SYSTEMS AND METHODS FOR WELL DATA ANALYSIS

• US 20090165548A1
• Filed: 12/31/2007
• Published: 07/02/2009
• Est. Priority Date: 12/31/2007
• Status: Active Grant

• Current Assignee: Schlumberger Technology Corporation (Schlumberger NV)
• Original Assignee: Schlumberger Technology Corporation (Schlumberger NV)
• Inventors: Follini, Jean-Marc, Pop, Julian
• Granted Patent: US 8,136,395 B2
• Time in Patent Office: Days
• US Class Current: 73/152.510
• CPC Class Codes: E21B 49/008 by injection test; by analysing pressure variations in an injection or production test, e.g. for estimating the skin factor measuring pressure E21B47/06

Abstract

Examples of techniques for analyzing well data which may be encountered during formation testing are disclosed. Certain portions of the tests may exhibit an indication of anomalous behavior, defects, errors or events that may have occurred during testing. One or more confidence tokens may be identified during or after the execution of a test. One or more of these confidence tokens may be analyzed to determine whether such anomalous behavior, defects, errors or events have occurred during the test. These confidence tokens may then be used to determine a level of confidence in the results derived from the tests performed and/or their underlying data and interpretation.

Claims

1. A method for determining a confidence in measurements taken by a while drilling testing tool positioned in a wellbore penetrating a subterranean formation, the method comprising:

establishing a pressure coupling between a pressure sensor conveyed by the testing tool and the formation;

performing a first drawdown with the testing tool;

measuring data indicative of pressure with the pressure sensor;

determining at least one confidence token based on the pressure data; and

displaying the at least one confidence token.

2. The method of claim 1 further including a second drawdown.

3. The method of claim 2 wherein the second drawdown parameters are based at least in part on the at least one confidence token.

4. The method of claim 2 wherein the confidence token is determined using a parameter comparison technique.

5. The method of claim 1 further including terminating the pressure coupling.

6. The method of claim 1 further including identifying a downhole condition.

7. The method of claim 6 further including displaying at the surface the identified condition.

8. A method for determining a confidence in measurements taken by a testing tool positioned in a wellbore penetrating a subterranean formation, the method comprising:

establishing a pressure coupling between a pressure sensor conveyed by the testing tool and the formation;

performing a first drawdown with the testing tool;

measuring data indicative of a pressure with the pressure sensor;

determining at least one confidence token based on the pressure data using one of a trend analysis technique and a noise scattering analysis technique; and

displaying the at least one confidence token.

9. The method of claim 8 wherein the trend analysis technique is a global trend analysis technique.

10. The method of claim 8 wherein the scattering analysis technique is a global scattering analysis technique.

11. The method of claim 8 further including determining a second confidence token using one of a pressure comparison technique, a parameter prediction technique, a model correlation technique, a gauge comparison technique and a supercharging technique.

12. The method of claim 8 wherein the trend analysis technique comprises reflecting pressure data beyond the end of a buildup cycle.

13. The method of claim 12 wherein the at least one confidence token is representative of a slope of a pressure curve at an end of a buildup cycle.

14. The method of claim 8 further including identifying a downhole condition.

15. The method of claim 14 further including displaying at the surface the identified condition.

16. A method for determining a confidence in measurements taken by a downhole tool positioned in a wellbore penetrating a subterranean formation, the method comprising:

selecting a plurality of downhole conditions;

associating a different value to each of the plurality of the downhole conditions;

performing a downhole measurement;

identifying one of the plurality of downhole conditions, wherein the identifying is based on the downhole measurement;

transmitting to a surface display a value associated with the identified condition;

receiving the value at the surface display; and

displaying indicia indicative of the identified downhole condition.

17. The method of claim 16 wherein identifying one of the plurality of downhole conditions comprises:

determining a plurality of confidence tokens; and

comparing each of the plurality of confidence token to a predetermined threshold.

18. The method of claim 16 further including:

determining at least one confidence token; and

displaying the confidence token.

19. The method of claim 17 further comprising:

identifying a plurality of events associated with the operation of said downhole tool;

selecting data points for transmission by said downhole tool, said data points being selected as a function of said plurality of events and a growth function;

determining values associated with said plurality of events and said data points for transmission by said downhole tool;

transmitting to a surface display the determined values; and

displaying the transmitted data on a well log.