Multiphase flow measurement system

• US 20030136185A1
• Filed: 02/05/2003
• Published: 07/24/2003
• Est. Priority Date: 10/28/1999
• Status: Active Grant

• Current Assignee: Chad Steele, Robert E. Dutton
• Original Assignee: Chad Steele, Robert E. Dutton
• Inventors: Dutton, Robert E., Steele, Chad
• Granted Patent: US 6,810,719 B2
• Time in Patent Office: Days
• US Class Current: 73/61.44
• CPC Class Codes: E21B 49/0875 determining specific fluid parameters
• CPC Class Codes: G01F 1/74 Devices for measuring flow of a fluid or flow of a fluent solid material in suspension in another fluid
• CPC Class Codes: G01F 1/84 Coriolis or gyroscopic mass flowmeters
• CPC Class Codes: G01F 15/08 Air or gas separators in combination with liquid meters; Liquid separators in combination with gas-meters
• CPC Class Codes: G01N 9/002 using variation of the resonant frequency of an element vibrating in contact with the material submitted to analysis G01N9/34 takes precedence

Abstract

A fully automated Coriolis-based well system which can deliver accurate volumetric flow rate measurements in three phase flow. Measurements are performed according to a process including using N equations and N unknowns technique.

Claims

1. A method of performing multiphase flow measurements in a multiphase flow stream including liquid and gas components, said method comprising:

determining a flow rate of said multiphase flow stream; and

calculating to quantify flow rates of discrete liquid and gas components, said calculation comprising solving N equations with N unknowns.

2. The method of claim 1 wherein said step of measuring a flow rate of said multiphase flow stream is performed using a mass flowmeter.

3. The method of claim 2 wherein said mass flow meter is a Coriolis flow meter.

4. The method of claim 1 wherein said N equations with said N unknowns comprise:

ρ

_oq_o+ρ

_wq_w+ρ

_gq_g=ρ

_B

ƒ

(sat)=M q_o+q_w+q_g=1

wherein ρ

_w is the density of water in the flow stream, ρ

_o is the density of oil in the flow stream, ρ

_g is the density of gas in the flow stream, ρ

_B is the density of the combined flow stream, q_w is the fractional flow rate of water by volume (i.e., a water-cut), q_o is the fractional flow rate of oil by volume, q_g is the fractional flow rate of gas by volume, and ƒ

(sat) is a function of flow stream content that is unique to a particular type of water-cut meter providing a total meter reading M.

5. The method of claim 4 wherein the values of ρ

_w, ρ

_o and ρ

_g are obtained from laboratory measurements or based upon temperature and pressure information using correlations from an industry standards group.

6. The method of claim 4 wherein ƒ

(sat) operates according to the relationship;

7. The method of claim 4 wherein determining said water cut of said multiphase flow stream comprises:

measuring said water cut using a microwave-based monitor.

8. The method of claim 1 further comprising the steps of:

determining a temperature of said multiphase flow;

determining a pressure of said multiphase flow; and

correcting said flow rate of said discrete liquid component to a standard volume flow rate using said temperature measurement, said pressure and correlations obtained from an industry standards group.

9. The method of claim 1 further comprising the steps of:

determining a temperature of said multiphase flow;

determining a pressure of said multiphase flow; and

correcting said flow rate of said discrete gas component to a standard volume flow rate using said temperature measurement, said pressure and correlations obtained from an industry standards group.

10. A multiphase flow stream measurement system for use in flow streams including multiple liquid components and a gas component comprising:

means for measuring a flow rate of said multiphase flow stream; and

means for measuring a flow rate of said liquid and gas components, wherein said means for measuring a flow rate of said liquid and gas components uses a calculation to quantify flow rates of discrete liquid and gas phases in said multiphase flow stream, said calculation comprising solving N equations with N unknowns.

11. The multiphase flow measurement system of claim 10 wherein said means for measuring a flow rate of said multiphase flow stream comprises a mass flowmeter.

12. The multiphase flow measurement system of claim 11 wherein said mass flowmeter is a Coriolis mass flowmeter.

13. The multiphase flow measurement system of claim 10 wherein said means for measuring a flow rate of said multiphase flow stream comprises a means for measuring a density of said multiphase flow stream.

14. The multiphase flow measurement system of claim 10 wherein said N equations with N unknowns comprise:

ρ

_oq_o+ρ

_wq_w+ρ

_gq_g=ρ

_B ƒ

(sat)=M q_o+q_w+q_g=1

wherein ρ

_w is the density of water in the flow stream, ρ

_o is the density of oil in the flow stream, ρ

_g is the density of gas in the flow stream, ρ

_Bis the density of the combined flow stream, q_w is the fractional flow rate of water by volume (i.e., a water-cut), q_o is the fractional flow rate of oil by volume, q_g is the fractional flow rate of gas by volume, and ƒ

(sat) is a function of flow stream content that is unique to a particular type of water-cut meter providing a total meter reading M.

15. The multiphase flow measurement system of claim 14 wherein ƒ

(sat) operates according to the relationship;

16. The multiphase flow measurement system of claim 10 further comprising:

means for determining a temperature of said multiphase flow;

means for determining a pressure of said multiphase flow; and

means for correcting said flow rate of said discrete components to a standard volume flow rate using said temperature measurement, said pressure measurement and correlations obtained from an industry standards group.

17. The multiphase flow measurement system of claim 16 wherein said means for determining said temperature is a Coriolis flow meter and said means for determining said pressure is a pressure transmitter.

18. A multiphase flow measurement system for performing multiphase flow measurements in flow streams including multiple liquid phases and a gas phase, said multiphase flow measurement system comprising:

a flow meter configured to receive said multiphase flow and determine a density of said multiphase flow;

a water cut monitor configured to receive said multiphase flow and determine a water cut of said multiphase flow; and

a controller configured to communicate with said Coriolis flowmeter and said water cut monitor, for measuring a flow rate of said liquid and gas components, wherein said controller uses a calculation to quantify flow rates of discrete liquid and gas phases in said multiphase flow stream, said calculation comprising solving N equations with N unknowns.

19. The multiphase flow measurement system of claim 18 wherein said flow meter comprises a Coriolis mass flowmeter.

20. The multiphase flow measurement system of claim 18 wherein said flow meter determines the flow rate of said multiphase flow.

21. The multiphase flow measurement system of claim 18 wherein said N equations with N unknowns comprise:

ρ

_oq_o+ρ

_wq_w+ρ

_gq_g=ρ

_B ƒ

(sat)=M q_o+q_w+q_g=1

wherein ρ

_w is the density of water in the flow stream, ρ

_o is the density of oil in the flow stream, ρ

_g is the density of gas in the flow stream, ρ

_B is the density of the combined flow stream, q_w is the fractional flow rate of water by volume (i.e., a water-cut), q_o is the fractional flow rate of oil by volume, q_g is the fractional flow rate of gas by volume, and ƒ

(sat) is a function of flow stream content that is unique to a particular type of water-cut meter providing a total meter reading M.

22. The multiphase flow measurement system of claim 21 wherein ƒ

(sat) operates according to the relationship;

23. The multiphase flow measurement system of claim 18 wherein said flow meter is configured to measure a temperature of said multiphase flow and said system further comprises:

a pressure transmitter for determining a pressure of said multiphase flow; and

means for correcting said flow rate of said discrete components to a standard volume flow rate using said temperature, said pressure and correlations obtained from an industry standards group.