An oil and gas flow metering device and method based on a pumping unit

Abstract

An oil and gas flow metering device and method based on a pumping unit, the invention mainly comprises a casing head, a casing, a pump barrel, a sucker rod, a plunger, a float, an ultrasonic probe, a calibration reflector plate, an oil and gas outlet pipe and the like. The ultrasonic probe emits ultrasonic waves along the sucker rod to obtain the height of the gas phase space in the pump barrel, and then the gas content of the pump barrel is obtained. The invention has the characteristics and advantages that the sucker rod of the pumping unit is both a power transmission device and an ultrasonic signal transmission device, without the need for additional equipment and instrument investment; the sound velocity is corrected in real time by using the reflector plate, the measurement result is not affected by the temperature and pressure of the gas phase in the body, the precision is high; the structure is simple, the operation is convenient, and it has a broad application prospect.

Description

Technical Field

[0001] This invention belongs to the field of fluid metering, specifically relating to an apparatus and method for metering the flow rates of gas and liquid phases produced from oil wells. Background Technology

[0002] In the petroleum industry, it is typically necessary to measure the flow rate of gas and liquid produced at the wellhead. Since oil well products are usually mixtures of gas and liquid, traditional single-phase metering methods are unsuitable, necessitating the use of multiphase metering techniques. Currently, research on multiphase metering mainly focuses on three methods: gas-liquid separation metering, gas-liquid mixed-phase metering, and split-sampling metering.

[0003] The complete separation method involves using separation equipment to separate a gas-liquid mixture into single-phase gas and single-phase liquid, which are then measured using a standard single-phase flow meter. This method transforms the measurement of two-phase flow into the measurement of single-phase flow, offering advantages such as reliable operation, high measurement accuracy, wide measurement range, and immunity to changes in the flow pattern of the gas and liquid phases. However, gas-liquid separation metering presents several challenges: ① The separation equipment is bulky and expensive; ② Due to the large buffer volume, there is a metering delay and poor real-time performance; ③ Dedicated metering stations and testing pipelines are required, significantly increasing metering costs.

[0004] Gas-liquid mixed-phase metering is currently the mainstream method for multiphase metering in industrial settings. This method eliminates the need for separation devices, resulting in a small size and compact structure. The total gas-liquid flow rate is typically measured using throttling devices such as Venturi jets, while phase fraction is measured using phase fraction sensors such as capacitance, conductivity, and radiation sensors. Gas-liquid mixed-phase flow metering presents the following challenges: ① Directly facing a two-phase gas-liquid flow, the complexity of the gas-liquid flow can lead to errors exceeding 10%; ② Using throttling devices like Venturi jets results in significant resistance losses; ③ Phase fraction sensors are affected by factors such as pipeline flow patterns and fluid salinity, requiring periodic calibration, and radiation methods also pose a risk of radioactive contamination.

[0005] The principle of gas-liquid two-phase split sampling and metering is to proportionally separate a small, representative multiphase mixture (splitter) from a multiphase flow, then separate it into single-phase gas and liquid, and measure the flow rate of each phase using a conventional flow meter. Finally, the total flow rate is determined based on the proportional relationship. Current technical challenges include: ① Phase separation usually occurs when the gas-liquid two-phase mixture passes through the sampling device, causing the sampled fluid to lose its representativeness; ② The sampling ratio is affected by upstream flow patterns and downstream pressure fluctuations, making it difficult to maintain stability; ③ Samplers with moving parts, such as impellers, are difficult to operate stably for extended periods under harsh field conditions.

[0006] Pumping units are commonly used equipment in oil and gas fields. They lift oil and gas from the wellbore to the surface gathering and transportation network through the reciprocating motion of a downhole plunger. Currently, oilfields widely use dynamometer cards for oil and gas metering. A dynamometer card is constructed by real-time monitoring of the sucker rod load using sensors installed at the wellhead, thereby predicting flow rate. However, the relationship between the dynamometer card and oil volume is complex, making it difficult to measure the produced gas flow rate. Furthermore, due to pump leakage and other factors, liquid volume measurement errors are significant.

[0007] To overcome the shortcomings of existing technologies, this invention proposes an oil and gas flow metering device and method based on an oil pumping unit. By emitting ultrasonic waves at the top of the sucker rod to measure the liquid level in the pump barrel, and combining this with the pump stroke characteristics, accurate measurement of oil and gas flow can be achieved. Summary of the Invention

[0008] This invention relates to an oil and gas flow metering device based on an oil pumping unit, which mainly includes a casing head, casing, pump barrel, sucker rod, plunger, float, ultrasonic probe, calibration reflector, oil and gas outlet pipe, etc. The casing head is installed at the top of the casing, the pump barrel is installed at the bottom of the casing, the sucker rod extends into the casing through the central hole of the casing head, and the plunger is installed at the end of the sucker rod and located inside the pump barrel.

[0009] The sleeve, pump barrel, and plunger are all cylindrical structures. The outer wall of the pump barrel is fixed to the inner wall of the sleeve, and the outer wall of the plunger is in close contact with the inner wall of the pump barrel. The plunger can slide freely up and down along the inner wall of the pump barrel.

[0010] The sucker rod passes through the center of the plunger, and the bottom of the sucker rod extends about 5 to 10 mm beyond the bottom plate of the plunger. The top of the plunger is provided with an outlet hole. The calibration reflector is mounted on the bottom plate of the plunger through a bracket. The calibration reflector is made of metal and is located about 30 to 50 mm away from the end of the sucker rod.

[0011] On the plunger base plate, a traveling valve is installed on each side of the sucker rod. The traveling valve closes when the sucker rod moves upward and opens when the sucker rod moves downward. A fixed valve is installed at the bottom of the pump barrel. The fixed valve opens when the sucker rod moves upward and closes when the sucker rod moves downward. A float is installed between the bottom of the pump barrel and the bottom of the plunger. The center of the float is a solid structure, and several vent holes are evenly distributed around it, allowing gas below the float to enter above the float through the vent holes. The outer diameter of the float is 3-5 mm smaller than the inner diameter of the pump barrel, and the density of the float is less than the density of the oil. Therefore, the float can float on the gas-liquid interface of the pump barrel and can float freely up and down along the pump barrel.

[0012] The sucker rod is a solid metal rod, free of internal cracks, bubbles, and other defects to facilitate ultrasonic wave transmission. An ultrasonic probe is mounted at the top of the sucker rod, capable of simultaneously emitting and receiving ultrasonic waves. The tip of the sucker rod is connected to the pumping unit's nozzle, and external power drives the sucker rod to reciprocate up and down within the pump barrel, thereby causing the plunger to move up and down within the pump barrel, extracting oil and gas to the oil and gas outlet pipe.

[0013] This invention relates to a method for measuring oil and gas flow rate based on an oil pumping unit, the specific implementation of which is as follows:

[0014] (1) At time T0, an ultrasonic probe installed at the top of the sucker rod emits an ultrasonic wave into the sucker rod, which is called the emitted wave;

[0015] (2) The emitted wave propagates along the sucker rod and a portion of it is reflected when it reaches the bottom of the sucker rod. The reflected echo is called the bottom echo of the sucker rod. The bottom echo of the sucker rod is transmitted to the top of the sucker rod and received by the ultrasonic probe. The time T1 is collected and recorded.

[0016] (3) When the transmitted wave reaches the bottom of the sucker rod, another part of the ultrasonic wave will be transmitted and propagated in the gas phase space formed between the bottom of the plunger and the float. A small part of the transmitted sound wave is reflected when it propagates to the calibration reflector. The reflected echo is called the reflector echo. The reflector echo is transmitted along the sucker rod to the top of the sucker rod and is received by the ultrasonic probe. The receiving time T2 is collected and recorded.

[0017] (4) Another part of the transmitted wave continues to propagate in the gas phase space until it reaches the floating plate. The sound wave is reflected at the center of the floating plate. The reflected wave is called the floating plate echo. The floating plate echo propagates along the sucker rod to the top of the sucker rod and is received by the ultrasonic probe located at the top of the sucker rod. The receiving time T3 is collected and recorded.

[0018] (5) The time interval between T1 and T2 is denoted as ΔT. 12 The time interval between T1 and T3 is denoted as ΔT. 13 L is the distance from the reflector plate to the bottom of the sucker rod, then the height of the gas phase space inside the pump barrel is...

[0019] (6) Given that the cross-sectional area of ​​the plunger is F, the stroke of the sucker rod is S, and the number of sucker rod strokes is N, then the gas phase fraction inside the pump barrel is... The daily fluid production of the oil well is Q. L =1440·F·N·S(1-φ), the daily gas production of the oil well is Q G =1440·F·N·S·φ.

[0020] Compared with the prior art, the present invention has the following advantages:

[0021] (1) The sucker rod of the pumping unit is both a power transmission device and a signal transmission device. No additional equipment or instruments are required. An ultrasonic probe can be installed on the top of the sucker rod to measure the height of the gas space in the pump barrel, thereby accurately obtaining the actual volume of gas and liquid in the pump barrel.

[0022] (2) The sound velocity is corrected in real time by using a reflector. The temperature and pressure of the gas phase inside the tube will not affect the gas phase fraction measurement results in the pump cylinder, resulting in high accuracy.

[0023] (3) The present invention has a simple structure. It can achieve accurate measurement of oil flow rate by making a small modification to the plunger of the existing oil pumping unit. It is easy to operate and has broad prospects for promotion and application. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the components of the present invention;

[0025] Figure 2 This is a top view of the floating platform of the present invention;

[0026] Figure 3 This is a schematic diagram of the top stroke of the present invention;

[0027] Figure 4 This is a schematic diagram of the downstroke of the present invention;

[0028] Figure 5 This is a schematic diagram of echo propagation in this invention;

[0029] Figure 6 This is a schematic diagram of the echo time difference of the present invention.

[0030] 1-Casing head; 2-Casing; 3-Pump barrel; 4-Suck rod; 5-Plunger; 6-Float; 7-Ultrasonic probe; 8-Calibration reflector; 9-Oil / gas outlet pipe; 10-Outlet orifice; 11-Wandering valve; 12-Fixed valve; 13-Leakage hole; 14-Emitting wave; 15-Suck rod bottom echo; 16-Reflector echo; 17-Float echo. Detailed Implementation

[0031] like Figure 1 As shown, the present invention mainly includes a casing head 1, a casing 2, a pump barrel 3, a sucker rod 4, a plunger 5, a float 6, an ultrasonic probe 7, a calibration reflector 8, an oil and gas outlet pipe 9, etc. The casing head 1 is installed on the top of the casing 2, the pump barrel 3 is installed on the bottom of the casing 2, the sucker rod 4 extends into the casing 2 through the central hole of the casing head 1, and the plunger 5 is installed at the end of the sucker rod 4 and is located inside the pump barrel 3.

[0032] The sleeve 2, pump barrel 3, and plunger 5 are all cylindrical structures and are coaxial. The outer wall of the pump barrel 3 is fixed to the inner wall of the sleeve 2, and the outer wall of the plunger 5 is in close contact with the inner wall of the pump barrel 3. The plunger 5 can slide freely up and down along the inner wall of the pump barrel 3.

[0033] The sucker rod 4 passes through the center of the plunger 5, and the bottom of the sucker rod 4 extends about 5 to 10 mm beyond the bottom plate of the plunger 5. The top of the plunger 5 is provided with an outlet hole 10. The calibration reflector 8 is mounted on the bottom plate of the plunger 5 by a bracket. The calibration reflector 8 is made of metal and is located about 30 to 50 mm away from the end of the sucker rod 4.

[0034] On the bottom plate of the plunger 5, a traveling valve 11 is installed on each side of the sucker rod 4. The traveling valve 11 is closed when the sucker rod 4 moves upward and is opened when the sucker rod 4 moves downward. A fixed valve 12 is installed at the bottom of the pump barrel 3. The fixed valve 12 is opened when the sucker rod 4 moves upward and is closed when the sucker rod 4 moves downward. A float 6 is installed between the bottom of the pump barrel 3 and the bottom of the plunger 5.

[0035] like Figure 2 As shown, the center of the floating plate 6 is a solid structure, and several air leakage holes 13 are evenly distributed around it, allowing gas below the floating plate 6 to enter above the floating plate 6 through the air leakage holes 13. The outer diameter of the floating plate 6 is 3-5 mm smaller than the inner diameter of the pump barrel 3, the density of the floating plate 6 is less than the density of the oil, and it can float freely up and down along the pump barrel 3.

[0036] During operation, the power unit on the ground rotates at high speed, transmitting the power to the crankshaft via belt and gearbox, causing the crank to rotate at low speed. The crank, through the connecting rod and crossbeam, drives the walking beam to swing up and down. The suspension rope device hanging on the donkey head then drives the sucker rod 4 to reciprocate up and down. The sucker rod 4 also drives the plunger 5 at its end to reciprocate up and down inside the pump barrel 3, thereby drawing the formation oil and gas to the surface.

[0037] like Figure 3 As shown, when the sucker rod 4 rises, a low pressure is generated inside the pump barrel 3. The liquid below the pump pushes open the fixed valve 12 and enters the pump barrel 3, while the traveling valve 11 closes due to the pressure above the plunger 5. As oil and gas in the reservoir continuously enter the pump barrel 3 through the fixed valve 12, the liquid level inside the pump barrel 3 continuously rises. The float 6, with a density less than the liquid phase, floats above the liquid surface. The extracted gas enters above the float 6 through the vent hole 13 on the float 6. As the liquid level rises, the float 6 continuously rises, always floating above the liquid surface in the pump barrel 3. The function of the float 6 is to suppress gas-liquid interface fluctuations and create favorable conditions for ultrasonic wave reflection. When the sucker rod 4 rises to its highest position, i.e., the top dead center, the amount of oil and gas collected in the pump barrel 3 reaches its maximum. At this time, the space from the top of the float 6 to the bottom of the plunger 5 is the gas phase space, while the pump barrel 3 below the float 6 is entirely liquid.

[0038] like Figure 4 As shown, when the sucker rod 4 begins to descend from the top dead center, the fixed valve 12 at the bottom of the pump closes due to pressure, while the two floating valves 11 above open. At this time, the gas-liquid mixture in the pump barrel 3 enters the area above the plunger 5 through the floating valves 11, and finally reaches the ground through the oil and gas outlet pipe 9.

[0039] The tip of the sucker rod 4 is connected to the pumping unit's nozzle. External power drives the sucker rod 4 to reciprocate up and down within the pump casing 3, continuously extracting oil and gas from the bottom layer to the surface. Ideally, the volume of liquid entering and exiting the pump casing 3 in each stroke of the plunger 5 is equal to the volume displaced by the plunger 5, calculated using the following formula:

[0040] V=FS (1)

[0041] The pump's displacement per minute is:

[0042] V m =FSN (2)

[0043] The theoretical displacement of the pump is:

[0044] Q = 1440FSN (3)

[0045] f p : Piston cross-sectional area, m 2 ;

[0046] S: Stroke, which is the length of the stroke from top dead center to bottom dead center, in meters;

[0047] N: Stroke count, also known as strokes, is the number of strokes the plunger completes per minute, 1 / min;

[0048] Q t Theoretical displacement of the pump, in meters (m) 3 / d.

[0049] But in fact, as Figure 3 As shown, the gas phase in the reservoir also enters the pump cylinder 3, causing a portion of the space inside the pump cylinder 3 to be occupied by the gas phase. If the size of the space occupied by the gas phase can be measured, the oil and gas flow rates can be measured accurately simultaneously. This invention utilizes ultrasonic echoes to achieve non-invasive measurement of the gas phase space height.

[0050] like Figure 5 As shown, the sucker rod 4 is a solid metal rod without internal cracks, bubbles, or other defects to facilitate ultrasonic wave transmission. An ultrasonic probe 7 is installed at the top of the sucker rod 4, which can simultaneously emit and receive ultrasonic waves. By analyzing the time difference between the received ultrasonic echoes reaching the probe, the height of the gas phase space inside the pump barrel 3 can be measured.

[0051] like Figure 6As shown, at time T0, the ultrasonic probe 7 installed at the top of the sucker rod 4 emits ultrasonic waves into the sucker rod 4, referred to as emitted wave 14. Emitted wave 14 propagates along the sucker rod 4, and a portion of it is reflected when it reaches the bottom of the sucker rod 4. This reflected echo is called the sucker rod bottom echo 15. The sucker rod bottom echo 15 propagates towards the top of the sucker rod 4 and is received by the ultrasonic probe 7; this reception time is recorded as T1. When emitted wave 14 reaches the bottom of the sucker rod 4, another portion of the sound wave is transmitted. The transmitted wave propagates in the gas phase space formed between the bottom of the plunger 5 and the float 6. A small portion of the transmitted sound wave encounters the calibration reflector 8 and is reflected during propagation; this echo is called the reflector echo 16. The reflector echo 16 propagates along the sucker rod 4 towards the top of the sucker rod 4 and is received by the ultrasonic probe 7; this reception time is recorded as T2. Another portion of the transmitted wave continues to propagate in the gas phase space until it reaches the floating plate 6. The sound wave is reflected at the center of the floating plate 6. At this time, the reflected wave is called the floating plate echo 17. The floating plate echo 17 propagates along the sucker rod 4 to the top of the sucker rod 4 and is received by the ultrasonic probe 7 located at the top of the sucker rod 4. The time of reception is recorded as T3.

[0052] The time interval between T1 and T2 is denoted as ΔT. 12 The bottom echo 15 of the sucker rod and the reflector echo 16 travel for the same amount of time within the sucker rod 4, and their time difference ΔT 12 The time taken for the ultrasonic wave to travel twice the distance from the bottom of the sucker rod 4 to the reflector is given. If L is the distance from the reflector to the bottom of the sucker rod, and C is the velocity of sound in the gas phase, then the formula is as follows:

[0053]

[0054] Similarly, the time interval between T1 and T3 is denoted as ΔT. 13 The bottom echo 15 of the sucker rod and the float echo 17 travel for the same amount of time within the sucker rod 4, and their time difference ΔT 13 The time taken for the ultrasonic wave to travel twice the distance from the bottom of the sucker rod 4 to the floating roof 6 is given. Since the velocity of sound in the gas phase is C, the height H of the gas phase space is expressed by the following formula:

[0055]

[0056] From equations (5) and (6), we can obtain:

[0057]

[0058] Since the distance L between the reflector 8 and the bottom of the sucker rod 4 is a known constant, it can be known from formula (6) that the time difference ΔT between the bottom echo 15 of the sucker rod and the echo 16 of the reflector can be measured. 12 And the time difference ΔT between the bottom echo 15 of the sucker rod and the echo 17 of the floating roof. 13This allows for the measurement of the gas phase height inside pump cylinder 3.

[0059] The distance from the top dead center to the bottom dead center during one stroke of the pumping unit is the height of the pump barrel volume enclosed by plunger 5, denoted by stroke S, and is a known constant. If the gas phase height inside pump barrel 3 is known, the gas phase volume fraction φ inside pump barrel 3 can be calculated using the following formula:

[0060]

[0061] Therefore, in practice, the volume of liquid entering and exiting the plunger 5 in each subsequent cycle is equal to the product of the volume vacated by the plunger 5 and the liquid phase fraction:

[0062] V L =FS(1-φ) (8)

[0063] The gas volume is equal to the product of the volume displaced by plunger 5 and the gas phase fraction:

[0064] V G =FSφ (9)

[0065] If the number of strokes of sucker rod 4 is N, then according to formula (3), the daily production of the oil well is:

[0066] Q L =1440×FNS(1-φ) (10)

[0067] Similarly, the daily fluid production of the oil well is:

[0068] Q G =1440×FNSφ (11)

[0069] Therefore, the present invention relates to an oil and gas flow metering device and method based on an oil pumping unit, specifically implemented as follows:

[0070] (1) At time T0, the ultrasonic probe 7 installed on the top of the sucker rod 4 emits ultrasonic waves into the sucker rod 4, which are called emission waves 14.

[0071] (2) The emitted wave 14 propagates along the sucker rod 4. When it reaches the bottom of the sucker rod 4, a part of it will be reflected. At this time, the reflected echo is called the bottom echo 15 of the sucker rod. The bottom echo 15 of the sucker rod is transmitted to the top of the sucker rod 4 and is received by the ultrasonic probe 7. The time T1 is collected and recorded.

[0072] (3) When the transmitted wave 14 is transmitted to the bottom of the sucker rod 4, another part will be transmitted and transmitted in the gas phase space formed between the bottom of the plunger 5 and the float 6. A small part of the transmitted sound wave is reflected when it reaches the calibration reflector 8. The reflected echo is called the reflector echo 16. The reflector echo 16 is transmitted along the sucker rod 4 to the top of the sucker rod 4 and is received by the ultrasonic probe 7. The receiving time T2 is collected and recorded.

[0073] (4) Another part of the transmitted wave continues to propagate in the gas phase space until it reaches the floating plate 6. The sound wave is emitted at the center of the floating plate 6. At this time, the reflected wave is called the floating plate echo 17. The floating plate echo 17 propagates along the sucker rod 4 to the top of the sucker rod 4 and is received by the ultrasonic probe 7 located at the top of the sucker rod 4. The receiving time T3 is collected and recorded.

[0074] (5) The time interval between T1 and T2 is denoted as ΔT. 12 The time interval between T1 and T3 is denoted as ΔT. 13 L is the distance from the reflector plate 8 to the bottom of the sucker rod 4, then the height of the gas phase space inside the pump barrel 3 is...

[0075] (6) Given that the cross-sectional area of ​​plunger 5 is F, the stroke of sucker rod 4 is S, and the number of strokes of sucker rod 4 is N, then the gas phase fraction inside pump barrel 3 is... The daily fluid production of the oil well is Q. L =1440×FNS(1-φ), the daily gas production of the oil well is Q G =1440×FNSφ.

[0076] This invention ingeniously uses the sucker rod 4 of the pumping unit as the ultrasonic signal propagation carrier for phase fraction measurement within the pump barrel 3. Thanks to the use of a reflector 8, automatic sound velocity correction is cleverly achieved, eliminating the need to measure downhole pressure and temperature. Pumping units are among the most widely used oil production equipment in oilfields. Based on the traditional pumping unit, this invention modifies the pump barrel 3 by installing a float 6 and modifying the plunger 5, enabling accurate measurement of gas-liquid flow rates by emitting ultrasonic waves through the sucker rod 4. Compared to traditional dynamometer-based oil measurement techniques, this invention can simultaneously measure both gas and liquid phase flow rates, showing broad prospects for widespread application.

Claims

1. An oil and gas flow metering device based on an oil pumping unit, characterized in that... include: The casing head (1), casing (2), pump barrel (3), sucker rod (4), plunger (5), float (6), ultrasonic probe (7), calibration reflector (8), and oil and gas outlet pipe (9) are installed. The casing head (1) is installed on the top of the casing (2), the pump barrel (3) is installed on the bottom of the casing (2), the sucker rod (4) is inserted into the casing (2) through the center hole of the casing head (1), and the plunger (5) is installed at the end of the sucker rod (4) and is located inside the pump barrel (3). The sleeve (2), pump cylinder (3), and plunger (5) are all cylindrical structures. The outer wall of the pump cylinder (3) is fixed on the inner wall of the sleeve (2), and the outer wall of the plunger (5) is in close contact with the inner wall of the pump cylinder (3). The plunger (5) can slide freely up and down along the inner wall of the pump cylinder (3). The sucker rod (4) passes through the center of the plunger (5), and the bottom of the sucker rod (4) extends 5~10mm out of the bottom plate of the plunger (5). The top of the plunger (5) is provided with an outlet hole (10). The calibration reflector (8) is mounted on the bottom plate of the plunger (5) through a bracket. The calibration reflector (8) is made of metal and its position is 30~50mm away from the end of the sucker rod (4). On the bottom plate of the plunger (5), a traveling valve (11) is installed on each side of the sucker rod (4). When the sucker rod (4) moves upward, the traveling valve (11) is closed, and when the sucker rod (4) moves downward, the traveling valve (11) is opened. A fixed valve (12) is installed at the bottom of the pump barrel (3). When the sucker rod (4) moves upward, the fixed valve (12) is opened, and when the sucker rod (4) moves downward, the fixed valve (12) is closed. A float (6) is installed between the bottom of the pump barrel (3) and the bottom of the plunger (5). The center of the float (6) is a solid structure, and several air leakage holes (13) that penetrate the float (6) are evenly distributed around it. Gas below the float (6) can enter the area above the float (6) through the air leakage holes (13). The outer diameter of the float (6) is 3~5mm smaller than the inner diameter of the pump barrel (3). The density of the float (6) is less than the density of the oil. Therefore, the float can float on the gas-liquid interface of the pump barrel (3) and can float freely up and down along the pump barrel (3). The sucker rod (4) is a solid metal rod with no internal cracks or bubble defects. An ultrasonic probe (7) is installed on the top of the sucker rod (4). The ultrasonic probe (7) can simultaneously emit and receive ultrasonic waves.

2. A method for measuring oil and gas flow rate based on an oil pumping unit, characterized in that, The specific implementation steps of the oil and gas flow metering device based on an oil pumping unit as described in claim 1 are as follows: (1) At time T0, ultrasonic waves are emitted into the sucker rod (4) by the ultrasonic probe (7) installed at the top of the sucker rod (4), which is called the emitted wave (14). (2) The emitted wave (14) propagates along the sucker rod (4). When it reaches the bottom of the sucker rod (4), a part of it will be reflected. The reflected echo is called the bottom echo (15) of the sucker rod. The bottom echo (15) of the sucker rod is transmitted to the top of the sucker rod (4) and received by the ultrasonic probe (7). The time T1 is collected and recorded. (3) When the transmitted wave (14) reaches the bottom of the sucker rod (4), another part of the ultrasonic wave will be transmitted and propagated in the gas phase space formed between the bottom of the plunger (5) and the float (6). A small part of the transmitted sound wave is reflected when it propagates to the calibration reflector (8). The reflected echo is called the reflector echo (16). The reflector echo (16) is transmitted along the sucker rod (4) to the top of the sucker rod (4) and is received by the ultrasonic probe (7). The receiving time T2 is collected and recorded. (4) Another part of the transmitted wave continues to propagate in the gas phase space until it reaches the floating plate (6). The sound wave is reflected at the center of the floating plate (6). At this time, the reflected wave is called the floating plate echo (17). The floating plate echo (17) propagates along the sucker rod (4) to the top of the sucker rod (4) and is received by the ultrasonic probe (7) located at the top of the sucker rod (4). The receiving time T3 is collected and recorded. (5) The time interval between T1 and T2 is denoted as ΔT. 12 The time interval between T1 and T3 is denoted as ΔT. 13 L is the distance between the reflector (8) and the bottom of the sucker rod (4), then the height of the gas phase space inside the pump barrel (3) is... ; (6) Given that the cross-sectional area of ​​the plunger (5) is F, the stroke of the sucker rod (4) is S, and the number of strokes of the sucker rod (4) is N, then the gas phase fraction inside the pump barrel (3) is The daily production of the oil well is The daily gas production of the oil well is .

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