Determination of borehole characteristics using orientation components of azimuthal electromagnetic signals

Patent metadata

Field	Value
Publication number	US-11467312-B2
Application number	US-202017089340-A
Country	US
Kind code	B2
Filing date	Nov 4, 2020
Priority date	Nov 4, 2020
Publication date	Oct 11, 2022
Grant date	Oct 11, 2022

Abstract

The disclosure provides a method of determining one or more characteristics associated with a borehole, a computer program product that directs operations of a processor when executed to determine characteristics associated with a borehole, and a borehole characterizing system. In one example the method includes: (1) receiving azimuthal electromagnetic signals obtained in the borehole, wherein the azimuthal electromagnetic signals are transmitted at two operating frequencies in the borehole, (2) decoupling orientation components from the azimuthal electromagnetic signals of the two frequencies, (3) determining one or more borehole characteristics using one or more of the orientation components at the two operating frequencies, and (4) performing a borehole correction based on at least one of the one or more borehole characteristics.

First claim

What is claimed is:

1. A method of determining one or more characteristics associated with a borehole, comprising:
receiving azimuthal electromagnetic signals obtained in the borehole using at least two receivers spaced at a same transmitter-receiver spacing, wherein the azimuthal electromagnetic signals are transmitted at two operating frequencies in the borehole;
decoupling orientation components from the azimuthal electromagnetic signals of the two operating frequencies;
determining one or more borehole characteristics using one or more of the orientation components at the two operating frequencies based on a ratio of the one or more orientation components at the two operating frequencies;
determining a borehole correction based on at least one of the one or more borehole characteristics;
accurately determining a formation resistivity surrounding a tool in the wellbore from the borehole characteristics; and
steering a drill bit based on the determined formation resistivity by indicating when a target formation region has been entered or exited.

2. The method as recited in claim 1 , wherein the determining includes adjusting one or more synthetic parameters until the adjusted one or more synthetic parameters produce synthetic components that match the one or more orientation components within a pre-defined threshold difference.

3. The method as recited in claim 2 , wherein the determining is based on an iterative inversion process or a look-up table process.

4. The method as recited in claim 3 , wherein the one or more synthetic parameter is provided as an output for the one or more borehole characteristic when the iterative process or look-up table searching converges.

5. The method as recited in claim 2 , where the synthetic components are calculated from a forward modeling or pre-calculated database based on the forward modeling.

6. The method as recited in claim 1 , wherein the one or more borehole characteristic includes formation resistivity, mud resistivity, or borehole size.

7. The method as recited in claim 6 , wherein the one or more of the orientation components is a decoupled V zz multi-component and the determining the formation resistivity is based on the V zz multi-component at the two operating frequencies, wherein the V zz multi-component is insensitive to a presence of the mud resistivity in the borehole.

8. The method as recited in claim 7 , wherein the determining the mud resistivity in is based on a decoupled V xx multi-component at one of the two frequencies and the determined formation resistivity, wherein the V xx multi-component is sensitive to both a presence of the formation resistivity and the mud resistivity.

9. The method as recited in claim 1 , further comprising:
generating first azimuthal electromagnetic signals from a transmitter in the borehole at a first operating frequency,
generating second azimuthal electromagnetic signals from the transmitter at a second operating frequency, and
receiving the first and the second azimuthal electromagnetic signals at a receiver in the borehole, wherein the first and second operating frequencies are the two operating frequencies.

10. The method as recited in claim 9 , further comprising storing the azimuthal electromagnetic signals as bin voltages.

11. The method as recited in claim 10 , wherein the orientation components are decoupled multi-components from the bin voltages.

12. The method as recited in claim 1 , wherein a transmitter to receiver spacing for obtaining the azimuthal electromagnetic signals at a first one of the two operating frequencies is different than a transmitter to receiver spacing for obtaining the azimuthal electromagnetic signals at a second one of the two operating frequencies.

13. A computer program product having a series of operating instructions stored on a non-transitory computer readable medium that direct operations of a processor when executed to determine characteristics associated with a borehole, the operations comprising:
determining orientation components from azimuthal electromagnetic signals obtained in the borehole using at least two receivers at a same transmitter-receiver spacing, wherein the azimuthal electromagnetic signals are transmitted at two operating frequencies in the borehole;
selecting at least one of the orientation components;
determining one or more borehole characteristics using the at least one of the orientation components at the two operating frequencies based on a ratio of the one or more orientation components at the two operating frequencies;
determining a borehole correction based on at least one of the one or more borehole characteristics;
accurately determining a formation resistivity surrounding a tool in the wellbore from the borehole characteristics; and
steering a drill bit based on the determined formation resistivity by indicating when a target formation region has been entered or exited.

14. The computer program product as recited in claim 13 , wherein the determining includes using the at least one of the orientation components at the two operating frequencies.

15. The computer program product as recited in claim 13 , wherein the one more borehole characteristic includes formation resistivity, mud resistivity, and borehole size.

16. The computer program product as recited in claim 13 , wherein the determining is based on an iterative inversion process using the at least one of the orientation components as an input.

17. The computer program product as recited in claim 13 , wherein the azimuthal electromagnetic signals represented by bin voltages and the orientation components are decoupled multi-components from the bin voltages.

18. The computer program product as recited in claim 17 , wherein the one or more borehole characteristics includes a formation resistivity and a mud resistivity, and the determining includes determining the formation resistivity and the mud resistivity together using V xx at one of the two operating frequencies and V zz from both of the two operating frequencies as the at least one orientation component.

19. A borehole characterizing system, comprising:
a memory configured to store orientation components from azimuthal electromagnetic signals obtained in a borehole using at least two receivers at a same transmitter-receiver spacing, wherein the azimuthal electromagnetic signals are transmitted at two operating frequencies in the borehole; and
a processor configured to:
determine one or more borehole characteristic using one or more of the orientation components at the two operating frequencies based on a ratio of one or more orientation components at the two operating frequencies;
determine a borehole correction based on at least one of the one or more borehole characteristics;
accurately determine a formation resistivity surrounding a tool in the wellbore from the borehole characteristics; and
steer a drill bit based on the determined formation resistivity by indicating when a target formation region has been entered or exited.

20. The borehole characterizing system as recited in claim 19 , wherein the processor is configured to determine the one or more borehole characteristic using an iterative inversion process and the one or more orientation components as an input for the iterative inversion process.

21. The borehole characterizing system as recited in claim 19 , wherein the one or more of the orientation components are one or more of decoupled multi-components V zz or V xx at one of the two

Assignees

• Halliburton Energy Services Inc

Inventors

• Pan Li
• Wu Hsu-Hsiang
• Fan Yijing

Classifications

• G01V3/38 Primary

  Processing data, e.g. for analysis, for interpretation, for correction · CPC title

• G01V3/30 Primary

  operating with electromagnetic waves · CPC title

• G01V3/20

  operating with propagation of electric current · CPC title