Interpretation of dielectric tool measurements using general mixing laws

Patent metadata

Field	Value
Publication number	US-11892586-B2
Application number	US-202217572686-A
Country	US
Kind code	B2
Filing date	Jan 11, 2022
Priority date	Jan 11, 2022
Publication date	Feb 6, 2024
Grant date	Feb 6, 2024

Abstract

Methods for determining water-filled porosity using a general volumetric mixing law and the measurements of a dielectric tool are described. The water-filled porosity estimates are used to obtain water salinity estimates and the optimal parameters of the volumetric mixing law. These estimates are in turn used to generate novel quality indicators.

First claim

What is claimed is:

1. A method to determine parameters of a volumetric mixing law and water salinity using complex measurements obtained by a downhole dielectric tool, the method comprising:
calculating, using real measurements obtained by the dielectric tool, a first estimate of water-filled porosity;
calculating, using imaginary measurements obtained by the dielectric tool, a second estimate of water-filled porosity;
calculating, using complex measurements obtained by the dielectric tool, a third estimate of water-filled porosity;
calculating values of the volumetric mixing law parameters and water salinity that minimize a difference between at least two of the first, second, or third estimates of water-filled porosity, thereby resulting in an optimal water salinity and volumetric mixing law parameters;
using the optimal water salinity and volumetric mixing law parameters to determine a final estimate of the water-filled porosity; and
performing a downhole operation based upon the final estimate of the water-filled porosity.

2. The method as defined in claim 1 , further comprising:
calculating a final estimate of water-filled porosity based on a fit of the volumetric mixing law to at least one of the real, imaginary, or complex measurements using the optimal water salinity and volumetric mixing law parameters; or
calculating a final estimate of the water-filled porosity based on a weighted average of at least two of the first, second, or third estimates of the water-filled porosity.

3. The method as defined in claim 2 , further comprising determining a quality indicator based upon a fit of the real, imaginary, or complex measurements to the volumetric mixing law using the final estimate of water-filled porosity and the optimal water salinity.

4. The method as defined in claim 1 , wherein the dielectric tool is a multi-frequency tool and wherein more than three water-filled porosity estimates are applied to calculate the optimal water salinity and volumetric mixing law parameters.

5. The method as defined in claim 1 , further comprising generating an image of a hydrocarbon-bearing formation using the optimal water salinity and volumetric mixing parameters.

6. The method as defined in claim 1 , further comprising determining a quality indicator based upon a normalized difference between the first, second, and third estimates of the water-filled porosity.

7. The method as defined in claim 1 , further comprising determining a quality indicator by:
equating the obtained dielectric tool measurements to different models for permittivity of water or refractive index of water to obtain different water salinity estimates;
comparing the water salinity estimates; and
determining a quality of the different water salinity estimates based upon a deviation of the different water salinity estimates from a mean.

8. The method as defined in claim 1 , further comprising:
determining a plurality of quality indicators for the water-filled porosity estimates, the quality indicators being determined using different methods; and
determining a total quality indicator based upon a weighted average of the quality indicators.

9. A system to determine parameters of a volumetric mixing law and water salinity using complex measurements obtained by a downhole dielectric tool, the system comprising:
a dielectric tool; and
processing circuitry communicably coupled to the dielectric tool to perform operations comprising:
calculating, using real measurements obtained by the dielectric tool, a first estimate of water-filled porosity;
calculating, using imaginary measurements obtained by the dielectric tool, a second estimate of water-filled porosity;
calculating, using complex measurements obtained by the dielectric tool, a third estimate of water-filled porosity;
calculating values of the volumetric mixing law parameters and water salinity that minimize a difference between at least two of the first, second, or third estimates of water-filled porosity, thereby resulting in an optimal water salinity and volumetric mixing law parameters;
using the optimal water salinity and volumetric mixing law parameters to determine a final estimate of the water-filled porosity; and
performing a downhole operation based upon the final estimate of the water-filled porosity.

10. The system as defined in claim 9 , further comprising:
calculating a final estimate of water-filled porosity based on a fit of the volumetric mixing law to at least one of the real, imaginary, or complex measurements using the optimal water salinity and volumetric mixing law parameters.

11. The system as defined in claim 10 , further comprising determining a quality indicator based upon a fit of the real, imaginary, or complex measurements to the volumetric mixing law using the final estimate of water-filled porosity and the optimal water salinity.

12. The system as defined in claim 9 , wherein:
the dielectric tool is a multi-frequency tool; and
more than three water-filled porosity estimates are applied to calculate the optimal water salinity and volumetric mixing law parameters.

13. The system as defined in claim 9 , further comprising generating an image of a hydrocarbon-bearing formation using the optimal water salinity and volumetric mixing parameters.

14. The system as defined in claim 9 , further comprising determining a quality indicator based upon a normalized difference between the first, second and third estimates of the water-filled porosity.

15. The system as defined in claim 9 , further comprising determining a quality indicator comprising:
equating the obtained dielectric tool measurements to different models for permittivity of water or refractive index of water to obtain different water salinity estimates;
comparing the water salinity estimates; and
determining a quality of the different water salinity estimates based upon a deviation of the different water salinity estimates from a mean.

16. The system as defined in claim 9 , further comprising:
determining a plurality of quality indicators for the water-filled porosity estimates, the quality indicators being determined using different methods;
determining a total quality indicator based upon a weighted average of the quality indicators.

17. The system as defined in claim 9 , further comprising:
calculating a final estimate of the water filled porosity based on a weighted average of at least two or the first, second, or third estimates of the water filled porosity.

Assignees

• Halliburton Energy Services Inc

Inventors

• Hou Junsheng
• Guner Baris
• Fouda Ahmed

Classifications

• G01V3/32 Primary

  operating with electron or nuclear magnetic resonance · CPC title

• E21B47/04

  Measuring depth or liquid level · CPC title

• E21B47/07

  Temperature · CPC title

• G01V3/38

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

• E21B49/087

  Well testing, e.g. testing for reservoir productivity or formation parameters · CPC title