Non-intrusive multiphase flow meter

• US 20040139791A1
• Filed: 01/21/2003
• Published: 07/22/2004
• Est. Priority Date: 01/21/2003
• Status: Active Grant

• Current Assignee: Weatherford Technology Holdings, LLC (Weatherford International PLC)
• Original Assignee: Weatherford/Lamb Incorporated (Weatherford International PLC)
• Inventors: Johansen, Espen S.
• Granted Patent: US 6,945,095 B2
• Time in Patent Office: Days
• US Class Current: 73/61.44
• CPC Class Codes: E21B 47/10 Locating fluid leaks, intrusions or movements
• CPC Class Codes: G01N 2291/024 Mixtures
• CPC Class Codes: G01N 2291/02433 Gases in liquids, e.g. bubbles, foams
• CPC Class Codes: G01N 2291/02818 Density, viscosity
• CPC Class Codes: G01N 29/024 by measuring propagation velocity or propagation time of acoustic waves
• CPC Class Codes: G01N 33/2823 raw oil, drilling fluid or polyphasic mixtures hydrocarbon content of earth materials G01N33/241; prospecting G01V; drilling per se E21B
• CPC Class Codes: G01N 9/26 by measuring pressure differences
• CPC Class Codes: G01N 9/36 Analysing materials by measuring the density or specific gravity, e.g. determining quantity of moisture methods of measurement in general G01N9/02 - G01N9/32

Abstract

Embodiments of the present invention generally provide methods, apparatus, and systems for determining void fractions of individual phase components of a multiphase mixture. The void fractions may be determined based on measured parameters of the mixture as a whole, such as differential pressure, bulk velocity of the mixture and speed of sound in the mixture. According to some embodiments, the mixture parameters may be measured using non-intrusive fiber optic based sensors. Various other parameters may also be derived from the void fractions, such as individual phase flow rates, liquid holdup and watercut parameters (for oil and gas mixtures).

Claims

1. A method for determining one or more volumetric fractions of individual phases of a multiphase mixture flowing through a pipe, comprising:

determining a density of the mixture;

measuring a speed of sound in the mixture; and

determining a volumetric phase fraction for one or more of the individual phases based on the determined mixture density and the measured speed of sound in the mixture.

2. The method of claim 1, wherein the method further comprises:

measuring a differential pressure between two locations along the pipe;

measuring a bulk velocity of the mixture; and

wherein determining the density of the mixture comprises determining the mixture density based on the measured differential pressure and the measured bulk velocity.

3. The method of claim 2, wherein determining a density of the mixture based on the measured differential pressure and measured bulk velocity of the mixture comprises estimating an amount of frictional loss based on the bulk velocity.

4. The method of claim 1, further comprising:

measuring a temperature and pressure of the mixture; and

estimating densities and speeds of sound for the individual phases based on the measured temperature and pressure of the mixture.

5. The method of claim 4, wherein the estimated densities and speeds of sound for the individual phases are used in determining the volumetric phase fraction for the one or more of the individual phases.

6. The method of claim 1, further comprising determining a percentage amount of liquid phase content of the mixture based on the determined volumetric phase fractions.

7. The method of claim 1, further comprising determining a volumetric flow rate for one or more of the individual phases based on the determined volumetric phase fractions by applying a multiphase flow model.

8. A method for determining one or more volumetric fractions of individual phases of a multiphase mixture flowing through a wellbore pipe, comprising:

measuring a differential pressure between at least two vertically displaced downhole locations along the pipe;

measuring a bulk velocity of the mixture and speed of sound in the mixture; and

determining a volumetric phase fraction for one or more of the individual phases based on the measured differential pressure, measured bulk velocity of the mixture and measured speed of sound in the mixture.

9. The method of claim 8, wherein determining the volumetric phase fraction for one or more of the individual phases comprises determining a density of the mixture based on the measured differential pressure and measured bulk velocity of the mixture.

10. The method of claim 9, wherein determining the volumetric phase fraction for one or more of the individual phases comprises determining the volumetric phase fraction for one of the individual phases as a function of the determined density of the mixture, estimated density of the individual phases, and estimated speed of sound in the individual phases.

11. The method of claim 9, wherein determining the density of the mixture based on the measured differential pressure and measured bulk velocity of the mixture comprises estimating an amount of frictional loss based on the measured bulk velocity of the mixture.

12. The method of claim 8, further comprising determining a volumetric flow rate for one or more of the individual phases, or a combination of individual phases, based on the determined volumetric phase fractions by applying a multiphase flow model.

13. A method for determining one or more volumetric fractions of individual phase components of a multiphase mixture flowing through a wellbore pipe, comprising:

measuring a temperature and pressure of the mixture at one or more downhole locations;

estimating densities and speeds of sound for the individual phase components based on the measured temperature and pressure of the mixture;

measuring a differential pressure between at least two vertically displaced downhole locations along the pipe;

measuring a bulk velocity of the mixture and speed of sound in the mixture; and

determining a volumetric phase fraction for one or more of the individual phase components based on the estimated densities and speeds of sound for the individual phase components, the measured differential pressure, the measured bulk velocity of the mixture, and the measured speed of sound in the mixture.

14. The method of claim 13, wherein measuring the differential pressure between the at least two vertically displaced downhole locations comprises measuring absolute pressures at each of the at least two vertically displaced downhole locations.

15. The method of claim 13, wherein measuring a temperature of the mixture at one or more downhole locations comprises detecting temperature induced changes in an optical fiber.

16. The method of claim 13, wherein measuring the temperature and pressure of the mixture at one or more downhole locations comprises measuring the temperature and pressure of the mixture using one or more fiber optic based sensors.

17. The method of claim 13, wherein measuring the bulk velocity of the mixture and speed of sound in the mixture comprises measuring the bulk velocity of the mixture and speed of sound in the mixture using one or more fiber optic based sensors.

18. The method of claim 17, wherein the one or more fiber optic based sensors are non-intrusive.

19. The method of claim 13, further comprising determining a liquid holdup value for the mixture based on the one or more determined volumetric phase fractions.

20. The method of claim 13, further comprising determining a watercut value for the mixture based on the one or more determined volumetric phase fractions.

21. An apparatus for measuring a volumetric phase fraction of one or more phases of a multiphase mixture in a pipe, comprising:

a means for sensing differential pressure at two or more vertically displaced locations along the pipe;

a velocity sensor for sensing a bulk velocity of the mixture;

a speed of sound sensor for sensing a speed of sound in the mixture; and

control circuitry adapted to determine a volumetric phase fraction of at least one of the phases based on one or more signals received from the means for sensing differential pressure, the velocity sensor, and the speed of sound sensor.

22. The apparatus of claim 21, wherein the means for measuring differential pressure comprises at least two absolute pressure sensors disposed at the two or more vertically displaced locations along the pipe.

23. The apparatus of claim 21, further comprising at least one temperature sensor, wherein the control circuitry is further adapted to determine a speed of sound and density of each of the phases based on one or more signals received from the temperature sensor and an absolute pressure sensor.

24. The apparatus of claim 23, wherein the temperature sensor and absolute pressure sensor form an integrated sensor.

25. The apparatus of claim 21, wherein an inner diameter of the apparatus is equal to or greater than an inner diameter of the pipe on at least one end of the apparatus.

26. The apparatus of claim 21, wherein the control circuitry is further configured to determine a volumetric flow rate for at least one of the phases by applying a multiphase flow model.

27. The apparatus of claim 21, wherein the control circuitry is further configured to determine a percentage amount of liquid phase content of the mixture.

28. An apparatus for measuring a volumetric fraction of one or more phase components of a multiphase mixture in a wellbore pipe, comprising:

an absolute pressure sensor;

a temperature sensor;

a means for sensing differential pressure at two or more vertically displaced downhole locations along the pipe;

a velocity sensor for sensing a bulk velocity of the mixture;

a speed of sound sensor for sensing a speed of sound in the mixture; and

control circuitry configured to estimate individual phase densities and speeds of sound based on signals received from the absolute pressure sensor and temperature sensor, and to determine a volumetric fraction of at least one of the phase components based on one or more signals received from the means for sensing differential pressure, the velocity sensor, and the speed of sound sensor, and the estimated individual phase densities and speeds of sound.

29. The apparatus of claim 28, wherein the control circuitry is configured to calculate a density of the mixture based on one or more signals received from the means for sensing differential pressure and the velocity sensor prior to determining the volumetric fraction of at least one of the phase components.

30. The apparatus of claim 28, wherein the control circuitry is located at a surface of the wellbore.

31. The apparatus of claim 28, wherein the means for sensing differential pressure comprises two fiber optic based absolute pressure sensors, each comprising one or more Bragg gratings.

32. The apparatus of claim 31, wherein the temperature sensor is integrated with one of the pressure sensors.

33. The apparatus of claim 31, wherein the temperature sensor, the means for sensing differential pressure, the velocity sensor, and the speed of sound sensor comprise one or more fiber optic sensors coupled with the control circuitry via one or more optical fibers.

34. The apparatus of claim 33, wherein each of the one or more fiber optic sensors are coupled with the control circuitry via a common optical fiber.

35. The apparatus of claim 28, wherein the control circuitry is configured to calculate a watercut parameter based on determined volumetric fractions of oil and water in the mixture.

36. The apparatus of claim 28, wherein the control circuitry is configured to calculate a liquid holdup parameter based on determined volumetric fractions of oil and water in the mixture.

37. The apparatus of claim 28, wherein at least one of the temperature sensor, the means for sensing differential pressure, the velocity sensor, and the speed of sound sensor is an electrical sensor.

38. An system for measuring a volumetric fraction of one or more phase components of a multiphase mixture in a wellbore pipe, comprising:

an absolute pressure sensor;

a temperature sensor;

a means for measuring a density of the mixture;

a speed of sound sensor for sensing a speed of sound in the mixture; and

control circuitry configured to estimate individual phase densities and speeds of sound based on signals received from the absolute pressure and temperature sensors, and to determine a volumetric fraction of at least one of the phase components based on one or more signals received from the means for measuring a density of the mixture, one or more signals received from the speed of sound sensor, and the estimated individual phase densities and speeds of sound.

39. The system of claim 38, wherein the means for measuring density of the mixture is a nuclear densitometer.

40. The system of claim 38, wherein the speed of sound sensor is an ultrasonic speed of sound sensor.