RU2301887C2 - Measurement method and device for component flow-rate of three-component gas-and-liquid flow - Google Patents

Abstract

FIELD: measuring equipment, particularly used in oil production industry to control oil producing well operation without gas-and-liquid well product separation in fractions directly in wells or in oil accumulation areas.

SUBSTANCE: method involves directing gas-and-liquid flow in measuring device built-in main pipeline; measuring pressure, temperature and density of gas-and-liquid flow by pressure and temperature sensors and by gamma densitometer correspondingly; determining total flow-rate of gas-and-liquid flow and oil, gas and water content in the flow and calculating output of separate phases in gas-and-liquid flow. To direct gas-and-liquid flow into measuring device symmetric gas-and-liquid flow direction change scheme is used. The symmetric scheme includes ascending, horizontal and descending branches. Pressure drop in ascending and descending branches are set by means of replaceable throttle members installed in front, rear end and in center of horizontal branch. Two double-probe gamma densitometers are arranged in ascending and descending branches. Each gamma densitometer includes ionizing gamma-radiation source and gamma-radiation detectors of major and minor probes. Gas-and-liquid flow density is determined in ascending and descending branches under different working pressures. Then gas-and-liquid flow conductivity and dielectric permeability are measured by non-contact method through ascending and descending branch sections of gas-and-liquid flow defined by vertical pipes formed of radio transparent highly-strength material with the use of two electromagnetic probes operating on low and high frequencies. Volumetric water content in gas-and-liquid flow is determined from above measured conductivity and dielectric permeability. Volumetric gas-and-liquid flow rate in ascending branch is measured from pressure drop in central throttle member with the use of throttle flowmeter with taking into consideration flow density determined by gamma densitometer. Hydrocarbon content in gas-and-liquid flow is calculated from difference between volumetric gas-and-liquid flow rate and volumetric water content. Volumetric oil content in gas-and-liquid flow is determined from difference between hydrocarbon content and volumetric gas content in gas-and-liquid flow. Device for above method realization is also disclosed.

EFFECT: increased accuracy of separate component flow-rate in three-component, namely oil-gas-water flow and extended field of application due to possibility of measurement execution in wide range of gas-and-liquid flow component content.

25 cl, 2 dwg

Description

The invention relates to measuring technique and can be used to measure the flow rate of a three-component gas-liquid flow, in particular, in the oil and gas industry, while monitoring the operation of oil wells without fractioning (without separating) the gas-liquid mixture of production products directly at the wells or in sections of reservoirs for oil production.

Known methods for measuring the component flow rate of a three-component gas-liquid flow are based on determining the speed and density of fractions by indirect methods by measuring a number of intermediate physical parameters of the flow: differential pressure, vibration noise and dynamic pressure, energy absorption or reflection of radio waves and microwave radiation, electrical conductivity, capacitance, etc. P. Devices of flow meters based on them often contain structural elements placed in the stream, for example volumetric and turbine meters, Coriolis meters (patent US 5029482, G01F 1/74, publ. 1991), meters using a diaphragm (patent US 4662219, G01F 1 / 76, G01F 1/36 publ. 1987). Known methods include the forced accumulation or partial separation of the components of the mixture (for example, US patent 5211842, E21 B 49/08, publ. 1993), or the preliminary formation of a steady stream of a certain type, for example, see patent US 5251488, G01F 15/08, publ . 1993. The disadvantage of the known methods for measuring the component flow rate of a three-component gas-liquid flow and devices for their implementation is the high error in determining the content of individual components.

Known methods for measuring the component flow rate of a three-component gas-liquid flow and devices for their implementation based on the use of gamma radiation sources for measuring the density of components of a gas-liquid mixture. For example, the method of measuring the component flow rate of a three-component gas-liquid flow, implemented in the device according to the patent US 4458524, G01N 33/22, publ. 1984, according to which the dielectric constant of the mixture, flow density and temperature are measured using a flow analyzer, and based on the obtained data, the component composition of the gas-liquid mixture is determined by calculation. This analyzer device contains a pipe section made of non-conductive material, on which receiving and transmitting inductive coils, a gamma radiation source (Cesium 137) and pressure and temperature sensors are fixed. Also known is the method and device according to patent US 5025160, G01F 1/00, publ. 1991, based on the use of dual energy characteristics of gamma radiation.

Closest to the claimed is a method for determining the component flow rate of a three-component gas-liquid flow, also known as "radio densitometry", based on the use of double energy characteristics of gamma radiation and a Venturi (E. Toski, V. Hansen, D. Smith, B. Teuveni. “The evolution of multiphase flow measurements and their impact on operational management”, Scientific and Technical Journal “Fuel and Energy Technologies”, December 2003, pp. 50-57). A device that implements this method contains a measuring section, which consists of the following elements: Venturi tubes with pressure, temperature and differential pressure sensors; a gamma radiation detector operating on the principle of a double energy spectral characteristic and located at the narrowing of the venturi, as well as a radioactive chemical source. The pressure difference between the inlet of the venturi and the point of its narrowing is used to calculate the total flow rate, pressure and temperature measurements are used to evaluate the properties of the fluid in the flow line conditions. Using a gamma radiation meter, the fractions of oil, water and gas, as well as the density of the gas-liquid mixture, are determined. The flow rates of individual phases are calculated by multiplying the total flow rate (flow rate) by the mass fraction of the phase.

The above methods and devices based on the use of gamma radiation sources have the following disadvantages. The collimator method used to measure the density with a narrow beam of gamma radiation does not guarantee the correct measurement of the density of the gas-liquid mixture, because large fluctuations in the flow can create conditions when most of the gas (in the form of bubbles, rosaries, etc.) will pass by a narrow beam of gamma radiation without finding a response to the gamma radiation detector. The location of the gamma densitometer in the place of the highest flow velocity in the meter does not increase its accuracy characteristics, but, on the contrary, significantly reduces them, because the inertia of the gamma radiation detector and the short residence time of the flow inhomogeneities in the cross section of the collimator gamma densitometer can give an effect comparable to the fluctuation of the readings of the gamma radiation detector. The use of a high-energy chemical source of gamma radiation is associated with the need to register it with the Sanitary-Epidemiological Inspectorate, using storage facilities, special transportation devices, training personnel to work with it, etc. The disadvantage of this method and device is also the lack of measurement of background gamma activity of the liquid phase of the gas-liquid mixture, reaching significant values.

The present invention is aimed at solving the problem of improving the accuracy of measuring the component flow rate of a three-component gas-liquid flow, consisting of oil, gas and water, and expanding the scope due to the possibility of carrying out measurements over a wide range of the relative contents of the components of the gas-liquid mixture. The technical result of the proposed invention is also the possibility of contactless determination of the component flow rate of a three-component gas-liquid flow at virtually any volume fractions of gas and flow rates of wells in the flow of real non-standard flows of a gas-liquid mixture. An additional technical result of the invention is the expansion of the functionality of the proposed device by determining directly in the flow of the production well background gamma activity, the change of which is associated with the approach to the production well of the front of salinization of water injected into the reservoirs to maintain reservoir pressure, as well as by measuring the redox potential of the liquid produced products, the values of which are associated with an increased content Dissolved oxygen in the composition of the water pumped into the layers of the open reservoirs.

The essence of the invention lies in the fact that in the method of measuring the component flow rate of a three-component gas-liquid flow, including the direction of the gas-liquid flow into a measuring device integrated in the main pipeline, in which the pressure, differential pressure, temperature and density of the gas-liquid flow are measured by pressure, temperature and gamma sensors, respectively densitometer, determining the total flow rate of a gas-liquid stream and the proportions of oil, gas and water in it and calculating the flow rates of individual phases of a gas-liquid flow current, the invention is directed to a gas-liquid flow measuring device using a symmetric scheme change liquid flow direction, consisting of ascending, descending and horizontal branches. In this case, the pressure drop in the ascending and descending branches is set due to the installation of replaceable narrowing devices at the beginning, middle and end of the horizontal branch. On the ascending and descending branches of gas-liquid flows, two two-probe gamma densitometers are installed, each of which contains a source of ionizing gamma radiation, a gamma radiation detector of a small probe and a gamma radiation detector of a large probe, and the density of the gas-liquid flow on the ascending and descending branches is measured for different operating pressure and the difference in the readings of the detectors of small and large probes determine the volumetric gas content of the gas-liquid flow. In addition, the conductivity and permittivity of the gas-liquid flow are measured by the inductive method contactlessly through the sections of the ascending and descending branches of the gas-liquid flow, formed by vertically arranged tubes made of high-transparent radio-transparent material by two electromagnetic probes operating at low and high frequencies, and the volumetric water content is determined from them in a gas-liquid stream. Using the pressure drop across the middle constricting device, the throttle flow meter, taking into account the flux density determined by the gamma densitometer, measures the volumetric flow rate of the gas-liquid stream in the ascending branch, the content of the hydrocarbon portion of the gas-liquid stream is determined by the difference between the volumetric flow rate of the gas-liquid stream and the volumetric content of water, and the difference between the hydrocarbon content of the gas-liquid stream and the volumetric gas content determine the volumetric oil content in the stream.

As a source of ionizing gamma radiation of gamma densitometers, a low-background natural source in the form of sylvine, safe for service personnel, can be used, and scintillation detectors can be used as gamma radiation detectors of small and large probes.

In addition, the background values of the gamma activity of the liquid-gas flow are measured by a compensation gamma-ray detector, similar to gamma-ray detectors used in small and large gamma-ray density probes, but protected from an ionizing gamma-ray source.

From the readings of the gamma radiation detectors of the small and large gamma densitometer probes located in the ascending and descending branches of the gas-liquid flow, the readings of the compensation detector of the background gamma activity are subtracted, and the density of the gas-liquid flow in the ascending and descending branches of the flows is determined as the logarithm of the ratio of the readings of the gamma detectors radiation of small and large probes of a gamma densitometer taking into account the background gamma activity of a liquid in a gas-liquid flow.

By increasing the readings of the compensation detector of background gamma activity, the moment of appearance of the salinization front having increased radioactivity in the well production is recorded.

The density of the gas-liquid flow in the ascending and descending branches at different operating pressures is additionally measured by two hydrostatic densitometers based on differential pressure transducers.

Additionally, the magnitude of the redox potential of the fluid flow is measured and the change in the values of the redox potential is used to record the appearance of water in the well production that is in contact with the atmosphere before injection and has a high content of dissolved oxygen.

The volumetric content of water is determined taking into account its mineralization, determined by the periodic analysis of the selected liquid samples.

Additionally, the determination of the oil and gas content in the hydrocarbon portion of the gas-liquid stream is carried out taking into account the volumetric gas content determined by the readings of two hydrostatic densitometers under different operating pressures.

The determination of the gas and liquid content in the stream, water and oil in the liquid part of the gas-liquid stream and oil and gas in the hydrocarbon part of the gas-liquid stream is additionally carried out through the initial densities of the components taking into account the operating temperature and pressure according to both gamma densitometers and hydrostatic densitometers.

The control measurement of the volumetric flow rate of the three-component gas-liquid flow is additionally carried out by the tagging method according to variations in the pressure differential readings on the three constricting devices through the transport delay of the gas-liquid flow.

An additional control measurement of the volumetric flow rate of a three-component gas-liquid flow is carried out by the tagged method according to variations in the readings of inductive electromagnetic conductivity and dielectric permittivity probes located on the ascending and descending branches of the gas-liquid flow through transport delay.

The volumetric gas content in the three-component gas-liquid flow is additionally determined by the temperature and pressure difference to the constrictors and after them arising due to the throttling of gas and liquid through the constrictors, by measuring the temperature and pressure drop in the device with high-precision pressure and temperature sensors.

The essence of the invention lies in the fact that the device for measuring the component flow rate of a three-component gas-liquid stream, built into the main pipeline for transporting a gas-liquid stream, including a source and a gamma-ray detector and pressure and temperature sensors, according to the invention is made in the form of a symmetrical structure consisting of two vertically and parallel pipes made of high-strength radiolucent fiberglass material with metal tips ending flanges connected in the upper and lower parts by two horizontal metal pipes with vertically arranged flanged connecting bends, in the flanged connecting bends of the upper horizontal pipe and in its middle there are three interchangeable narrowing devices, which are washers, the diameter of the passage opening of which is 2-4 times smaller the inner diameter of vertically arranged fiberglass pipes, due to which the necessary pressure drop is created between the ascending and descending flows, on which The lower horizontal pipe has flange connections designed to be installed in the main pipeline, shutoff ball valves are located in the middle and on the vertical branches of the lower horizontal metal pipe, with which gas-liquid flow can be directed through the lower horizontal metal pipe or through the bypass line of the device , forming the ascending, horizontal and descending branches of the gas-liquid flow, on the lower metal tips of vertically arranged pipes four opposite pressure and temperature sensors are symmetrically located on the opposite parts of the upper horizontal metal pipe, two gamma densitometers are symmetrically located on the vertically arranged pipes, each of which contains an ionizing radiation source, which is a container filled with KCl in them, and two gamma radiation detectors forming small and large probes of gamma-densitometers, and two electromagnetic probes of conductivity and permittivity, on the upper horizontal metal pipes symmetrically installed in the left side - a compensation detector of background gamma activity, and in the right side - a probe of redox potential, while pressure and temperature sensors, gamma radiation detectors of small and large gamma densitometer probes, electromagnetic conductivity and dielectric permittivity probes, a compensation detector of background gamma activity and a redox potential probe are connected to the electronics unit, the computing device, and the energy unit introduced into the device independent memory with the ability to collect and process information from them, perform calculations according to predetermined algorithms, store calibration data, which are the basis of comparison, and archive output data for a long measurement period.

The redox probe contains a platinum electrode and a reference electrode.

Electromagnetic conductivity and permittivity probes are made in the form of inductive coils located on the outer surface of vertically arranged pipes with the possibility of non-contact measurements of attenuation and phase shift.

Inductive coils on the ascending and descending branches of the gas-liquid flow are spaced apart by distances that provide measurement of the velocity of the gas-liquid mixture due to its inhomogeneity in conductivity and dielectric constant.

Detectors of gamma radiation of small and large probes in gamma densitometers and a detector of background gamma activity can be made in the form of scintiblocks consisting of a NaJ or ZsJ crystal and a photoelectronic multiplier.

To minimize the influence of the cosmic background, the gamma-ray detectors of small and large gamma-densitometer probes are protected from the outside by protective shields, for example, from leaded rubber.

Pressure and temperature sensors can be made in the form of high-precision quartz pressure and temperature converters with a frequency output, which are switched on differentially with the accumulation of differential signals for the average transport delay time of the gas-liquid flow between the middle of the measurement bases, forming hydrostatic densitometers for additional density measurement.

The device contains an emergency battery supply system that ensures operability when the power supply is disconnected for a period of at least 24 hours.

The emergency battery system contains a unit for automatically recharging batteries when the mains is turned on.

To prevent buildup of asphalt-resinous and paraffin deposits on the inner surface of the device, the walls of the device have a protective coating.

The device is covered by a thermally insulated protective cover.

Figure 1 presents a diagram of a device for measuring the component flow rate of a three-component gas-liquid flow. Figure 2 shows a diagram of the direction of flow of a gas-liquid mixture when connecting the device to the pipeline.

The device for measuring the component flow rate of a three-component gas-liquid flow, shown in figure 1, is made in the form of a symmetrical structure consisting of two vertically and parallel pipes 1 and 2 made of high-strength radiolucent material (for example, fiberglass) with metal ends 3 ending flanges 4. The upper parts of the vertically arranged pipes 1 and 2 are connected by the upper horizontal metal pipe 5 with the vertically located flange connecting and bends 6 and 7. In the flange connecting bends 6 and 7 and in the middle of the horizontal metal pipe 5 there are three interchangeable narrowing devices 8, 9, 10, which are washers, the diameter of the passage opening of which is 2-4 times smaller than the inner diameter of the vertically arranged fiberglass pipes 1, 2. The lower parts of vertically arranged fiberglass pipes 1, 2 are connected to vertically located flange connecting bends 11, 12 of the lower horizontal metal pipe 13. At the ends of the lower horizontal Thallic pipes 13 are flange connections 14, designed to be embedded in the main pipeline. In the middle of the lower horizontal metal pipe 13 and on the vertically arranged flange connecting bends 11, 12 there are locking ball valves 15, 16, 17. On the lower metal tips 3 of the vertically arranged fiberglass pipes 1, 2 and on the opposite parts of the upper horizontal metal pipe 5 symmetrically there are four sensors 18, 19, 20, 21, designed to measure both pressure and temperature in the gas-liquid mixture stream. To perform these functions, the sensors 18, 19, 20, 21 can be made in the form of quartz pressure and temperature transducers, for example, PDTK-4.0-MR converter manufactured by SKTB ElPA LLC, Uglich. The approximate distance between the sensors 18-19 and 20-21 in the vertical direction is about 1 m, between the sensors 19-20 in the horizontal direction - 0.6 m. Two vertically arranged fiberglass pipes 1 and 2 are symmetrically arranged with two gamma densitometers, each of which contains a source of ionizing gamma radiation 22, 23 and two gamma radiation detectors 24, 26 and 25, 27, respectively, forming small and large gamma densitometer probes, and two electromagnetic conductivity and permittivity probes 28 and 29. Electromagnetic probes 28 and 29 of conductivity and permittivity are made in the form of inductive coils located on the outer surface of vertically arranged pipes 1 and 2.

On the upper horizontal metal pipe 5, a compensation detector 30 of background gamma activity is installed symmetrically in the left side, and a redox probe 31 containing a platinum electrode and a reference electrode (not shown) in the right side. The design of the device is symmetrical geometrically and hydraulically balanced. Sources 22, 23 of gamma radiation are made in the form of containers with a volume of about 7.5 l with a backfill of KCl in them, which is safe for staff. As detectors 24, 25, 26, 27 of gamma radiation and a compensation detector 30 of background gamma activity, scintillation crystals NaJ (Tl) or ZsJ with photomultiplier tubes (PMTs) were used. In order to eliminate the influence of the cosmic background, the detectors 24, 25, 26, 27 are closed from the outside by protective shields 32 of leaded rubber. Sensors 18, 19, 20, 21, detectors 24, 25, 26, 27 of gamma radiation of small and large probes of gamma densitometers, electromagnetic probes 28 and 29 of conductivity and permittivity, compensation detector 30 of gamma activity and a probe 31 redox potential are connected to the electronics unit, the computing device, the non-volatile memory unit and the emergency power storage unit (not shown) introduced into the device. The entire measuring device is covered by a protective casing 33 with thermal insulation 34, the inner walls of the device have a protective coating (not shown) to prevent buildup on the inner surface of asphalt-resinous and paraffin deposits.

The proposed method for measuring the component flow rate of a three-component gas-liquid flow, in particular, the production of producing oil wells is as follows.

A device for measuring the component flow rate of a three-component gas-liquid flow through flange connections 14 is built into the pipeline through which the gas-liquid mixture is transported. Using shut-off ball valves 15, 16, 17, the gas-liquid flow is directed either through the lower horizontal metal pipe 13 (the valve 15 is open, the valves 16 and 17 are closed) or through the bypass line of the device, consisting of a vertically located pipe 1, the upper horizontal metal pipe 5 and a vertically located pipe 2, thus forming an ascending, horizontal and descending branch of the gas-liquid stream (valve 15 is closed, valves 16 and 17 are open). When the direction of gas-liquid flow through the bypass line of the device (according to the scheme shown in figure 2), the internal cavity of the device is filled with well products. This creates a pressure drop of gas-liquid flow on each of the interchangeable narrowing devices 8, 9, 10 located respectively at the beginning, middle and end of the horizontal branch. The density of the gas-liquid flow is measured on the ascending and descending branches at different operating pressures by two gamma densitometers installed on vertically arranged pipes 1 and 2, and by the difference in readings of the small and large probe detectors (gamma radiation detectors 24, 26 and 25, 27, respectively ascending and descending branches) determine the volumetric gas content of the gas-liquid stream. The gamma densitometers used in the device differ in the following features:

- sources (22, 23) of gamma radiation containing sylvin (KCl) are low-background, therefore they are completely safe for service personnel and do not require their registration with the Sanitary and Epidemiological Inspectorate;

- unlike collimator gamma densitometers, the gamma densitometers installed in the proposed device are volumetric and dual-probe, covering the entire flow cross section, while the determined density is a function of the ratio of the readings of small and large probes, which significantly eliminates the possible temporary instability of the detectors gamma radiation and improves the accuracy of determining the density of gas-liquid flow.

The symmetric arrangement of gamma densitometers on the ascending and descending branches of the gas-liquid flow provides the ability to continuously determine the volumetric gas content of the gas-liquid mixture both from gas, oil and water calibration data, and from the density difference in the ascending and descending flows under different operating pressures.

The presence in the device of the compensation detector 30 of gamma activity allows you to take into account the influence of the natural radioactivity of the liquid, due to the approach of the front of the injected water, and also to determine the value of the background radioactivity of the liquid, which is additional important information about the state of the producing well. For example, with a small probe length of 20 cm and a large probe of 70 cm, the dependence of the density of the gas-liquid mixture on the readings of gamma radiation detectors with an error of not more than ± 0.1% is approximated by the equation:

where J _m is the accumulated number of pulses by the gamma radiation detector of the small probe during the measurement τ;

J _b is the accumulated number of pulses by the gamma radiation detector of the large probe during the measurement time τ;

J _f - the accumulated number of pulses by the compensation detector of the background gamma activity during the measurement τ.

The measurement time τ (time constant) is adjustable within 60 ÷ 600 s with a change of values according to the moving average rule after 10 s.

The background values of the natural gamma activity of the produced fluid (in imp / min) are also determined by a separate parameter with averaging the readings over 60 ÷ 600 s and changing the values after 10 s.

Registration parameter _f J compensation detector 30, the background gamma activity also allows to fix the moment of appearance in front of well production salinity having enhanced activity due to the content in the liquid mixture of barium salt and gamma activity decline over time with increasing water content.

Gamma densitometer allows direct instrumental determination of true gas content according to the results of its calibration at various pressures (from 1 to 40 kgf / cm ² ) on a liquid (oil or water) and gas. In this case, the true gas content is determined by the formula:

where (J _cm ), (J _g ), (J _g ) are the ratios of the readings of the small and large probes of the gamma-density meter, measured while passing gamma radiation through a gas-liquid mixture, liquid and gas.

In parallel with the quantitative high-precision determination of the true gas content, the registration of the parameter φ ^gp makes it possible to clearly determine the structural forms of the gas-liquid mixture flow, which makes it possible to increase the measurement accuracy by changing the averaging time constant τ and connecting duplicate measurement methods.

заключается в использовании значений плотности, определенных гамма-плотномером в восходящей и нисходящей ветвях потока и рабочих давлений газожидкостного потока в каждой из ветвей по формуле:The second way to determine the true gas content of the mixture

consists in using the density values determined by the gamma densitometer in the ascending and descending flow branches and the working pressures of the gas-liquid flow in each of the branches according to the formula:

where ρ _VOS is the density of the gas-liquid mixture in the ascending branch,

ρ _nis is the density of the gas-liquid mixture in the descending branch,

P ₁ , P _{4 -} pressure in the ascending and descending branches.

является суммой произведений плотности газовой ρ_гр и жидкой

фаз на их долевое содержание в смеси

,

:Determined by gamma densitometers density of gas-liquid mixture

is the sum of the products of the density of gas ρ _g and liquid

phases to their fractional content in the mixture

,

:

,

,

gas density ρ _g under operating conditions, calculated by the formula

where ρ _gst - gas density under standard conditions, kg / m ³ ;

T _article - standard temperature, 288.5 K

R _article - standard (atmospheric) pressure, 1 kgf / cm ² ;

R _p - working pressure, kgf / cm ² ;

T _p - operating temperature, K;

Z is the gas compressibility coefficient, determined through the reduced temperature T _ol and the reduced pressure R _ol (in the range of operating pressures from 0.5 to 4 MPa it varies from 0.98 to 0.87).

The liquid content in the gas-liquid mixture ***** is defined as

fluid density:

water content:

and oil content

Thus, the use of two two-probe volume gamma densitometers allows one to determine with high accuracy both the density of the gas-liquid mixture in the ascending and descending branches, and the fractional content of water, oil and gas.

The symmetrical arrangement on the ascending and descending branches of four sensors 18, 19, 20, 21, made in the form of high-precision quartz pressure and temperature transducers with a frequency output, switched on differentially, forms hydrostatic densitometers for additional density measurement.

When a gas-liquid flow passes through the measuring device, a pressure drop _{ΔР Su1} , _{ΔР Su2} , _{ΔР Su3,} respectively, is created on each narrowing device 8, 9, 10, while due to the continuity of the flow with an equal density of the gas-liquid mixture throughout the flow

At the same time, on vertically arranged fiberglass pipes 1 and 2, the pressure difference up to and after the constricting devices 8 and 10 will also be affected by the component of hydrostatic pressure. The pressure difference ΔP _gs between the pressure measuring points P ₁ and P ₂ (sensors 18 and 19) and P ₃ and P ₄ (sensors 20 and 21) (see figure 2):

where Δh is the distance between the sensors in height,

ρ is the density of the gas-liquid mixture in the area between the measurement points.

Since the hydrostatic pressure in the ascending branch of the gas-liquid flow is directed against the flow, and in the descending branch, in the flow, the pressure drop between the measurement points will be equal to:

- on the ascending branch

- on a horizontal branch

- on the descending branch

Neglecting friction losses, which are insignificant on the horizontal branch, and compensated on the ascending and descending branches, and taking into account that due to the continuity of the gas-liquid flow at its constant density, the flow velocities in the narrowing devices 8, 9, 10 are equal to each other, as a result of which the pressure drops in the constricting devices ΔP _su are equal. Using the pressure values P ₁ , P ₂ , P ₃ , p ₄ at the measurement points and the pressure drops between them, we obtain a series of equations that look like this:

From equations (18), (19), (20) it follows that

Thus, a system of four sensors 18, 19, 20, 21, symmetrically placed at certain points of the device and allowing to measure pressure at these points with high accuracy, allows you to determine the following parameters in the flow of gas-liquid mixture passing through the measuring device:

P ₁ is the pressure of the gas-liquid flow at the inlet to the device;

P ₄ is the pressure of the gas-liquid stream at the outlet of the device;

ΔP _1-4 is the pressure drop across the measuring device as a whole, equal to three times the pressure drop across each of the constricting devices;

ΔР _2-3 - pressure drop on a single (average or second downstream) narrowing device;

ρ _1-2 - the density of the gas-liquid flow in the area between the pressure measurement points P ₁ and P ₂ ;

ρ _3-4 - the density of the gas-liquid flow in the area between the pressure measurement points P ₃ and P ₄ ;

ρ _1-4 is the average (integral) density in the device for measuring in the area between the pressure measuring points P ₁ and P ₄ .

The information obtained allows us to determine the following parameters of gas-liquid flow:

Q _about - the volumetric flow rate of gas-liquid flow in the expression:

- mass flow of gas-liquid flow in the expression:

where A _about , A _m - volumetric and mass flow coefficients, determined on the calibration device;

D is the pipe diameter;

ΔР - differential on the constriction device;

ρ is the flux density.

When substituting the previously defined values in equations (24) and (25) we get:

- volumetric flow rate through the middle constricting device 9:

- mass flow rate through the middle constricting device 9:

- volumetric integral flow through three constricting devices 8, 9, 10:

- mass integral flow through three narrowing devices 8, 9, 10:

With a constant density of the gas-liquid flow, equations (26) and (27) and (28) and (29) will give the same results in volume and mass flow rates.

The control measurement of the volumetric flow rate of the three-component gas-liquid flow can be additionally made by the tagging method according to the variations in the pressure differential readings on the three constricting devices through the transport delay of the gas-liquid flow. Under real conditions, the transported gas-liquid stream is not always uniform in density (for example, due to the appearance of a gas "bubble" whose density is much lower than the density of the liquid in the gas-liquid stream). We call the density ratio ρ _1-2 / ρ _{3-4 the} coefficient of heterogeneity, gas-liquid flow. If ρ _1-2 and ρ _3-4 are equal:

If density inhomogeneity appears in the ascending branch of the gas-liquid flow, the K _n value will change: when passing the ascending branch, it will be less than 1, and when passing the descending branch, it will be more than unity.

в функции времени на вычислительном устройстве позволяет вычислить времена t_1-2, t_2-3, t_3-4, t_1-4, прохождения естественных «меток», определяющих время транспортного запаздывания, возникающего за счет неоднородности газожидкостного потока между измерительными базами, образованными датчиками 18, 19, 20, 21.Dependency handling

as a function of time on a computing device allows you to calculate the times t _1-2 , t _2-3 , t _3-4 , t _1-4 , the passage of natural "marks" that determine the time of transport lag arising due to the heterogeneity of the gas-liquid flow between the measuring bases, educated sensors 18, 19, 20, 21.

Knowing the distances between the measuring bases l _1-2 , l _2-3 , l _3-4 , l _1-4 , the volumes of the measuring bases V _1-2 , V _2-3 , V _3-4 , V _1-4 , we can determine speed ν and volumetric flow rates Q ' _o "labels" on the corresponding sections of the measuring device according to one of the expressions:

If the “mark” is formed by a gas “bubble”, then the speeds of its movement on the ascending, horizontal and descending sections of the measuring device will be different, therefore, preference should be given to the integral values of the speed of movement (34) and volumetric flow (38).

Moreover, by increasing the length l _1-4 and the volume V _{1-4, the} accuracy of determining ν _1-4 and Q ' _o1-4 in relation to shorter measuring bases increases.

Under “plug” or “clear” regimes of gas-liquid flow movement, the volume of gas passed through can be determined by integrating the volume of gas “plugs” by the value of density change ρ (t) during the movement along one of the measuring bases taking into account operating pressure and temperature.

An additional determination of the oil and gas content in the hydrocarbon portion of the gas-liquid stream, taking into account the volumetric gas content determined by the readings of two hydrostatic densitometers under different operating pressures, is carried out as follows. Since the densities ρ _1-2 and ρ _{3-4 are} determined at different pressures P ₁ and P ₄ , the gas volume content C _g can also be determined through their values by the expression (in fractions of unity):

The density determined by a hydrostatic densitometer (ρ _1-2 , ρ _3-4 , ρ _1-4 ) of a gas-liquid mixture is the sum of the products of the density of the gas and liquid phases by their fractional content in the mixture:

ρ _gr gas density under operating conditions, determined by the formula (5).

The liquid content in the gas-liquid mixture is determined similarly to the formula (6):

The density of the liquid ρ _W is determined by the expression similar to the formula (7):

The determination of oil and water content according to hydrostatic densitometers is determined based on the condition:

where ρ _in and ρ _n are set according to laboratory analysis of well production,

C _{w is} determined by the expression (41), ρ _w - by the expression (42).

Then the water content is determined similarly to the formula (8)

oil content is similar to formula (9)

Gas volume flow, oil and water are determined from the condition that the volume flow rate of the gas-liquid mixture Q _o2 through narrowing device 9 and the volume integral flow Q _He three narrowing means 8, 9, 10, defined by the expressions (26, 30) equal to the sum of costs components of the mixture by their share in the volume of the mixture:

Then

When measured ρ _cm and calculated ρ _gr (31) and ρ _W (34), the volumetric gas flow rate β is additionally determined by the expression (in fractions of volume):

Thus, the determination of the density of a gas-liquid mixture through hydrostatic densitometers and volumetric flow rate through constriction devices also makes it possible to determine the content of all phases in a three-phase flow and their volumetric flow rate. The volumetric flow rates of gas, oil and water using these gamma-densitometers are determined by the formulas similar to (51-53):

The volumetric gas flow rate β in this case is determined by the expression similar to formula (54):

Electromagnetic probes 28 and 29 of conductivity and permittivity allow additionally to continuously determine in the ascending and descending branches the volumetric water content in the gas-liquid mixture (at least up to 40-45% water cut in case of separate and bubble-plug traffic).

The water content in the mixture is determined in this case by the expression:

where ε _cm is the dielectric constant of the gas-liquid mixture;

ε _in - dielectric constant of water;

ε _coal is the dielectric constant of hydrocarbons.

Taking ε _angle = 1.6, expression (60) is reduced to the form:

The hydrocarbon content in the mixture is defined as:

From the condition

hydrocarbon density is determined

and then the known values of ρ _n and ρ _gr determine the content of oil and gas in the hydrocarbon mixture:

Verification is carried out by the expression:

and also in comparison with equations (39, 44, 45).

The volumetric flow rate of the phases in this case is determined similarly to equations (48-53).

Inductive coils of electromagnetic probes 28, 29 on the ascending and descending branches of the gas-liquid flow are spaced apart by distances that allow measuring the velocity of the gas-liquid mixture due to its inhomogeneity in conductivity and permittivity. An additional control measurement of the volumetric flow rate of a three-component gas-liquid flow is carried out by the tagged method according to the variations in the readings of inductive electromagnetic probes 28, 29 of conductivity and dielectric constant located on the ascending and descending branches of the gas-liquid flow through the transport delay. In the presence of inhomogeneities in the gas-liquid mixture flow, the readings of the electromagnetic probes 28, 29 change stepwise and the total volumetric flow rate of the gas-liquid flow through the measuring device is determined by the time the inhomogeneities pass between the measurement points.

The redox potential probe 31, located in the upper horizontal metal pipe 5 of the measuring device, provides additional information related to the appearance in the well production of water pumped into injection wells from open reservoirs and having a high content of dissolved oxygen. By measuring the values of the redox potential, it is possible to record the moment of a breakthrough into the well of water injected from the surface of the day and timely take measures to isolate the place of their entry into the well.

The value of the redox potential is measured through the potential Eh of the inert electrode immersed in the redox medium relative to this medium.

There is a relation (Pirson S.J. Redox log interprets reservoir potential. "Oil and Gas Journal", 1968, 66, No. 31, pp. 69-75 (English).):

where Eh is the potential of the inert electrode, referred to the standard hydrogen electrode;

Eo - systems constant (electrode potential, measured at 50% ^SG oxidation systems);

R = 8.315 J and F = 96.540 K are thermodynamic constants;

T is the absolute temperature;

n is the number of electrons involved in the reaction;

OX and Red are the concentrations of oxidizing and reducing agents, respectively.

A gold or platinum electrode can be used as an inert electrode in a redox probe, and a lead electrode calibrated relative to a standard hydrogen electrode (calomel) can be used as a comparative electrode. The method consists in continuously measuring the potential Eh with averaging over the measurement time τ, which can be changed from 10 to 120 s. The limits of measurement of Eh are from +500 to -500 mV.

The volumetric gas content in the three-component gas-liquid flow is additionally determined by the temperature and pressure difference to the constricting devices 8, 9, 10 and after them, arising due to the throttling of gas and liquid through the constricting devices, by measuring the temperature and pressure drop in the device with high-precision pressure and temperature sensors 18, 19, 20, 21.

The method is based on the Joule-Thomson effect (Cooling X. Handbook of physics. Translated from German. - M .: Mir, 1982 - 520 pp. (P. 174-175)) that occurs when the gas-liquid flow is throttled through the constriction devices 8 , 9, 10 (chokes) in the form of washers. Joule-Thomson integral coefficient:

where ΔТ is the temperature difference on the narrowing device;

ΔР is the pressure drop across the constriction device.

для воды - 0,235°С/МПа, для нефти - 0,4-0,6°С/МПа, и для газа - 3-6°С/МПа (для метана ≈ 4°С/МПа).From the reference value

0.235 ° C / MPa for water, 0.4-0.6 ° C / MPa for oil, and 3-6 ° C / MPa for gas (≈ 4 ° C / MPa for methane).

(меняется).At temperatures below critical temperatures, the passage of liquids (oil, water) through the throttle causes them to heat, and the passage of gas through the throttle causes it to cool (sign

(changing).

для газа на порядок больше, чем для жидкостей, а также то обстоятельство, что при дросселировании газа меняется и знак

, этот параметр целесообразно дополнительно использовать для определения объемного содержания газа в потоке (особенно при его значительных количествах) по уравнению:Given that

for gas, an order of magnitude greater than for liquids, as well as the fact that the sign changes during gas throttling

, this parameter is advisable to additionally use to determine the volumetric gas content in the stream (especially with significant quantities) according to the equation:

,because

,

- коэффициент Джоуля-Томсона для смеси;Where

- Joule-Thomson coefficient for the mixture;

,

,

,

- коэффициент Джоуля-Томсона для воды, нефти, газа и жидкости;

,

,

,

- Joule-Thomson coefficient for water, oil, gas and liquid;

With _in , With _n , With _g , and With _W - the proportion of water, oil, gas and liquid in the mixture;

then you can write

.

.

и

, имеем

.Taking

and

, we have

.

Taking Cr = (1-Cr), we obtain

From here

For example, at Δt ° = -0.062 ° С and ΔР = 0.041 MPa

C _w = 1-0.4318 = 0.5652

уточняются по составу газа, а

- по долям нефти и воды, определенным по уравнениям (3-9), (47), (48), (59), (63).Values

are specified by gas composition, and

- according to the fractions of oil and water determined by the equations (3-9), (47), (48), (59), (63).

The value of the differential pressure ΔP _1-4 = P ₁ -P ₄ is determined by the difference in pressure readings by the sensors 18 and 21, and the value of the differential pressure Δt is determined by the difference in temperature readings by the sensors 18 and 21, performing the function of measuring temperature in this case Δt _1-4 = t ° ₁ -t ° ₄ .

Thus, the present invention solves the urgent task of the oil and gas industry - measuring the flow rate of three-component product flows of producing wells without building expensive bulky separation devices in individual wells and well clusters. Quantitative measurements of the component flow rate of the production of wells can be carried out by mounting the insert of the device according to the invention in the flow line from the well or group of wells. Moreover, the relative content of the components of gas-liquid flows can vary within wide limits - the gas factor from 1 to 500 m ³ / m ³ , water cut from 0 to 98%. The device for measuring can also be mounted on a mobile vehicle, such as a trailer, and used for research when developing and putting a well into operation, which expands its scope.

Claims (25)

1. A method of measuring the component flow rate of a three-component gas-liquid flow, including directing a gas-liquid flow into a measuring device integrated in the main pipe, in which pressure, temperature and density of a gas-liquid flow are measured by pressure, temperature and gamma-density meters, respectively, determining a total gas-liquid flow rate and fractions oil, gas and water in it and the calculation of the flow rates of the individual phases of the gas-liquid stream, characterized in that the gas-liquid stream is sent to a device for measurement, using a symmetric scheme for changing the direction of the gas-liquid flow, consisting of ascending, horizontal and descending branches, while the pressure drop in the ascending and descending branches is set by installing replaceable narrowing devices at the beginning, middle and end of the horizontal branch, on the ascending and two descending gamma densitometers, each of which contains a source of ionizing gamma radiation, a small gamma radiation detector, and a descending branches of gas-liquid flows the probe and the gamma radiation detector of the large probe, and measure the density of the gas-liquid flow on the ascending and descending branches at different operating pressures, and from the difference in the readings of the detectors of the small and large probes, the gas-liquid flow is determined, the conductivity and permittivity of the gas-liquid flow are measured by the inductive method contactlessly through sections of ascending and descending branches of the gas-liquid flow formed by vertically arranged pipes made of radiolucent high-strength material, two electromagnetic probes operating at low and high frequencies, and from them determine the volumetric content of water in the gas-liquid flow, the pressure drop on the average narrowing device with a throttle flow meter taking into account the flux density determined by the gamma densitometer, measure the volumetric flow of gas-liquid flow in the ascending branch, the content of the hydrocarbon part of the gas-liquid stream is determined by the difference between the volumetric flow rate of the gas-liquid stream and the volumetric water content, and the difference between the content of the hydrocarbon part of the gas-liquid stream and the volumetric gas content determine the volumetric oil content in the stream. 2. The method according to claim 1, characterized in that a low-background natural source in the form of sylvine (KCl), which is safe for service personnel, is used as a source of ionizing gamma radiation, and scintillation detectors are used as gamma radiation detectors of small and large probes. 3. The method according to claim 2, characterized in that the background values of the gamma activity of the liquid gas-liquid flow are additionally measured by a compensation gamma-ray detector, similar to gamma-ray detectors used in small and large gamma-density probes, but protected from an ionizing gamma source -radiation. 4. The method according to claim 3, characterized in that from the readings of gamma radiation detectors of small and large probes of gamma densitometers located in the ascending and descending branches of the gas-liquid flow, the readings of the compensation detector of the background gamma activity of the liquid of the gas-liquid flow are subtracted, and the density of the gas-liquid flow in the ascending and descending flow branches is defined as the logarithm of the ratio of the readings of the gamma radiation detectors of the small and large gamma densitometer probes taking into account the gamma activity of the gaseous fluid bone stream. 5. The method according to claim 3, characterized in that by increasing the readings of the compensation detector of background gamma activity, the moment of appearance of a salinization front having increased radioactivity in the well production is recorded. 6. The method according to claim 1, characterized in that the density of the gas-liquid flow in the ascending and descending branches at different operating pressures is additionally measured by two hydrostatic densitometers based on differential pressure transducers. 7. The method according to claim 1, characterized in that it further measures the value of the redox potential of the fluid stream. 8. The method according to claim 7, characterized in that by changing the values of the redox potential, the occurrence of water in the well production that is in contact with the atmosphere and has a high dissolved oxygen content prior to injection is recorded. 9. The method according to claim 1, characterized in that the volumetric water content is determined taking into account its salinity, as determined by periodic analysis of fluid samples taken. 10. The method according to claim 6, characterized in that the determination of the oil and gas content in the hydrocarbon portion of the gas-liquid stream is additionally carried out taking into account the volumetric gas content determined from the readings of two hydrostatic densitometers under different operating pressures. 11. The method according to claim 1, characterized in that the determination of the gas and liquid content in the water and oil stream in the liquid part of the gas-liquid stream and oil and gas in the hydrocarbon part of the gas-liquid stream is additionally carried out through the initial density of the components taking into account the operating temperature and pressure according to indications both gamma densitometers and hydrostatic densitometers. 12. The method according to claim 1, characterized in that the control measurement of the volumetric flow rate of the three-component gas-liquid flow is additionally carried out by the tagging method according to variations in the pressure differential across the three constricting devices through the transport delay of the gas-liquid flow. 13. The method according to claim 1, characterized in that the additional control measurement of the volumetric flow rate of the three-component gas-liquid flow is carried out by the label method according to variations in the readings of inductive electromagnetic conductivity and dielectric permittivity probes located on the ascending and descending branches of the gas-liquid flow through transport delay. 14. The method according to claim 1, characterized in that the volumetric gas content in the three-component gas-liquid flow is additionally determined by the difference in temperature and pressure to the constricting devices and after them, arising due to the throttling of gas and liquid through the constricting device, by measuring the temperature and pressure drop in the device with high-precision pressure and temperature sensors. 15. Device for measuring the component flow rate of a three-component gas-liquid stream, built into the main pipeline for transporting a gas-liquid stream, including a source and a gamma-ray detector and pressure and temperature sensors, characterized in that it is made in the form of a symmetrical structure consisting of two vertically and in parallel located pipes made of high-strength radiolucent material - fiberglass with metal tips ending in flanges connected to the upper and lower parts of it with two horizontal metal pipes with vertically arranged flanged connecting bends, in the flanged connecting bends of the upper horizontal pipe and in its middle there are three interchangeable narrowing devices, which are washers, the diameter of the passage opening of which is 2-4 times smaller than the inner diameter of the vertically arranged fiberglass pipes due to which the necessary pressure difference is created between the ascending and descending flows, at the ends of the lower horizontal pipe laid flange connections designed to be embedded in the main pipeline, shutoff ball valves are located in the middle and on the vertical branches of the lower horizontal pipe, with which gas-liquid flow can be directed through the lower horizontal metal pipe, or through the bypass line of the device, forming an upward, horizontal and the descending branches of the gas-liquid flow, on the lower metal tips of vertically arranged pipes and on the opposite parts of the upper horizontal hydrochloric metal pipe symmetrically arranged four pressure sensors and temperature; two gamma densitometers are symmetrically located on vertically arranged pipes, each of which contains an ionizing radiation source, which is a container filled with KCl in them and two gamma radiation detectors forming small and large gamma densitometer probes, and two electromagnetic conductivity and dielectric probes permeability, on the upper horizontal metal pipe symmetrically installed in the left side - a compensation detector of background gamma activity, and in the right side - a redox probe potential sensors, pressure and temperature sensors, gamma radiation detectors of small and large gamma-density probes, electromagnetic conductivity and permittivity probes, a compensation detector for background gamma activity, and a redox probe connected to an electronic unit introduced into the device, a computational a device and a non-volatile memory unit with the ability to collect and process information from them, perform calculations according to predetermined algorithms, store cal calibration data, which are the basis of comparison, and archiving of output data for a long measurement period. 16. The device according to clause 15, wherein the redox probe contains a platinum electrode and a reference electrode. 17. The device according to p. 15, characterized in that the electromagnetic conductivity and permittivity probes are made in the form of inductive coils located on the outer surface of vertically arranged pipes with the possibility of non-contact measurements of attenuation and phase shift. 18. The device according to 17, characterized in that the inductive coils on the ascending and descending branches of the gas-liquid flow are spaced apart by distances that allow measuring the velocity of the gas-liquid mixture due to its inhomogeneity in conductivity and permittivity. 19. The device according to p. 15, characterized in that the gamma-ray detectors of small and large probes in gamma-density meters and a background gamma-ray detector are made in the form of scintillation blocks consisting of a NaJ (Tl) or ZsJ crystal and a photoelectronic multiplier. 20. The device according to p. 15 or 19, characterized in that in order to minimize the influence of the cosmic background, the gamma radiation detectors of small and large gamma densitometer probes are protected from the outside by protective shields, for example, from leaded rubber. 21. The device according to p. 15, characterized in that the pressure and temperature sensors are made in the form of high-precision quartz pressure and temperature converters with a frequency output, which are switched on differentially with the accumulation of differential signals for the average transport delay time of the gas-liquid flow between the middle of the measurement bases, forming hydrostatic Density meters for additional density measurement. 22. The device according to p. 15, characterized in that it contains an emergency battery system, which ensures operability when the power supply is disconnected for a period of at least 24 hours 23. The device according to clause 15, wherein the emergency battery system contains a unit for automatically recharging the batteries when the power is turned on. 24. The device according to p. 15, characterized in that to prevent buildup on the inner surface of the device asphalt-resinous and paraffin deposits, the walls of the device have a protective coating. 25. The device according to p. 15, characterized in that it is closed by a thermally insulated protective casing.

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