RU2023986C1 - Method of quantitative assessment of gas-fluid mixture - Google Patents

Abstract

FIELD: extracting geothermal water. SUBSTANCE: mixture is fed to measuring tank and separated into gas and liquid phases. Flow rate of each phase is measured. Pressure and temperature of the mixture is determined in supplying the mixture. In measuring flow rate of each phase one sets level of fluid in the measuring tank at top limit, stops discharging gas to atmosphere, increases discharging liquid and measures a time interval for which the fluid issues from the top to bottom limit providing constant gas pressure in the measuring tank. Then one reliefs gas to atmosphere, stops discharging liquid from the measuring tank, measures a time interval for filling the measuring tank with liquid from bottom to top limit and calculates gas factor. EFFECT: enhanced accuracy. 1 dwg

Description

 The invention relates to the oil field and can be used in the extraction of geothermal water.

 There is a method of determining the gas factor of a fluid as the ratio of the measured volumes of gas and liquid discharged by the well per unit time [1].

 The disadvantage of this method is that the determination of the gas factor is carried out after separation of the source fluid into gas and liquid flows and measuring the performance of individual flows with appropriate instruments, for example differential pressure gauges.

 With a small number of wells, the measurement of the productivity of an individual well in the liquid is carried out by calibrating the device in which the fluid is separated (gas is separated) [1].

 And in this case, there remains the need for separate measurement of gas productivity, and hence the equipment of the line along which the gas is discharged, with appropriate measuring instruments.

 The closest is a method for quantifying a gas-liquid mixture, including feeding the mixture into a measured tank, separating it into gas and liquid phases and measuring the flow rate of each phase [2].

 The disadvantage of this method is the lack of information, since the gas factor is not determined.

 The purpose of the invention is to increase the information content due to the additional determination of the gas factor.

, где Р, Т - давление и температура двухфазной смеси;
ρ_o , ρ_t - плотность жидкости соответственно при нормальных условиях и при условиях, в которых производится измерение;
K =

.The goal is achieved by the fact that when the mixture is supplied, its pressure and temperature are determined, when the flow rate of each phase is changed, the liquid level in the measuring tank is brought to the upper limit, the gas withdrawal to the atmosphere is stopped, the liquid discharge is increased and its expiration time τ _{1 is} measured from the upper to the lower limit providing a constant gas pressure in a measuring vessel, a gas outlet open to the atmosphere, stop fluid discharge from measuring container and the time τ ₂ dimensional filling containers with liquid from the lower to the upper limit, in GOR ychislyayut formula
GF = K

where P, T - pressure and temperature of a two-phase mixture;
ρ _o , ρ _t are the liquid density, respectively, under normal conditions and under the conditions in which the measurement is made;
K =

.

 The method is as follows.

 The gas factor is determined by backdividing the liquid flow rate, defined as the filling rate of the separator degasser volume, limited by the upper and lower level sensors (TLD and DNU), for some time to the flow rate of gas released from the liquid during the same time, the gas flow rate is determined in stationary mode well operation on the same equipment for the newly established pressure with an increase in the output of fluid from it during its source from TLD to DNU.

, м³/c, где S - площадь поперечного сечения емкости, м²;
h - расстояние между датчиками, м;
τ₂ - время заполнения объема между ДНУ и ДВУ, с.Measurement of the fluid flow rate is obvious: in stationary mode, a degasser-separator having a TLD and a DND receives fluid and the time it takes to fill the tank from the DNU to the TLD is measured. The debit is equal
gt =

, m ³ / s, where S is the cross-sectional area of the tank, m ² ;
h is the distance between the sensors, m;
τ ₂ - the time of filling the volume between DNU and TLD, s.

 Then, increasing the flow rate of the liquid discharged from the degasser, for example, by an additional shutter installed in its lower part, and closing the gas vent valve, the liquid is discharged from the tank. When the TLD level is reached, the time begins. By adjusting the opening of the gate valve, which drains the liquid from the tank, and the shutters, they ensure that the level decreases at constant pressure, especially near the DNU. At the DNU level, the countdown is stopped.

=

, м³/c, где τ₁ - время опорожнения объема жидкости, заключенного между ДВУ и ДНУ, с.The gas flow rate is determined as follows:
v =

=

, m ³ / s, where τ ₁ is the time of emptying the volume of liquid enclosed between the TLD and DNU, s.

 Next, the volumes are reduced to nu

, м³/c.v _o =

, m ³ / s.

=

, м³/c.Based on the fact that the fluid mass is constant, we can write
g _t ˙ ρ _t = g _o ˙ ρ _o ;
g _o =

=

, m ³ / s.

=

=

, м³/м³. Для воды, поскольку ρ₁₀₀o _C отличается от ρ₂₀o C меньше, чем на 5%, можно упростить
ГФ =

, т.е., зная температуру жидкости и давление и замерив время наполнения и опорожнения заданного объема, можно вычислить газовый фактор флюида.The gas factor is
GF =

=

=

, m ³ / m ³ . For water, since ρ ₁₀₀ o _C differs from ρ ₂₀ o C less than 5%, you can simplify
GF =

, i.e., knowing the temperature of the liquid and the pressure and measuring the time of filling and emptying a given volume, it is possible to calculate the gas factor of the fluid.

 The drawing shows a device that implements the proposed TR.

 The device consists of a tank 1, where the phase separation occurs, a pipe for venting gas with a valve 2, a nozzle for venting a fluid equipped with a valve 3, a nozzle for increasing fluid outlet with a damper 4, an inlet nozzle with a shutter 5 and two upper and lower level sensors. The well with the help of the valve 5 is connected to the tank 1, which is connected with the atmosphere through the valve 2, with the load through the valve 3, with a dump barn through the valve 4.

 Consider the operation of the device when measuring the gas factor of geothermal waters. The device works as a degasser, which can be used to measure the gas factor.

 In stationary mode, the water level in the degasser is maintained at a certain height due to the steady-state gas pressure above the water level and the equality of masses of the masses of gases and water entering and leaving the degasser. The initial data for calculating the gas factor are determined in the following order.

 The water level in the degasser is adjusted through the TLD, for which, if it is higher than the TLD, open either the valve 3 or the damper 4, if the level is lower than the TLD, then close the valve 3, when the TLD is reached, close the gas exhaust valve and open the damper completely, start the countdown .

 The begun decrease in the water level in the degasser is controlled by the drainage of the valve 3 so that it occurs at constant pressure, especially when approaching the DND.

Upon reaching the DND, time τ ₁ and pressure are detected, the shutter 4 and the shutter 3 are closed, the gas exhaust valve is opened and the time starts again, but for a filling tank.

Upon reaching the TLD, the time τ _{2 is} detected, the valve 3 is opened and the degasser is brought to the stationary mode of operation.

Claims (1)

METHOD FOR QUANTITATIVE EVALUATION OF A GAS-LIQUID MIXTURE, which includes feeding the mixture into a measured tank, separating it into gas and liquid phases and measuring the flow rate of each phase, characterized in that, in order to increase the information content by additionally determining the gas factor, its pressure is determined when the mixture is supplied and temperature, when measuring the flow rate of each phase, bring the liquid level in the measuring tank to the upper limit, stop the gas discharge to the atmosphere, increase the liquid discharge and measure the time τ _{1 of} its expiration from the upper to the lower limit, providing a constant gas pressure in the measuring tank, open the gas outlet to the atmosphere, stop the liquid from the measuring tank and measure the time τ ₂ filling the measuring tank with liquid from the lower to the upper limit, and the gas factor is calculated by the formula
GF = K

where P, T - pressure and temperature of a two-phase mixture;
ρ _o , ρ _t are the liquid density, respectively, under normal conditions and under the conditions in which the measurement is made;
K =

.

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