Method and device for measuring content of water in water-oil-gas mixture

FIELD: measurement technology.

SUBSTANCE: sample is taken and is allowed to settle, after it the hydrostatic pressure is measured. Time for which ultrasonic pulse passes through layer of settled water is measured additionally. Mass concentration W of water is defined from ratio W = g ρw Cw(t1-t0)/2ΔP, where g is free fall acceleration, ρw is density of water after temperature and pressure reached the steady state, Cw is speed of sound in water medium, ΔP is hydrostatic pressure, (t1-t0) is time interval during which direct and reflected ultrasonic pulses pass. Device for measuring content of water has water-tight casing (vessel for taking samples) provided with pressure, temperature and hydrostatic (differential) pressure detectors. Acoustic transformer intended for receiving and irradiating ultrasonic pulses should be mounted at bottom side of casing.

EFFECT: increased precision of measurement.

4 cl, 1 dwg

 

The invention relates to measuring the concentration of water in the mixture and can be used to determine the water content of oil wells.

The known method of determining water content in the oil to change the dielectric constant of the mixture flowing between the plates of a capacitor, is omitted in the analyzed mixture [1. Gesloten. Collection and preparation of oil, gas and water. M., Nedra, 1974, -p.30-32, Fig. 11].

The method leads to large errors in the measurement of moisture content, since the dielectric permittivity of saline water and water-free oil are not constant, but vary in a fairly wide range. In addition, the measurement accuracy is significantly reduced because of the heterogeneity of the mixture and the phenomenon of flocculation.

The closest is a method of automatic measurement of water production wells, based on hydrostatical the density measurement of oil-water mixture (hydrostatic weighing) with subsequent recalculation of the formula in which the volume concentration of water To be expressed in the form K=(ρ -ρn)/(ρinn), where ρ , ρnthat ρin-density, respectively, of the mixture of oil and water. The density of water and oil are known, and the density of the mixture is calculated from the measured hydrostatic pressure measured at is definitely the pressure and temperature [2. Oilfield equipment, No. 10/2000, - s-121, Fig. 3].

Watering goods is determined by the device consisting of a vessel for sampling and differential pressure gauge for measuring the hydrostatic pressure. The instrument is calibrated in accordance with known dependency.

The disadvantages of the method are related to the fact that the density of oil is not constant due to changes in its composition due to phase transitions, and the mixture may contain a significant amount of free gas. The error in the estimation of the volume concentration of water in the mixture can reach 10%.

The technical task of the invention is to improve the accuracy of measuring the concentration of water in the mixture by eliminating the need to use in the calculation of the a priori density values of oil.

To solve the problem in measuring the concentration of water in water oil and gas mixture comprising sampling water oil and gas mixture, defence and measurement of hydrostatic pressure at fixed temperature and pressure, pre-exercise separation of gas from water oil and gas mixture and optionally measure the transit time of an ultrasonic pulse through a layer of distilled water, and the mass concentration of water in the mixture is determined from the dependencies

W=gρinCinΔt/2Δ P = gρinCin(t1-t0)/2Δ P, where:

g - free fall acceleration;

ρin- the density of water at temperature T and pressure P;

Within- the speed of sound in water at temperature T and pressure P;

Δ P is the hydrostatic pressure of the column of the mixture in the vessel;

Δ t=(t1-t0- the interval time of the ultrasonic pulse through a layer of distilled water in both directions (forward and reflected pulses);

t0- the moment of emission of the ultrasonic pulse;

t1- the moment of reception of the ultrasonic pulse.

To ensure the implementation of the method a device for measuring the concentration of water in water oil and gas mixture, containing a sealed vessel with inlet and outlet nozzles, pressure sensors, temperature and hydrostatic pressure, equipped with a hydrocyclone separator installed in the bottom part of the vessel acoustic transducer for emitting and receiving ultrasonic pulses.

To reduce the effects of temperature and avoid plugging of the tube of the pressure transducer filled with a separating liquid with a low coefficient of thermal expansion, and the ends of the pulse tubes, connecting the pressure transducer to the vessel, closed flexible memb what'am.

The invention is illustrated by the drawing, which is given a diagram of a device for measuring the concentration of water in water oil and gas mixture.

A device designed to implement the method, consists of a sealed container 1, provided with an inlet pipe 2 with the valve 3 and the outlet 4 with the valve 5.

The device is equipped with a pressure sensor 6, the temperature sensor 7, the pressure transducer 8 is connected to the vessel pulse tubes 9 and 10, and is installed in the bottom part of the vessel acoustic transducer 11.

In addition, the device is provided with a heater 12 for heating selected in the capacity of the sample and the dispenser 13 to supply in her demulsifier.

To improve the accuracy of the pulse tube transducer (differential) pressure-filled separator liquid with a low coefficient of thermal expansion, such as polymethyl-siloxane fluid, and the ends of the pulse tubes are closed by flexible membranes 14 and 15 in contact with the capacitance of the investigated mixture. To improve the stability of the “zero” differential pressure gauge is placed in the immediate vicinity of the cover 1 and its “negative” pulse tube 9 is located horizontally, and “zero” pulse tube 10 is upright.

Order to improve the surveillance of the reliability of the measurements by increasing the representativeness of the sample water oil and gas mixture it is taken after a preliminary gas separation in a hydrocyclone separator 16.

The method can be implemented as follows.

Water oil and gas mixture from the well enters the hydrocyclone separator 16, which under the influence of gravity the liquid with residual fine gas flows down and through the pipe 2 through the open valve 3 is fed into the measuring container 1 with a closed valve 5. A set of fluid is stopped when reaching the hydrostatic pressure of the column a mixture of height L of a certain, pre-specified value Δ R, which is measured by the differential pressure gauge 8. Then the valve 3 is closed, and in a mixture of automatic dispenser 13 enter the demulsifier and heat it to a pre-set temperature values.

Due to the heat and the action of a demulsifier mixture splits into gas, oil and water with the formation of a phase boundary (GRF) and the boundary component (GRK). The separation process is controlled by the pressure sensor 6 and the temperature 7, and by means of an acoustic transducer (piezosensor) 11, a radiating and receiving reflected ultrasonic pulses from the GRF and GRK.

The emergence of distinct pulses reflect from GRK and GnRH signals the completion of the phase separation process and the component.

After completion of the separation process are measured the following values:

Δ P - differential pressure signal with Yes the Chica 8 (match measured values Δ P before and after the separation proves the tightness of the tank and valves 3 and 5);

(t1-t0- the interval transit time of the pulse in both directions (forward and reflected pulses) through the layer of distilled water;

T and R is the steady-state values of temperature and pressure.

At the end of the measurement, the valves 3 and 5 are open and dialed sample of the mixture is displaced into the reservoir under the action of gravity and the pressure differential between the hydrocyclone separator and collector.

When calculating the mass concentration are given (known) the following values:

ρg- gas density at standard conditions;

ρin- the density of water at temperature T and pressure P. the Function ρinin(T, P, S), where S is the total mineralization of the water is usually known and tabulated;

Within- the speed of sound in water at temperature T and pressure P. the Function Within=Cin(T, R, S) - also known and tabulated.

Mass concentration of water W in the mixture is calculated by the formula:

g - free fall acceleration;

ρin- the density of water at temperature T and pressure P;

Within- the speed of sound in water at temperature T and pressure P;

Δ P-hydrostatic pressure of the column of the mixture in the vessel;

Δ t=(t1-t0)in eral time of the ultrasonic pulse through a layer of distilled water in both directions (forward and reflected pulses);

t0- the moment of emission of the ultrasonic pulse;

t1- the moment of reception of the ultrasonic pulse.

Formula (1) is derived on the basis of the following considerations.

By definition, the average density of the mixture in the tank ρ (before and after separation of the phases and components) is calculated by the formula:

where: V - volume of a cylindrical tank of height L and cross sectional area S;

min, mn, mgweight of water, oil and gas in the tank, respectively.

By definition, the mass concentration of water in the mixture W is expressed by the formula:

Expressing the total weight of the mixture (min+mn+mgfrom formulas (2) and substituting this expression into the formula (3), we get the formula:

The mass of water in the mixture minis expressed by the formula:

where: h - height of the provisions of the GRK.

Substituting the expression minin the formula (5), we get the formula:

In accordance with the basic formula hydrostatic method, the density of the mixture ρ is expressed by the formula:

Substituting the expression ρ from the formula (6) in formula (7) have the formula:

The value of h is expressed by the formula:

Substituting the expression for h in the formula (9) in formula (8) we obtain the formula (1):

1. The method of measuring the concentration of water in water oil and gas mixture comprising sampling water oil and gas mixture, defence and measurement of hydrostatic pressure at fixed temperature and pressure, wherein the pre-carry out the separation of gas from water oil and gas mixture and optionally measure the transit time of an ultrasonic pulse through a layer of distilled water, and the mass concentration of water in the mixture is determined from the dependencies

W=gρin·WithinΔ·t/2Δ P=gρin·Within(t1-t0)/2Δ P, where

g - free fall acceleration;

ρin- the density of water at temperature T and pressure P;

Within- the speed of sound in water at temperature T and pressure P;

Δ P is the hydrostatic pressure of the column of the mixture in the vessel;

Δ t=(t1-t0- the interval time of the ultrasonic pulse through a layer of distilled water in both directions (forward and reflected pulses);

t0- the moment of emission of the ultrasonic pulse;

t1- the moment of reception of the ultrasonic pulse.

2. Device for smartyjonescrzy water water oil and gas mixture, containing a sealed vessel with inlet and outlet nozzles, pressure sensors, temperature and hydrostatic pressure, characterized in that it is provided with a hydrocyclone separator installed in the bottom part of the vessel acoustic transducer for emitting and receiving ultrasonic pulses.

3. The device according to claim 2, characterized in that the pulse tube of the pressure transducer filled with a separating liquid with a low coefficient of thermal expansion, and the ends of the pulse tubes, connecting the pressure transducer to the tank is closed by a flexible membrane.



 

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FIELD: measurement technology.

SUBSTANCE: sample is taken and is allowed to settle, after it the hydrostatic pressure is measured. Time for which ultrasonic pulse passes through layer of settled water is measured additionally. Mass concentration W of water is defined from ratio W = g ρw Cw(t1-t0)/2ΔP, where g is free fall acceleration, ρw is density of water after temperature and pressure reached the steady state, Cw is speed of sound in water medium, ΔP is hydrostatic pressure, (t1-t0) is time interval during which direct and reflected ultrasonic pulses pass. Device for measuring content of water has water-tight casing (vessel for taking samples) provided with pressure, temperature and hydrostatic (differential) pressure detectors. Acoustic transformer intended for receiving and irradiating ultrasonic pulses should be mounted at bottom side of casing.

EFFECT: increased precision of measurement.

4 cl, 1 dwg

FIELD: technology for determining moisture in organic solvents.

SUBSTANCE: sorptionally sensitive element is positioned directly in analyzed liquid. Depending on viscosity of analyzed environment and oscillations frequency of sensitive element, power fed to sensitive element is set by altering power voltage fed to electronic generator in accordance to formula: where P - power, fed to sorptional-frequency sensitive element, Wt; K - proportionality coefficient, numerically equal to 18,5·103 Wt·Hz/centipoises; η - viscosity of analyzed environment, centipoises; F0 - nominal oscillations frequency of soprtional-frequency sensitive element, Hz.

EFFECT: increased sensitivity, precision and simplified measuring process.

2 tbl

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