Metering device for oil well yield

Abstract

The invention relates to the technical field of oil well yield metering, in particular to an oil well yield metering device which comprises a hollow separation tank and a control unit, a liquid inlet is formed in the left side of the upper portion of the separation tank, a liquid inlet pipe is fixedly installed in the liquid inlet, a liquid outlet is formed in the middle of the lower end of the separation tank, and a liquid drainage pipe is fixedly installed in the liquid outlet. The device is reasonable and compact in structure and convenient to use, gas-liquid separation and mixing of an oil well gas-liquid mixture are achieved through the separation tank with the upper cavity and the lower cavity, and the gas production rate detection part, the liquid production rate and moisture estimation part, the liquid production rate accurate measurement part and the control unit are arranged between the upper cavity and the lower cavity. The water content in the oil well output liquid is measured, the gas production amount and the oil well liquid production amount are calculated, the automation degree is high, the manual participation degree and the labor intensity of detection personnel are greatly reduced, the device is good in compatibility with an existing automatic system of an oil field, the detection cost is low, the metering precision is stable, no hole shrinkage exists on a metering pipeline, and potential safety hazards are avoided.

Description

Technical Field

[0001] The invention relates to the technical field of oil well production metering, in particular to an oil well production metering device. Background Art

[0002] The pumping well system mainly consists of three parts: the pumping unit, the sucker rod and the pump. The pumping unit suspension point reciprocates under the drive of the motor, and transmits the ground power to the downhole pump through the sucker rod, driving the downhole plunger pump to pump oil. The fixed valve is located on the upper part of the pump barrel, and the floating valve is located inside the plunger. During the up and down stroke, as the floating valve and the fixed valve are opened and closed, the crude oil is lifted to the ground. The production measurement of oil wells is an important task in oilfield production. Accurate and timely measurement of oil well production is of great guiding significance for understanding the status of oil wells, reservoir dynamics, and formulating production plans.

[0003] In the process of oil extraction, ground oil extraction equipment, such as pumping units, extract a mixture of oil, gas and water from the formation and transport it through ground pipelines, such as to oil storage tanks. In order to ensure the safety of transportation, it is necessary to measure various parameters, such as the pressure, temperature and flow rate of the mixed liquid output at the wellhead; in order to understand the output of the oil well, it is necessary to install a metering device for measurement.

[0004] In the prior art, corresponding parameters are generally measured by installing various instruments. For example, a pressure sensor is connected to a hole in the ground pipeline to measure the pressure of the liquid in the ground pipeline on the pipeline; a thermocouple or a surface-mount temperature sensor is used to obtain temperature data; a flow meter is used to measure the flow in the ground pipeline, etc.

[0005] When measuring production, vortex flowmeters, ultrasonic flowmeters, metal float flowmeters and other devices are usually installed in the pipeline. The measured flow rate is converted into the oil well's liquid production; or an oil well weighing metering device is used to calculate the oil well's liquid production using a weighing sensor and the number of bucket flips; or an oil well dynamometer diagram is collected and the oil well's liquid production is calculated based on the dynamometer diagram.

[0006] Therefore, the oil well production metering devices commonly used in existing oil fields have the following shortcomings in actual use: low degree of automation and high labor intensity for detection personnel; high manual participation and low compatibility with oil field automation systems; high cost of mass flow meter detection, safety hazards caused by reduced diameter of metering pipelines, and unstable metering accuracy. Summary of the invention

[0007] The present invention provides an oil well production metering device, which overcomes the deficiencies of the above-mentioned prior art and can effectively solve the problems of low automation, unstable accuracy, high detection cost and potential safety hazards in the actual use of the oil well production metering devices commonly used in existing oil fields.

[0008] The technical solution of the present invention is achieved through the following measures: a metering device for oil well production, including a hollow separation tank and a control unit, a liquid inlet is provided on the left side of the upper part of the separation tank, a liquid inlet pipe is fixedly installed in the liquid inlet, a liquid outlet is provided in the middle part of the lower end of the separation tank, a liquid discharge pipe is fixedly installed in the liquid outlet; a partition is fixedly installed on the inner side of the middle part of the separation tank, the partition separates the separation tank into an upper cavity and a lower cavity, a gas production detection part capable of detecting the gas production of the oil well is provided between the middle part of the upper end of the upper cavity and the right side of the upper part of the lower cavity, a liquid production and moisture estimation part capable of preliminarily estimating the liquid production of the oil well is provided between the left side of the middle part of the upper cavity and the left side of the upper part of the lower cavity, and the control unit is electrically connected to the gas production detection part and the liquid production and moisture estimation part respectively.

[0009] The following are further optimizations and / or improvements to the above technical solutions: The above-mentioned liquid production and moisture estimation part may include an oil inlet pipe, a water content analyzer, an inverted U-shaped siphon and a liquid production estimation unit. An oil inlet is provided on the left side of the separation tank corresponding to the upper position of the lower cavity, and an oil inlet pipe with a blind end on the left end is fixedly installed in the oil inlet. A water content analyzer is provided on the left end of the oil inlet pipe, and a liquid through hole communicating with the inside and outside is provided on the upper left side of the oil inlet pipe. An oil outlet is provided on the left side of the separation tank corresponding to the middle position of the upper cavity, and an inverted U-shaped siphon with the outer side of the lower left end and the inner side of the liquid through hole fixedly installed in the oil outlet, the lower right end of the inverted U-shaped siphon is located in the upper cavity, and a liquid production estimation unit capable of detecting the number and duration of siphoning phenomena occurring per unit time is provided on the upper left part of the inverted U-shaped siphon, and the water content analyzer and the liquid production estimation unit are electrically connected to the control unit respectively.

[0010] The above-mentioned liquid production estimation unit may be a capacitive liquid level sensor.

[0011] The above-mentioned gas production detection part may include a connecting pipe and a natural gas flow meter. A gas outlet is provided in the middle of the upper end of the separation tank, and an air inlet is provided on the right side of the separation tank corresponding to the upper position of the lower cavity. A connecting pipe is fixedly installed between the air inlet and the gas outlet, and a natural gas flow meter is provided on the connecting pipe. The natural gas flow meter is electrically connected to the control unit.

[0012] A liquid production precision measuring part capable of accurately detecting the liquid production may be provided between the middle of the above-mentioned separation tank and the upper part of the connecting pipe. The liquid production precision measuring part may include a liquid level connecting vessel, a detection tube, a first liquid level sensor and a second liquid level sensor. A measuring hole penetrating from top to bottom is provided in the middle of the partition. The liquid level connecting vessel is fixedly installed in the measuring hole. A detection hole penetrating from inside to outside is provided on the separation tank corresponding to the lower end of the liquid level connecting vessel. A detection tube is fixedly installed at the lower end of the liquid level connecting vessel. The other end of the detection tube passes through the detection hole and is connected to the lower side of the upper part of the connecting pipe and is fixedly installed together. The detection tubes corresponding to the lower right end of the inverted U-shaped siphon and the upper bending part thereof are respectively provided with a first liquid level sensor and a second liquid level sensor. The first liquid level sensor and the second liquid level sensor are respectively electrically connected to the control unit.

[0013] The above-mentioned liquid production precision measurement part can also include a water injection pipe and a water injection control valve. A water injection port that runs through the inside and outside is provided on the upper part of the detection tube. An L-shaped water injection pipe with a funnel-shaped upper end is fixedly installed in the water injection port, and a water injection control valve is provided on the horizontal part of the water injection pipe.

[0014] The right end of the liquid outlet pipe and the right end of the oil inlet pipe can be bent downward into an arc shape.

[0015] The liquid inlet pipe may be an expanded pipe with a shape of being thin on the left and thick on the right.

[0016] The invention has a reasonable and compact structure and is easy to use. It first reduces the pressure of the gas-liquid mixture and performs preliminary gas-liquid separation through the expansion pipe, and then further separates the gas-liquid mixture through the upper cavity. In the process of the separated natural gas flowing from the upper cavity to the lower cavity through the connecting pipe, the natural gas flow meter can accurately measure the flow rate of the natural gas per unit time. In the process of the separated oil-water mixture flowing from the upper cavity to the lower cavity through the inverted U-shaped siphon and the oil inlet pipe, the water content and flow rate of the oil-water mixture can be estimated and measured by the water content analyzer and the liquid production estimation unit respectively. In addition, the oil-water mixture can be further accurately measured by the first liquid level sensor and the second liquid level sensor. The control unit can directly obtain or automatically calculate the water content, liquid production and gas production of the oil well through the above-mentioned measurement data. The control unit has a high degree of automation, can also realize remote transmission and control through the network, has good compatibility with the existing automation system of the oil field, greatly reduces the degree of manual participation and the labor intensity of the detection personnel, has low detection cost, stable measurement accuracy, no shrinkage on the measurement pipeline, and avoids safety hazards. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Attached Figure 1 It is a schematic diagram of the front cross-sectional structure of embodiments 1-8 of the present invention.

[0018] The codes in the accompanying drawings are: 1 is a separation tank, 2 is a liquid inlet pipe, 3 is a liquid discharge pipe, 4 is a partition, 5 is an upper cavity, 6 is a lower cavity, 7 is an oil inlet pipe, 8 is a water content analyzer, 9 is an inverted U-shaped siphon, 10 is a liquid production estimation unit, 11 is a connecting pipe, 12 is a natural gas flow meter, 13 is a liquid level communicating vessel, 14 is a detection tube, 15 is a first liquid level sensor, 16 is a second liquid level sensor, 17 is a water injection pipe, and 18 is a water injection control valve. DETAILED DESCRIPTION

[0019] The present invention is not limited by the following embodiments, and specific implementation methods can be determined based on the technical solution of the present invention and actual conditions.

[0020] In the present invention, for the convenience of description, the relative position relationship of each component is described according to the attached Figure 1 The positional relationships such as front, back, top, bottom, left, and right are described according to the layout directions of the drawings in the specification.

[0021] The present invention will be further described below in conjunction with embodiments and drawings: Embodiment 1: As attached Figure 1 As shown, the metering device for the oil well production includes a hollow separation tank 1 and a control unit. A liquid inlet is provided on the left upper part of the separation tank 1, and a liquid inlet pipe 2 is fixedly installed in the liquid inlet. A liquid outlet is provided in the middle of the lower end of the separation tank 1, and a liquid discharge pipe 3 is fixedly installed in the liquid outlet; a partition 4 is fixedly installed on the inner side of the middle part of the separation tank 1, and the partition 4 divides the separation tank 1 into an upper cavity 5 and a lower cavity 6. A gas production detection part capable of detecting the gas production of the oil well is provided between the middle part of the upper end of the upper cavity 5 and the right upper part of the lower cavity 6, and a liquid production and water content estimation part capable of preliminarily estimating the liquid production of the oil well is provided between the left middle part of the upper cavity 5 and the left upper part of the lower cavity 6. The control unit is electrically connected to the gas production detection part and the liquid production and water content estimation part, respectively.

[0022] By such arrangement, the gas-liquid mixture produced by the oil well flows into the upper cavity 5 through the liquid inlet pipe 2 for gas-liquid separation, and the separated gas flows into the lower cavity 6 from the middle of the upper end of the upper cavity 5 through the gas production detection unit. The gas production detection unit uploads the measured natural gas flow value to the control unit, and the control unit can calculate the natural gas production of the oil well according to the instantaneous flow value or the cumulative flow value, and can further draw a natural gas production map of the oil well through the program; in the process of the separated oil-water mixture flowing from the upper cavity 5 to the lower cavity 6 through the liquid production and water estimation unit, the liquid production and water estimation unit uploads the measured water content in the oil-water mixture and the flow value of the oil-water mixture per unit time to the control unit, and the control unit can preliminarily estimate the liquid production of the oil well through the flow value of the oil-water mixture, and can further draw a water content and liquid production map of the oil well output liquid, and can also cooperate with a memory, a printer and a network to store, print, remotely transmit and control the above measurement results; the gas-liquid mixture reunited in the lower cavity 6 can be transported to a designated location through the discharge pipe 3.

[0023] According to the requirements, the separation tank 1 with the upper and lower cavities can also be realized by two tank bodies; the gas production detection part can be realized by a natural gas flow meter or a natural gas flow meter installed on the pipeline; the liquid production and moisture estimation part can be realized by an oil water content analyzer or an online crude oil water content analyzer or an oil product water content sensor or an online crude oil water content detector installed on the pipeline, as well as a liquid flow sensor or a liquid level sensor or a float type liquid level transmitter; the control unit can be realized by a PLC or a single chip microcomputer or a computer in the existing known technology, or by a distributed computer control unit (DCS); in addition, the present invention can also set a temperature sensor inside / outside the upper cavity 5 to monitor the temperature of the gas-liquid mixture.

[0024] The present invention has a reasonable and compact structure and is easy to use. It realizes gas-liquid separation and mixing of the gas-liquid mixture of the oil well through a separation tank 1 with upper and lower cavities. It realizes the measurement of gas production and water content in the produced fluid of the oil well and a preliminary estimation of the liquid production of the oil well through a gas production detection part, a liquid production and water content estimation part and a control unit arranged between the upper and lower cavities. It has a high degree of automation, greatly reduces the degree of manual participation and the labor intensity of detection personnel, has good compatibility with the existing automation system of the oil field, has low detection cost, stable metering accuracy, no shrinkage on the metering pipeline, and avoids safety hazards.

[0025] The above-mentioned oil well production metering device can be further optimized and / or improved according to actual needs: Embodiment 2: As attached Figure 1As shown, the liquid production and moisture estimation part includes an oil inlet pipe 7, a water content analyzer 8, an inverted U-shaped siphon 9 and a liquid production estimation unit 10. An oil inlet is provided on the left side of the separation tank 1 corresponding to the upper position of the lower cavity 6, and an oil inlet pipe 7 with a blind end on the left end is fixedly installed in the oil inlet. A water content analyzer 8 is provided on the left end of the oil inlet pipe 7, and a liquid through hole communicating with the inside and outside is provided on the upper left side of the oil inlet pipe 7. An oil outlet is provided on the left side of the separation tank 1 corresponding to the middle position of the upper cavity 5, and an inverted U-shaped siphon 9 with the outer side of the lower left end and the inner side of the liquid through hole fixedly installed in the oil outlet, the lower right end of the inverted U-shaped siphon 9 is located in the upper cavity 5, and a liquid production estimation unit 10 capable of detecting the number and duration of siphon phenomena occurring per unit time is provided on the upper left part of the inverted U-shaped siphon 9, and the water content analyzer 8 and the liquid production estimation unit 10 are electrically connected to the control unit respectively.

[0026] During use, after the gas-liquid mixture produced by the oil well is separated, the oil-water mixture gathers at the bottom of the upper cavity 5. When the liquid level of the oil-water mixture in the upper cavity 5 is higher than the curved part at the upper end of the inverted U-shaped siphon tube 9, a siphon phenomenon will occur. The siphon effect can make the oil-water mixture in the upper cavity 5 flow into the lower cavity 6 through the outlet at the lower left end of the inverted U-shaped siphon tube 9 and the oil inlet pipe 7. When the liquid level of the oil-water mixture in the upper cavity 5 is lower than the inlet at the lower right end of the inverted U-shaped siphon tube 9, the siphon phenomenon in the inverted U-shaped siphon tube 9 Stop, that is, the oil-water mixture stops flowing in the inverted U-shaped siphon 9, and the oil-water mixture gathers at the bottom of the upper cavity 5 again until the siphon phenomenon occurs again, and the cycle repeats; during this process, the liquid production estimation unit 10 will measure the number and duration of the siphon phenomenon in the inverted U-shaped siphon 9 per unit time, and the control unit can preliminarily estimate the liquid production of the oil well through the above-mentioned measured values, and the water content analyzer 8 can obtain the water content of the oil well output fluid by measuring the water content of the oil-water mixture in the inverted U-shaped siphon 9. According to the needs, the oil inlet pipe 7 with a blind end at the left end in this embodiment can be realized by a J-shaped pipe in the prior art and a blind flange connected to the left end of the J-shaped pipe; the liquid production estimation unit 10 can be realized by a float type liquid level sensor or a float type liquid level sensor or a static pressure type liquid level sensor in the prior art, and the water content analyzer 8 can be realized by the Universal IV UCM series online water content analyzer in oil of DREXELBROOK in the prior art.

[0027] Embodiment 3: As attached Figure 1 As shown, the liquid production estimation unit 10 is a capacitive liquid level sensor. This configuration is mainly because the capacitive liquid level sensor has the advantages of large dynamic range, fast response speed, small zero drift, simple structure and strong adaptability.

[0028] Embodiment 4: As attached Figure 1As shown, the gas production detection unit includes a connecting pipe 11 and a natural gas flow meter 12. A gas outlet is provided in the middle of the upper end of the separation tank 1, and an air inlet is provided on the right side of the separation tank 1 corresponding to the upper position of the lower cavity 6. A connecting pipe 11 is fixedly installed between the air inlet and the air outlet, and a natural gas flow meter 12 is provided on the connecting pipe 11. The natural gas flow meter 12 is electrically connected to the control unit.

[0029] By such an arrangement, after the gas-liquid mixture of the oil well is separated into gas and liquid in the upper cavity 5, the natural gas floats up and escapes from the upper end of the separation tank 1, and flows into the lower cavity 6 from the connecting pipe 11. The flow of natural gas flowing through the connecting pipe 11 can be measured by the natural gas flow meter 12. The natural gas flow meter 12 in the prior art can usually accurately and stably measure the instantaneous flow value and the cumulative flow value of the natural gas. The control unit can quickly and accurately calculate the gas production of the oil well according to the natural gas flow value per unit time. The natural gas flow meter 12 can be realized by a digital display natural gas turbine flow sensor in the prior art as needed.

[0030] Embodiment 5: As attached Figure 1 As shown, a liquid production precision measuring part capable of accurately detecting the liquid production is provided between the middle of the separation tank 1 and the upper part of the connecting pipe 11, the liquid production precision measuring part comprises a liquid level communicating vessel 12, a detection tube 14, a first liquid level sensor 15 and a second liquid level sensor 16, a measuring hole which passes through from top to bottom is provided in the middle of the partition 4, the liquid level communicating vessel 12 is fixedly installed in the measuring hole, a detection hole which passes through from inside to outside is provided on the separation tank 1 at the position corresponding to the lower end of the liquid level communicating vessel 12, a detection tube 14 is fixedly installed at the lower end of the liquid level communicating vessel 12, the other end of the detection tube 14 passes through the detection hole and is connected with the lower side of the upper part of the connecting pipe 11 and is fixedly installed together, a first liquid level sensor 15 and a second liquid level sensor 16 are respectively provided on the detection tube 14 at the right lower end and the upper bending part of the inverted U-shaped siphon tube 9, and the first liquid level sensor 15 and the second liquid level sensor 16 are respectively electrically connected to the control unit.

[0031] During use, the oil-water mixture at the bottom of the upper cavity 5 can enter the detection tube 14 through the liquid level communication vessel 12. When the first liquid level sensor 15 detects the liquid level, the liquid level of the oil-water mixture in the upper cavity 5 is just flush with the inlet position of the lower right end of the inverted U-shaped siphon 9. When the second liquid level sensor 16 detects the liquid level, the liquid level of the oil-water mixture just reaches the outlet position of the upper end bend of the inverted U-shaped siphon 9 and a siphon phenomenon occurs. The control unit can accurately calculate the liquid production of the oil well according to the time difference between the first liquid level sensor 15 and the second liquid level sensor 16 detecting the liquid level data, the inner cavity volume of the separation tank 1 corresponding to the lower right end of the inverted U-shaped siphon 9, and the inner cavity volume of the separation tank 1 corresponding to the position between the lower right end and the bend of the inverted U-shaped siphon 9. According to the needs, the first liquid level sensor 15 and the second liquid level sensor 16 can be realized by the contact liquid level sensor or the non-contact liquid level sensor in the prior art; the detection tube 14 and the detection hole can be directly fixed together, or fixedly connected together through a pipe joint.

[0032] Embodiment 6: As attached Figure 1 As shown, the liquid production precision measurement unit also includes a water injection pipe 17 and a water injection control valve 18. A water injection port that passes through the inside and outside is provided on the upper part of the detection tube 14. An L-shaped water injection pipe 17 with a funnel-shaped upper end is fixedly installed in the water injection port, and a water injection control valve 18 is provided on the horizontal part of the water injection pipe 17.

[0033] When in use, open the water injection control valve 18, and inject clean water into the detection tube 14 and the communicating vessel through the L-shaped water injection pipe 17, so that the liquid level of the clean water in the detection tube 14 is below the first liquid level sensor 15. In this way, when the liquid level of the oil-water mixture reaches the inlet at the lower right end of the inverted U-shaped siphon 9, the oil-water mixture can push the clean water level to reach the first liquid level sensor 15. When the liquid level of the oil-water mixture reaches the outlet of the curved part of the U-shaped siphon, the clean water level just reaches the second liquid level sensor 16, so that the probes of the first liquid level sensor 15 and the second sensor are always in contact with clean water, keeping the first liquid level sensor 15 and the second sensor clean, and preventing the oil-water mixture from corroding the probes.

[0034] Embodiment 7: As attached Figure 1 As shown, the right end of the liquid outlet pipe and the right end of the oil inlet pipe 7 are both bent downward into an arc shape.

[0035] Through such an arrangement, the bend at the right end of the liquid outlet pipe can make the gas-liquid mixture produced by the oil well flow into the bottom of the upper cavity 5, preventing the floating natural gas from re-dissolving in the mixed liquid and affecting the measurement of the natural gas production, while avoiding the gas-liquid mixture from splashing and hanging on the wall; the bend at the right end of the oil inlet pipe 7 can effectively avoid the splashing and separation of the oil-water mixture, allowing the oil-water mixture to flow out quickly through the liquid outlet pipe.

[0036] Embodiment 8: As attached Figure 1As shown, the liquid inlet pipe 2 can be an expanded pipe with a thin left side and a thick right side. During use, the expanded pipe with a thin left side and a thick right side can reduce the pressure of the gas-liquid mixture, so that the pressure of the gas-liquid mixture is initially separated, and then the gas-liquid mixture is separated again through the upper cavity 5, which can make the gas-liquid separation effect better and the measurement value more accurate.

[0037] The above technical features constitute the embodiments of the present invention, which have strong adaptability and implementation effect. Non-essential technical features can be added or reduced according to actual needs to meet the requirements of different situations.

Claims

1. A device for measuring oil well production, characterized in that It includes a hollow separation tank and a control unit. A liquid inlet is provided on the left side of the upper part of the separation tank, and a liquid inlet pipe is fixedly installed in the liquid inlet. A liquid outlet is provided in the middle part of the lower end of the separation tank, and a liquid discharge pipe is fixedly installed in the liquid outlet. A partition is fixedly installed on the inner side of the middle part of the separation tank, and the partition divides the separation tank into an upper cavity and a lower cavity. A gas production detection part capable of detecting the gas production of the oil well is provided between the middle part of the upper end of the upper cavity and the right side of the upper part of the lower cavity. A liquid production and water content estimation part capable of preliminarily estimating the liquid production of the oil well is provided between the left side of the middle part of the upper cavity and the left side of the upper part of the lower cavity. The control unit is electrically connected to the gas production detection part and the liquid production and water content estimation part respectively.

2. The oil well production metering device according to claim 1, characterized in that The liquid production and moisture estimation part includes an oil inlet pipe, a water content analyzer, an inverted U-shaped siphon and a liquid production estimation unit. An oil inlet is provided on the left side of the separation tank corresponding to the upper position of the lower cavity, an oil inlet pipe with a blind end on the left end is fixedly installed in the oil inlet, a water content analyzer is provided on the left end of the oil inlet pipe, and a liquid through hole connected inside and outside is provided on the upper left side of the oil inlet pipe. An oil outlet is provided on the left side of the separation tank corresponding to the middle position of the upper cavity, an inverted U-shaped siphon with the outer side of the lower left end and the inner side of the liquid through hole fixedly installed in the oil outlet, the lower right end of the inverted U-shaped siphon is located in the upper cavity, and a liquid production estimation unit capable of detecting the number and duration of siphoning phenomena occurring per unit time is provided on the upper left part of the inverted U-shaped siphon, and the water content analyzer and the liquid production estimation unit are electrically connected to the control unit respectively.

3. The oil well production metering device according to claim 2, characterized in that The liquid production estimation unit is a capacitive liquid level sensor.

4. The oil well production metering device according to claim 2 or 3, characterized in that The gas production detection unit includes a connecting pipe and a natural gas flow meter. A gas outlet is provided in the middle of the upper end of the separation tank, and an air inlet is provided on the right side of the separation tank corresponding to the upper position of the lower cavity. A connecting pipe is fixedly installed between the air inlet and the gas outlet, and a natural gas flow meter is provided on the connecting pipe. The natural gas flow meter is electrically connected to the control unit.

5. The oil well production metering device according to claim 4, characterized in that A liquid production precision measuring part capable of accurately detecting the liquid production is provided between the middle of the separation tank and the upper part of the connecting pipe. The liquid production precision measuring part comprises a liquid level connecting vessel, a detection tube, a first liquid level sensor and a second liquid level sensor. A measuring hole which passes through from top to bottom is provided in the middle of the partition. The liquid level connecting vessel is fixedly installed in the measuring hole. A detection hole which passes through from inside to outside is provided on the separation tank corresponding to the lower end of the liquid level connecting vessel. A detection tube is fixedly installed at the lower end of the liquid level connecting vessel. The other end of the detection tube passes through the detection hole and is connected with the lower side of the upper part of the connecting pipe and is fixedly installed together. The first liquid level sensor and the second liquid level sensor are respectively provided on the detection tubes corresponding to the lower right end of the inverted U-shaped siphon and the upper bending part thereof. The first liquid level sensor and the second liquid level sensor are respectively electrically connected to the control unit.

6. The oil well production metering device according to claim 5, characterized in that The liquid production precision measurement unit also includes a water injection pipe and a water injection control valve. A water injection port that runs through the inside and outside of the detection tube is provided on the upper part of the detection tube. An L-shaped water injection pipe with a funnel-shaped upper end is fixedly installed in the water injection port, and a water injection control valve is provided on the horizontal part of the water injection pipe.

7. The oil well production metering device according to claim 5 or 6, characterized in that The right end of the liquid outlet pipe and the right end of the oil inlet pipe are both bent downward into an arc shape.

8. The oil well production metering device according to claim 1, 2, 3, 5 or 6, characterized in that The liquid inlet pipe is an expanded pipe with a shape of being thin on the left and thick on the right.

9. The oil well production metering device according to claim 4, characterized in that The liquid inlet pipe is an expanded pipe with a shape of being thin on the left and thick on the right.

10. The oil well production metering device according to claim 7, characterized in that The liquid inlet pipe is an expanded pipe with a shape of being thin on the left and thick on the right.

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