SYSTEM AND METHOD FOR REAL-TIME MANAGEMENT OF FORMATION FLUID SAMPLING WITH A GUARDED PROBE

• US 20080125973A1
• Filed: 09/22/2006
• Published: 05/29/2008
• Est. Priority Date: 09/22/2006
• Status: Active Grant

• Current Assignee: Schlumberger Technology Corporation (Schlumberger NV)
• Original Assignee: Schlumberger Technology Corporation (Schlumberger NV)
• Inventors: Mullins, Oliver C., Sherwood, John D.
• Granted Patent: US 7,757,760 B2
• Time in Patent Office: Days
• US Class Current: 702/11
• CPC Class Codes: E21B 49/10 using side-wall fluid samplers or testers

Abstract

Embodiments of the present invention relate to systems and methods for real-time management of formation fluid sampling down a wellbore using a guarded probe. More specifically, but not by way of limitation, embodiments of the present invention provide for management of downhole fluid sampling by sensing properties of fluids collected by a downhole-fluid-sampling-device, modeling the fluid sampling process from these sensed properties and using the modeling of the fluid sampling process to manage in real-time the fluid sampling process.

Claims

1. A method for real-time management of sampling of formation fluids from an earth formation surrounding a wellbore, the region of the formation immediately surrounding the wellbore being at least partially invaded by wellbore fluids, comprising:

withdrawing fluids from the earth formation;

sensing a physical or chemical property of the withdrawn fluids;

outputting a signal corresponding to the sensed physical or chemical property;

using the output signal to model properties of the withdrawn fluids; and

using the modeled properties of the fluid sample for the real-time management of the sampling of the formation fluids.

2. The method of claim 1, wherein the modeling of the properties of the fluid sample comprises predicting properties of subsequently withdrawn fluids, wherein the subsequently withdrawn fluids comprise the formation fluids withdrawn from the earth formation subsequent to the sensing.

3. A method for real-time management of sampling of formation fluids from an earth formation surrounding a wellbore, the region of the formation immediately surrounding the wellbore being at least partially invaded by wellbore fluids, comprising:

lowering a wellbore tool with a fluid sampling device into the wellbore, the fluid sampling device comprising a sampling probe and a guard probe, wherein the sampling probe and the guard probe are adjacent to one another and wherein the sampling probe is configured for withdrawing a first fluid sample from the formation and the guard probe is configured for withdrawing a second fluid sample from the formation;

urging the fluid sampling device into contact with a wellbore wall;

withdrawing the first and the second fluid samples from the formation;

determining a first property of the first fluid sample;

determining a second property of the second fluid sample; and

using a processor to process in real-time a delta value, wherein the delta value comprises a difference between the first property and the second property.

4. The method of claim 3, wherein the sampling probe comprises an inner probe and the guard probe comprises an outer probe, and wherein the outer probe surrounds the inner probe.

5. The method of claim 3, wherein the sampling probe is maintained at a first pressure and the guard probe is maintained at a second pressure.

6. The method of claim 5, wherein the first pressure is higher than the second pressure.

7. The method of claim 3, wherein the first property is a first contamination amount of the first fluid sample and the second property is a second contamination amount of the second fluid sample.

8. The method of claim 4, further comprising:

identifying in real-time the existence of a maximum of the delta value.

9. The method of claim 5, further comprising:

collecting a portion of the first fluid sample.

10. The method of claim 5, further comprising:

determining in real-time that for a selected period of time after the identification of the maximum of the delta value the delta value is continuously decreasing.

11. The method of claim 7, further comprising:

collecting a portion of the first fluid sample.

12. The method of claim 3, further comprising:

displaying in real-time the processed delta value.

13. The method of claim 3, wherein a single sensor is used to determine the first property of the first fluid sample and the second property of the second fluid sample.

14. The method of claim 3, further comprising:

normalizing a first initial value of the first property and a second initial value of the second property, wherein the first and the second initial values are values of the first and the second property when sampling from the formation commences.

15. The method of claim 4, further comprising:

using the delta value to mathematically model in real-time future properties of the first fluid sample; and

adjusting the first pressure or the second pressure.

16. The method of claim 3, further comprising:

extrapolating in real-time a first future property of the first fluid sample from the delta value.

17. The method of claim 16, further comprising:

using results from the extrapolation to determine when to collect a portion of the first fluid sample.

18. The method of claim 3, further comprising:

extrapolating in real-time a second future property of the second fluid sample from the delta value.

19. The method of claim 16, further comprising:

using results from the extrapolation to determine when to collect a portion of the second fluid sample.

20. The method of claim 19, further comprising:

using results from the extrapolation to determine when to collect a combined portion of the first and the second fluid sample.

21. The method of claim 3, wherein a single sensor is used to determine the first property of the first fluid sample and the second property of the second fluid sample.

22. A system for monitoring sampling of formation fluids from an earth formation surrounding a wellbore, the region of the formation immediately surrounding the wellbore being at least partially invaded by wellbore fluids, comprising:

a wellbore tool configured for use inside the wellbore;

a sampling probe coupled with the wellbore tool and configured for withdrawing a first fluid sample from the formation;

a guard probe coupled with the wellbore tool disposed adjacent to the sampling probe and configured for withdrawing a second fluid sample from the formation;

a first sensor configured to measure a first property of the first fluid sample;

a second sensor configured to measure a second property of the second fluid sample; and

a processor configured to process in real-time a delta value, wherein the delta value comprises a difference between the first property and the second property.

27. The system of claim 22, wherein the first and second sensor comprise a single sensor, and wherein the first fluid sample and the second fluid sample are provided separately to the single sensor for analysis.

28. The system of claim 22, wherein the sampling probe comprises an inner probe and the guard probe comprises an outer probe, and wherein the outer probe surrounds the inner probe.

29. The system of claim 22, wherein the sampling probe is maintained at a first pressure and the guard probe is maintained at a second pressure.

31. The system of claim 22, wherein the wellbore tool is configured for use on a wireline or a drillstring.

32. The system of claim 22, wherein the first and the guard probe are configured to penetrate through the wellbore wall.

33. The system of claim 22, wherein the first and the guard probe are configured to penetrate the formation.

34. The system of claim 22, further comprising:

an interface coupled with the wellbore tool and configured to display an output from the processor.

23. The system of 22, wherein the processor is configured to extrapolate in real-time a first contamination value of the first fluid sample or a second contamination value of the second fluid sample using the delta value.

24. The system of 22, further comprising:

a collection container coupled with the sampling probe or the guard probe and configured for collecting a portion of the first or the second fluid sample.

25. The system of 22, further comprising:

a collection container coupled with the first and the guard probe and configured for collecting a portion of the first and the second fluid sample.

30. The system of claim 25, wherein the processor controls the first and the second pressure.

26. The system of 24, wherein the processor is configured to extrapolate in real-time a first contamination value of the first fluid sample or a second contamination value of the second fluid sample using the delta value, and wherein the processor is configured in real-time to control the collection container to collect a portion of the first or the second fluid sample based upon results of the extrapolation.