Downhole fluid analysis methods for determining viscosity

Patent metadata

Field	Value
Publication number	US-10480316-B2
Application number	US-201715822293-A
Country	US
Kind code	B2
Filing date	Nov 27, 2017
Priority date	Dec 6, 2013
Publication date	Nov 19, 2019
Grant date	Nov 19, 2019

Abstract

The present disclosure relates to methods and apparatus for determining a viscosity-pressure profile of downhole fluid by measuring the viscosity at several different pressures during a sampling operation. According to certain embodiments, the viscosity may be measured at different times during a sampling operation and used to generate the viscosity-pressure profile. For example, the viscosity may be measured at the beginning of pumping, during filling of a sample chamber, during a pressure-build up period, and while retracting the probe. The measured viscosities may then be employed to determine a profile that represents the change in viscosity that occurs with pressure.

First claim

What is claimed is:

1. A downhole tool comprising:
a pressure sensor to measure pressures of formation fluid within a flowline during a pumping phase, a sample chamber filling phase, a pressure build-up phase, and a probe retraction phase of a sampling operation;
a viscosity sensor to measure viscosities of the formation fluid within the flowline during the pumping phase, the sample chamber filling phase, the pressure build-up phase, and the probe retraction phase;
a controller configured to execute instructions stored within the downhole tool to determine a pressure-viscosity profile based on the measured pressures and viscosities; and
a display communicatively coupled to the controller and configured to display a graphical representation of the pressure-viscosity profile.

2. The downhole tool of claim 1 , comprising a fluid analyzer to determine properties of the formation fluid, wherein the controller is configured to initiate the sample chamber filling phase based on the fluid properties.

3. The downhole tool of claim 1 , comprising an extendable probe to direct the formation fluid into the downhole tool.

4. The downhole tool of claim 3 , wherein the probe is engaged with a wellbore wall during the pumping phase, the sample chamber filling phase, and the pressure build-up phase.

5. The downhole tool of claim 1 , comprising a pump to direct the formation fluid through a flowline during the pumping phase and the sample chamber filling phase.

6. The downhole tool of claim 1 , comprising a sample chamber to receive the formation fluid during the sample chamber filling phase.

7. A downhole tool comprising:
a pressure sensor to measure a first pressure of formation fluid within a flowline during a first pressure phase of a sampling operation, a second pressure of the formation fluid within the flowline during a second pressure phase of the sampling operation, a third pressure during a third pressure phase of the sampling operation, and a fourth pressure during a fourth pressure phase of the sampling operation;
a viscosity sensor to measure a first viscosity of the formation fluid within the flowline during the first pressure phase of the sampling operation, a second viscosity of the formation fluid within the flowline during the second pressure phase of the sampling operation, a third viscosity during the third pressure phase of the sampling operation, and a fourth viscosity during the fourth phase of the sampling operation; and
a controller configured to execute instructions stored within the downhole tool to determine a pressure-viscosity profile based on the measured first, second, third, and fourth viscosities and the measured first, second, third and fourth pressures, wherein determining the pressure-viscosity profile comprises fitting a curve to the first, second, third, and fourth viscosities and pressures.

8. The downhole tool of claim 7 , wherein the first pressure phase comprises pumping formation fluid through the downhole tool and expelling the formation fluid into the wellbore, and wherein the second pressure phase comprises directing the formation fluid into a sample chamber of the downhole tool.

9. The downhole tool of claim 7 , wherein the first pressure phase comprises directing the formation fluid into a sample chamber of the downhole tool, and wherein the second pressure phase comprises retracting a probe from the formation.

10. The downhole tool of claim 7 , wherein the first pressure phase comprises pumping formation fluid through the downhole tool and expelling the formation fluid into the wellbore, and wherein the second pressure phase comprises retracting a probe from the formation.

11. The downhole fluid analysis method of claim 7 , wherein each of the first, second, third, and fourth pressure phases produce a different pressure within a flowline of the downhole tool.

12. A downhole tool comprising:
a pressure sensor to measure pressures of formation fluid within a flowline;
a viscosity sensor to measure viscosities of the formation fluid within the flowline; and
a controller configured to execute instructions stored within the downhole tool to:
initiate a sampling operation with the downhole tool disposed in a wellbore;
measure a first viscosity and a first pressure in the flowline during a pumping phase of the sampling operation;
measure a second viscosity and a second pressure in the flowline during a sample chamber filling phase of the sampling operation;
measure a third viscosity and a third pressure in the flowline during a pressure build-up phase of the sampling operation;
measure a fourth viscosity and a fourth pressure in the flowline during a probe retraction phase of the sampling operation;
determine a viscosity-pressure profile based on the measured first, second, third, and fourth viscosities and pressures; and
display a graphical representation of the viscosity-pressure profile.

13. The downhole tool of claim 12 , wherein the pumping phase comprises directing formation fluid into the downhole tool through a probe and expelling the formation fluid from the downhole tool into the wellbore.

14. The downhole tool of claim 12 , wherein the sample chamber filling phase comprises directing the formation fluid into a sample chamber of the downhole tool.

15. The downhole tool of claim 14 , wherein directing the formation fluid into the sample chamber comprises displacing a buffer fluid from the sample chamber.

16. The downhole tool of claim 12 , wherein the pressure build-up phase comprises stopping operation of a pump while a probe is engaged with a wall of the wellbore.

17. The downhole tool of claim 16 , wherein the probe retraction phase comprises retracting the probe from the wall of the wellbore.

18. The downhole tool of claim 12 , wherein determining the viscosity-pressure profile comprises determining a logarithmic function representing a change in the measured first, second, third, and fourth viscosities with respect to the first, second, third, and fourth pressures.

Assignees

• Schlumberger Technology Corp

Inventors

• Dumont Hadrien
• Zuo Youxiang
• Barbosa Beatriz E

Classifications

• E21B49/0875

  determining specific fluid parameters · CPC title

• E21B49/10 Primary

  using side-wall fluid samplers or testers · CPC title

• G01V9/00

  Prospecting or detecting by methods not provided for in groups G01V1/00 - G01V8/00 · CPC title

• E21B49/088 Primary

  combined with sampling · CPC title

• E21B34/06

  in wells · CPC title