Claims
- 1. A method for determining formation characteristics comprising:
establishing baseline casing conditions for a string of casing disposed within a wellbore in a formation; measuring updated casing conditions for the string of casing at a first time interval from the establishing of the baseline casing conditions; comparing the baseline casing conditions to the updated casing conditions to determine changes in the string of casing over the first time interval; using the changes in the string of casing to determine formation characteristics.
- 2. The method of claim 1 wherein the baseline and updated casing conditions comprise geometric data taken from a plurality of depths within the string of casing.
- 3. The method of claim 2 wherein the geometric data comprises one or more of diameter, thickness, and eccentricity at a single depth within the string of casing.
- 4. The method of claim 1 wherein the formation characteristics comprise one or more of compaction, strain, failure prediction, and permeability.
- 5. The method of claim 1 further comprising adjusting reservoir management in response to the determined formation characteristics.
- 6. The method of claim 1 wherein the casing conditions are measured by acquiring ultrasonic data.
- 7. The method of claim 6 wherein the ultrasonic data includes two-way travel time and amplitude of first arrival of an ultrasonic signal.
- 8. A method for determining formation compaction comprising:
disposing an ultrasonic tool within a cased wellbore disposed within a formation; performing an ultrasonic evaluation of the casing at a plurality of depths within the wellbore, wherein the ultrasonic evaluation produces an ultrasonic waveform response; using the ultrasonic waveform response to determine geometric properties of the casing; and using the geometric properties of the casing to determine formation compaction.
- 9. The method of claim 8 wherein performing the ultrasonic evaluation further comprises:
transmitting a signal from the ultrasonic tool toward the formation; receiving the signal from the formation; monitoring an amplitude of first arrival and a two-way travel time of the signal to and from the formation; determining a thickness of the casing using the amplitude of first arrival; and determining a diameter of the cased wellbore using the two way travel time.
- 10. The method of claim 9 wherein performing the ultrasonic evaluation further comprises:
determining the relationship between the center of the ultrasonic tool and the center of the casing; and determining a corrected radius by adjusting for the relationship between the center of the ultrasonic tool and the center of the casing.
- 11. The method of claim 9 wherein performing the ultrasonic evaluation further comprises:
determining a casing diameter from the corrected radius; calculating a cross-sectional casing area from the corrected radius; and determining formation compaction from the cross-sectional casing area.
- 12. The method of claim 8 further comprising using the geometric properties of the casing to determine formation strain.
- 13. The method of claim 8 further comprising using the geometric properties of the casing to determine formation permeability.
- 14. The method of claim 8 further comprising using the geometric properties of the casing to predict failure of the wellbore.
- 15. The method of claim 8 further comprising adjusting reservoir management in response to the formation compaction.
- 16. A method for determining formation compaction comprising:
establishing baseline values for a property of a casing string disposed within a wellbore drilled in a formation, wherein the baseline values are determined at a plurality of depths in the wellbore; determining updated values for the geometric property at a plurality of depths in the wellbore; comparing the updated values to the baseline values to determine changes in the one or more geometric properties; and determining formation compaction based on an established correlation between formation compaction and changes in the geometric property.
- 17. The method of claim 16 wherein the correlation is established by comparing compaction logs to geometric properties of a portion of a cased wellbore that has markers locatable by a compaction logging tool.
- 18. The method of claim 17 wherein the portion of the cased wellbore that has markers is a reference well drilled in a separate location in the formation.
- 19. The method of claim 16 wherein the baseline values are determined by inspection logs performed prior to the updated values being determined.
- 20. The method of claim 16 wherein the baseline values are determined by casing data acquired before the casing is installed in the wellbore.
- 21. The method of claim 20 wherein the baseline values are determined by adjusting the casing data for in-situ effects from the formation.
- 22. The method of claim 16 further comprising monitoring production from the wellbore in the time period prior to determining the updated values of the geometric property.
- 23. The method of claim 22 further comprising regulating production from the wellbore in response to determined formation compaction.
- 24. The method of claim 22 further comprising adjusting production from other wells in the formation in response to determined formation compaction.
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to U.S. Provisional Patent Application 06/469,526, filed May 9, 2003, and entitled “Formation Characterization using Wellbore Logging Data,” which is hereby incorporated by reference herein for all purposes.
Provisional Applications (1)
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Number |
Date |
Country |
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60469526 |
May 2003 |
US |