CN103822677B - A kind of measuring method of constant volume tube piston type natural gas wet gas meter - Google Patents

Abstract

The invention provides the measuring method of a kind of constant volume piston type natural gas wet gas meter, comprise the steps: measurement column plug tube volume V, plunger barrel pressure P₁, plunger barrel temperature T₁, movement time t between the upper and lower stop of piston；In high temperature, low pressure, i.e. it is less than under the operating mode of 2.5Mpa gas flow according to the following formula: when pressure is bigger, is i.e. more than under the operating mode of 2.5Mpa gas flow according to the following formula: wherein: normal atmosphere P_S=101.325kpa, normal atmosphere temperature T_S=0 DEG C；Z passes through equation Z³‑Z²‑(B²+ B A) Z AB=0 determines, wherein T_CR, P_CRBeing respectively critical temperature and the critical pressure of gas, its value depends on that the one-tenth of natural gas is grouped into.The present invention measures process and the physical parameter of tested natural gas dampness and the flow parameter such as flow velocity, fluidised form is unrelated, measures flow and is susceptible to flowed fluctuation impact, has higher precision.

Description

A kind of measuring method of constant volume tube piston type natural gas wet gas meter

Technical field

The invention belongs to crude oil well recovery and produce associated gas and natural gas well extraction natural gas flux of moisture metering technology Field, the present invention relates to the measuring method of a kind of constant volume tube piston type natural gas wet gas meter.

Background technology

During exploitation of oil-gas field in most cases.The output of natural gas invariably accompany liquid hydrocarbon, free water and The output of saturated steam.Therefore, from individual well, natural gas is exploiting that many wells collection is defeated, during purified treatment, pressure-increasing unit All can relate to dampness metering.Owing to well yield metering is closely related with the economic interests of exploitation side, and the stoichiometric number of individual well According to being also oil-gas field management side's understanding gas well liquid loading ability, significant data of production status.Therefore, the accurate of dampness metering is improved Property and reliability are the most increasingly paid attention to by the most each major oil companies.Since early 1990s, international gas Flux experiment room and international major oil companies have carried out the correlational study of dampness metering technical elements the most successively.Dampness measurement technology Having been subjected to the development of more than 20 year, the developed country, the especially U.S. and Norway such as American-European are in the accuracy, stable of wet gas meter Research in terms of property and versatility achieved with some achievements, effusion meter type selecting, test, calibrate, operation and maintenance and The suitability aspect of various operating modes has obtained substantial amounts of experience.China's Daqing oil field the most once carried out excess moisture meter in 20 end of the centurys Amount technical research, some research institutions and effusion meter manufacturer have carried out the research of this respect the most on a small scale.

As a rule, through dehydration, purify and process for recovering light hydrocarbon, extract the natural gas after liquefied gas and light oil and claim For dry gas.The natural gas of undressed oil gas field extraction is many containing a small amount of condensation water or oil, saturated steam and light hydrocarbon, Containing droplet constituent, referred to as dampness.Dampness belongs to the category of multiphase flow.Relatively for single-phase flow, dampness measurement technology is the most multiple Miscellaneous and difficult, its main cause is as follows:

1. in pipeline wet gas current state because of the gas pressure in pipeline, flow velocity, content liquid and Pipe installing position (water Flat, tilt or vertical) different and different, fluidised form is complex.

2. the change of dampness metering field working conditions is relatively large, if effusion meter type selecting is unreasonable, easily causes effusion meter used It is not suitable for the working condition that metering is on-the-spot, even causes Causing Flowmeter Damages.

3. dampness metering effusion meter have employed the mode of Off-line calibration mostly, but general calibrating or calibration laboratory Calibrating medium and working condition and real medium and working condition have obviously difference so that flowmeter in-situ Targets Can be difficult to ensure that.

In recent years. although some effusion meter production firms also develop some type of wet gas meter (or multiphase flow rates Meter).But the metering of current dampness both domestic and external mainly still uses traditional way flow flow techniques, due to the depositing of liquid phase in pipeline . the fluidised form in pipeline has severely impacted the metering performance of effusion meter, according to up-to-date experimental study, its error in dipping maximum up to 15%.

Summary of the invention

It is an object of the invention to provide and a kind of the aerosolized fluid of contained a small amount of drop can be overcome in natural gas natural gas The measuring method of the constant volume tube piston type natural gas wet gas meter of flux of moisture metering impact.

In order to solve the problems referred to above, the present invention provides the measurement side of a kind of constant volume piston type natural gas wet gas meter Method, wherein, described effusion meter includes the cylinder gauge line of constant volume, built-in piston moving up and down；The two of described gauge line Head respectively connects two electrodynamic valves and controls intake and exhaust commutation, can control described gauge line realize respectively lower air inlet, upper aerofluxus metering with And upper air, lower aerofluxus metering；Temperature and pressure transmitter it is also equipped with, it is achieved the volume of natural gas dampness on described gauge line Flow measurement, comprises the steps:

Measurement column plug tube volume V, plunger barrel pressure P₁, plunger barrel temperature T₁, movement time t between the upper and lower stop of piston；

In high temperature, low pressure, i.e. less than gas flow according to the following formula under the operating mode of 2.5Mpa:

$F_A=\frac{P_{1}V(T_S+273.15)}{P_S(T_1+273.15)t};$

When pressure is bigger, i.e. more than gas flow according to the following formula under the operating mode of 2.5Mpa:

$F_A=\frac{P_{1}V(T_S+273.15)}{{\mathrm{ZP}}_S(T_1+273.15)t};$

Wherein: normal atmosphere P_S=101.325kpa, normal atmosphere temperature T_S=0 DEG C；

Z passes through equation Z³-Z²-(B²+ B-A) Z-AB=0 determines, wherein T_CR, P_CRIt is respectively critical temperature and the critical pressure of gas, its Value depends on that the one-tenth of natural gas is grouped into.

Relative to prior art, the present invention has a following technique effect:

The constant volume tube piston type natural gas wet gas meter that the present invention provides is effusion meter based on volumetric measurement, can overcome In natural gas, the aerosolized fluid of contained a small amount of drop is on the metering impact of natural gas flux of moisture, thus the process of measurement and tested natural Physical parameter and the flow parameter such as flow velocity, fluidised form of air humidity gas are unrelated, measure flow and are susceptible to flowed fluctuation impact, have higher Precision.

Accompanying drawing explanation

Fig. 1 be the embodiment of the present invention constant volume tube piston type natural gas wet gas meter under air inlet, upper instroke time Structural representation.

When Fig. 2 is the constant volume tube piston type natural gas wet gas meter upper air of the embodiment of the present invention, lower instroke Structural representation.

Detailed description of the invention

Below in conjunction with accompanying drawing, embodiments of the invention are described in detail.It should be noted that do not conflicting In the case of, the embodiment in the application and the feature in embodiment can mutual combination in any.

Embodiment one:

The invention provides a kind of constant volume tube piston type natural gas wet gas meter as shown in accompanying drawing 1-2, including constant volume Long-pending cylinder gauge line, built-in piston moving up and down, is slip tight fit between piston and tube wall, and the gas of piston both sides is close Envelope；Two of gauge line respectively connects two electrodynamic valves and controls intake and exhaust commutation, can control gauge line and realize lower air inlet, upper row respectively Gas metering and upper air, lower aerofluxus metering；Temperature and pressure transmitter it is also equipped with, it is achieved natural gas dampness on gauge line Volume flow is measured.

Commutate and controlled flow direction by the opening and closing order of 4 electrodynamic valves of Controlled by Programmable Controller, realize natural respectively The lower air inlet of air humidity gas, upper instroke and upper air, lower instroke；Shuttling movement and so forth, coordinates piston movement Up and down during stroke counter between stop, the metering of the volume flow of natural gas dampness can be realized.

One, lower air inlet, upper instroke

Gas flow direction when lower air inlet, upper instroke is as shown by the arrows in Figure 1:

The valve that in figure, black line passes through is opened, and remaining is closed.After gas is come in by lower section, under pressure promotes, upwards Promote piston movement.Piston is t (HOUR) by the lower dead center arrival top dead centre used time, and piston arrives after top dead center to be stopped, and position is opened Pass provides stopping signal, at this moment reads pressure signal P₁With temperature signal T₁；After completing, PLC sends commutation instruction, electronic valve actuation Make, it is achieved flowing commutation.

Two, upper air, lower instroke

Gas flow direction when upper air, lower instroke is as shown by the arrows in Figure 2:

After commutation, the valve that in figure, black line passes through is opened, and remaining is closed.After gas is come in by top, promote at pressure Under, push down on piston movement.Piston is t (HOUR) by the top dead centre arrival lower dead center used time, and piston arrives and stops after bottom dead center, Position switch provides stopping signal, at this moment reads pressure signal P₁With temperature signal T₁；After completing, PLC sends commutation instruction, electronic Valve events, it is achieved flowing commutation.

Three, flow rate calculation

High temperature, low pressure (in this example less than 2.5Mpa) operating mode under the equation of gaseous state of ideal gas can be used to calculate.

Plunger barrel volume V (M³), measuring instruments records plunger barrel pressure P₁(kpa), measuring instruments records plunger barrel temperature T₁ (DEG C), the movement time between the upper and lower stop of piston recorded is t (HOUR)；Normal atmosphere P_S=101.325kpa, standard is big Othermohygrometer T_S=0 DEG C, constant R=8.31, gas volume during normal atmosphere is V_S(M³)。

Ideal gas equation of gaseous state: PV=NRT

Gaseous mass:

Mass conservation when being converted into the plunger gas volume of standard atmosphere pressure:

$\frac{P_{1}V}{R(T_1+273.15)}=\frac{P_S{V}_S}{R(T_S+273.15)}$

Normal atmosphere lower volume:

$V_S=\frac{P_{1}V(T_S+273.15)}{P_S(T_1+273.15)}$

Gas flow:

(M³/H)

When in pipeline, gas pressure is bigger, natural gas no longer observes The Ideal-Gas Equation, now introduces compression Coefficient Z

Z=1 during ideal gas, for real gas, Z<1, Z when pressure is bigger>1 when pressure is less.

Theoretical according to corresponding states, the gas under identical corresponding states is identical to the departure degree of ideal gas behavior, I.e. having identical coefficient of compressibility, corresponding states refers to that gas is in identical reduced temperature T_RWith reduced pressure P_RUnder

$T_R=\frac{T_s}{T_{CR}},P_R=\frac{P_s}{P_{CR}}$

T in formula_CR(K), P_CR(Mpa) being respectively critical temperature and the critical pressure of gas, its value depends on the one-tenth of natural gas It is grouped into.

The size of coefficient of compressibility Z is only dependent upon T_RAnd P_R, i.e. Z=f (T_R,P_R)

Contrast Redl ich-Kwong is utilized to generalize equation solution Z

Z³-Z²-(B²+ B-A) Z-AB=0

Wherein

Gas flow:(M³/H)

The foregoing is only the preferred embodiments of the present invention, be not limited to the present invention, for the skill of this area For art personnel, the present invention can have various modifications and variations.All within the spirit and principles in the present invention, that is made any repaiies Change, equivalent, improvement etc., should be included within the scope of the present invention.

Claims (1)

1. a measuring method for constant volume piston type natural gas wet gas meter, wherein, described effusion meter includes constant volume Cylinder gauge line, built-in piston moving up and down；Two of described gauge line respectively connects two electrodynamic valves and controls intake and exhaust commutation, Described gauge line can be controlled and realize lower air inlet, upper aerofluxus metering and upper air, lower aerofluxus metering respectively；On described gauge line It is also equipped with temperature and pressure transmitter, it is achieved the volume flow metering of natural gas dampness, it is characterised in that include walking as follows Rapid:

Measurement column plug tube volume V, plunger barrel pressure P₁, plunger barrel temperature T₁, movement time t between the upper and lower stop of piston；

In high temperature, low pressure, i.e. less than gas flow according to the following formula under the operating mode of 2.5Mpa:

$F_A=\frac{P_{1}V(T_S+273.15)}{P_S(T_1+273.15)t};$

When pressure is bigger, i.e. more than gas flow according to the following formula under the operating mode of 2.5Mpa:

$F_A=\frac{P_{1}V(T_S+273.15)}{{\mathrm{ZP}}_S(T_1+273.15)t};$

Wherein: normal atmosphere P_S=101.325kpa, normal atmosphere temperature T_S=0 DEG C；

Z passes through equation Z³-Z²-(B²+ B-A) Z-AB=0 determines, wherein T_CR, P_CRIt is respectively critical temperature and the critical pressure of gas, its Value depends on that the one-tenth of natural gas is grouped into.