CN203572524U - Device for on-line measurement of flow of oil, gas and water in unconventional natural gas - Google Patents

Abstract

The utility model relates to a device for on-line measurement of the flow of oil, gas and water in unconventional natural gas. The device for on-line measurement of the flow of the oil, gas and water in the unconventional natural gas comprises a switchable Venturi tube assembly, a single-energy Gamma sensor, an on-line gas-liquid separating device and a dual-energy Gamma sensor, wherein the Venturi tube assembly comprises at least two Venturi tubes, the Venturi tubes have Beta values which are different from one another, the single-energy Gamma sensor comprises a single-energy Gamma ray transmitter and a Gamma ray detector which are arranged on an inlet or that throat portion of the Venturi tube, in the working state, of the switchable Venturi tube assembly in the radial direction, the on-line gas-liquid separating device is arranged on the backward position of the switchable Venturi tube assembly and comprises an inlet pipe, a gas-liquid separator, a gas outlet pipe and a liquid outlet pipe, and the dual-energy Gamma sensor comprises a dual-energy Gamma ray transmitter and a Gamma ray detector which are arranged on the two sides of the liquid outlet pipe in the radial direction. The utility model further discloses a method based on the device for on-line measurement of the flow of the oil, gas and water in the unconventional natural gas.

Description

The device of oil, gas, water three-phase flow in the unconventional rock gas of a kind of on-line measurement

Technical field

The utility model belongs to unconventional rock gas (for example shale gas, coal-seam gas, tight gas) flow metering field.Particularly, the utility model relates to the device of oil, gas, discharge in the unconventional rock gas of a kind of on-line measurement, and relates to the method for oil, gas, discharge in the unconventional rock gas of a kind of on-line measurement.

Background technology

" unconventional rock gas " refers to the natural gas source that can not obtain economic yield by the routine means of exploiting.Unconventional rock gas mainly comprises shale gas, coal-seam gas, tight gas, deep source gas, shallow biogas etc.The principal character of unconventional rock gas is, per-well production is low, and short-term production rate fluctuation is larger, but on long terms, output becomes decline trend, and the production cycle is long.In addition, the potpourri of the unconventional rock gas oil gas water three phase that void fraction is very high often, for example void fraction is more than 85%, even higher, for example, up to 95%, even up to 99%.Shale gas is typical unconventional rock gas.

Shale gas refers to that those are gathered in dark-coloured mud shale or high-carbon mud shale, take and adsorbs or rock gas that free state is main existing way.The physicochemical property of it and conventional gas is just the same, only compose and be stored among the mud shale that permeability, factor of porosity are extremely low, the resistance ratios conventional gas of air-flow is large, has increased to a great extent the exploitation difficulty of shale gas, therefore by industry, is classified as unconventional gas resources.The net porosity of shale self is very low, shale gas reservoir is mainly the regional fracture of growing due on a large scale, or thermal cracking gas generating phase generation surpressure is provided as and hides the required MIN porosity and permeability that preserves in the crack of concentrating face, lithology contact transition face or fragility plane of weakness to produce along stress.Conventionally factor of porosity is only up to 4%～5%, and permeability is less than 1 * 10-3 μ m.Compare with conventional gas, production life of well is long, and the production cycle is long.

The world wide Nei Jin U.S. grasps the technology of business exploitation shale gas at present, and only America & Canada has business exploitation shale gas gas field.2010, U.S.'s shale gas output surpassed 1379 billion cubic meters, accounts for 23% of national rock gas gross annual output amount, and surpassing Russia becomes global first rock gas producing country.

According to the data of Ministry of Land and Resources website disclosure yesterday, in recent years, preliminary Potential Evaluation has been done to rich Shale Regions, 1,500,000 square kilometres, ground such as Hubei Province, Guizhou Province, Chongqing of Sichuan, illiteracy Shanxi, Shan, Xinjiang by Ministry of Land and Resources, rough calculation China shale gas mining resources potentiality approximately 31 tcms.

Shale gas exploitation has strategic importance to China.The shale gas of clean low-carbon (LC) can increase natural gas supply, and Optimization of Energy Structure is alleviated and reduced discharging pressure.According to < < BP world energy sources, add up 2011 > > data, it is 4.0% that China's natural gas in 2010 accounts for the ratio of primary energy consumption, and the same period, world's average was 23.81%, differ nearly 6 times, reach the rock gas ratio target of the year two thousand twenty 9%, the year two thousand thirty 12%, mean that natural gas consumption need to complete the growth of multiple level.Accelerate shale gas exploratory development and utilization, to meet socio-economic development for the demand of clean energy resource, control greenhouse gas emission, to improve Civil Energy Consumption environment significant.

According to american energy information administration, (EIA) in April, 2,011 48 shale gas basins of 32 countries in the whole world are carried out the initial results of stock assessment, China's shale gas Resource geology reserves 100 tcms, mining resources amount 36 tcms.

According to International Energy Agency (IEA), predict, the stock number of world's shale gas is in advance in respect of 456 tcms, wherein mainly be distributed in the areas such as North America, the Central Asia, the Middle East, north African, Latin America, Russia, U.S.'s shale gas mining resources reserves are about 28 tcms.

Shale gas is as a kind of special unconventional rock gas, tax is stored in mud stone or shale, have from being conigenous storage, air free water interface, large area and become continuously Tibetan, low hole, the feature such as hypotonic, generally without natural production capacity or low yield, need Massive Hydraulic Fracturing and horizontal well technology just can carry out the economic exploitation, per-well production is very low, successively decreases fast, production cycle is long, and typical individual well production feature is shown in accompanying drawing 6.So, after entering operation, how effectively individual well to be carried out to production optimum management, thereby effectively implement well stimulation, improve output and recovery ratio most important, and per-well production this feature soon of successively decreasing requires must have wider range for the production of the instrument of metering.Meanwhile, in shale gas recovery process, the shale gas of extraction is all the situation of middle high gassiness conventionally, and liquid holdup is lower, and then the water percentage in liquid phase is lower.In the situation that liquid holdup is low, carry out moisture accurate measurement is the difficult problem in heterogeneous on-line metering field all the time.

And be applied at present shale gas, measure oil, gas, water flow device and be mainly separation vessel, its principle of work is as follows: by separation vessel, gas-liquid two-phase fluid-mixing is almost separated into gas phase and liquid phase completely, this separation vessel is generally to realize gas-liquid separation by gravity, or realize gas-liquid separation by cyclone separator, then measure respectively the volumetric flow rate of gas phase and liquid phase, on Ye road, carry out corresponding moisture metering simultaneously.But due to separation vessel and relevant affiliated facility tens of tons that weigh, takes up an area tens square metres, and controlling unit is many, makes the maintenance and management of separation vessel very complicated, be unfavorable for the robotization that production run is managed, be especially unfavorable for using in desert and offshore oilfield.And this method of measuring after first separated is On-line Measuring Method not also, has the hysteresis quality of measuring, the accuracy of oil, gas, the measurement of the water three-phase gas-liquid separation effect that places one's entire reliance upon.

Therefore, this area need a kind of can be simply and the online apparatus and method of measuring in real time oil, gas, water three-phase flow in unconventional rock gas accurately, and adopt the technical scheme of noncontact, high precision, wide-range, real time dynamic measurement, so that the production of in time correct assurance oil well is dynamic, specific aim takes measures oil reservoir to carry out scientific management.

Above-mentioned target realizes by apparatus and method of the present utility model.

Utility model content

First aspect of the present utility model provides the device of Oil, Water, Gas three-phase flow in the unconventional rock gas of a kind of on-line measurement, and it comprises with lower member:

Changeable Venturi tube assembly, this assembly comprises at least two Venturi tubes, and each Venturi tube has the β value differing from one another, and described β value is defined as the pipe diameter d of throat of Venturi tube and the ratio of inlet duct diameter D;

Monoenergetic gamma sensor, it comprises monoenergetic gamma ray generator and gamma detector, the arrangement of the two makes the gamma rays that described monoenergetic gamma rays generator sends can radially pass the porch of the in running order Venturi tube in described changeable Venturi tube assembly or the xsect that throat locates, and reaches described gamma ray detector;

Online gas-liquid separation device, it is arranged in the downstream of described changeable Venturi tube assembly, and it comprises: inlet duct, gas-liquid separator, gas vent pipeline and liquid outlet pipeline;

Dual intensity gamma sensor, it comprises dual intensity gamma ray generator and gamma detector, the arrangement of the two makes the gamma rays that described dual intensity gamma rays generator sends radially through the xsect of described liquid outlet pipeline, to reach described gamma ray detector.

Second aspect of the present utility model relates to the method for Oil, Water, Gas three-phase flow in the unconventional rock gas of a kind of on-line measurement, comprises the following steps:

1) unconventional rock gas is flowed in the in running order Venturi tube of the changeable Venturi tube assembly vertically arranging;

2) utilize the total volumetric flow rate Q of this in running order this unconventional rock gas of Venturi measuring _v;

3) the void fraction GVF that utilizes monoenergetic gamma sensor to measure described unconventional rock gas at porch or the throat place of described in running order Venturi tube;

4) utilize the online gas-liquid separation device in described changeable Venturi tube downstream to carry out gas-liquid separation to described unconventional rock gas;

5) liquid phase stream that makes to obtain after gas-liquid separation in previous step is crossed one section of vertical pipeline, and uses dual intensity gamma sensor to measure the water percentage WLR in liquid phase;

6) calculate oil, the gas of described unconventional rock gas, the volumetric flow rate of each phase of water;

7) when the variation of the flow of described unconventional rock gas surpasses predetermined threshold value, switch the Venturi tube in described changeable Venturi tube assembly, repeat above-mentioned steps 1)～step 6), after changing with the flow at described unconventional rock gas, still keep predetermined measuring accuracy.

For the ease of understanding the utility model, first some terms in unconventional rock gas and multiphase flow metering field are simply described below:

" unconventional rock gas " and " shale gas " define as one joint of background technology above.

" polyphasic flow " refers to the fluid-mixing consisting of gas phase, liquid phase.Wherein liquid phase can be divided into oil phase and water, and oil phase is mainly crude oil, the water that water is used while mainly carrying out waterfrac treatment from underground water and for recover petroleum, and oil phase and water be immiscible substantially.Gas phase can be stratum associated gas, for example various alkane.

" vertically " refer to acceleration of gravity direction in the same way or oppositely.

" level " refers to the direction that is 90 ° of angles with acceleration of gravity direction.

" phase fraction " refers to liquid phase in polyphasic flow (being divided into again oil phase or water) or the shared number percent of gas phase.Phase fraction is divided into linear phase fraction, cross section phase fraction, volume phase fraction conventionally, and in measuring in polyphasic flow, we need to suppose that three-phase medium evenly mixes conventionally.In measurement, conventionally can in polyphasic flow pipeline, be provided with the device that special promotion fluid mixes, such as mixer or baffle or blind threeway etc., so that oil gas water three phase fully mixes, so that actual conditions reach or approach as far as possible the hypothesis of above-mentioned " evenly mixing ".According to gamma-ray exponential damping law, the thickness of the medium that the gamma-ray intensity of transmission is passed with it is relevant, and what with γ sensor, directly measure is the Thickness Ratio of each phase medium in the approach of walking at it, and what directly measure is " linear phase fraction ".Under the mixed uniformly prerequisite of three-phase medium, can be by linear phase fraction in conjunction with pipeline cross section geometric coaptation area phase fraction.And in actual total flow is measured, we process three-phase mutually as one, this just needs us to suppose each alternate phase velocity poor (not having slippage) that do not exist, and the gas phase in three-phase flow has identical flowing velocity with liquid phase in any one cross-section.Under the violent condition of mixing of liquid phase, it has been generally acknowledged that this prerequisite without slippage sets up.Under the prerequisite of " without slippage ", on cross-section of pipeline, the shared area of gas phase just equals void fraction with the ratio (phase area ratio) that cross-section of pipeline amasss.Similarly, when the water in liquid phase has identical flowing velocity with oil in certain, on the cross-section of pipeline at this place, the shared area of water just equals water percentage with the ratio (phase area ratio) of liquid phase area occupied, and thinks that area phase fraction is exactly volume phase fraction.In this invention, if do not particularly not pointed out, based on " evenly mix " and " without slippage " these two prerequisites, think and measured the linear phase fraction of a certain each phase of section, the geometric parameter based on pipeline section, just can calculate area phase fraction and the volume phase fraction of this section.

" void fraction " (GVF) is defined as: the ratio of (under operating mode) volumetric flow of gas and polyphasic flow total volumetric flow rate under the condition of environment temperature and pressure.Conventionally with percentage, represent.Under the prerequisite of " evenly mixing " and " without slippage ", void fraction is exactly the gas phase area phase fraction in cross section.

" water percentage " (WC) is defined as: (under mark condition) volumetric flow rate of water and the ratio of liquid volume flow under the condition of standard temperature and pressure (STP).Conventionally with percentage, represent.Under the prerequisite of " evenly mixing " and " without slippage ", water percentage is exactly the water area phase fraction in cross section.

The utility model first aspect relates to oil in a kind of unconventional rock gas, gas, the online flow measurement device of water three-phase, below its included member is described in detail.

The changeable Venturi tube assembly of the utility model device comprises at least two Venturi tubes, and each Venturi tube has the β value differing from one another, and described β value is defined as the pipe diameter d of throat of Venturi tube and the ratio of inlet duct diameter D.Referring to accompanying drawing 3, these at least two Venturi tubes are contained in the main body 3-1 of changeable Venturi tube assembly, and are furnished with the 3-2 of travel mechanism that switches each Venturi tube for online.Wherein each Venturi tube is comprised of entrance pipeline section, circular cone contraction section, cylinder throat, circular cone diffuser, and wherein circular cone diffuser the widest part diameter D of each Venturi tube is identical, but has the cylinder throat diameter d differing from one another.The installation parallel to each other of described at least two Venturi tubes, and described assembly upstream connects fluid input tube road, connection fluid output tube road, downstream.Wherein, that Venturi tube that fluid circulates just is within it called in running order Venturi tube.In Venturi tube, be also provided with for measuring the measuring sensor of temperature and porch and throat's place's pressure reduction, these are all the standard fittings of Venturi tube, repeat no more.About detailed structure and the processing specification of Venturi tube, can, referring to CNS GB-T2624, repeat no more herein.In the utility model patent, it needs to be noted, the β value of Venturi tube (being defined as the ratio of throat diameter d value with the entrance pipeline section maximum dimension D of Venturi tube, i.e. β=d/D) is the important parameter that determines the measurement range of Venturi tube.Each Venturi tube in changeable Venturi tube assembly as herein described has different β values, and for example β value can change between 0.35 to 0.75, and now the maximum measurement range of flow and the ratio of minimum measurement range can reach 32.Certainly, choosing of concrete different Venturi tube β values can need to change according to actual design in other numerical range, to reach the ratio of larger maximum measurement range with minimum measurement range.Described moving structure is any device that is applicable to making described apparatus main body generation translation or rotation, to switch each Venturi tube, make at a time always to have a venturi pipeline to be connected with device upstream and downstream pipeline, realize in this way the switching of throat diameter d.Wherein said movement comprises translation or rotation.Described moving structure can manually move or by machinery, apparatus main body be moved, for example, under the control of automatic controls, move.Above described moving structure, stop means can also be set as required, to make the switching of each Venturi tube more accurate, or make to switch rear Venturi tube position and fix.

In the situation that keep the exit port end maximum dimension D of each Venturi tube identical and throat diameter d is different, according to venturi design specifications, the circular cone contraction section of the Venturi tube of different beta value and the length of circular cone diffuser can there are differences, for the ease of with the engaging of upstream and downstream pipeline, can be furnished with polishing straight pipeline and be furnished with polishing straight pipeline at endpiece at the entrance point with the Venturi tube of compare great throat pipe diameter, to carry out length polishing, the length that makes to have the Venturi tube of compare great throat pipe diameter adds after the length of polishing straight pipeline at its two ends, equal to there is the length compared with the Venturi tube of small larynx portion pipe diameter.The outside of described device also needs to be set with seal case to prevent fluid leakage.In the situation that effectively preventing fluid leakage, can switch online each Venturi tube and without closing upstream and downstream pipeline.The structure of seal case can be any structure that fluid is not revealed, and can be designed as the case may be by those skilled in the art.

In the utility model, described changeable Venturi tube assembly is vertically arranged.In preferred embodiment of the present utility model, horizontal pipe place in the upstream of described Venturi tube preferably also arranges a blind threeway, so that polyphasic flow by horizontal flow to transferring the vertical flow direction to, and in the collision effect of blind threeway place, polyphasic flow is mixed by fluid.

Monoenergetic gamma sensor in the utility model device, is mainly comprised of gamma-ray emission device and gamma detector.Gamma ray detectors is a kind of detector conventional in multiphase flow rate meter field, and its principle of work is, is sent that to have certain initial strength be emissive porwer N by the radioactive source that is arranged in the gamma-ray emission device of pipeline one side ₀gamma rays, be preferably the gamma rays through collimation, when this gamma rays passes absorbing medium, can because of with the interaction such as absorbing medium generation photoelectric effect, Compton scattering and electron pair generation, and generation strength retrogression, be absorbed Absorption of Medium and fall at least a portion, being then positioned at the gamma ray intensity that the gamma detector of pipeline opposite side detects after decay is intensity in transmission N, and the formula based on certain calculates the absorption coefficient of absorbing medium.Wherein said radioactive source can adopt various suitable radioactive sources.

At heterogeneous fluid as absorbing medium in the situation that, because gas phase, liquid phase (this liquid phase is divided into again oil phase and water) have different absorption coefficients for gamma rays, therefore, polyphasic flow for having different gas phases one oil phase one water three-phase ratio, will have different absorption coefficients.Absorption coefficient in conjunction with pure gas, pure oil phase and pure water phase, carries out analytical calculation to the absorption coefficient of the three-phase mixture recording, and will likely provide the information of the phase fraction of each phase.

Monoenergetic gamma sensor is to utilize the isotope gauge of the γ photon beam transmission principle of the single energy collimating, for example, use 241Am radioactive source, and the energy of the gamma rays that it sends is 59.5keV; Or use 137Cs radioactive source, the energy of γ ray sending: 662keV.In multiphase flow metering field, monoenergetic gamma sensor is mainly used to measure the phase fraction of heterogeneous fluid, be mainly used to measure void fraction or three-phase hybrid density, its structure as shown in Figure 2, gamma-ray emission device mainly comprises radioactive source and Yuan Cang (2-1), storehouse, source sheath (2-2) and sealing gasket (2-3), and gamma detector mainly comprises gamma detector (2-5), sealing gasket (2-4), detector sleeve (2-6).

In the utility model, require the monoenergetic gamma-ray emission device of monoenergetic gamma sensor and the arrangement of gamma detector to make the gamma rays that described monoenergetic gamma-ray burster sends can radially pass the porch of the in running order Venturi tube in described changeable Venturi tube assembly or the xsect that throat locates, reach described gamma ray detector.

Dual intensity gamma sensor in device of the present utility model is mainly comprised of dual intensity gamma ray generator and gamma receiver.Dual intensity gamma generator is to utilize a dual gamma bundle (wherein comprising two kinds of different γ photons of energy) through measured medium, then by dual intensity gamma receiver, is measured respectively the intensity in transmission of two kinds of energy photons.It is equivalent to two monoenergetic gamma sensor like this, but on following 2, is different from again two monoenergetic γ sensors.One, two groups of γ photon energies are different, and therefore can list two independently absorbs equation, and the situation of the γ medium that photon pass of its two, two kinds of energy is identical, so measured in two absorption equations is same medium.Can absorb equations simultaneousness two thus and solve two unknown numbers: water percentage and liquid phase thickness (liquid holdup, wherein liquid holdup=1-void fraction).The restriction that when it has just solved monoenergetic water-containing machine and measures crude oil water content like this, tested crude oil can not gassiness.

The structure of dual gamma sensor is identical with monoenergetic substantially.The structure in different is storehouse, source need to be carried out respective design according to choosing of radioactive source.The storehouse, source that conventional feasible scheme is dual gamma source is by two ²⁴¹the composite structure that Am source forms or select ¹³³single the radioactive source structure of Ba.For example, using ²⁴¹in the situation of Am radioactive source, produce the gamma rays of 59.5keV, make one in this gamma rays as high energy gamma rays directly through absorbing medium, and thereby the target that another burst of bombardment in this gamma rays made by silver excites silver hair to go out the low energy gamma rays that energy is 22keV, and along the path identical with aforementioned high energy gamma rays, pass through this absorbing medium, and by gamma ray detector, detected their intensity in transmission together; Can also otherwise obtain dual intensity gamma rays, for example, use ¹³³ba, the gamma rays that this radioactive source sends has three main energy levels, is respectively 31keV, 81keV, 356keV, chooses the combination of any two kinds wherein, for example adopt the array mode of 31keV+81keV, respectively as described high energy gamma rays and low energy gamma rays.Use dual intensity gamma rays, the information more forming about heterogeneous fluid inside can be provided.In the selection of dual energy gamma ray detector, those skilled in the art can select concrete two kinds of energy that use according to the specific nature of object to be measured.For example, measure dense medium and need to select the gamma-rays that energy is higher.To light substance, as oil water mixture, two most suitable scopes of energy roughly at 20KeV between 100KeV.Conventionally energy in the gamma-rays of two kinds of energy higher call energetic gamma rays, another is low-energyγ-ray.The gamma ray detectors of using in the utility model is dual intensity gamma-ray detector, and it is known, about its more principle of work and device specifics, and can be referring to relevant monograph.Repeat no more herein.

In brief, gamma-ray detector is a kind of method of information of each phase composition with noncontact, non-invasive mode measuring tube inner fluid.In device of the present utility model, dual intensity gamma-ray burster and gamma rays receiver will be radial arrangement along the xsect of vertical pipe.

Online gas-liquid separation device in the utility model device, Main Function is separated by online liquid phase or part is separated, compares with original polyphasic flow, obtains being relatively more rich in the gas phase and the relative liquid phase that is more rich in liquid of gas.This online gas-liquid separation device is positioned at the downstream of described changeable Venturi tube assembly.As previously mentioned, if liquid holdup is too low in polyphasic flow, the water percentage time error in measuring liquid phase can be larger.By carrying out online gas-liquid separation, can carry out measurement of water ratio to the described liquid phase that is relatively more rich in liquid, improve measuring precision of water content in water.Described online gas-liquid separation device also can be called online fluid sampling device, and it is generally incorporated into a mouthful pipeline, gas-liquid separator, gas vent pipeline and liquid outlet pipeline, and other necessary annex etc.The mode of online gas-liquid separation can have a variety of, what the utility model adopted is the mode of " cyclonic separation+collision is separated ", its structure is shown in accompanying drawing 4, mainly by inlet duct (4-1), forward spin flow storehouse (4-2), cavity (4-3), lower eddy flow storehouse (4-4), liquid outlet pipeline (4-5), collision storehouse (4-6) forms.The main body of this online gas-liquid separation device is two eddy flow storehouses, and it can be columniform, conical or cylindrical and conical the two combination.For example, it can be upper prop inferior pyramidal shape.In working order, the general vertical placement of the axis in this eddy flow storehouse.For guaranteeing fully to form more stable fluidised form after eddy flow at polyphasic flow in storehouse, make in storehouse liquid outlet gas content lower, the diameter in eddy flow storehouse is generally the more than 6 times of inlet duct diameter, be highly the more than 2 times of inlet duct diameter, and cavity diameter is got 2 times of inlet duct diameters.Inlet duct passes into this eddy flow storehouse in the side in eddy flow storehouse along tangent to periphery direction.Described inlet duct upstream connects polyphasic flow input channel.In general, this inlet duct passes into this eddy flow storehouse in the middle and upper part, side in eddy flow storehouse along tangent to periphery direction.Preferably, this inlet duct passes into this eddy flow storehouse in the side top in eddy flow storehouse along tangent to periphery direction.Cross sectional shape to this inlet duct does not require, but is preferably circle.This inlet duct and horizontal angle are between 0 to 90 degree, preferably between 0-75 degree, more preferably between 0-60 degree.In practice, for optimization device height and convenient connection, preferred levels is installed.

At the top in eddy flow storehouse, be provided with a collision storehouse, the entrance in this collision storehouse is communicated with the top in described eddy flow storehouse, and the entrance in this collision storehouse itself is as the gas vent pipeline in described eddy flow storehouse.At least 2 layers of screen cloth that are crisscross arranged in this collision storehouse, when eddy flow storehouse exit gas is flowed through this screen cloth, the liquid phase of wherein carrying is trapped by screen cloth through collision effect, and is back in eddy flow storehouse.Therefore, the existence in this collision storehouse, can greatly reduce amount of liquid entrained in gas, and then be conducive to improve the gas-liquid separation efficiency of online gas-liquid separator.The concrete structure in described collision storehouse can be board-like, can be also a barrel formula, and design simultaneously need to consider circulation and the crushing of gas-liquid.

On the liquid outlet pipeline of described online gas-liquid separation device, measurement of water ratio instrument can be set, dual intensity gamma rays sensor described in the utility model for example, to measure the water percentage of fluid sample.In preferred embodiments, described dual intensity gamma sensor is arranged on one section of pipeline place vertically arranging of this liquid outlet pipeline, to eliminate the impact of profit layering, improves accuracy of measurement.The arrangement that dual intensity gamma sensor in the utility model comprises dual intensity gamma-ray emission device and gamma detector makes the gamma rays that described dual intensity gamma-ray burster sends radially through the xsect of described liquid outlet pipeline, to reach described gamma ray detector.

The size of each parts of described online gas-liquid separation device and arrangement relation each other, it is mainly inlet angle, structure and the size in collision storehouse, can be used fluid calculation software to calculate rear optimization for the particular range of oil well void fraction, or according to carrying out optimal design after limited number of time experiment.

The gas phase and the liquid phase that by described online gas-liquid separation device, are divided into, can converge in the somewhere in device of the present utility model downstream as required, regenerates unconventional natural gas flow thigh, continues to carry.Therefore, device of the present utility model does not cause interference to the conveying of unconventional rock gas.

Second aspect of the present utility model relates to the method for Oil, Water, Gas three-phase flow in the unconventional rock gas of a kind of on-line measurement, and the device using in the method as described above.Below each included step of the method is described in detail.

In the unconventional rock gas of on-line measurement of the present utility model, the method for Oil, Water, Gas three-phase flow comprises:

1) unconventional rock gas is flowed in the in running order Venturi tube of the changeable Venturi tube assembly vertically arranging.If described unconventional rock gas is to flow in horizontal tube before, make it to flow through a blind threeway flow direction is become vertically upward from level, then enter in this in running order Venturi tube vertically arranging.The effect of blind threeway is also to collide by the baffling of fluid, impels fluid to mix.

2) utilize the total volumetric flow rate Q of this in running order this unconventional rock gas of Venturi measuring _v; Venturi tube can be used for measuring the porch of this unconventional rock gas and the pressure differential deltap p between throat place.Use these data, in conjunction with the design parameter of Venturi tube itself, just can calculate the total volumetric flow rate of this unconventional rock gas, concrete formula is as follows:

$Q_v=0.0040{\mathrm{CEd}}^2\sqrt{\frac{\mathrm{\&Delta;p}}{{\mathrm{\&rho;}}_{\mathrm{mix}}}}---\left(1\right)$

${\mathrm{\&rho;}}_{\mathrm{mix}}=(1-\mathrm{GVF})[{\mathrm{\&rho;}}_o+\mathrm{WLR}({\mathrm{\&rho;}}_w-{\mathrm{\&rho;}}_o)]+\mathrm{GVF}{\mathrm{\&rho;}}_g---\left(2\right)$

Wherein:

C venturi efflux coefficient; Dimensionless, is provided by venturi design parameter

The progressive velocity coefficient of E, dimensionless, is provided by venturi design parameter;

D venturi throat diameter, mm, is provided by venturi design parameter;

The porch of Δ p Venturi tube and the differential pressure between throat, Pa;

ρ _mixoil, gas, water three-phase hybrid density, kg/m ³;

Q _vtotal volumetric flow rate, m ³/ h;

Void fraction in the described unconventional rock gas that GVF is recorded by monoenergetic gamma sensor;

The liquid phase water percentage that WLR is recorded by dual intensity gamma sensor;

ρ _wwater operating mode density kg/m ³

ρ _ooil phase operating mode density kg/m ³

ρ _ggas phase operating mode density kg/m ³

Wherein, the efflux coefficient C of classical venturi tube is relevant to Reynolds number, has many experimental formulas can reference.For shale gas three phase metering, be generally high gassiness and oil, gas, water and mix that viscosity is lower, Reynolds number is higher, the desirable classical value 0.995 of C in shale gas metering.

3) the void fraction GVF that utilizes monoenergetic gamma sensor to measure described unconventional rock gas at porch or the throat place of described in running order Venturi tube; Specific formula for calculation is as follows:

$\mathrm{GVF}=\frac{[{\mathrm{\&rho;}}_o{\mathrm{\&mu;}}_o^s+\mathrm{WLR}({\mathrm{\&rho;}}_w{\mathrm{\&mu;}}_w^s-{\mathrm{\&rho;}}_o{\mathrm{\&mu;}}_o^s)]-\ln (N_0^s/N_x^s)/D_1}{[{\mathrm{\&rho;}}_o{\mathrm{\&mu;}}_o^s+\mathrm{WLR}({\mathrm{\&rho;}}_w{\mathrm{\&mu;}}_w^s-{\mathrm{\&rho;}}_o{\mathrm{\&mu;}}_o^s)]-{\mathrm{\&rho;}}_g{\mathrm{\&mu;}}_g^s}---\left(3\right)$

Wherein:

monoenergetic gamma rays blank pipe counting dimensionless

monoenergetic gamma rays on-line counting dimensionless

full oil ga(u)ge is the mass absorption coefficient m of monoenergetic gamma rays regularly ²/ kg

full water gauge is the mass absorption coefficient m of monoenergetic gamma rays regularly ²/ kg

the mass absorption coefficient m of full gas timing signal monoenergetic gamma rays ²/ kg

ρ _wwater operating mode density kg/m ³

ρ _ooil phase operating mode density kg/m ³

ρ _ggas phase operating mode density kg/m ³

Water percentage in the liquid phase that WLR is measured by described dual intensity gamma sensor

D ₁monoenergetic gamma sensor installation site pipeline interior diameter m.

4) utilize the online gas-liquid separation device in described changeable Venturi tube downstream to carry out gas-liquid separation to described unconventional rock gas.This gas-liquid separation is compared the relative liquid phase that is more rich in the gas phase of gas and is relatively more rich in liquid by obtaining with original polyphasic flow, so that the liquid phase that can relatively more be rich in liquid to this is carried out measurement of water ratio.

5) liquid phase stream that makes to obtain after gas-liquid separation in previous step is crossed one section of vertical pipeline, and uses dual intensity gamma sensor to measure the water percentage WLR in liquid phase.Wherein by following formula, by the measurement data of described dual intensity gamma sensor, calculate water percentage:

$\mathrm{\&lambda;}=\frac{({\mathrm{\&mu;}}_{-}^L\&CenterDot;M-{\mathrm{\&mu;}}_{-}^H\&CenterDot;P)-({\mathrm{\&rho;}}_o{\mathrm{\&mu;}}_o^H\&CenterDot;{\mathrm{\&mu;}}_{-}^L-{\mathrm{\&rho;}}_o{\mathrm{\&mu;}}_o\&CenterDot;{\mathrm{\&mu;}}_{-}^H)}{({\mathrm{\&mu;}}_{-}^L\&CenterDot;{\mathrm{\&rho;}}_g{\mathrm{\&mu;}}_g^H-{\mathrm{\&mu;}}_{-}^H\&CenterDot;{\mathrm{\&rho;}}_g{\mathrm{\&mu;}}_g^L)-({\mathrm{\&rho;}}_o{\mathrm{\&mu;}}_o^H\&CenterDot;{\mathrm{\&mu;}}_{-}^L-{\mathrm{\&rho;}}_o{\mathrm{\&mu;}}_o^L\&CenterDot;{\mathrm{\&mu;}}_{-}^H)}---\left(4\right)$

$\mathrm{WLR}=\frac{P-{\mathrm{\&rho;}}_o{\mathrm{\&mu;}}_o^L(1-\mathrm{\&lambda;})-{\mathrm{\&rho;}}_g{\mathrm{\&mu;}}_g^L\&CenterDot;\mathrm{\&lambda;}}{{\mathrm{\&mu;}}_{-}^L(1-\mathrm{\&lambda;})}---\left(5\right)$

Four intermediate variables in above-mentioned formula are defined as follows:

$M=\ln \left(\frac{N_0^H}{N_X^H}\right)\&CenterDot;\frac{1}{D},P=\ln \left(\frac{N_0^L}{N_X^L}\right)\&CenterDot;\frac{1}{D}$

${\mathrm{\&mu;}}_{-}^H=({\mathrm{\&rho;}}_w{\mathrm{\&mu;}}_w^H-{\mathrm{\&rho;}}_o{\mathrm{\&mu;}}_o^H),{\mathrm{\&mu;}}_{-}^L=({\mathrm{\&rho;}}_w{\mathrm{\&mu;}}_w^L-{\mathrm{\&rho;}}_o{\mathrm{\&mu;}}_o^L)$

Wherein:

ρ _wwater operating mode density kg/m ³

ρ _ooil phase operating mode density kg/m ³

ρ _ggas phase operating mode density kg/m ³

full oil ga(u)ge is dual intensity gamma sensor high energy mass absorption coefficient m regularly ²/ kg

full oil ga(u)ge is dual intensity gamma sensor low energy mass absorption coefficient m regularly ²/ kg

full water gauge is dual intensity gamma sensor high energy mass absorption coefficient m regularly ²/ kg

full water gauge is dual intensity gamma sensor low energy mass absorption coefficient m regularly ²/ kg

full gas timing signal dual intensity gamma sensor high energy mass absorption coefficient m ²/ kg

full gas timing signal dual intensity gamma sensor low energy mass absorption coefficient m ²/ kg

λ dual intensity gamma sensor is measured the void fraction of pipeline section place oil, gas, water three-phase

Water percentage in the liquid phase at WLR dual intensity gamma sensor measurement pipeline section place

blank pipe low energy counting dimensionless

blank pipe high energy counting dimensionless

low energy on-line counting dimensionless

high energy on-line counting dimensionless

D ₂dual intensity gamma sensor is measured the pipeline interior diameter m at pipeline section place

Wherein with the symbol of upper right corner band " H ", represent the physical quantity relevant with energetic gamma rays.Band " L " represents the physical quantity relevant with low-energyγ-ray.

6) calculate oil, the gas of described unconventional rock gas, the volumetric flow rate of each phase of water, according to following formula, calculate oil, gas, the water three-phase operating mode flow in described unconventional rock gas, wherein LC represents operating mode:

$Q_{\mathrm{gas}}^{\mathrm{LC}}=Q_v\mathrm{GVF}---\left(6\right)$

$Q_{\mathrm{water}}^{\mathrm{LC}}=Q_v(1-\mathrm{GVF})\mathrm{WLR}---\left(7\right)$

$Q_{\mathrm{oil}}^{\mathrm{LC}}=Q_v(1-\mathrm{GVF})(1-\mathrm{WLR})---\left(8\right)$

Wherein:

gas operating mode flow, am ³/ h;

oil operating mode flow, am ³/ h

water condition flow, am ³/ h

Q _vtotal flow, am ³/ h

Void fraction in the described unconventional rock gas that GVF is measured by monoenergetic gamma sensor

Water percentage in the liquid phase that WLR is measured by dual intensity gamma sensor

In preferred embodiments, this step also can further comprise utilizes PVT model that the operating mode flow of the oil in described unconventional rock gas, gas, water is converted to mark condition flow, usings as last standardization Output rusults.Detailed process is as follows: by the multivariable transmitter of installing on the utility model device, gather the temperature, pressure of shale gas and oil, gas, water and in conjunction with the media property of fluid, utilize PVT model that oil, gas, discharge under operating mode are converted under mark condition as final output quantity.

$Q_{\mathrm{oil}}^{\mathrm{SC}}=\frac{Q_{\mathrm{oil}}^{\mathrm{LC}}}{B_o}---\left(9\right)$

$Q_{\mathrm{water}}^{\mathrm{SC}}=\frac{Q_{\mathrm{water}}^{\mathrm{LC}}}{B_w}---\left(10\right)$

$Q_{\mathrm{gas}}^{\mathrm{SC}}=\frac{Q_{\mathrm{gas}}^{\mathrm{LC}}}{B_g}+R_s{Q}_{\mathrm{oil}}^{\mathrm{SC}}---\left(11\right)$

Wherein:

gas operating mode flow, am ³/ h;

oil operating mode flow, am ³/ h

water condition flow, am ³/ h

gas operating mode flow, sm ³/ h;

oil operating mode flow, sm ³/ h

water condition flow, sm ³/ h

B _ooil volume coefficient, dimensionless

B _wwater volume coefficient, dimensionless

B _ggas volume factor, dimensionless

R _ssolution gas-oil ratio, sm ³/ sm ³

Because PVT related volume coefficient can calculate according to the pressure and temperature gathering by black-oil-type simulation model or client model, in multiphase flow metering industry, be well known, therefore PVT is not calculated and is described in detail at this.

7) when the variation of the flow of described unconventional rock gas surpasses predetermined threshold value, switch the Venturi tube in described changeable Venturi tube assembly, repeat above-mentioned steps 1)～step 6), after changing with the flow at described unconventional rock gas, still keep predetermined measuring accuracy.This predetermined threshold can by oil field client rule of thumb data set voluntarily.For example, when the output of unconventional rock gas declines over predetermined threshold gradually, switch to the Venturi tube with less β value and measure.Above-mentioned switching, can manual switching, also can automatically switch.This changeable Venturi tube be arranged so that oil field client needn't dismantle flowmeter from oil gas pipeline and just can under low oil and gas production, maintain and measuring accuracy consistent under high oil and gas production.

Due to the parameter needing in measuring process of the present utility model and computation process and formula numerous, some parameter is field measurement variable, some parameter is need to measure by experiment in advance and as constant, use during in-site measurement, the prerequisite that some parameter is also calculated each other each other, for the ease of understanding the measuring method of these parameters and the effect in computation process, below in conjunction with Fig. 5, computation process is discussed in detail:

First, before the oil in unconventional rock gas, gas, water three-phase flow are measured, need to do in advance measurement and the staking-out work of better basic parameter, after mensuration, when the oil in unconventional rock gas, gas, water three-phase flow carry out online measurement in real time, think that these basic parameters are all known constants.

be respectively single gamma sensor energy and the full gal sensor of dual intensity blank pipe calibration value, refer to monoenergetic gamma ray count, high energy gamma ray counts and low energy gamma ray counts measured when measuring pipeline for sky.

ρ _o, ρ _g, ρ _wrespectively oil phase, water, gas phase operating mode density.Wherein each phase operating mode density is used conventional gas-liquid-solid three-phase separator to carry out after three phase separation, for each, being measured mutually thoroughly to unconventional rock gas to be measured, or by PVT model, the mark condition density of each phase is converted to operating mode, above-mentioned PVT model rule is known in the art, can, referring to any fluid mechanics textbook, not repeat them here.

the mass absorption coefficient m of monoenergetic gamma rays during full oil ga(u)ge fixed (measure in pipeline be full of oil) ²/ kg

the mass absorption coefficient m of monoenergetic gamma rays during full water gauge fixed (measure in pipeline be full of water) ²/ kg

the mass absorption coefficient m of monoenergetic gamma rays when full gas is demarcated (measure in pipeline be full of gas) ²/ kg

full oil ga(u)ge is dual intensity gamma sensor high energy mass absorption coefficient m regularly ²/ kg

full oil ga(u)ge is dual intensity gamma sensor low energy mass absorption coefficient m regularly ²/ kg

full water gauge is dual intensity gamma sensor high energy mass absorption coefficient m regularly ²/ kg

full water gauge is dual intensity gamma sensor low energy mass absorption coefficient m regularly ²/ kg

full gas timing signal dual intensity gamma sensor high energy mass absorption coefficient m ²/ kg

full gas timing signal dual intensity gamma sensor low energy mass absorption coefficient m ²/ kg

After each absorption coefficient can be used conventional gas-liquid-solid three-phase separator to be thoroughly separated to unconventional rock gas to be measured above, each is full of respectively to full measuring channel mutually, then records respectively the on-line proving counting of each phase, according to the initial strength N of gamma rays ₀with intensity in transmission N _x, adopt Absorption Formula to calculate.Can certainly demarcate mutually with above-mentioned other above-mentioned each that replace mutually that is easy to obtain being respectively close by composition or character.These calculate and calibration process is all to well known to a person skilled in the art technology.

D ₁, D ₂be respectively monoenergetic gamma sensor and dual intensity gamma sensor installation site pipeline interior diameter (m), this parameter is determined according to this contrive equipment design and machined parameters.

B _。oil volume coefficient, dimensionless

B _wwater volume coefficient, dimensionless

B _ggas volume factor, dimensionless

R _ssolution gas-oil ratio, sm ³/ sm ³

Above PVT parameter is relevant to tactful medium temperature, pressure and measuring media attribute, due in this area for everybody is known, its acquisition process is no longer set forth at this.

Accompanying drawing explanation

Fig. 1 is the structural representation of the device of oil, gas, water three-phase flow in the unconventional rock gas of measurement of the present utility model.

Fig. 2 is the structural representation of the monoenergetic gamma sensor in the utility model device.

Fig. 3 is the apparatus structure schematic diagram of changeable Venturi tube assembly of the present utility model and monoenergetic gamma sensor.

Fig. 4 is the apparatus structure schematic diagram of online gas-liquid separator of the present utility model and dual intensity gamma sensor.

Fig. 5 is parameter measurement process flow diagram and the net result calculation flow chart of oil, gas, water three-phase flow in the unconventional rock gas of measurement of the present utility model.

Fig. 6 is typical shale gas per-well production variation characteristic figure.

Embodiment

Provide following examples to be elaborated, embodiment is only indicative, and nonrestrictive.

In order to verify the exploitativeness of apparatus and method of the present utility model, by the polyphasic flow of International Certification, demarcate loop wire this device and measuring method are carried out to online verification.In order comprehensively to verify the test performance of this device, simulate truly the hole condition feature of unconventional rock gas, the design discharge condition of test point is chosen the feature that wide, the high void fraction of flow range is master that stresses.This polyphasic flow loop wire oil phase adopts the crude oil of oil well production, and water is mineralized water, and gas adopts rock gas.First oil, gas, water are carried out to normal flow metering by single-phase test line, then by mixer, carrying out oil, gas, water fully mixes, the measurement mechanism of the present utility model that obtains flowing through after stable polyphasic flow carries out oil, gas, water three-phase flow on-line measurement, the separation vessel that finally enters test loop downstream carries out the separation of oil, gas, water, oil after separation, gas, water single-phase medium continue to enter single-phase measurement pipeline section, form a mixing, heterogeneous on-line metering, separated decomposite loop test system.The standard value of a metering cycle and measurement mechanism measured value of the present utility model and the measuring error that compares to check corresponding output quantity, need the output quantity of paying close attention to have liquid measure, tolerance, water percentage conventionally the most at last.

Required known quantity while being the measurement mechanism of the present utility model work obtaining by prior demarcation and mensuration in experiment below:

In order fully to verify the feasibility of these apparatus and method, carried out altogether the contrast experiment of 22 groups of polyphasic flow conditions, under every group of experiment condition, measure 10 minutes.The measurement comparing result that in measuring process, this device calculates this contrive equipment under every group of experiment condition by the known quantity in conjunction with above and formula (1)-(11) is as follows:

By standard polyphasic flow loop wire, the utility model device is carried out to flow calibration result known, the measurement result that apparatus and method of the present utility model realize and true value are very approaching, and the reappearance of measurement result is very good, be well positioned to meet the measuring accuracy requirement of unconventional natural gas and oil, gas, water three-phase flow at present.In addition, the utility model at void fraction up to 99% in the situation that, the measuring error of water percentage is still very little, and this illustrates that the unique design of online liquid sampler makes dual intensity gamma sensor measuring precision of water content in water not be subject to the impact of void fraction, has realized moisture accurate measurement under GVF gamut condition.By contrast, common unconventional natural gas flowmeter, higher than 95% time, will produce sizable measurement of water ratio error at void fraction GVF, causes measuring accuracy significantly to decline.

The device and method of oil, gas, water three-phase flow in the unconventional rock gas of on-line measurement of the present utility model, tool has the following advantages:

1. the utility model device is realized the measurement of total flow and phase fraction by non-contacting mode to unconventional Gas Exploitation, not only measurement mechanism is simplified greatly, compact conformation, installation and maintenance workload is little, without movable member, and timely to measured fluidic response, truly realized real-time online measuring.

2. in the utility model device, adopt the structure of automatic changeable venturi, expanded greatly traditional differential pressure flowmeter total flow measurement range, maximum range ratio can expand to 1:32 by 1:8, thereby it is fast fundamentally to have solved under unconventional rock gas hole condition condition production rate decline, and measurement mechanism range ability is required to a wide difficult problem.And under various flow conditions, maintain basically identical measuring accuracy.

3. in the utility model device, adopt online gas-liquid separation device to contain the method for water gaging, for dual intensity measurement provides representational liquid sample and reduced void fraction to the disturbance containing water gaging, this measuring method has solved in unconventional rock gas the very large problem of measurement of water ratio error in liquid phase under high gassiness condition.From above-mentioned formula, the measuring accuracy direct relation of water percentage the measuring accuracy of gas phase, oil phase and each phase of water, therefore, has improved the measuring accuracy of water percentage, has also just greatly improved the measuring accuracy of each phase flow rate.

Claims (7)

1. a device for oil, gas, water three-phase flow in the unconventional rock gas of on-line measurement, it comprises with lower member:

Changeable Venturi tube assembly, this assembly comprises at least two Venturi tubes, and each Venturi tube has the β value differing from one another, and described β value is defined as the pipe diameter d of throat of Venturi tube and the ratio of inlet duct diameter D;

Monoenergetic gamma sensor, it comprises monoenergetic gamma-ray emission device and gamma detector, the arrangement of the two makes the gamma rays that described monoenergetic gamma-ray burster sends can radially pass the porch of the in running order Venturi tube in described changeable Venturi tube assembly or the xsect that throat locates, and reaches described gamma ray detector;

Online gas-liquid separation device, it is arranged in the downstream of described changeable Venturi tube assembly, and it comprises: inlet duct, gas-liquid separator, gas vent pipeline and liquid outlet pipeline;

Dual intensity gamma sensor, it comprises dual intensity gamma-ray emission device and gamma detector, the arrangement of the two makes the gamma rays that described dual intensity gamma-ray burster sends radially through the xsect of described liquid outlet pipeline, to reach described gamma ray detector.

2. according to the device of claim 1, it also comprises the device for fluid is mixed that is positioned at described changeable Venturi tube assembly upstream.

3. according to the device of claim 1, wherein said changeable Venturi tube assembly is vertically arranged; And described dual intensity gamma sensor is arranged on one section of pipeline place vertically arranging of described liquid outlet pipeline.

4. according to the device of claim 1, wherein said monoenergetic gamma sensor is used 241Am or 137Cs as gamma radioactive source, and the energy of the gamma rays that wherein 241Am sends is 59.5keV, and the energy of γ ray that 137Cs sends is 662keV; Described dual intensity gamma ray detectors is used 241Am or 133Ba as gamma ray radiation source, wherein in the situation that using 241Am radioactive source, produce the gamma rays of 59.5keV, wherein first strand of gamma rays directly absorbed through absorbing medium, thereby another strand bombards the target sheet of being made by silver excites silver hair to go out the relatively low gamma rays of energy that energy is 22keV, and be absorbed by this absorbing medium along the path identical with first strand of gamma rays, and by gamma ray detector, detected their intensity in transmission together; And in the situation that using 133Ba as radioactive source, the gamma rays that 133Ba sends has three main energy levels, is respectively 31keV, 81keV, 356keV, chooses the combination of any two kinds wherein, respectively as described dual intensity gamma rays.

5. according to the device of claim 1, wherein said changeable venturi assembly comprises travel mechanism, by this travel mechanism, described at least two Venturi tubes with different beta value is switched online, and described switching comprises that translation is switched or rotation is switched.

6. according to the device of claim 1, gas-liquid separator in wherein said online gas-liquid separation device comprises eddy flow storehouse and collision storehouse, wherein by making fluid enter via the inlet duct that is arranged tangential with this eddy flow storehouse the cyclonic separation that eddy flow storehouse produces, be used for carrying out gas-liquid separation, at least 2 layers of screen cloth of the alternative arrangement of the gas flow obtaining after separation in being arranged on described collision storehouse, further to trap liquid phase, improve gas-liquid separation efficiency.

7. according to the device of claim 6, the axis in wherein said eddy flow storehouse vertically arranges.

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