# Method for measuring concentration of water in water-oil-gas mixture

FIELD: possible use for determining water presence level in product of oil wells.

SUBSTANCE: method for measuring mass concentration of water in water-oil-gas mixture includes taking of a sample of water-oil-gas mixture in hermetic cylinder-shaped vessel with given volume V and height H and measurement of hydrostatic pressure P_{1} at fixed values of temperature T and pressure P_{a} in aforementioned vessel. After measuring of hydrostatic pressure volume of vessel hollow is decreased until full solution of gas and hydrostatic pressure P_{2} is measured, and mass concentration of water W in water-oil-gas mixture is determined in accordance to mathematical expression , where g - free fall acceleration.

EFFECT: improved precision of measurements of mass concentration of water in liquid due to prevented influence of gas separation.

1 dwg

The invention relates to measuring the concentration of water in the mixture and can be used for determination of water production in 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, 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 the way of measuring of water production wells, including sampling of water-oil-gas mixture and the measurement of the hydrostatic pressure at fixed values of temperature and pressure. The method is based on the hydrostatic 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-ρ_{n})/(ρ_{in}-ρ_{n}), where ρ, ρ_{n}that ρ_{in}- density, respectively, of the mixture of oil and water, when this is m density of water and oil are assumed to be known [2.
Oilfield equipment, No. 10/2000, - s-121, 3].

The disadvantage of this method is that the liquid remains fine (occluded) oil gas due to imperfect separation. This leads to a fatal methodological errors, as the concentration of gas in oil-water liquid remains unknown.

The technical task of the invention is to improve the accuracy of measurement of mass concentration of water in the liquid due to the exclusion of the influence of quality of gas separation.

To solve technical problems in measuring the mass concentration of water in water-oil mixture, after sampling the water-oil mixture in a sealed cylindrical vessel with a given volume V and height H and measuring the hydrostatic pressure P_{1}with fixed values of temperature T and pressure P_{and}in the vessel, reduce the volume of the cavity of the vessel (and respectively selected him in the samples by the amount of ΔV until dissolved gas and again measure the hydrostatic pressure P_{2}and the mass concentration of water W in the water-oil mixture determine of dependencies

where P_{1}P_{2}values of hydrostatic pressure in the vessel when the value of the volume of the mixture V and (V-ΔV), respectively;

ρ_{in}that ρ
_{n}that ρ_{g}- the density of water, oil and gas, respectively, when the measured values of the absolute pressure P_{and}and the absolute temperature T in the volume of the vessel V;

g - acceleration of free fall.

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

The device comprises a sealed cylindrical vessel (building) 1, provided with an inlet pipe 2 controlled by valve 3 and the outlet 4 with a controlled valve 5. In the cavity of the vessel 1 is set to a hydrostatic pressure sensor 6, the absolute pressure sensor 7 and the absolute temperature sensor 8.

In the cavity of the vessel 1 at one end is inserted, the piston 9, the other end of which is connected with the actuator 10, which provides the possibility of reciprocating motion of the piston 9.

The method is implemented as follows.

Water-oil mixture from the wells pre-enters the hydrocyclone separator 11 from which under the influence of gravity the liquid with residual fine gas through open valve 3 through the pipe 2 enters into the measuring cavity (volume V and height H) of the vessel 1.

The valve 5 is closed, and the piston 9 is in the lower position where its upper edge coincides with the bottom of the vessel 1.

After filling the vessel 1 masuklah 3 closed
and fix the sensor 6 values of hydrostatic pressure P_{1}sensor 7 is the absolute pressure P_{and}and the sensor 8 is the absolute temperature T.

Then, using the actuator 10 of the piston 9 vidvigayt in the vessel 1, reducing the volume of its cavity to jump the growth of the absolute pressure in the vessel, that is, until complete dissolution of the gas in the liquid, the volume of the vessel V is reduced by the amount ΔV.

After that, the sensor 6 is fixed hydrostatic pressure P_{2}.

On the measured values of P_{1}P_{2}, R_{and}and T in the formula (1) is determined by the mass concentration of water W.

For the next metering piston 9 is lowered to its original position, the valves 3 and 5 are open. The mixture from the vessel and filtered, and the device is ready to set a new portion of water-oil mixture.

Formula (1) is derived as follows.

It is known that the mass concentration of water in oil-water fluid (with no gas) is determined by expression (2):

where m_{in}, m_{n}- mass of water and oil, respectively;

ρ_{W}- density of water-oil fluid.

Settings ρ_{n}and ρ_{in}well - known, and the parameter ρ_{W}is determined according to the proposed method.

In a cylindrical vessel of volume V and height H contains a mixture of water, oil and gas massumi m_{
in}, m_{n}and m_{g}respectively. Known hydrostatic method is measured density of the mixture ρ_{1}by the formula (3):

Next, the volume of the vessel is forcibly reduced by the amount of ΔV until dissolved gas in oil. Again hydrostatic method is determined by the density of the mixture ρ_{2}in the new volume (V-Δ (V) the measured values of the hydrostatic pressure P_{2}.

From (3) and (4) is defined by ΔV:

The density of the fluid before compression was determined by the formula (6):

where m=m_{in}+m_{n}+m_{g}- weight of water-oil mixtures;

ρ_{g}- the density of the gas prior to compression of the mixture at an absolute pressure P_{and}and the absolute temperature T in the vessel is determined from the equation of state.

Substituting the expression ΔV from (5) (6) taking into account that ρ_{2}/ρ_{1}=P_{2}/P_{1}get (7):

Substituting ρ_{W}from (7) in (2), we obtain the formula (1).

The method of measuring the concentration of water in water-oil mixtures, including sampling of water-oil mixture in a sealed cylindrical container with a predetermined volume and height, the measurement of hydrostatic pressure when fixyou the different values of temperature and pressure in the vessel, characterized in that reduce the volume of the cavity of the vessel until complete dissolution of the gas and re-measure the hydrostatic pressure and the mass concentration of water in water-oil mixture is determined from the dependencies

where W is the mass concentration of water;

P_{1}P_{2}values of hydrostatic pressure in the vessel when the value of the volume of the mixture V and (V-ΔV), respectively;

ρ_{in}that ρ_{n}that ρ_{g}- the density of water, oil and gas, respectively, when the measured values of the absolute pressure P_{and}and the absolute temperature T in the volume of the vessel V;

H - height of the cylindrical vessel;

g - acceleration of free fall.

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FIELD: chemical industry; methods of determination of acetic acid concentration.

SUBSTANCE: the invention is pertaining to the field of chemical industry, in particular, to the method of determination of acetic acid concentration in a broad band of temperatures. The technical result is an increased accuracy at determination of concentration of acetic acid within the range of temperatures from 0° up to 40°C. The offered method allows using the linear interpolation to determine dependence of density on the concentration and the temperature in 1°C within the range of temperatures from 0°C up to 40°C according to the known dependence of density from concentration over the range from 0 up to 100 % and on the temperature - from 0°C up to 40°C in 5; 10°C. Then they homogenize the solution and determine the temperature of the solution in the pressure tank with accuracy 0.1°C and the density. At the integer values of the temperature using the received dependence determine two values of density that are the most close to the experimental values and two values of concentration corresponding to them and determine the first derivative from concentration according to the density. If |dc/dp | ≤ 3.3*10,^{} the concentration is determined by the linear interpolation method according to the received dependence of density on concentration with accuracy up to 0.1 %. If |dc/dp |> 3.3*10^{3}, then into pressure tank inject water in a such amount that to get into the zone of |dc/dp | <3.3*10^{3} for determination of concentration of the acetic acid. In the case of non-integral values of the temperature it is necessary to conduct the following operations: for the most close to the experimental integer value of the temperature select two values of density the most close to the experimental value of density and corresponding to them two values of concentration. Using the received dependence of the density on the temperature find two values of density at the temperature of the experiment and determine the first derivative from concentration on the density, and then the operations are iterated as for the integer value of the temperature.

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5 ex, 4 tbl, 3 dwg

FIELD: technology for determining moisture load of solid materials, possible use for construction, chemical and other industries.

SUBSTANCE: UHF method for determining moisture load of solid materials on basis of Brewster angle includes positioning researched material into high-frequency electromagnetic field with following registration of parameters alternation, characterizing high-frequency emission. Ring-shaped multi-slit antenna with electronic-controlled direction diagram excites electromagnetic wave, falling onto dielectric material. Direction diagram inclination angle is measured until moment, at which minimal power of reflected wave is detected, wave length of UHF generator is determined and Brewster angle is calculated. Then on basis of normalized mathematical formulae moisture load value of surface layer of W_{s} is calculated for measured material. Further, power of refracted wave is stabilized by changing power of falling wave, temperature of subject material T_{1} is measured, and after given time span - temperature T_{2} and moisture level are determined for volume of material from given mathematical relation. Device for realization of given method includes UHF generator, UHF detector, wave-guiding Y-circulator, input shoulder of which has generator block controlled by voltage, attenuator, controlled by central microprocessor unit, UHF watt-meter with output to central microprocessor unit device for controlling and stabilization of output power, diode pulse modulator and video pulse generator, controlled by central microprocessor unit, peak detector. First output shoulder of Y-circulator has absorbing synchronized load, and second output shoulder has complex cone antenna, consisting of emitting portion in form of ring-shaped multi-slit antenna and cone-shaped receipt portion, to which gate is connected as well as second UHF watt-meter, connected to extreme digital controller for searching and indication of power minimum of returned wave and resonator indicator of wave meter. UHF generator is powered by central microprocessor unit controlled power block, video pulse counter is connected to digital wave meter, and thermal pairs block is connected to central microprocessor unit device.

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2 cl, 3 dwg

FIELD: oil and gas industry, particularly survey of boreholes or wells.

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EFFECT: increased efficiency and accuracy of water content determination.

2 dwg

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SUBSTANCE: device helps to get real pattern of liquid pressure distribution which flows about "blown-about" object in water tunnel. Device has driven frequency pulse oscillator, frequency divider, control pulse counter, longitudinal contact multiplexer which connect capacitors with shelves, lateral contact multiplexer which connect the other output of capacitors, matching unit, analog-to-digital converter, indication unit, water tunnel, blown-about object, grid with capacitive detector.

EFFECT: improved precision of measurement.

2 dwg

FIELD: oil industry.

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,

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4 cl, 7 dwg, 1 tbl

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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 ρ_{w} C_{w}(t_{1}-t_{0})/2ΔP, where g is free fall acceleration, ρ_{w} is density of water after temperature and pressure reached the steady state, C_{w} is speed of sound in water medium, ΔP is hydrostatic pressure, (t_{1}-t_{0}) 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.

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SUBSTANCE: invention relates to automated determination of solution concentrations, in particular from measured boiling temperature, and can be used in natural gas fields and in underground gas holders on gas absorption drying installations, wherein aqueous solution of di- or triethylene glycol is used as absorbent. Concentration of aqueous glycol solution comprises measurement of boiling point and vapor phase pressure over boiling solution. Sought concentration is calculated from following relationships: (1) Cg=Mg*Xg*100/(Mg+Xg+Mw*(1-Xg)), where Xg=(10^{Zw(T)}-P)/(10^{Zw(T)}-10^{Zg(T)}; (2) Zw(T)=8.006-1691/(230+T); (3) Xg(T)=9.270-3035/(230+T) for diethylene glycol; (4) Xg(T)=8.54-2927.5/(230+T) for triethylene glycol; where Zw(T) is exponent value in determination of saturated water vapor pressure, Zg(T) is exponent value in determination of saturated glycol vapor pressure, Mw=18 kg/kmole (molecular mass of water), Mg is molecular mass of glycol, Mg=106 kg/kmole for diethylene glycol, Mg=150.17 kg/kmole for triethylene glycol, T is boiling temperature of glycol solution, °C, P is pressure of vapor phase over boiling solution, kg/cm^{2}.

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