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CN-121994313-A - Gas-liquid two-phase flow measuring method based on single pore plate and acoustic emission technology

CN121994313ACN 121994313 ACN121994313 ACN 121994313ACN-121994313-A

Abstract

A gas-liquid two-phase flow measuring method based on a single pore plate and acoustic emission technology belongs to the field of gas-liquid two-phase flow measurement in the petroleum industry. The method comprises the steps of installing a single pore plate at the section of a horizontal pipeline, installing an acoustic emission sensor right above the horizontal pipeline and on the front side and the rear side of the single pore plate, arranging pressure taking points of a differential pressure transmitter below the front side and the rear side of the single pore plate, controlling the flow pattern of gas-liquid two-phase flow, inputting known apparent liquid velocity V SL and apparent gas velocity V SG , changing V SL and V SG , calculating an effective voltage value RMS through acoustic signals, establishing three relations by utilizing the obtained RMS and V SL and V SG to fit, transforming Lin Zonghu differential pressure flow models containing differential pressure delta P m , obtaining expressions of V SL and V SG under various flow patterns represented by the RMS, delta P m and fitting parameters, and calculating actual apparent liquid velocity and gas velocity by utilizing the expressions. The invention has the advantages of simple structure, low measurement cost, real-time measurement, non-invasive performance and the like.

Inventors

  • WANG XIN
  • BAI ZHE
  • SHEN LING
  • ZHANG SHENGLEI

Assignees

  • 中国石油大学(华东)

Dates

Publication Date
20260508
Application Date
20260403

Claims (7)

  1. 1. A gas-liquid two-phase flow measuring method based on a single pore plate and acoustic emission technology is characterized by comprising the following steps: Step 1, installing a single pore plate through a flange at the section of a horizontal pipeline, arranging a pore center on the axis of the pipeline, installing an acoustic emission sensor right above the horizontal pipeline, installing a pair of acoustic emission sensors at the positions of the right above the horizontal pipeline, the front side and the rear side of the single pore plate and the positions of the two sides of the single pore plate, and arranging pressure sampling points of a differential pressure transmitter at the positions of the right below the horizontal pipeline and the front side and the rear side of the single pore plate so as to acquire a differential pressure signal delta P m ; Step 2, controlling the flow pattern of the gas-liquid two-phase flow into various flow patterns, inputting apparent liquid velocity V SL and apparent gas velocity V SG with known velocities, and changing apparent liquid velocity V SL and apparent gas velocity V SG ; Step 3, after 125kHz low-pass filtering is carried out on N sound emission signals respectively collected by sound emission sensors on two sides of the single pore plate, calculating an effective voltage value RMS of the sound emission signals at the single pore plate; Step 4, using the obtained RMS was fitted to the known apparent liquid velocity V SL and apparent gas velocity V SG with the following formulas: (1) Establishing a correlation between RMS and apparent liquid velocity V SL and apparent gas velocity V SG , wherein b, I, x, y is an acoustic emission correlation coefficient in the formula (1); And 5, transforming the Lin Zonghu differential pressure flow model, as shown in a formula (2): (2) In the formula (2), the gas phase mass flow of m G is kg/s, the liquid phase mass flow of m L is kg/s, epsilon is the gas expansion coefficient, C d is the outflow coefficient, theta is the correction coefficient, beta is the throttling ratio, rho G is the gas phase density, kg/m 3 ; ρ L is the liquid phase density, kg/m 3 , A is the pipeline cross-sectional area, and m 2 ;ΔP m is the pressure difference between the front and back of the gas-liquid mixed fluid flowing through the orifice plate and Pa; In step 6, there is an equivalence relation between V SL and m L , and between V SG and m G , as shown in formula (3) and formula (4): (3) (4) obtaining expressions of apparent liquid velocity V SL and apparent gas velocity V SG under various flow patterns by using formulas (1) - (4) and embodying the expressions by RMS, delta P m and fitting parameters; And 7, installing a single pore plate, an acoustic emission sensor and a pressure sampling point of a differential pressure transmitter in a mode of step 1 for horizontal pipelines of the same specification, identifying a flow pattern of gas-liquid two-phase flow in the pipeline by using the acoustic emission signals of the gas-liquid two-phase flow acquired by the acoustic emission sensor right above the horizontal pipeline, obtaining an effective voltage value RMS and a mixed pressure difference DeltaP m of the acoustic emission signals when the gas-liquid two-phase flow to be measured passes through the single pore plate when the flow pattern in the pipeline is a certain flow pattern, inputting the obtained RMS and DeltaP m by using the expression of the flow pattern obtained in step 6, and calculating to obtain an apparent liquid velocity and an apparent gas velocity, thereby completing the calculation of the flow rate of the gas-liquid two-phase flow.
  2. 2. The method of claim 1, wherein in step 1, the acoustic emission sensor is located above the horizontal pipe at a linear distance of not less than 5d from the orifice plate, d being the pipe inner diameter.
  3. 3. The method of claim 1, wherein in the step 3, the RMS calculation method specifically includes that after 125kHz low-pass filtering is performed on N acoustic emission signals collected at the front and rear sides of the single-hole plate, effective voltage values of the acoustic emission signals at the front and rear sides are calculated by using a root mean square formula shown in formula (5): (5) Wherein, N is the collection number of times, V i is the average value when single hole board one side acoustic emission sensor is the ith collection time, and the effective voltage value of both sides acoustic emission signal is recorded respectively as: and (3) with Then RMS is And (3) with Average value of (2).
  4. 4. The method of claim 1, wherein in step 3, N has a value of 2X 10 8 or more.
  5. 5. The method of claim 1, wherein in the step 5, the correction coefficient θ in the formula (2) is calculated by the formula (6): (6)。
  6. 6. The method of claim 1, wherein in the step 5, the throttle ratio β in the formula (2) is calculated by the formula (7): (7) Wherein A t is the pore plate measuring pore area, m 2 , and A is the inner cross-sectional area of the tube.
  7. 7. The method according to claim 1, wherein in the step 5, the expansion coefficient ε and the outflow coefficient C d in the formula (2) are solved according to the formulas provided in national standard GB/T21446-2008, as shown in the formulas (8) and (9): (8) (9) Wherein, P 1 is the absolute static pressure of the air flow at the downstream of the orifice plate, pa, P 2 is the absolute static pressure of the air flow at the upstream of the orifice plate, pa, kappa is the isentropic index, re D is the Reynolds number when only single-phase gas flows in the pipeline, and D is the inner diameter of the experimental pipeline, and mm.

Description

Gas-liquid two-phase flow measuring method based on single pore plate and acoustic emission technology Technical Field The invention relates to a gas-liquid two-phase flow measuring method based on a single orifice plate and an acoustic emission technology, which belongs to the field of gas-liquid two-phase flow measurement in the petroleum industry. Background With the large-scale development of carbon dioxide flooding projects, the demand for single well flow metering is increasing. Because the produced fluid at the wellhead is a gas-liquid two-phase flow, and the change range of the gas-oil ratio of the fluid produced by the production well is wide, single well metering has become a technical challenge. The traditional multiphase flow metering is metering after separation by using a separator, but the separator is large and heavy, and is high in cost and difficult to measure in real time. Therefore, the development of the two-phase flow metering method which has low cost and can be online in real time has important engineering significance. At present, various technologies are used in the field of gas-liquid two-phase flow measurement, and have advantages and limitations. For example, coriolis flowmeters are extremely accurate in single phase fluid mass flow and density measurements, but the accuracy is significantly degraded when measuring two phase flow. Electromagnetic conductivity measurement methods are fast in response and high in accuracy, but require complex calibration to ensure accurate readings. The orifice plate flowmeter is used as a differential pressure type flowmeter, and has a single orifice plate flowmeter and a porous orifice plate flowmeter, which have very mature application products in single-phase flow measurement and corresponding measurement standards, and have applications of simultaneously using a plurality of orifice plates in multiphase flow measurement, but the porous orifice plate flowmeter is commonly used for high-precision measurement of special fluids, such as liquid nitrogen, liquid oxygen and other single-phase fluids, in oilfield mines, the problems of wax deposition, bottom sediment carrying, hydrate particles and the like are easy to occur in oil and gas wells and pipelines, and the 10% precision in wellhead oil and gas water measurement can be used for meeting engineering requirements, so that the single-orifice plate flowmeter with better pollution discharge is commonly used in oilfield sites, but the porous orifice plate flowmeter with poorer pollution discharge is not used. As a passive acoustic measurement method, the acoustic emission technology has the advantages of low energy consumption, no pollution, simple and convenient operation, non-invasiveness and the like, and has proved to be applied to the aspect of flow pattern identification of multiphase flow and also has certain application in the aspect of multiphase flow phase content measurement. Then, a method for measuring the flow rate of the gas-liquid two-phase flow by combining the two measurement technologies simultaneously does not exist. Disclosure of Invention The invention provides a gas-liquid two-phase flow measuring method based on a single pore plate and acoustic emission technology, which is based on the prior art, the relation between the acoustic emission signal generated when the fluid passes through the single pore plate and the apparent flow velocity of the gas-liquid is further researched, and the classical differential pressure flow formula is combined, so that the problems existing in the current gas-liquid two-phase flow measurement are solved. A gas-liquid two-phase flow measuring method based on a single pore plate and acoustic emission technology is characterized by comprising the following steps: Step 1, installing a single pore plate through a flange at the section of a horizontal pipeline, arranging a pore center on the axis of the pipeline, installing an acoustic emission sensor right above the horizontal pipeline, installing a pair of acoustic emission sensors at the positions of the front side and the rear side of the single pore plate, which are close to the flange, and arranging pressure sampling points of a differential pressure transmitter at the positions of the right below the horizontal pipeline and the front side and the rear side of the single pore plate so as to acquire a differential pressure signal delta P m. And 2, controlling the flow pattern of the gas-liquid two-phase flow into various flow patterns, inputting apparent liquid velocity V SL and apparent gas velocity V SG with known velocities, and changing apparent liquid velocity V SL and apparent gas velocity V SG. And step 3, after 125kHz low-pass filtering is carried out on N sound emission signals respectively acquired by the sound emission sensors at the two sides of the single pore plate, calculating the effective voltage value RMS of the sound emission signals at the single pore plate. Step 4, fittin