CN110905480A - A kind of oil and gas wellhead production measurement device and production capacity evaluation method - Google Patents

Abstract

The invention relates to an oil and gas wellhead production measurement device and a production capacity evaluation method, comprising a throttling element, a multi-parameter sensor and an optical quantum phase splitter installed on the throttling element, and data respectively communicated with the multi-parameter sensor and the optical quantum phase splitter. The acquisition unit and the central processing unit communicated with the data acquisition unit. Through the throttling element and the multi-parameter sensor, the invention can calculate the total mass passing through the unit time, measure the phase fractionation rate of the passing multiphase fluid with the multiphase photon quantum phase splitter, and combine the built-in adaptive flow model to calculate the The gas mass, liquid mass and solid mass passing through unit time, and then according to the pressure and temperature measured by the multi-parameter sensor, the volume of gas and the volume flow of liquid can be calculated, so as to realize the control of the gas in the gas well product during the gas production test. , real-time continuous online measurement of liquids and solids, which can fit and evaluate the production conditions of test wells in the whole life cycle of production, and scientifically evaluate the production capacity of gas wells.

Description

A kind of oil and gas wellhead production measurement device and production capacity evaluation method

technical field

The invention relates to the technical field of gas well production evaluation, and more particularly, to an oil and gas wellhead production measurement device and a production capacity evaluation method.

Background technique

Gas production engineering refers to the completion and commissioning of gas field development, gas well production system and gas production process selection, downhole operation technology, well testing and production logging technology, production stimulation and potential tapping measures, natural gas production, downhole Operation and well workover, surface gathering and transportation and processing, etc., and the evaluation of production and gas testing are an indispensable and important part of well testing and production logging. The purpose of well logging is the last process of well completion operations. The main purpose is to By testing the stable gas output, the production capacity is determined and the production is carried out.

Before the gas well is exploited, there is a process of exploratory wells, and the reserves of the gas well are estimated to determine whether it has exploitation value. If there is value, then drilling and mining. When mining, the nozzle is driven into the ground, and the natural gas in the gas well is pressed up by pressure.

According to the gas well binomial infiltration equation and the analysis of the stable well test indication curve, as shown in Figure 1, it is the relationship curve between gas production and production pressure difference. The gas production increases with the increase of the production pressure difference. When the production exceeds its limit value, the increase of production does not show a linear proportional relationship, that is, the gas production per unit production pressure difference becomes smaller and smaller, which makes the energy utilization of the gas well and gas reservoir insufficient. Reasonable. At present, gas wells can be divided into four stages: rising, stable production, declining, and final stable production. The core factor that affects the stable production period of gas wells is the speed of gas production. The higher the gas extraction rate is, the shorter the stable production period is, and vice versa, the longer the stable production period is.

The speed of gas production is also related to the local gas demand. If the local gas demand is large and more gas is needed per unit time, the gas production speed needs to be increased; if the local gas demand is small, the It is necessary to reduce the speed of gas extraction, otherwise too much gas will be supplied, which will cause the pipeline to be overloaded, and the excess gas will be exhausted, which will cause waste.

Therefore, a test gas production process is required to evaluate the production of gas wells before formal gas production.

At present, the commonly used method is usually to test the production under back pressure, and the stable well test method can also be used. The common test process is mainly composed of gas production wellhead, blowout pipeline, gas-water separator, critical velocity flowmeter and combustion cylinder at the blowout outlet. . The flow calculation formula is as follows:

Among them, Q is the gas flow rate, m ³ /d; d is the diameter of the orifice plate, mm; P1 is the upstream pressure, MPa; T is the upstream temperature, K; q is the relative density of natural gas; Z is the natural gas deviation coefficient.

However, in the existing mining process, the original measurement equipment for the trial production and gas test needs to be removed after the trial production and gas test. The ground process only retains the Christmas tree, and then re-installs the production metering device. Due to the large volume of the test production and gas test equipment, the subsequent production measurement device will be affected if not removed; the cost is also high, and installing a set for each gas well will increase a lot of cost, so generally after a gas well is tested, the test production is removed The gas test equipment is then used to test other gas wells; however, after the production test gas test device is dismantled, there is no continuous measurement of the wellhead flow during subsequent formal production, which is not conducive to the evaluation of gas well production.

In the process of gas production test in gas wells, the mixture of gas, liquid and solid is often ejected from the wellhead. In order to determine the natural gas production of each gas well, or to analyze the changes of the gas storage structure in the formation for dynamic analysis, it is necessary to measure the mass flow of gas, liquid and solid in the pipeline online. Real-time online measurement of gas, liquid and solid mass flow in pipelines is very necessary. Only by calculating the specific flow, can the extraction volume be judged according to the speed and time of gas extraction, so as to adjust it according to the actual demand.

In addition, the follow-up production stimulation and production, gathering and transportation can only be solved in the gas production engineering design plan. With the development technology of modern natural gas production and the needs of people's life, the data for the evaluation of well testing and gas testing have gradually It cannot play a guiding role. The demand for natural gas in people's life has changes in the use cycle. After the weather is exploited, it can no longer meet the demand after entering the gathering and transportation station and then to the gas storage to the people's life. The regionalization of natural gas has become obvious. It will be the future goal to ensure the use of large quantities by the people, and the requirements for gas test evaluation will also increase. Under different pressure conditions, the output of gas wells will be an important part of the gas production project of gas wells.

SUMMARY OF THE INVENTION

In view of the deficiencies in the prior art, the purpose of the present invention is to provide an oil and gas wellhead production measurement device and a production capacity evaluation method, which can scientifically evaluate the gas production test capability of a production test well.

To achieve the above object, the present invention provides the following technical solutions: a method for evaluating the productivity of oil and gas wells, comprising the following steps:

S1. Extract the tested medium from the gas tree of the test well;

S2. Control the medium to flow through the throttling element. The multi-parameter sensor on the throttling element measures the differential pressure, temperature and pressure of the medium, and calculates the total mass of the medium passing through the unit time;

S3. When the medium passes through the throat section of the throttling element, the optical quantum phase splitter installed on the throttling element measures the composition ratio of each phase of the medium, and calculates the phase fraction of the gas phase, the liquid phase and the solid phase in the medium. phase fraction;

S4. Calculate the gas mass, liquid mass and solid mass passing through unit time in combination with the embedded adaptive flow model;

S5. Continuously upload the mass flow data of each phase of the medium to the computer, and the computer evaluates the productivity of the oil and gas well according to the data statistics.

Through the above technical solution, the natural gas from gas well production to gas test, relying on the production evaluation device at the first position of the test production wellhead, real-time online measurement of the gas production curve of the test production well, and mathematical fitting through time accumulation, can The scientific evaluation of the production capacity of test wells to achieve production.

Preferably, the medium is thoroughly mixed by a static mixer before entering the throttling element.

Through the above technical solution, the static mixer can use the mixing unit fixed in the pipe to change the flow state of the fluid in the pipe, so as to achieve the purpose of good dispersion and sufficient mixing between different fluids. Through the static mixer at the front end, the high-pressure, high-velocity measured medium changes its flow state in the tube, so as to achieve the purpose of good dispersion and full mixing between different fluids, so that the solid, liquid, and gaseous media are fully mixed, and subsequent measurement The results are more accurate.

Preferably, the throat section of the throttling element is treated with a high temperature and high pressure process.

Through the above technical scheme, the medium can be guaranteed not to leak when used in the production test well environment.

Preferably, the method for evaluating the productivity of oil and gas wells according to claim 1 is characterized in that: in the step S2, the formula for calculating the total mass of the medium passing through the unit time is as follows:

Among them, Q _m is the mass flow rate of the medium, in kg/s;

ΔP is the pressure difference, in Pa;

ρ _mix is the mixing density of the multiphase medium, in kg/m ³ ;

K is the conventional coefficient of the throttle element.

Preferably, in the step S3, the optical quantum phase splitter measures the composition ratio of each phase of the medium passing through, and the calculation steps are as follows:

m _g +m ₁ +m _s =m (3)

Mixing density of a multiphase flow across the measured cross section:

ρ _mix =(m _g +m ₁ +m _s )/v

The following system of equations can be listed:

GMF+LMF+SMF=1 (9)

ρ _mix = m/v (11)

Based on the above formula, the gas phase mass fraction GMF, the liquid phase mass fraction LMF, and the solid mass fraction SMF of the medium can be calculated;

in,

介质单位质量上的衰减系数，其为可标定量，kg^-1；

Attenuation coefficient per unit mass of medium, which is a calibratable quantity, kg ^-1 ;

N ₀ : the initial count value of photons, which is a calibratable quantity;

Nx: the actual count value of the light quantum after passing through the multiphase fluid medium, which is the measured value;

m: mass, kg;

t: time, s;

v: volume, m ³ ;

Q _m : mass flow, kg/s;

m=Q _m ^* t, when t=1s, m and Q _m have the same value;

ρ: density, kg/m ³ ;

ρ _mix =(m _g +m ₁ +m _s )/v, when v=1m ³ , ρ _mix has the same value as m _g +m ₁ +m _a ;

ΔP: differential pressure, Pa, real-time measurement

Q _mg : gas mass flow, kg/s

Q _ml : liquid phase mass flow, kg/s

Q _ms : solid phase mass flow, kg/s

GMF: gas phase mass fraction, the ratio of gas mass to total mass in a multiphase mixed fluid, dimensionless

LMF: liquid phase mass fraction ratio, the ratio of liquid phase mass to total mass in a multiphase mixed fluid, dimensionless

SMF: solid mass phase fraction, the ratio of solid mass to total mass in a multiphase mixed fluid, dimensionless

ρ _mix : mixed density of multiple phases, kg/m ³

Subscript:

h: high energy photon

I: low energy photons

g: gas phase

I: liquid phase

s: solid phase

m: Mass based.

Preferably, in the step S4, according to the calculated phase fractions GMF, LMF, SMF of each phase of the medium, and the total mass flow Q _m , calculate the mass of the gas phase, the mass of the liquid phase and the mass of the solid phase passing through the unit time, and the formula is as follows :

Q _mg = Q _m *GMF

Q _ml =Q _m *LMF

Q _ms =Q _m *SMF

The mass of each phase in the medium can be calculated based on the time the medium flows through.

The invention also provides an oil and gas wellhead production measuring device, comprising a throttle element, a multi-parameter sensor and an optical quantum phase splitter installed on the throttle element, and a data acquisition unit respectively communicatively connected to the multi-parameter sensor and the optical quantum phase splitter , and the central processing unit communicated with the data acquisition unit.

The throttling element is used to connect the gas well, and the natural gas enters the throttling element after being pressed out of the gas well; the multi-parameter sensor is a new type of variable pressure transmitter, a temperature transmitter, a pressure transmitter and a flow totalizer. It can display working pressure, temperature, instantaneous and cumulative flow, and can perform automatic temperature and pressure compensation for gas and steam, realizing the function of directly displaying standard flow and mass flow on site; The mass flow rate of gas, liquid and solid contained in the medium of the throttling element; the data acquisition unit is used to collect the data measured by the multi-parameter sensor and the optical quantum phase splitter; the central processor is used to summarize and record the data and perform statistical evaluation.

Through the above technical solution, the measured medium is drawn out from the gas tree of the test production well. Through the throttling element and the multi-parameter sensor, the total mass passing through the unit time can be calculated, and the multi-phase optical quantum phase splitter is used to measure the passage of the multi-phase fluid. According to the pressure and temperature measured by the multi-parameter sensor, the volume of gas and the volume flow of liquid can be calculated to realize the test production. The real-time continuous online measurement of gas, liquid and solid in the gas well product during the gas test process can make a fitting evaluation of the production conditions of the test well in the whole production life cycle, and scientifically evaluate the production capacity of the gas well.

The whole set of measuring equipment is small in size and low in cost. It does not need to be dismantled after the test is completed. From trial production and gas test to normal production process, it can be directly completed with a set of processes, which can also ensure continuous measurement of gas well production during subsequent production.

Preferably, the inlet end of the throttle element is provided with a static mixer, one end of the static mixer is connected to the throttle element, and the other end is connected to the gas wellhead.

Through the above technical solution, the static mixer can use the mixing unit fixed in the pipe to change the flow state of the fluid in the pipe, so as to achieve the purpose of good dispersion and sufficient mixing between different fluids. Through the static mixer at the front end, the high-pressure, high-velocity measured medium changes its flow state in the tube, so as to achieve the purpose of good dispersion and full mixing between different fluids, so that the solid, liquid, and gaseous media are fully mixed, and subsequent measurement The results are more accurate.

Preferably, the static mixer comprises a cylindrical pipe with both ends open, and the inner wall of the pipe is provided with a helical flow channel.

Through the above technical solution, the spiral flow channel can guide the flow direction of the medium, so that the medium flows spirally in the pipeline, and the purpose of good dispersion and sufficient mixing between different fluids can be achieved; the medium flowing out of the static mixer enters the throttling element, Measurements are more accurate.

Preferably, the inner diameter of the throttling element gradually decreases from both ends to the middle, and the part with the smallest inner diameter in the middle is the throat section; through holes are opened at the corresponding positions on both sides of the throat section, and the through holes are provided with high-pressure seals .

Since the natural gas extruded from the gas wellhead has a high pressure, sometimes it even reaches an ultra-high pressure state, and because the device of the present invention is small in size, the pressure bearing capacity is higher than that of the large-scale equipment in the prior art. The general throttling element has a limited ability to withstand pressure, especially in the throat section, the speed of the medium speed increases, the pressure increases, and the erosion of the throttling element is greater. Therefore, in order to relieve the pressure of the throttling element, a through hole is opened in the throat section of the throttling element, and a high-pressure seal is added in the through hole, and the seal can share the pressure, so that the pressure on the throttling element is reduced, avoiding the The flow element is damaged.

Preferably, the high-pressure sealing member includes a sealing head and an abutting member, the front end of the sealing head is inserted into the through hole, the rear end of the sealing head is fixed with the abutting member, and the abutting member is in abutment with the pipe wall outside the throat section .

Through the above technical solutions, the sealing head can ensure the sealing of the through hole and prevent the medium from overflowing along the through hole; the design of the abutting member makes no gap between the sealing member and the throttling element, which can better withstand the pressure and can improve the sealing effect.

Preferably, a sealing ring is provided between the abutting member and the pipe wall outside the throat section, and the sealing ring can enhance the sealing effect between the abutting member and the throttling element.

Preferably, the pipe wall outside the throat section is stepped, the shape of the abutting member is matched with the pipe wall, and a sealing ring is provided at each turning point of the stepped pipe wall.

Through the above technical solution, the pipe wall is set in a stepped shape, which increases the contact area between the abutting member and the pipe wall, so that the two can be better seamlessly matched, so that the abutting member is close to the pipe wall and ensures the bearing of the sealing member. Pressure capacity; the sealing ring at the turning point can further ensure the sealing effect.

Preferably, the end of the abutting member is provided with a pressing sleeve, the optical quantum phase splitter is arranged in the pressing sleeve, and the front end of the optical quantum phase splitter is aligned with the abutting member.

Through the above technical solutions, the compression sleeve can enhance the pressure bearing capacity of the seal; the front end of the optical quantum phase splitter is aligned with the abutment, and the medium flowing through the throat section can be detected.

To sum up, the present invention has the following beneficial effects: the measured medium is drawn out from the gas tree of the test production well, and through the throttling element and the multi-parameter sensor, the total mass passing through the unit time can be calculated, and the multi-phase optical quantum phase The sub-meter measures the phase fraction of the multiphase fluid, combined with the embedded adaptive flow model, the gas mass, liquid mass and solid mass passing through unit time can be calculated, and then the pressure and temperature measured by the multi-parameter sensor can be calculated. Calculate the volume of gas and volume flow of liquid, realize real-time continuous online measurement of gas, liquid and solid in gas well products in the process of gas test production and test production, and can perform fitting evaluation of production conditions of test production wells in the whole production life cycle , Scientific evaluation of gas well productivity.

Description of drawings

Fig. 1 is a relationship curve between gas production and production pressure difference in the prior art.

FIG. 2 is a schematic structural diagram of the present invention.

Figure 3 is a schematic diagram of the present invention for illustrating a static mixer.

FIG. 4 is an enlarged view of the seal portion of FIG. 3 .

Detailed ways

The present invention will be further described in detail below with reference to the accompanying drawings.

Example 1:

2-3, an oil and gas wellhead production measurement device includes a throttle element 1, a static mixer 6 installed at the inlet end of the throttle element 1, a high-pressure seal 5 installed at the throat section of the throttle element 1, The multi-parameter sensor 3 and the optical quantum phase splitter 2 installed on the throttling element 1, the data acquisition unit 4 communicatively connected to the multi-parameter sensor 3 and the optical quantum phase splitter 2 respectively, and the central processing unit communicatively connected to the data acquisition unit 4.

The medium to be tested is produced from the gas tree of the test production well, and passes through the static mixer 6 at the front end to change the flow state of the medium to be tested in the tube with high pressure and high flow rate, so as to achieve the purpose of good dispersion and sufficient mixing between different fluids , after the solid, liquid and gaseous media are fully mixed, the total mass passing through the unit time can be calculated through the throttling element 1 and the multi-parameter sensor 3. Combined with the built-in adaptive flow model, the gas mass, liquid mass and solid mass passing through unit time can be calculated, and then the volume of gas and liquid can be calculated according to the pressure and temperature measured by the multi-parameter sensor 3. The volume flow rate can realize the real-time continuous online measurement of gas, liquid and solid in the gas well products during the production and testing process. The whole set of measuring equipment is small in size and low in cost. It does not need to be dismantled after the test is completed. From trial production and gas test to normal production process, it can be directly completed with a set of processes, which can also ensure continuous measurement of gas well production during subsequent production.

In this embodiment, one end of the static mixer 6 is connected to the throttling element 1, and the other end is connected to the gas wellhead. The static mixer 6 includes a cylindrical pipe with both ends open, and the inner wall of the pipe is provided with a helical flow channel 61 .

The spiral flow channel 61 can guide the flow direction of the medium, so that the medium flows spirally in the pipeline, which can achieve the purpose of good dispersion and sufficient mixing between different fluids; the medium flowing out of the static mixer 6 enters the throttling element 1, and the measurement is more precise.

Referring to FIG. 4 , in this embodiment, the throttling element 1 is a Venturi tube, the inner diameter of the Venturi tube gradually decreases from both ends to the middle, and the part with the smallest inner diameter in the middle is the throat section 11 ; the two sides of the throat section 11 correspond to A through hole 12 is opened at the position of , and a high pressure seal 5 is arranged in the through hole 12 . The high-pressure seal 5 is located at the throat section 11 of the venturi, and can ensure that the medium does not leak when used in a well test environment.

Since the natural gas extruded from the gas wellhead has a high pressure, sometimes it even reaches an ultra-high pressure state, and because the device of the present invention is small in size, the pressure bearing capacity is higher than that of the large-scale equipment in the prior art. However, the general throttling element has a limited ability to withstand pressure, especially in the throat section 11, when the flow velocity of the medium increases and the pressure increases, the erosion of the throttling element 1 is greater. Therefore, in order to relieve the pressure of the throttling element, a through hole 12 is opened in the throat section 11 of the throttling element 1, and a high-pressure seal is added in the through hole 12. The seal 5 can share the pressure, so that the throttling element 1 bears the pressure. The pressure is reduced to avoid damage to the throttling element.

In this embodiment, the high-pressure sealing member 5 includes a sealing head 51 and an abutting member 52. The front end of the sealing head 51 is inserted into the through hole 12, the rear end of the sealing head 51 is fixed to the abutting member 52, and the abutting member 52 is connected to the throat. The pipe wall on the outside of the segment 11 abuts. The sealing head 51 can ensure the sealing of the through hole 12 and prevent the medium from overflowing along the through hole 12; the design of the abutting member 52 makes no gap between the sealing member 5 and the throttling element 1, which can better withstand pressure and can also Improve sealing effect.

A sealing ring 53 is further provided between the abutting member 52 and the pipe wall outside the throat section 11 , and the sealing ring 53 can enhance the sealing effect between the abutting member 52 and the throttling element.

In this embodiment, the pipe wall 13 outside the throat section 11 is stepped, the shape of the abutting member 52 is matched with the pipe wall 13 , and each turning point of the stepped pipe wall 13 is provided with a sealing ring 53 . The stepped tube wall 13 can increase the contact area between the abutting member 52 and the tube wall 13 , so that the two can be better seamlessly matched, so that the abutting member 52 is close to the tube wall 13 to ensure the pressure bearing of the sealing member 5 Capability; the sealing ring 53 at the turning point can further ensure the sealing effect.

In this embodiment, a pressing sleeve 54 is provided at the end of the abutting member 52 , the optical quantum phase splitter 2 is arranged in the pressing sleeve 54 , and the front end of the optical quantum phase splitting device 2 is aligned with the abutting member 52 . The compression sleeve 54 can enhance the pressure bearing capacity of the seal; the front end of the optical quantum phase splitter 2 is aligned with the abutment member 52 to detect the medium flowing through the throat section 11 . The optical quantum phase splitter 2 is a device for detecting the phase fraction of the fluid. The company has applied for a patent. For details, please refer to the patent document with the publication number CN209166558U, which will not be repeated here.

In this embodiment, the multi-parameter sensor 3 can detect data such as flow rate, differential pressure, temperature, and pressure of the throttling element 1 , and integrates various sensors into one, making the installation more convenient.

Example 2:

The present embodiment discloses a method for evaluating the productivity of oil and gas wells, comprising the following steps:

S1. Extract the tested medium from the gas tree of the test well;

S2. Control the medium to flow through the throttling element 1, and the multi-parameter sensor 3 on the throttling element 1 measures the differential pressure, temperature and pressure of the medium, and calculates the total mass of the medium passing through the unit time;

S3. When the medium passes through the throat section of the throttling element 1, the optical quantum phase splitter 2 installed on the throttling element 1 measures the composition ratio of each phase of the medium, and calculates the phase fraction of the gas phase and the phase fraction of the liquid phase in the medium. rate and phase fraction of the solid phase;

S4. Calculate the gas mass, liquid mass and solid mass passing through unit time in combination with the embedded adaptive flow model;

S5. Continuously upload the mass flow data of each phase of the medium to the computer, and the computer evaluates the productivity of the oil and gas well according to the data statistics.

From the production of natural gas to the gas test, relying on the production evaluation device at the first position of the test production wellhead, the gas production curve of the test production well is measured online in real time. Scientific assessment of gas production capacity to production.

Before the medium enters the throttling element 1 , it can be thoroughly mixed by the static mixer 6 . For the measured medium with high pressure and high flow rate, the flow state in the tube is changed to achieve the purpose of good dispersion and full mixing between different fluids, so that the solid, liquid and gaseous media are fully mixed, and the subsequent measurement results are more accurate.

In this embodiment, the throat section of the throttling element 1 is processed by a high temperature and high pressure process. It can ensure that the medium does not leak when used in the test production well environment.

In the above step S2, through the throttling element 1 and the multi-parameter sensor 3, the formula for calculating the total mass of the medium passing through the unit time is as follows:

Among them, Q _m is the mass flow rate of the medium, in kg/s;

ΔP is the pressure difference, in Pa;

ρ _mix is the mixing density of the multiphase medium, in kg/m ³ ;

K is the conventional coefficient of the throttle element 1 .

In step S3, the optical quantum phase splitter 2 measures the composition ratio of each phase of the medium passing through, and the calculation steps are as follows:

m _g +m ₁ +m _s =m (3)

Mixing density of a multiphase flow across the measured cross section:

ρ _mix =(m _g +m ₁ +m _s )/v

The following system of equations can be listed:

GMF+LMF+SMF=1 (9)

ρ _mix = m/v (11)

Based on the above formula, the gas phase mass fraction GMF, the liquid phase mass fraction LMF, and the solid mass fraction SMF of the medium can be calculated;

in,

介质单位质量上的衰减系数，其为可标定量，kg^-1；

Attenuation coefficient per unit mass of medium, which is a calibratable quantity, kg ^-1 ;

N ₀ : the initial count value of photons, which is a calibratable quantity;

Nx: the actual count value of the light quantum after passing through the multiphase fluid medium, which is the measured value;

m: mass, kg;

t: time, s;

v: volume, m ³ ;

Q _m : mass flow, kg/s;

m=Q _m ^* t, when t=1s, m and Q _m have the same value;

ρ: density, kg/m ³ ;

ρ _mix =(m _g +m ₁ +m _s )/v, when v=1m ³ , ρ _mix has the same value as m _g +m ₁ +m ₃ ;

ΔP: differential pressure, Pa, real-time measurement

Q _mg : gas mass flow, kg/s

Q _ml : liquid phase mass flow, kg/s

Q _ms : solid phase mass flow, kg/s

GMF: gas phase mass fraction, the ratio of gas mass to total mass in a multiphase mixed fluid, dimensionless

LMF: liquid phase mass fraction ratio, the ratio of liquid phase mass to total mass in a multiphase mixed fluid, dimensionless

SMF: solid mass phase fraction, the ratio of solid mass to total mass in a multiphase mixed fluid, dimensionless

ρ _mix : mixed density of multiple phases, kg/m ³

Subscript:

h: high energy photon

I: low energy photons

g: gas phase

I: liquid phase

s: solid phase

m: Mass based.

In step S4, according to the calculated phase fractions GMF, LMF, SMF of each phase of the medium, and the total mass flow Q _m , calculate the mass of the gas phase, the mass of the liquid phase and the mass of the solid phase passing through the unit time, and the formula is as follows:

Q _mg = Q _m *GMF

Q _ml =Q _m *LMF

Q _ms =Q _m *SMF

According to the passage time of the medium, the mass of each phase in the medium can be calculated, and then according to the pressure and temperature measured by the multi-parameter sensor 3, the volume of gas and the volumetric flow of liquid can be calculated, so as to realize the detection of gas well products in the process of test production and test. The real-time continuous online measurement of gas, liquid and solid in the medium can be used to fit and evaluate the production conditions of test wells in the whole life cycle of production, and scientifically evaluate the production capacity of gas wells.

This specific embodiment is only an explanation of the present invention, and it does not limit the present invention. Those skilled in the art can make modifications without creative contribution to the present embodiment as required after reading this specification, but as long as the rights of the present invention are used All claims are protected by patent law.

Claims (10)

1. A productivity assessment method for oil and gas wells is characterized by comprising the following steps: the method comprises the following steps:

s1, extracting the tested medium from the gas extraction tree of the pilot production well;

s2, controlling the medium to flow through the throttling element (1), measuring the differential pressure, the temperature and the pressure of the medium by the multi-parameter sensor (3) on the throttling element (1), and calculating the total mass of the medium passing through in unit time;

s3, when the medium passes through the throat section (11) of the throttling element (1), the light quantum phase splitter (2) arranged on the throttling element (1) measures the component proportion of each phase of the medium, and calculates the phase fraction of a gas phase, the phase fraction of a liquid phase and the phase fraction of a solid phase in the medium;

s4, calculating the mass of a gas phase, the mass of a liquid phase and the mass of a solid phase passing through the unit time by combining an embedded self-adaptive flow model;

and S5, continuously uploading mass flow data of each phase of the medium to a computer, and generating a gas production curve for the gas production according to data statistics by the computer to evaluate the production capacity of the oil and gas well.

2. The method of evaluating the productivity of an oil and gas well according to claim 1, wherein: the medium is thoroughly mixed by a static mixer (6) before it enters the throttling element (1).

3. The method of evaluating the productivity of an oil and gas well according to claim 1, wherein: the throat section (11) of the throttling element (1) is treated by a high-temperature and high-pressure resistant process.

4. The method of evaluating the productivity of an oil and gas well according to claim 1, wherein: in step S2, the total mass formula of the medium passing through per unit time is calculated by the throttling element (1) and the multi-parameter sensor (3) as follows:

wherein Q is_mIs the mass flow of the medium, Δ P is the pressure difference, ρ_mixIs the mixed density of the multi-phase medium;

k is the conventional coefficient of the throttling element (1).

5. The method of evaluating the productivity of an oil and gas well according to claim 4, wherein: in the step S3, the optical quantum phase splitter (2) measures the component ratio of each phase of the medium passing through, and the calculation steps are as follows:

m_g+m₁+m₃＝m (3)

mixed density of multiphase flow over the measured cross section:

ρ_mix＝(m_g+m₁+m₃)/v

the following set of equations may be listed:

GMF+LMF+SMF＝1 (9)

ρ_mix＝m/v (11)

based on the formula, the gas phase mass phase fraction GMF, the liquid phase mass phase fraction LMF and the solid phase mass phase fraction SMF of the medium can be calculated;

wherein,

attenuation coefficient per unit mass of medium, which is a calibratable amount, kg^-1；

N₀: an initial count of photons, which is a calibratable amount;

nx: the actual count value of the light quantum after passing through the multi-phase fluid medium is an actual measurement value;

m: mass, kg;

t: time, s;

v: volume, m³；

Q_m: mass flow, kg/s;

m＝Q_m＊ t, when t is 1s, m and Q_mThe numerical values are the same;

ρ: density, kg/m³；

ρ_mix＝(m_g+m₁+m₃) V, when v is 1m³，ρ_mixAnd m_g+m₁+m₃The numerical values are the same;

Δ P: pressure difference, Pa, real-time measurement;

Q_mg: gas phase mass flow, kg/s;

Q_ml: mass flow of liquid phase, kg/s;

Q_ms: solid phase mass flow, kg/s;

GMF: mass-phase fraction of gas phase, mass-to-total mass ratio of gas phase in the multiphase mixed fluid, dimensionless;

LMF: mass-phase fraction of liquid phase, ratio of mass of liquid phase to total mass in the multiphase mixed fluid, dimensionless;

SMF: the mass-phase fraction of the solid phase, the ratio of the mass of the solid phase to the total mass in the multiphase mixed fluid, and no dimension;

ρ_mix: mixed density of phases, kg/m³；

Subscripts:

h: a high energy photon;

i: a low energy photon of light;

g: a gas phase;

i: a liquid phase;

s: solid phase;

m: based on the quality.

6. The method of evaluating the productivity of an oil and gas well according to claim 5, wherein: in step S4, the GMF, LMF, SMF and total mass flow Q are calculated according to the phase fractions of the media_mAnd calculating the mass of the gas phase, the mass of the liquid phase and the mass of the solid phase passing through the unit time according to the following formula:

Q_mg＝Q_m＊GMF

Q_ml＝Q_m＊LMF

Q_ms＝Q_m＊SMF

the mass of each phase in the medium can be calculated according to the time of flowing of the medium.

7. The utility model provides an oil gas wellhead production measuring device which characterized in that: the device comprises a throttling element (1), a multi-parameter sensor (3) and a light quantum phase analyzer (2) which are arranged on the throttling element (1), a data acquisition unit (4) which is respectively in communication connection with the multi-parameter sensor (3) and the light quantum phase analyzer (2), and a central processing unit which is in communication connection with the data acquisition unit (4).

8. An oil and gas wellhead production measurement device as claimed in claim 7, wherein: the inlet end of the throttling element (1) is provided with a static mixer (6), one end of the static mixer (6) is connected with the throttling element (1), and the other end of the static mixer is connected with a gas well head.

9. An oil and gas wellhead production measurement device as claimed in claim 7, wherein: the inner diameter of the throttling element (1) is gradually reduced from two ends to the middle, and the part with the smallest middle inner diameter is a throat part (11); through holes (12) are formed in the corresponding positions of the two sides of the throat part section (11), and high-pressure sealing pieces (5) are arranged in the through holes (12).

10. An oil and gas wellhead production measurement device as claimed in claim 9, wherein: the high-pressure sealing element (5) comprises a sealing head (51) and an abutting piece (52), the front end of the sealing head (51) is inserted into the through hole (12), the rear end of the sealing head (51) is fixed with the abutting piece (52), and the abutting piece (52) abuts against the pipe wall on the outer side of the throat section (11).

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