# US 10,480,316 B2 · Downhole fluid analysis methods for determining viscosity

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 10,480,316 B2
- Document ID: US10480316B2
- Status: Granted
- Kind: B2
- Application number: 15/822,293
- Filed: 2017-11-27
- Published: 2018-03-29
- Granted: 2019-11-19
- Earliest claimed: 2013-12-06
- Assignees: Schlumberger Technology Corporation
- Applicants: Schlumberger Technology Corporation
- Inventors: Hadrien Dumont; Youxiang Zuo; Beatriz E. Barbosa
- Web page: https://patentgrep.com/patent/US10480316B2

## CPC

- E21B 49/10: using side-wall fluid samplers or testers
- E21B 47/06: Measuring temperature or pressure
- E21B 49/088: {combined with sampling}
- G01V 9/00: Prospecting or detecting by methods not provided for in groups G01V1/00 - G01V8/00
- E21B 34/06: in wells
- E21B 49/0875: {determining specific fluid parameters}
- E21B: EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- G01V: GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS (means for indicating the location of accidentally buried, e.g. snow-buried, persons A63B29/02)

## 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.

## Claims

### Claim 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.

### Claim 2 (depends on 1)

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.

### Claim 3 (depends on 1)

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

### Claim 4 (depends on 3)

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.

### Claim 5 (depends on 1)

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.

### Claim 6 (depends on 1)

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

### Claim 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.

### Claim 8 (depends on 7)

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.

### Claim 9 (depends on 7)

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.

### Claim 10 (depends on 7)

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.

### Claim 11 (depends on 7)

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.

### Claim 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.

### Claim 13 (depends on 12)

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.

### Claim 14 (depends on 12)

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.

### Claim 15 (depends on 14)

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

### Claim 16 (depends on 12)

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.

### Claim 17 (depends on 16)

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

### Claim 18 (depends on 12)

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.