Patent EA-003869-B1 (EA)
Title: Simultaneous determination of multiphase flowrates and concentrations
Inventor: MELNIKOV VLADIMIR IVANOVICH
IPC: G01F1/66
Filed: 2001-03-05
Abstract: 1. Method for determining flow rates of gas and liquid phases of a flow of a multiphase mixture along a pipeline, comprising the steps of: a. measuring a real velocity w of at least one phase of the mixture in a section (1) of the pipeline; b. measuring an acoustic conductivity of the mixture in the pipeline section (1); c. determining a volume concentration (phi) of a gas phase of the mixture in the pipeline section (1) on the basis of the measured acoustic conductivity of the mixture in the pipeline section (1); d. determining volume flow rates of the gas phase Qg, and of first and second components Q1, Q2 of the liquid phase QL of the mixture by using values of said real velocity w and said volume concentration; characterized by, with said pipeline section being a first pipeline section (1): e. providing a second pipeline section (2) in series with the first pipeline section (1), the first and second pipeline sections (1, 2) having different cross sections, such that a change in flow velocity of the mixture occurs at the junction of the two sections (1, 2); f. measuring the real velocity in the second pipeline section (2); g. measuring the acoustic conductivity in the second pipeline section (2) ; h. determining the volume concentration phi of the gas phase in the second pipeline section (2) on the basis of the measured acoustic conductivity of the mixture in the second pipeline section (2); i. determining a volume concentration W of different liquid phase components of the mixture on the basis of the measured acoustic conductivity of the mixture in at least one pipeline section; j. determining the volume flow rates Qg, QL, Q1, Q2 by using values of the real velocity w and the volume concentrations obtained for the first and second pipeline sections (1, 2) in combination. 2. Method according to claim 1 characterized in that the area F1 of the cross-section of the first pipeline division (1) differs from the area F2 of the cross-section of pipeline division (2) F2 = kF1, where k [not equal] 1. 3. Method according to claim 2, characterized in that the volume flow rate value of liquid phase is determined by the formula: QL = [k / (1 - k) F1 [w2 (1 - phi2) - w1 (1 - phi1)], where w1, w2 is an average real velocity of gas phase in the first pipeline division (1) and the second pipeline division (2) respectively, phi1, phi2 is an average real volume gas concentration in the mixture in the first pipeline division (1) and the second pipeline division (2) respectively; the volume flow rate of gas phase is determined by: Qg= F1w1phi1 or Qg = F2w2phi2, the volume flow rate of the first component of liquid phase is determined by: Q1= WQL, and the volume flow rate of the second component of liquid phase is determined by: Q2 = (1 - W)QL. 4. Method according to one of the preceding claims, characterized in that the velocity w of gas phase is measured at different radial locations in each of said cross-sections of the first and second pipeline divisions (1, 2), and measured local velocity values for each cross-section are averaged to provide a value for use as velocity value in calculations. 5. Method according to one of the preceding claims, characterized in that the concentration of gas phase, phi is measured at different radial locations in each of said cross-sections of the first and the second pipeline divisions (1, 2), and measured volume concentration values for each cross-section are averaged to provide a value for use as concentration value in calculations. 6. Method according to one of the preceding claims, characterized in that measurements are carried out by the use of ultrasonic transducers. 7. Method according to a preceding claim, characterized in that volume concentrations of liquid phase components W of the mixture are determined by using ultrasonic transducers in at least one cross-section in at least one of the pipeline divisions (1, 2) and by measuring time of passage of ultrasonic pulses through the mixture from the transducers. 8. Method according to a preceding claim, characterized in that volume concentrations of gas phase components phi of the mixture are determined by using ultrasonic transducers in at least one cross-section of the first and the second pipeline divisions (1, 2) and by measuring amplitude of ultrasonic pulses passed through the mixture from the transducers. 9. Method according to a preceding claim, characterized in that velocities w of the mixture phases are determined by using ultrasonic transducers in a least one cross-section of the first and the second pipeline divisions (1, 2) and by cross-correlation or autocorrelation methods. 10. Method according to a preceding claim, characterized in that velocities w of the mixture phases are determined by using ultrasonic transducers in at least one cross-section of the first and the second pipeline divisions (1, 2) and by measuring Doppler frequency of ultrasonic pulses from the transducers. 11. Method according to claims 1, 2, 3, 4, 5, characterized in that measurements are carried out by the use of electrical conductivity transducers. 12. Method according to claims 1, 2, 3, 4, 5, characterized in that measurements are carried out by the use of electrical capacity transducers. 13. Method according to claims 1, 2, 3, 4, 5, characterized in that measurements are carried out by the use of optical sensors. 14. Method according to claim 8, characterized in that the liquid phase components of the mixture are water and oil. 15. Device for determining flow rates of gas and liquid phases of a flow of a multiphase mixture along a pipeline, comprising: a. a velocity sensor (5) which is arranged in a section (1) of the pipeline and which is connected to circuitry for measuring a real velocity w of at least one phase of the mixture in the pipeline section (1); b. an acoustic conductivity sensor (6) which is arranged in the pipeline section (1) and which is connected to circuitry for measuring an acoustic conductivity of the mixture in the pipeline section (1) and for determining a volume concentration (phi) of the gas phase of the mixture in the pipeline section (1) on the basis of the measured acoustic conductivity of the mixture in the pipeline section (1); c. a processor which is connected to said circuitry for determining volume flow rates of the gas phase Qg, and of first and second components Q1, Q2 of the liquid phase QL of the mixture by using values of said real velocity w and said volume concentration; characterized by, with said pipeline section being a first pipeline section (1): d, a second pipeline section (2) which is arranged in series with the first pipeline section (1), the first (1) and second (2) pipeline sections having different cross sections, such that a change in flow velocity of the mixture occurs at the junction of the two sections (1, 2); e. a further velocity sensor (5) which is arranged in the second pipeline section (2) and which is connected to circuitry for measuring a real velocity w of at least one phase of the mixture in the second pipeline section (2); f. a further acoustic conductivity sensor (6) which is arranged in the second pipeline section (2) and which is connected to circuitry for measuring an acoustic conductivity of the mixture in the second pipeline section (2) and for determining a volume concentration phi of the gas phase of the mixture in the second pipeline section (2) on the basis of the measured acoustic conductivity of the mixture in the second pipeline section (2); g. a liquid concentration sensor (7) which is arranged in one (1) of said pipeline sections (1, 2) and which is connected to further circuitry for determining a volume concentration W of different liquid phase components of the mixture on the basis of the measured acoustic conductivity of the mixture in said one pipeline section (1); and in which the processor is connected to the further circuitry and the processor uses values of the real velocity w and the volume concentrations obtained for the first and second pipeline sections (1, 2) in combination for determining the volume flow rates Qg, QL, Q1, Q2. 16.Device according to claim 15, in which for each pipeline division (1, 2) the following means for measuring local flow characteristics of at least one phase of the mixture are used: an ultrasonic gas velocity meter for measuring a real gas velocity w of the mixture based on correlation or Doppler's methods; an ultrasonic volume gas concentration meter; an ultrasonic meter of volume concentrations of liquid components. 17. Device according to claim 15, in which meters with electrical capacity or electrical conductivity transducers for measuring local flow properties of at least one phase of the mixture are used. 18. Device according to claim 15, in which for each pipeline division (1, 2) a gamma-meter for determining the volume gas concentration is used. 19. Device according to claim 15, in which for each pipeline division (1, 2) disposed vertically an apparatus for determining the volume gas concentration by means of measuring a static pressure difference is used. 20. Device according to claims 15, 16, 17, in which the gas velocity meter measures the velocity w of gas phase at different radial locations in each of said cross-sections of the first and the second pipeline divisions (1, 2), and measured local velocity values for each cross-section are averaged to provide a value for use as velocity value in calculations. 21. Device according to claims 15, 16, 17, in which the volume gas concentration meter measures the concentration of gas phase phi at different radial locations in each of said cross-sections of the first and the second pipeline divisions (1, 2), and measured volume concentration values for each cross-section are averaged to provide a value for use as concentration value in calculations. 22. Device according to claims 15, 16, 17, 18, 19, 20, 21, in which the area F1 of the cross-section of the first pipeline divisi