Method and apparatus for differential pressure measurement

Patent metadata

Field	Value
Publication number	US-8943900-B2
Application number	US-201013499813-A
Country	US
Kind code	B2
Filing date	Oct 4, 2010
Priority date	Oct 2, 2009
Publication date	Feb 3, 2015
Grant date	Feb 3, 2015

Abstract

A system and method for determining pressure differences of a fluid flowing through a differential pressure conduit positioned in a wellbore. The system comprises a first pressure measurement circuit positioned at a first pressure measuring station and including a first pressure sensor to generate a first pressure measurement signal indicative of the pressure measured by the first pressure sensor at a first signal point, and a second pressure measurement circuit positioned at a second pressure measuring station and including a second pressure sensor to generate a second pressure measurement signal indicative of the pressure measured by the second pressure sensor at a second signal point. The calculation of the pressure differential between the first and second pressure measuring stations is based on the first and second pressure measurement signals taken or read from the first and second signal points, wherein the first and third second points are symmetrical.

First claim

What is claimed is:

1. A flow rate device for measuring the flow rate of a fluid flowing through a wellbore, the flow rate device comprising:
a differential pressure conduit locatable in the wellbore, the differential pressure conduit defining an internal bore and adapted to create a differential pressure, the differential pressure conduit defining first and second pressure measuring stations axially spaced along the differential pressure conduit;
a first pressure sensor positioned at the first pressure measuring station, the first pressure sensor having a first Wheatstone bridge adapted to generate a first pressure measurement signal indicative of a first pressure at the first pressure measuring station; and
a second pressure sensor positioned at the second pressure measuring station, the second pressure sensor having a second Wheatstone bridge adapted to generate a second pressure measurement signal indicative of a second pressure at the second pressure measuring station;
wherein the first Wheatstone bridge and the second Wheatstone bridge are homogeneous and have similar characteristics with respect to at least one of a temperature sensitivity, a pressure sensitivity, and a non-linearity, the similar characteristics are within a range of 0.01 percent to 10.0 percent.

2. The flow rate device of claim 1 , wherein the first Wheatstone bridge is further defined as being configured to include a first signal point and the first pressure measurement signal is generated at the first signal point, the second Wheatstone bridge is configured to include a second signal point and the second pressure measurement signal is generated at the second signal point, and further wherein the first and second signal points are symmetrical with respect to the first and second Wheatstone bridges.

3. The flow rate device of claim 1 , further wherein the first and second pressure sensors share a common power source.

4. The flow rate device of claim 1 , wherein the first and second Wheatstone bridges are formed using one or more absolute pressure sensors.

5. The flow rate device of claim 4 , wherein at least one of the one or more absolute pressure sensors are silicon-on-insulator based sensors.

6. The flow rate device of claim 4 , wherein at least one of the one or more absolute pressure sensors are sized within a range of 0.01 millimeter and 1.0 centimeter.

7. The flow rate device of claim 4 , wherein at least one of the one or more absolute pressure sensors are sized within a range of 1.0 millimeter and 3.0 millimeter.

8. The flow rate device of claim 1 , wherein the similar characteristics are within a range of 0.01 percent to 1.0 percent.

9. The flow rate device of claim 1 , wherein the similar characteristics are within a range of 0.5 percent to 1.0 percent.

10. The flow rate device of claim 1 , further comprising an electronics common to and in electrical communication with the first and second pressure sensors.

11. A method for monitoring the flow rate of a fluid flowing through a wellbore, comprising the steps of:
placing a differential pressure conduit in the wellbore, the differential pressure conduit defining an internal bore and adapted to create a differential pressure, the differential pressure conduit defining first and second pressure measuring stations axially spaced along the differential pressure conduit;
measuring a first pressure at the first pressure measuring station using a first pressure sensor having a first Wheatstone bridge configured to include a first signal point and adapted to generate a first pressure measurement signal indicative of the first pressure measured by the first pressure sensor at the first signal point;
measuring a second pressure at the second pressure measuring station using a second pressure sensor having a second Wheatstone bridge configured to include a second signal point and adapted to generate a second pressure measurement signal indicative of the second pressure measured by the second pressure sensor at the second signal point; and
calculating the flow rate of a fluid flowing through the differential pressure conduit by determining the pressure differential between the first and second pressure measuring stations based on the first pressure measurement signal taken from the first signal point and the second pressure measurement signal taken from the second signal point, wherein the first and second signal points are symmetrical with respect to the first and second Wheatstone bridges.

12. The method of claim 11 , wherein the first and second Wheatstone bridges are formed using one or more absolute pressure sensors.

13. The method of claim 11 , wherein at least one of the one or more absolute pressure sensors are silicon-on-insulator based sensors.

14. The method of claim 12 , wherein at least one of the one or more absolute pressure sensors are sized within a range of 0.01 millimeter and 1.0 centimeter.

15. The method of claim 12 , wherein at least one of the one or more absolute pressure sensors are sized within a range of 1.0 millimeter and 3.0 millimeter.

16. The method of claim 12 , wherein the first and second pressure sensors share a common power source.

17. A system for determining pressure differences of a fluid flowing through a differential pressure conduit positioned in a wellbore, the system comprising:
a first pressure sensor positioned at a first pressure measuring station, the first pressure sensor having a first Wheatstone bridge adapted to generate a first pressure measurement signal indicative of a first pressure measured by the first pressure sensor at a first signal point; and
a second pressure sensor positioned at a second pressure measuring station, the second pressure sensor having a second Wheatstone bridge adapted to generate a second pressure measurement signal indicative of a second pressure measured by the second pressure sensor at a second signal point;
wherein the calculation of the pressure differential between the first and second pressure measuring stations is based on the first pressure measurement signal taken from the first signal point and the second pressure measurement signal taken from the second signal point, wherein the first and second signal points are symmetrical with respect to the first and second Wheatstone bridges.

18. The system of claim 17 , wherein the first Wheatstone bridge and the second Wheatstone bridge are homogeneous and have similar characteristics with respect to at least one of a temperature sensitivity, a pressure sensitivity, and a non-linearity, the similar characteristics are within a range of 0.01 percent to 10.0 percent.

19. The system of claim 18 , wherein the similar characteristics are within a range of 0.01 percent to 1.0 percent.

20. The system of claim 17 , wherein the first and second pressure sensors share a common power source.

21. The system of claim 17 , wherein the first and second Wheatstone bridges are formed using one or more absolute pressure sensors.

22. The system of claim 21 , wherein at least one of the one or more absolute pressure sensors are silicon-on-insulator based sensors.

23. The system of claim 21 , wherein at least one of the one or more absolute pressure sensors are sized within a range of 0.01 millimeter and 1.0 centimeter.

24. The system of claim 21 , wherein at least one of the one or more absolute pressure sensors are sized within a range of 1.0 millimeter and 3.0 millimeter.

25. A method

Assignees

• Rezgui Fadhel
• Buisson Alain
• Donzier Eric Paul
• Schlumberger Technology Corp

Inventors

• Rezgui Fadhel
• Buisson Alain
• Donzier Eric Paul

Classifications

• G01F1/44

  Venturi tubes · CPC title

• G01L9/04

  of resistance-strain gauges · CPC title

• E21B47/06 Primary

  Measuring temperature or pressure · CPC title

• G01F1/363

  with electrical or electro-mechanical indication (G01F1/37 and G01F1/38 take precedence) · CPC title

• G01L19/04

  Means for compensating for effects of changes of temperature {, i.e. other than electric compensation} · CPC title