and a model objective function.
- 9. The method of claim 7 wherein performing said inversion further comprises using a rapid inversion algorithm.
- 10. The method of claim 9 wherein said rapid inversion is performed substantially at the well site.
- 11. The method of claim 1 wherein said multicomponent measurements comprise measurements made at a plurality of frequencies.
- 12. The method of claim 1 wherein said multicomponent measurements comprise measurements made at two frequencies.
- 13. An apparatus for use in a borehole in an earth formation for determining a parameter of interest of the earth formation, the apparatus comprising:
(a) a first resistivity measuring instrument responsive to a property of the earth formation proximate to the borehole (near zone); (b) a processor for determining from said measurements made by said first instrument a first model comprising properties of said near zone, (c) a second resistivity measuring instrument for obtaining measurements indicative of a vertical resistivity of said earth formation; and (d) a processor for determining said parameter of interest from said first model and said measurements mad by said second instrument.
- 14. The apparatus of claim 13 wherein said first instrument comprises a galvanic instrument.
- 15. The apparatus of claim 14 wherein said galvanic instrument comprises at least one of (i) a Dual Laterolog/Microlaterolog (DLL/MLL), and, (ii) a High-Definition Lateral Log/Microlaterolog (HDLL/MLL).
- 16. The apparatus of claim 14 wherein said galvanic instrument comprises an array device.
- 17. The apparatus of claim 14 wherein said second instrument comprises an induction device having a plurality of transmitter-receiver combinations, wherein at least one transmitter or at least one receiver comprises an antenna with an axis inclined to an axis of the second instrument.
- 18. The apparatus of claim 14 wherein said model further comprises (i) thicknesses of a plurality of layers, (ii) a length and resistivity of an invaded zone corresponding to said plurality of layers, and, (iii) a horizontal resistivity of said earth formation outside said invaded zone.
- 19. The apparatus of claim 13 wherein said parameter of interest comprises at least one of (i) a vertical resistivity of said earth formation, and, (ii) an anisotropy factor for said earth formation.
- 20. The apparatus of claim 13 wherein determining said first model comprises performing an inversion of measurements made by said first instrument.
- 21. The apparatus of claim 13 wherein determining said parameter of interest further comprises performing an inversion of said measurements made by said second instrument wherein said thicknesses of said layers, and said length and resistivity corresponding to each of said plurality of layers are fixed in said inversion.
- 22. The apparatus of claim 13 wherein said processor in (d) performs said inversion substantially at the well site.
- 23. The apparatus of claim 13 wherein at least one of said processor in (b) and said processor in (d) is at a surface location.
- 24. The apparatus of claim 13 wherein at least one of said processor in (b) and said processor in (d) is at a downhole location.
- 25. A system for estimating a parameter of interest of an earth formation penetrated by a borehole, the system comprising:
(a) a first resistivity measuring instrument responsive to a property of the earth formation proximate to the borehole (near zone); (b) a processor for determining from said measurements made by said first instrument a first model comprising properties of said near zone, (c) a second resistivity measuring instrument for obtaining measurements indicative of a vertical resistivity of said earth formation; (d) a processor for determining said parameter of interest from said first model and said measurements mad by said second instrument; and (e) a conveyance device for conveying said first and second instruments into said borehole.
- 26. The system of claim 25 wherein said conveyance device comprises a wireline.
- 27. The system of claim 25 wherein said conveyance device comprises coiled tubing.
- 28. The system of claim 25 wherein said conveyance device comprises a drilling tubular.
- 29. The system of claim 25 wherein said second instrument comprises an induction device having a plurality of transmitter-receiver combinations, wherein at least on transmitter or at least one receiver comprises an antenna with an axis inclined to an axis of the second instrument.
- 30. The system of claim 25 further comprising an additional instrument for determining a parameter of instrument of said earth formation.
CROSS REFERENCES TO RELATED APPLICATIONS
[0001] This application claims priority from U.S. Provisional Patent Application Ser. No. 60/414,175 filed on 27 Sep. 2002.
Provisional Applications (1)
|
Number |
Date |
Country |
|
60414175 |
Sep 2002 |
US |