RU2396519C1 - Liquid-gas mixture flow metre - Google Patents

Abstract

FIELD: oil and gas production.

SUBSTANCE: liquid-gas mixture component-wise flow metre comprises a variable pressure drop flow metre in the form of a built-in fluid oscillator (3) with a power nozzle (5) and a jet collision chamber, a differential pressure pickup (8) on the fluid oscillator. In side walls (13) of the jet collision chamber, there is a measuring circuit (2) of a moisture metre so that the walls from both sides of the chamber are simultaneously regarded as a resonant circuit of the moisture metre. The moisture metre capacity is limited by the power nozzle (5) and a hydraulic outlet (6) of the fluid oscillator. The moisture metre and flow metre - moisture metre (3) are connected to a calculator (4).

EFFECT: higher accuracy of measuring volume flow rate of gas, condensate and water.

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Description

The invention relates to measuring technique and can be used to measure the flow rate of a gas-liquid mixture (GHS), in particular, in the oil industry while controlling the flow rate of oil and gas wells that extract raw gas.

A known method of chamber measurement of flow rate (productivity) of an oil well [1. SKZH counter for measuring the flow rate of an oil well. Description. Production NPO NTES, Bugulma] or through separate open sections. The counter [1] does not have the possibility of in-line measurement of the flow rate of individual phases of the mixture.

A known method of measuring the component flow rate of a three-component gas-liquid flow, including measuring its dielectric constant using a capacitive sensor [2. K.N. Franz, E. Dykesteen. Field Experience Wiht the CM1 Multi-phase Fraction Water Paper 3.3. North Sea Flow Measurement Work spop 1990. National Engineering laboratory. East Kilbride, Glasgow. 1990.]. The disadvantage of this method is the large error in the measurement of flow due to the slip of the phases of the stream.

There is also known a method of measuring the component flow rate of a gas-liquid stream, including preliminary preparation of the stream, sequentially measuring its density, phase ratio, flow rate and processing the measurement results, and a device comprising a flow preparation unit, a radio wave composition sensor of a liquid phase, a flow meter, a densitometer, and a computational device that are installed in series with it block [3. RF patent No.2008617]. The disadvantage of this method [3] is the flow measurement using a vortex flowmeter having a small measuring range, insufficient measurement accuracy, a complex signal conversion circuit characterizing the current flow rate. The presence of a heater in a poorly streamlined body also complicates the measuring circuit.

In addition, the vortex flowmeter has a limited minimum flow rate associated with the need to have a certain flow regime according to the Reynolds number (Re), less than the number of which the flowmeter has false readings, there are also restrictions on the diameter of the pipe.

The closest technical solution to the proposed device is a GJS flowmeter manufactured by Tyumennefteavtomatika, which uses the fluctuation method of a non-separating measurement of oil and gas wells, which is taken as a prototype (4. A.A. Vakulin, A.B.Shabarov. Diagnostics of thermophysical parameters in oil and gas technologies. Novosibirsk. Science. 1998. p. 201).

In a known flow meter containing absolute pressure, temperature and differential pressure meters, which are connected to the mixture channel by inputs and outputs to the calculator, pressure fluctuations arising from the movement of a gas-liquid flow through a sudden narrowing in a pipeline are used as a source of measurement information. The pressure recorded after constriction by a measuring microphone consists of two components - the average slowly varying pressure and variable pressure. The magnitude of the average pressure does not depend on the nature of the flow, its quantitative composition and is mainly determined by the level of static pressure in the gas collection system. The variable component is used to measure the flow rate of the gas-liquid flow components.

The disadvantage of this device is the large error in the measurement of flow (not better than 5%). The sudden constriction, made in the form of a diaphragm, creates additional resistance in the gas-liquid flow path. In addition, deposits may appear on the edges, leading to a change in the outflow coefficient, and so without this variable at different flows, the values of which must be entered into the computer for correction.

To address these shortcomings, a device for measuring the flow of GHS for small and large costs is proposed.

A device for measuring the flow rate of a gas-liquid mixture is proposed, comprising a constricting device in the pipe, a differential pressure sensor and a calculator, characterized in that a jet generator with a power nozzle, which serves as a constricting device, and a moisture meter with a measuring circuit located in the walls of the collision chamber connected to the calculator are introduced.

In this device, the entire flow of GHS is passed through a jet generator (SG). The constricting device (CS) is made in the form of a nozzle for supplying a jet generator, which provides a differential pressure for the operation of the jet generator and moisture meter.

A device for measuring the flow rate of a gas-liquid mixture is proposed, characterized in that the jet generator, made flat, is inserted into the bypass line to the pipe restriction device (SUT) together with a moisture meter, the differential sensor is connected in parallel with the jet generator.

To measure a large flow rate, a small part is passed through an SG flowmeter built into the bypass line, and the rest is passed through a CUT located in the stream through the pipe.

In the device for measuring a high flow rate, the SUT is made in the form of a conoidal nozzle in which smooth contours practically prevent deposits at the edges. The purpose of a smooth narrowing in the proposed device is to create a pressure differential for the flow of the gas-liquid mixture through the bypass line parallel to the measuring section, and inclusion in the operation of the measuring system.

The well-known traditional arrangement of a moisture meter in a pipe in which a flow of GHS flows is a separate arrangement from other measuring instruments. The proposed constructive solution is made in order to obtain a more reliable measurement result simultaneously in the pipe and in the chamber of the jet generator, in which the GHS flow is in the form of a jet and the vibrational mode of collision from wall to chamber wall. The components of the flow with different densities, flowing through the interaction chamber of a flat jet generator, are more intensively mixed, and the bulk masses of the liquid (condensate) are averaged, while the moisture content is measured with a smaller error using resonant frequencies. With a flat design of the interaction chamber, the jet generator together with the raw gas stream becomes more transparent for measurement (Fig. 1), requires less energy for scanning. In addition, organized scanning with a hygrometer with a higher resolution at the edge of the chamber, where the stream of raw gas during oscillations is alternately attracted to the walls of the chamber, will reduce the error of measurement of moisture content (figure 2, 3). Information about the frequency of oscillations of the jet inside the chamber of the jet generator through a moisture meter is transmitted to the calculator for further processing and determination of the mass components of the GHS. Further, flowing along the SG discharge channel, the separated flows (Fig. 4) are again combined and fall from the bypass into the pipe of the measuring section.

Figure 1 shows a device embedded in a pipe with a flow of raw gas and a measuring circuit of a moisture meter located on the flat surfaces of the SG.

Figure 2 shows a device embedded in a pipe with a flow of raw gas and a measuring circuit of a moisture meter located on the side walls of the SG chamber.

Figure 3 presents the device, cut into a pipe with a stream of raw gas and a measuring circuit of a moisture meter located on the side walls of the SG chamber along the jet stream until it exits the SG.

Figure 4 presents the diagram of the device for measuring the GHS, in which the SG, the moisture meter and the differential sensor are connected to the bypass line relative to the SUT located in the pipe with the measured parameters.

The following drawings indicate: 1 - the measuring section of the GHS pipe, 2 - the contour of the hygrometer, 3 - the jet generator (flow meter), 4 - the calculator, 5 - the nozzle for supplying the jet generator (or SU), 6 - the hydraulic output of the SG, 7 - information output calculator, 8 - differential pressure sensor, 9 - pressure differential pressure measurement point and at the same time the beginning of the bypass line, 10 - pressure differential pressure measurement point and at the same time the end of the bypass line, 11 - pipe restriction device (SUT), 12 - oscillating mixture stream, 13 - the wall of the inkjet chamber is impacted Iya SG, 14 - information output of the moisture meter.

Figure 1 on the right shows a projection of the device. The dotted line indicates the internal dimensions of the chamber. The measuring circuit of the hygrometer 2 is combined with the plates sealing the interaction chamber, and is in direct contact with the flow of GHS.

In Fig.2, the measuring circuit of the hygrometer 2 is located in the side walls of the collision chamber 13 for contact with the flow of the GHS. One of the walls 13 is taken out of the drawing separately.

Figure 2 and figure 3 is not shown fully measuring section 1, as well as the differential sensor and its connection with the computer, because these connections are similar to those shown in figure 1.

To measure small flow rates, the jet flow meter is built directly into the pipeline (FIGS. 1, 2, 3), and the entire stream passes through the power nozzle 5, the moisture meter 2, the measuring chamber 3 and the SG outlet 6. The pressure drop ΔР that occurs on the SG is measured by the differential sensor 8, its value is transmitted to the calculator to determine ρ _{cm of the} flow through the pressure sampling points 9 and 10. The measuring circuit of the hygrometer 2 can be located on the flat surface of the measuring section 1 of the SG (Fig. 1), as well as on both walls 13 of the chamber 3 of the SG, with which it strikes and then adjoins them during vibrations, the GHS jet (figure 2) or along the entire side surface of the chamber of the SG collision to exit 6 (figure 3).

In figure 2, the walls 13 on both sides of the collision chamber 3 are simultaneously the resonant circuit of the moisture meter 2. The nozzle 5 and the hydraulic outlet 6 of the SG are natural limiters of the current measuring volume during operation of the moisture meter (Figs. 1, 2, 3).

The volumetric flow rate Q _cm of the GHS mixture passing through the jet generator-flowmeter is determined by the formula Q _cm = qf _cm , where f _cm is the pulse frequency of the jet generator-flowmeter; q is the momentum unit volume, i.e. the volume of the measured medium of the GHS, per one pulse of oscillations of the jet flow meter.

Since the SG is a flowmeter of variable differential pressure (the differential pressure increases with increasing flow rate), having one minimum size of a jet flowmeter, it can be connected via bypass with respect to the narrowing in the main pipe of different sizes. The pulsed volume of the jet flow meter increases with an increase in the flow rate of the GHS in the main pipe, while one SG size with a fixed range of variation of the output frequency is saved.

In this case, the pulse unit volume of each size is determined by the formula q = Q / f _cm , where Q = Q _cy + Q _cm . Here Q is the total flow rate, Q _cy is the volumetric flow rate through the narrowing device in the main pipe along the measuring section 1, and Q _cm is the volumetric flow rate of the mixture through the jet flow meter. Thus, in a flowmeter of any size, the volumetric flow rate can be determined by the standard (typical) restriction 11 and the jet flow meter 3 with calculator 4.

The measuring section 1 is located in the pipe in which the GHS flows. The movement of the GHS is indicated by arrows with a double line. Signal information transmission is indicated by a simple arrow shape. The elements of the device 9, 5, 3, 6, 10 constitute a bypass line (parallel) for the flow of the GHS to the measuring section 1 of the pipe.

The device (figure 4) works as follows. Crude gas enters the pipe and passes the measuring section 1 in the direction of the arrow (in figures 1, 2 and 3, the flow passes to the power nozzle 5). The composition of the raw gas is a gas-liquid mixture of gas, gas condensate, water, oil condensate in the form of a foggy mixture. The differential pressure ΔP that occurs at the restriction 11 is measured by the differential pressure sensor 8, the signal of which is transmitted to the calculator 4. The channels through which the ΔP signal is transmitted simultaneously serve as channels of the bypass line for pumping the GHS through the measuring elements - a moisture meter 2 and a flow meter 3, made in form of SG. The measuring circuit of the hygrometer 2 contains information on the frequency and amplitude of the oscillation signal of the resonant frequency of the hygrometer, associated with the amount of moisture in the GHS, and also expresses the frequency of the oscillations of the jet in the SG. Information about the oscillation frequency of the jet and the relative amount of moisture is transmitted to the computer for processing.

, где обозначено Q_см - объемный расход ГЖС, m_см - масса 1 м³ ГЖС, k - коэффициент пропорциональности, учитывающий площадь сечения сужения.The main flow rate of the GHS passes through the pipe through the measuring section 1. To measure the mass flow rate, it is necessary to have current data on the pressure drop across the jet flow meter. Assuming the pressure drop ΔР to be proportional to mQ ² , where m is the mass of the mixture, the frequency f _{cm is} proportional to the volumetric flow Q, then the mass flow rate M _cm is determined by the formula

, where Q _cm is indicated - GHS volumetric flow rate, m _cm - mass of 1 m ³ GHS, k - proportionality coefficient taking into account the narrowing cross-sectional area.

The frequency f _{cm is} determined by the geometric parameters of the jet generator 3 and is measured by the contour of the hygrometer 2, ΔР _cm is measured by a differential pressure sensor 8, the relative volumetric water content α _in = Q _in / Q _cm in the total number of GHS is measured by a hygrometer 2. Based on the data obtained, it is possible to calculate the density of the mixture according to the formula ρ _cm = M _cm / Q _cm On the other hand, we have ρ _cm = α _g ρ _g + α _to ρ _to + α _in ρ _in ; α _z + α _to + α _a = 1.

When the measured moisture meter relative water α content _values and hydrocarbons α _v = α _r + α _k and α _y = 1 - α _in which denotes the relative volumetric gas content of α _r = Q _r / Q _cm condensate α _a = Q _k / Q _cm , as well as the a priori known ρ _в , ρ _g , ρ _к are the densities of water, gas and condensate, from the above equations we find α _к and α _г = (ρ _cm -α _in ρ _в -α _у ρ _к ) / (ρ _r + ρ _k ). Next, we determine the values of component costs by the formulas Q _g = α _g Q _cm , Q _k = α _to Q _cm , Q _in = α _in Q _cm ; M _r = α _g M _{cm to} M _to M = α _{cm, M} = α M _{in cm.}

Claims (1)

A device for measuring the component flow rate of a gas-liquid mixture containing a variable differential pressure meter in the form of a jet generator integrated in the pipeline with a power nozzle and a jet impact chamber, as well as a differential pressure sensor on the jet generator connected to the calculator, characterized in that a moisture meter connected to the calculator is additionally introduced whose measuring circuit is located on the side surface of the jet impact chamber of the jet generator so that the walls on both sides of the decree of the chamber at the same time are the resonant circuit of the hygrometer, while the nozzle and the hydraulic output of the jet generator are the limiters of the measuring volume of the hygrometer.

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