METHODS AND APPARATUS TO SAMPLE HEAVY OIL IN A SUBTERRANEAN FORMATION

• US 20090008079A1
• Filed: 12/21/2007
• Published: 01/08/2009
• Est. Priority Date: 01/17/2007
• Status: Active Grant

• Current Assignee: Schlumberger Technology Corporation (Schlumberger NV)
• Original Assignee: Schlumberger Technology Corporation (Schlumberger NV)
• Inventors: Zazovsky, Alexander, Goodwin, Anthony, Tabanou, Jacques R., Safinya, Kambiz A.
• Granted Patent: US 8,496,054 B2
• Time in Patent Office: Days
• US Class Current: 166/60
• CPC Class Codes: E21B 36/04 using electrical heaters
• CPC Class Codes: E21B 43/2401 by means of electricity
• CPC Class Codes: E21B 49/10 using side-wall fluid samplers or testers

Abstract

A method for sampling fluid in a subterranean formation includes, reducing a viscosity a fluid, pressurizing a portion of the subterranean formation, and collecting a fluid sample. Specifically, a viscosity of a fluid in a portion of the subterranean formation is reduced and a portion of the subterranean formation is pressurizing by injecting a displacement fluid into the subterranean formation. A sample of the fluid pressurized by the displacement fluid is then collected.

Claims

1. A method for sampling fluid in a subterranean formation, comprising:

producing heat in a portion of the subterranean formation by one of an ohmic heating and a dielectric heating;

pressurizing the heated portion of the subterranean formation by injecting a displacement fluid into the heated portion of the subterranean formation; and

collecting a sample of fluid mobilized by the displacement fluid from the heated portion of the subterranean formation via at least one formation interface.

2. A method as defined in claim 1, further comprising detecting a merging of a plurality of heated volumes of the subterranean formation.

3. A method as defined in claim 2, wherein pressurizing the heated portion of the subterranean formation comprises pressurizing the heated portion of the subterranean formation in response to detecting the merging of the plurality of the heated volumes of the subterranean formation.

4. A method as defined in claim 1, further comprising detecting a viscosity of a fluid in the heated portion of the subterranean formation.

5. A method as defined in claim 4, wherein detecting a viscosity of a fluid in the heated portion comprises performing a nuclear magnetic resonance measurement.

6. A method as defined in claim 4, wherein pressurizing the heated portion of the subterranean formation comprises pressurizing the heated portion of the subterranean formation in response to detecting the viscosity of the fluid.

7. A method as defined in claim 1, wherein producing heat in the portion of the subterranean formation comprises heating the portion of the subterranean formation based on a temperature of the portion of the subterranean formation.

8. A method as defined in claim 1, wherein collecting the sample of fluid comprises collecting the sample of fluid prior to the displacement fluid entering the at least one of the formation interfaces.

9. A method as defined in claim 1, wherein the displacement fluid comprises at least one of nitrogen, carbon dioxide, steam or dibromoethane.

10. An apparatus to sample fluid from a subterranean formation, comprising:

a formation interface that is hydraulically coupled to the subterranean formation;

at least one of a plurality of electrodes and a coil to produce heat in a portion of the subterranean formation by one of an ohmic heating and a dielectric heating;

a collection container to hold a fluid sample extracted from the subterranean formation via the formation interface; and

a pressurization device to inject a displacement fluid into the subterranean formation to urge the fluid sample toward the collection container.

11. An apparatus as defined in claim 10, wherein the at least one of a plurality of electrodes and a coil comprises a plurality of electrodes electrically insulated from a body of a downhole tool, and wherein the formation interface is disposed between the electrodes.

12. An apparatus as defined in claim 10, wherein the at least one of the plurality of electrodes and a coil is integrated with the formation interface.

13. An apparatus as defined in claim 10, wherein the at least one of an electrode and a coil is disposed between a sampling probe and an injection probe.

14. An apparatus as defined in claim 10, further comprising a fluid container to hold the displacement fluid.

15. An apparatus as defined in claim 10, wherein the at least one of an electrode and a coil comprises a focusing electrode.

16. An apparatus as defined in claim 10, further comprising a pressure sensor to detect a pressure at the formation interface.

17. An apparatus as defined in claim 10, further comprising a temperature sensor to measure a temperature of the portion of the subterranean formation.

18. An apparatus as defined in claim 10, further comprising a viscosity measurement unit to measure a viscosity of a fluid in the heated portion of the subterranean formation.

19. An apparatus as defined in claim 18, wherein the viscosity measurement unit comprises a nuclear magnetic resonance device.

20. An apparatus as defined in claim 10, wherein the at least one of a plurality of electrodes and a coil comprises a plurality of electrodes arranged to provide overlap of currents flowing between the electrodes.

21. An apparatus as defined in claim 10, wherein the displacement fluid comprises at least one of nitrogen, carbon dioxide, steam or dibromoethane.

22. An apparatus as defined in claim 10, wherein the collection container comprises a sampling piston configured to reduce a parasitic volume of sampling fluid associated with the formation interface.

23. A method for sampling fluid in a subterranean formation, comprising:

heating a portion of the subterranean formation;

pressurizing the heated portion of the subterranean formation by injecting a displacement fluid into the subterranean formation; and

collecting a sample of fluid mobilized by the displacement fluid.

24. An apparatus to sample fluid from a subterranean formation, comprising:

a formation interface that is hydraulically coupled to the subterranean formation;

a heater configured to provide heat to a portion of the subterranean formation;

a collection container to hold a fluid sample extracted from the subterranean formation via the formation interface; and

a pressurization device to inject a displacement fluid into the subterranean formation to urge the fluid sample toward the collection container.

25. A method for sampling fluid in a subterranean formation, comprising:

reducing a viscosity of a fluid in a portion of the subterranean formation;

pressurizing the portion of the subterranean formation having the reduced viscosity fluid by injecting a displacement fluid into the subterranean formation; and

collecting a sample of the fluid pressurized by the displacement fluid.