A multiphase flow magnetic resonance flowmeter single well metering device and method

Abstract

The present invention provides a multiphase flow magnetic resonance flowmeter single-well metering device and method, the device comprising a multiphase flow magnetic resonance flowmeter, a grit chamber, and a branch pipeline; the outlet of the oil and gas production tree at the wellhead of the oil field is connected to the inlet of the multiphase flow magnetic resonance flowmeter via an inlet pipeline via the grit chamber; the outlet of the multiphase flow magnetic resonance flowmeter is connected to the inlet of the oil tree via an outlet pipeline; a pressure relief port and a sampling port are respectively provided on the inlet pipeline between the grit chamber and the outlet of the oil tree; branch pipelines are installed at both ends of the multiphase flow magnetic resonance flowmeter, one end of the branch pipeline is connected to the outlet valve provided on the outlet pipeline, and the other end is connected to the inlet valve provided on the inlet pipeline between the inlet of the multiphase flow magnetic resonance flowmeter and the grit chamber. The present invention solves the problem of real-time multiphase flow metering in a single well, and can realize the use of the multiphase flow magnetic resonance flowmeter for on-site single-well metering in oil fields, especially single wells such as pumping wells whose liquid production changes in short cycles.

Description

Technical Field

[0001] The present invention relates to a single-well metering device and method for a multiphase flow magnetic resonance flowmeter, belonging to the technical fields of single-well metering, multiphase flow online metering, and low-field nuclear magnetic resonance application. Background Art

[0002] Multiphase flowmeters can perform real-time online measurement of the flow rates of each phase, without separating the oil, gas, and water. Despite years of exploration, commercial multiphase flowmeters still face numerous technical bottlenecks, such as limited applicability, limited range, limited accuracy, demanding environmental requirements, radioactivity in some technologies, and high costs. These factors hinder their widespread adoption and hinder their application to single-well metering.

[0003] Magnetic resonance (MR) technology, a mainstream indoor fluid composition analysis technique, is non-invasive, environmentally friendly, efficient, and accurate. It is currently being used in industrial sites for online measurement of complex mixed-phase fluids. The multiphase flow nuclear magnetic resonance flowmeter, developed in this context, has for the first time realized the application of MR technology in oil and gas metering. However, due to its high cost, it is currently mainly used on offshore and onshore oil platforms for aggregated metering of multiple wells, rather than for single-well metering. This means that the production dynamics of each oil well cannot be monitored in real time to guide production decision-making.

[0004] Compared to platform metering, single-well metering differs from platform metering only in terms of lower flow rates. Single-well metering requires the flowmeter to be directly connected to the Christmas tree, and the produced fluid enters the flowmeter without filtration or any pretreatment. Metal debris and formation rock debris contained in the produced fluid will inevitably affect flowmeters such as electromagnetic, magnetic resonance, and gamma spectroscopy. Furthermore, 90% of terrestrial oil and gas fields are produced using pump-lift systems, meaning that production fluctuates in real time during the pump's upstroke and downstroke, necessitating a high detection frequency or a well-defined detection cycle for the flowmeter.

[0005] Therefore, providing a multiphase flow magnetic resonance flowmeter single well metering device and method has become a technical problem that needs to be solved urgently in this field. Summary of the Invention

[0006] To address the aforementioned shortcomings and deficiencies, an object of the present invention is to provide a multiphase flow magnetic resonance flowmeter for single wells. The device provided by the present invention is a complex fluid flow meter suitable for installation at an oilfield production wellhead, and is applicable to industrial fields involving the measurement of flowing fluids.

[0007] Another object of the present invention is to provide a single-well metering method for a multiphase flow magnetic resonance flowmeter.

[0008] In order to achieve the above objectives, on the one hand, the present invention provides a multiphase flow magnetic resonance flowmeter single well metering device, wherein the multiphase flow magnetic resonance flowmeter single well metering device comprises:

[0009] A multiphase flow magnetic resonance flowmeter, a grit tank, and a branch pipeline; the outlet of an oil and gas production Christmas tree at an oilfield wellhead is connected to the inlet of the multiphase flow magnetic resonance flowmeter via an inlet pipeline and a grit tank; the outlet of the multiphase flow magnetic resonance flowmeter is connected to the inlet of the Christmas tree via an outlet pipeline;

[0010] A pressure relief port and a sampling port are respectively provided on the inlet pipe between the grit chamber and the outlet of the Christmas tree;

[0011] Branch pipelines are installed at both ends of the multiphase flow magnetic resonance flowmeter, and one end of the branch pipeline is connected to the outlet valve set on the outlet pipeline, and the other end is connected to the inlet valve set on the inlet pipeline between the inlet of the multiphase flow magnetic resonance flowmeter and the sand settling tank.

[0012] As a specific embodiment of the above-mentioned device of the present invention, a pressure gauge is provided on the inlet pipeline between the grit tank and the sampling port.

[0013] As a specific embodiment of the above-mentioned device of the present invention, the sampling port is provided with a manual sampling port valve.

[0014] As a specific embodiment of the above-mentioned device of the present invention, the pressure relief port is provided with a manual unloading valve for the pressure relief port.

[0015] In the present invention, the fluid enters the device through the inlet pipeline, and sampling and pressure relief operations can be performed through the manual valve of the sampling port and the manual unloading valve of the pressure relief port; the pressure gauge can display the internal pressure of the inlet pipeline in real time; the sand settling tank is used to filter paramagnetic substances that may be carried in the fluid to prevent the paramagnetic substances from affecting the measurement results of the multiphase flow magnetic resonance flowmeter; branch pipe manifolds are installed at both ends of the multiphase flow magnetic resonance flowmeter to maintain the normal flow of the fluid in the pipeline when the multiphase flow magnetic resonance flowmeter is switched to dynamic or static measurement, wherein the dynamic and static switching of the fluid in the inlet pipeline is realized by the outlet valve and the inlet valve, thereby realizing the dynamic or static measurement of the multiphase flow magnetic resonance flowmeter.

[0016] In the present invention, the multiphase flow magnetic resonance flowmeter, sand settling tank, pressure gauge, manual valve for the sampling port and manual unloading valve for the pressure relief port are all conventional equipment and can be purchased commercially.

[0017] On the other hand, the present invention also provides a multiphase flow magnetic resonance flowmeter single well measurement method, wherein the multiphase flow magnetic resonance flowmeter single well measurement method comprises:

[0018] Installing a multiphase flow magnetic resonance flowmeter single well metering device at an oil field wellhead, and connecting the inlet and outlet of the device to the outlet and inlet of an oil and gas production Christmas tree at the oil field wellhead, respectively;

[0019] Turn on the power and adjust the working modes of the outlet valve and the inlet valve to make the fluid in the inlet pipeline flow;

[0020] Automatically calibrate the pulse frequency of a multiphase magnetic resonance flowmeter so that the pulse frequency matches (i.e. is identical to) the magnet frequency;

[0021] Then, the working modes of the outlet valve and the inlet valve are adjusted to make the fluid in the inlet pipeline static, and the multiphase flow magnetic resonance flowmeter is used to perform static measurement, that is, to measure the fluid components;

[0022] The working modes of the outlet valve and the inlet valve are then adjusted to keep the fluid in the inlet pipeline in a flowing state, and the multiphase flow magnetic resonance flowmeter is used to perform dynamic measurement, that is, to measure the fluid flow rate.

[0023] Because the multiphase magnetic resonance flowmeter single-well metering device is used for single-well wellhead measurement, the multiphase magnetic resonance flowmeter operates in a field environment. To prevent the magnet temperature from fluctuating with ambient temperature, a mismatch between the pulse frequency emitted by the probe antenna and the magnet's own frequency occurs, leading to increased measurement accuracy and error in the results. Therefore, the present invention requires automatic pulse frequency correction of the multiphase magnetic resonance flowmeter before each continuous measurement cycle.

[0024] As a specific embodiment of the above method of the present invention, the automatic correction of the pulse frequency of the multiphase magnetic resonance flowmeter so that the pulse frequency matches the magnet frequency includes:

[0025] Before the start of each measurement cycle, the probe antenna of the multiphase flow magnetic resonance flowmeter transmits an FID pulse sequence, and the FID results are used to determine whether the pulse frequency matches the magnet frequency. If the two results match, a cycle of measurement begins. If the two results do not match, the pulse frequency parameters are automatically corrected until the two results match before starting a new cycle of measurement.

[0026] As a specific embodiment of the method described above, the method further includes: according to the set parameters of the oilfield wellhead pumping unit, accurately controlling the time spent on each step in the measurement cycle of the multiphase flow magnetic resonance flowmeter, such as the actuation time of the outlet valve and the inlet valve, the time for the multiphase flow magnetic resonance flowmeter to perform static measurement, and the time for the multiphase flow magnetic resonance flowmeter to perform dynamic measurement, so that the measurement frequency of the multiphase flow magnetic resonance flowmeter is consistent with the alternating frequency of the up and down strokes of the pumping unit, ensuring that the start and end time of each measurement corresponds to the position of the sucker rod unchanged. In this way, while obtaining flow data, it is possible to restore the law of the influence of the pumping unit on flow and manifold under different working conditions, creating conditions for more in-depth research in the future.

[0027] As a specific embodiment of the method described above, the measurement time required for each measurement cycle of the multiphase flow magnetic resonance flowmeter single well metering device is calculated according to the following formula 1):

[0028] T 周 =T 静 +T 动 +2T 阀 =NT 往 Formula 1);

[0029] In formula 1), T 周 T is the measurement time required for each measurement cycle of the multiphase magnetic resonance flowmeter single well metering device, in seconds; 静 T is the static measurement time of the multiphase magnetic resonance flowmeter, in seconds; 动 T is the time for dynamic measurement of multiphase magnetic resonance flowmeter, in seconds; 阀 is the action time of the outlet valve or inlet valve, in seconds; N is an integer, in times;

[0030] T 往 is the time it takes for the pump to reciprocate once, in seconds, where T 往 Calculated according to the following formula 2):

[0031]

[0032] In formula 2), S is the stroke count, which represents the number of reciprocating motions of the sucker rod of the pumping unit in 1 minute. One stroke count means that the sucker rod of the pumping unit moves up and down once per minute.

[0033] As a specific embodiment of the method described above, the action time T of the outlet valve or the inlet valve is 阀 Calculated according to the following formula 3):

[0034] 60s <T 阀 =N1×T往 <300s formula 3);

[0035] In formula 3), T 往 It is the time for the pump to reciprocate once, in seconds; N1 is an integer, in times.

[0036] During the measurement process of the present invention, it is necessary to control two electric valves (i.e., the inlet valve and the outlet valve) to switch the fluid in the inlet pipeline between dynamic and static. The action time of each valve is fixed. After the valve switches to the static state, it is necessary to wait for the fluid to stabilize before starting the static measurement. The waiting time is determined according to the fluid properties. For fluids with strong fluidity, the waiting time is T1≈60s; for heavy oil, a longer waiting time T2≈300s is required. At the same time, the valve action time T 阀 Should be T 往 The relationship is an integer multiple, so the action time T of the outlet valve or inlet valve in the present invention is 阀 It can be shown as the above formula 3).

[0037] In addition, in a specific embodiment of the present invention, the inlet valve and the outlet valve are the same, that is, the actuation time of the two is the same.

[0038] As a specific embodiment of the method described above, the multiphase magnetic resonance flowmeter performs static measurement for a time T 静 Calculated according to the following formula 4):

[0039] T 静 =ET 静 ×EC 静 ×Sc 静 +Sc 静 ×RT 静 =N2×T 往 Formula 4);

[0040] In formula 4), ET 静 is the echo interval, RT 静 is the magnetization time, EC 静 is the number of echoes, Sc 静 is the number of superpositions, T 往 It is the time for the pump to reciprocate once, in seconds; N2 is an integer, in times.

[0041] In the present invention, static measurement refers to the process of measuring fluid components using a multiphase magnetic resonance flowmeter. The time of static measurement is mainly related to the following parameters: echo interval ET 静 , magnetization time RT 静 , echo number EC 静 and the number of superpositions Sc 静 .

[0042] Among them, ET 静 、EC 静 Sc 静 is the instrument's inherent parameter, as shown in the above formula 4), which can be adjusted by adjusting RT 静 Change T 静 , so that T 静 T 往 Integer multiple relationship, N2 is an integer. At the same time, it should be noted that: magnetization time RT 静 Must not be less than three times the maximum longitudinal relaxation time in the fluid.

[0043] As a specific embodiment of the method described above, the multiphase magnetic resonance flowmeter performs dynamic measurement for a time T 动 Calculated according to the following formula 5) and formula 6):

[0044] T 动 =T1×FN+FN×RT 动 =N3×T 往 Formula 5);

[0045] T1=ET 动 ×EC 动 ×Sc 动 +Sc 动 ×FS≤T 单 Formula 6);

[0046] In formula 5) and formula 6), T1 is the time required for each flow measurement, in seconds, FN is the number of measurements, and T 往 is the time it takes for the pumping unit to reciprocate once, in seconds; N3 is an integer, in times;

[0047] ET 动 is the echo interval, RT 动 is the sampling interval, EC 动 is the number of echoes, Sc 动 is the number of superpositions, FS is the superposition interval; T 单 is the minimum one-way time of the pumping unit, in seconds, which is calculated according to the following formula 7);

[0048]

[0049] In formula 7), S is the stroke count, which represents the number of reciprocating motions of the sucker rod of the pumping unit in 1 minute. One stroke count means that the sucker rod of the pumping unit moves up and down once per minute.

[0050] Since the time taken for the upstroke and downstroke of the pumping unit is not exactly the same, the minimum one-way time of the pumping unit can be shown as the above formula 7).

[0051] In the present invention, dynamic measurement refers to the process of measuring fluid flow using a multiphase magnetic resonance flowmeter. The time of dynamic measurement is mainly related to the following parameters: echo interval ET 动 , sampling interval RT 动 , echo number EC 动 , number of superpositions Sc 动 , the number of measurements FN and the superposition interval FS. In order to make the flow measurement frequency consistent with or faster than the pumping unit reciprocating frequency, the time required for each flow measurement can be shown as in the above formula 6). 动 、EC 动 Sc 动 It is the inherent parameter of the instrument, as shown in formula 6), and T1 can be changed by adjusting FS so that T1 is less than or equal to T 单 , thus achieving the purpose of synchronous measurement with the pumping unit. In addition, the superposition interval Therefore, the time T for dynamic measurement of multiphase flow magnetic resonance flowmeter is 动 As shown in the above formula 5), ​​in formula 5), ​​the number of measurements FN should be set to an even number, and the RT can be adjusted 动 Change T 动 , so that T 动 T 往 The sampling interval RT is an integer multiple of 动 >FS.

[0052] In the present invention, N, N1, N2 and N3 are all integers. The present invention does not limit the value range of N, N1, N2 and N3. During actual operation, those skilled in the art can reasonably set the specific values ​​or value ranges of these integers N, N1, N2 and N3 as needed.

[0053] The multiphase flow magnetic resonance flowmeter single-well metering device and method provided by the present invention solves the problem of real-time multiphase flow measurement in a single well, and can realize the use of the multiphase flow magnetic resonance flowmeter for on-site single-well metering in oil fields, especially single wells such as pumping wells whose liquid production changes in short cycles. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0055] Figure 1 This is a structural schematic diagram of a single-well metering device for a multiphase flow magnetic resonance flowmeter provided by an embodiment of the present invention.

[0056] Figure 2 This is a specific process flow chart of the single-well metering method for multiphase flow magnetic resonance flowmeter provided by an embodiment of the present invention.

[0057] Description of main figures:

[0058] 1. Multiphase flow magnetic resonance flowmeter;

[0059] 2. Grit tank;

[0060] 3. Branch pipeline;

[0061] 4. Pressure gauge;

[0062] 5. Sampling port;

[0063] 6. Pressure relief port;

[0064] 7. Manual unloading valve at pressure relief port;

[0065] 8. Inlet valve;

[0066] 9. Outlet valve;

[0067] 10. Oil and gas production Christmas trees;

[0068] 100. Multiphase flow magnetic resonance flowmeter single well metering device. DETAILED DESCRIPTION

[0069] In order to have a clearer understanding of the technical features, objectives and beneficial effects of the present invention, the technical solutions of the present invention are described in detail below in conjunction with the following specific embodiments, but they should not be construed as limiting the scope of implementation of the present invention.

[0070] Example 1

[0071] This embodiment provides a multiphase flow magnetic resonance flowmeter single well metering device 100, the structural diagram of which is shown in FIG. Figure 1 As shown, from Figure 1 As can be seen, it includes:

[0072] A multiphase flow magnetic resonance flowmeter 1, a grit tank 2, and a branch pipeline 3; the outlet of an oil and gas production Christmas tree 10 at an oilfield wellhead is connected to the inlet of the multiphase flow magnetic resonance flowmeter 1 via an inlet pipeline via the grit tank 2; the outlet of the multiphase flow magnetic resonance flowmeter 1 is connected to the inlet of the oil and gas production Christmas tree 10 via an outlet pipeline;

[0073] A pressure relief port 6 and a sampling port 5 are respectively provided on the inlet pipeline between the grit chamber 2 and the outlet of the oil and gas production Christmas tree 10;

[0074] A branch line 3 is installed at both ends of the multiphase flow magnetic resonance flowmeter 1, and one end of the branch line 3 is connected to an outlet valve 9 provided on the outlet pipeline, and the other end is connected to an inlet valve 8 provided on the inlet pipeline between the inlet of the multiphase flow magnetic resonance flowmeter 1 and the sand settling tank 2;

[0075] In this embodiment, a pressure gauge 4 is provided on the inlet pipe between the grit chamber 2 and the sampling port 5;

[0076] In this embodiment, the sampling port 5 is provided with a manual sampling port valve (not shown in the figure);

[0077] In this embodiment, the pressure relief port 6 is provided with a pressure relief port manual unloading valve 7;

[0078] In this embodiment, the outlet valve 9 and the inlet valve 8 are both electric valves.

[0079] Example 2

[0080] This embodiment provides a multiphase flow magnetic resonance flowmeter single well metering method, which is achieved by the multiphase flow magnetic resonance flowmeter single well metering device provided in Example 1. The method has a brief process flow chart as shown in FIG. Figure 2 As shown, from Figure 2 As can be seen, it includes:

[0081] Installing a multiphase flow magnetic resonance flowmeter single well metering device at an oil field wellhead, and connecting the inlet and outlet of the device to the outlet and inlet of an oil and gas production Christmas tree at the oil field wellhead, respectively;

[0082] Turn on the power and adjust the working mode of the outlet valve and the inlet valve (the valve is in the flow mode) to make the fluid in the inlet pipeline flow;

[0083] The instrument is ready and starts continuous measurement;

[0084] Automatically correct the pulse frequency of the multiphase magnetic resonance flowmeter to match the pulse frequency with the magnet frequency;

[0085] Then, the fluid in the inlet pipeline is kept in a static state by adjusting the working modes of the outlet valve and the inlet valve (the valve is in a static mode), and the multiphase flow magnetic resonance flowmeter is used to perform static (stationary) measurement, that is, to measure the fluid components;

[0086] Then adjust the working mode of the outlet valve and the inlet valve (the valve is in the flow mode) to make the fluid in the inlet pipeline in a flowing state, and use the multiphase flow magnetic resonance flowmeter to perform dynamic (flow) measurement, that is, measure the fluid flow.

[0087] In this embodiment, the automatic correction of the pulse frequency of the multiphase magnetic resonance flowmeter so that the pulse frequency matches the magnet frequency includes:

[0088] Before the start of each measurement cycle, the probe antenna of the multiphase flow magnetic resonance flowmeter transmits an FID pulse sequence, and the FID results are used to determine whether the pulse frequency matches the magnet frequency. If the two results match, a cycle of measurement begins. If the two results do not match, the pulse frequency parameters are automatically corrected until the two results match before starting a new cycle of measurement.

[0089] In this embodiment, the method also includes: according to the set parameters of the oil field wellhead pumping unit, accurately controlling the action time of the outlet valve and the inlet valve, the time for the multiphase flow magnetic resonance flowmeter to perform static measurement, and the time for the multiphase flow magnetic resonance flowmeter to perform dynamic measurement, so that the measurement frequency of the multiphase flow magnetic resonance flowmeter is consistent with the alternating frequency of the up and down strokes of the pumping unit, ensuring that the start and end times of each measurement correspond to the position of the sucker rod remains unchanged.

[0090] In this embodiment, the measurement time required for each measurement cycle of the multiphase magnetic resonance flowmeter single well metering device is calculated according to the following formula 1):

[0091] T 周 =T 静 +T 动 +2T 阀 =NT 往 Formula 1);

[0092] In formula 1), T 周 T is the measurement time required for each measurement cycle of the multiphase magnetic resonance flowmeter single well metering device, in seconds; 静 T is the static measurement time of the multiphase magnetic resonance flowmeter, in seconds; 动 T is the time for dynamic measurement of multiphase magnetic resonance flowmeter, in seconds; 阀 is the action time of the outlet valve or inlet valve, in seconds; N is an integer, in times;

[0093] T 往 is the time it takes for the pump to reciprocate once, in seconds, where T 往 Calculated according to the following formula 2):

[0094]

[0095] In formula 2), S is the stroke count, which represents the number of reciprocating motions of the sucker rod of the pumping unit in 1 minute. One stroke count means that the sucker rod of the pumping unit moves up and down once per minute.

[0096] In this embodiment, the action time T of the outlet valve or the inlet valve is 阀 Calculated according to the following formula 3):

[0097] 60s <T 阀 =N1×T 往 <300s formula 3);

[0098] In formula 3), T 往 It is the time for the pump to reciprocate once, in seconds; N1 is an integer, in times.

[0099] In this embodiment, the time T for the multiphase magnetic resonance flowmeter to perform static measurement 静 Calculated according to the following formula 4):

[0100] T 静 =ET 静 ×EC 静 ×Sc 静 +Sc 静 ×RT 静 =N2×T 往 Formula 4);

[0101] In formula 4), ET 静 is the echo interval, RT 静 is the magnetization time, EC 静 is the number of echoes, Sc 静 is the number of superpositions, T 往 It is the time for the pump to reciprocate once, in seconds; N2 is an integer, in times.

[0102] In this embodiment, the multiphase magnetic resonance flowmeter performs dynamic measurement for a time T 动 Calculated according to the following formula 5) and formula 6):

[0103] T 动 =T1×FN+FN×RT 动 =N3×T 往 Formula 5);

[0104] T1=ET 动 ×EC 动 ×Sc 动 +Sc 动 ×FS≤T 单 Formula 6);

[0105] In formula 5) and formula 6), T1 is the time required for each flow measurement, in seconds, FN is the number of measurements, and T 往 is the time it takes for the pumping unit to reciprocate once, in seconds; N3 is an integer, in times;

[0106] ET动 is the echo interval, RT 动 is the sampling interval, EC 动 is the number of echoes, Sc 动 is the number of superpositions, FS is the superposition interval; T 单 is the minimum one-way time of the pumping unit, in seconds, which is calculated according to the following formula 7);

[0107]

[0108] In formula 7), S is the stroke count, which represents the number of reciprocating motions of the sucker rod of the pumping unit in 1 minute. One stroke count means that the sucker rod of the pumping unit moves up and down once per minute.

[0109] The multiphase flow magnetic resonance flowmeter single-well metering device and method provided in the embodiments of the present invention solve the problem of real-time multiphase flow measurement in a single well, and can realize the use of the multiphase flow magnetic resonance flowmeter for single-well metering on-site in oil fields, especially single wells such as pumping wells whose liquid production changes in short cycles.

[0110] The above description is merely a specific embodiment of the present invention and should not be construed as limiting the scope of the invention. Therefore, substitutions of equivalent components, or equivalent changes and modifications made within the scope of patent protection, should still fall within the scope of this patent. Furthermore, the technical features of this invention may be freely combined with one another, with other technical inventions, and with other technical inventions.

Claims

1. A multiphase flow magnetic resonance flowmeter single well measurement method, characterized in that: include: A multiphase flow magnetic resonance flowmeter single-well metering device is installed at the wellhead of an oil field, and the inlet and outlet of the device are respectively connected to the outlet and inlet of the oil and gas production Christmas tree at the wellhead of the oil field; wherein, the multiphase flow magnetic resonance flowmeter single-well metering device includes a multiphase flow magnetic resonance flowmeter, a sand settling tank and a branch pipeline; the outlet of the oil and gas production Christmas tree at the wellhead of the oil field is connected to the inlet of the multiphase flow magnetic resonance flowmeter via the sand settling tank through an inlet pipeline; the outlet of the multiphase flow magnetic resonance flowmeter is connected to the inlet of the Christmas tree through an outlet pipeline; a pressure relief port and a sampling port are respectively provided on the inlet pipeline between the sand settling tank and the outlet of the Christmas tree; branch pipelines are installed at both ends of the multiphase flow magnetic resonance flowmeter, and one end of the branch pipeline is connected to the outlet valve provided on the outlet pipeline, and the other end is connected to the inlet valve provided on the inlet pipeline between the inlet of the multiphase flow magnetic resonance flowmeter and the sand settling tank; Turn on the power and adjust the working modes of the outlet valve and the inlet valve to make the fluid in the inlet pipeline flow; Automatically calibrate the pulse frequency of the multiphase magnetic resonance flowmeter to match the pulse frequency with the magnet frequency, including: before each measurement cycle begins, the probe antenna of the multiphase magnetic resonance flowmeter transmits an FID pulse sequence, and determines whether the pulse frequency matches the magnet frequency based on the FID result; if the two results match, then a cycle of measurement begins; if the two results do not match, then the pulse frequency parameters are automatically corrected until the two results match before starting a new cycle of measurement; Then, the working modes of the outlet valve and the inlet valve are adjusted to make the fluid in the inlet pipeline static, and the multiphase flow magnetic resonance flowmeter is used to perform static measurement, that is, to measure the fluid components; Then, the working modes of the outlet valve and the inlet valve are adjusted to make the fluid in the inlet pipeline flow, and the multiphase flow magnetic resonance flowmeter is used to perform dynamic measurement, that is, to measure the fluid flow rate; The measurement time required for each measurement cycle of the multiphase flow magnetic resonance flowmeter single well metering device is calculated according to the following formula 1): T 周 =T 静 +T 动 +2T 阀 =NT 往 Formula 1); In formula 1), T 周 T is the measurement time required for each measurement cycle of the multiphase magnetic resonance flowmeter single well metering device, in seconds; 静 T is the static measurement time of the multiphase magnetic resonance flowmeter, in seconds; 动 T is the time for the multiphase magnetic resonance flowmeter to perform dynamic measurement, in seconds; 阀 is the action time of the outlet valve or inlet valve, in seconds; N is an integer, in times; T 往 is the time it takes for the pump to reciprocate once, in seconds, where T 往 Calculated according to the following formula 2): In formula 2), S is the stroke, which represents the number of reciprocating motions of the sucker rod of the pumping unit in 1 minute. One stroke means that the sucker rod of the pumping unit moves up and down once per minute.

2. The method according to claim 1, characterized in that The method further includes: accurately controlling the actuation time of the outlet valve and the inlet valve, the static measurement time of the multiphase flow magnetic resonance flowmeter, and the dynamic measurement time of the multiphase flow magnetic resonance flowmeter according to the set parameters of the oil field wellhead pumping unit, so that the measurement frequency of the multiphase flow magnetic resonance flowmeter is consistent with the alternating frequency of the up and down strokes of the pumping unit, ensuring that the start and end times of each measurement correspond to the position of the pumping rod remaining unchanged.

3. The method according to claim 1, characterized in that Action time T of outlet valve or inlet valve 阀 Calculated according to the following formula 3): 60s <T 阀 = N1 × T 往 <300s Formula 3); In formula 3), T 往 It is the time for the pump to reciprocate once, in seconds; N1 is an integer, in times.

4. The method according to claim 1, wherein The static measurement time T of the multiphase magnetic resonance flowmeter 静 Calculated according to the following formula 4): T 静 =ET 静 ×Ec 静 ×Sc 静 +Sc 静 ×RT 静 =N2×T 往 Formula 4); In formula 4), ET 静 is the echo interval, RT 静 is the magnetization time, EC 静 is the number of echoes, Sc 静 is the number of superpositions, T 往 It is the time for the pump to reciprocate once, in seconds; N2 is an integer, in times.

5. The method according to claim 1, wherein The time T for dynamic measurement of multiphase magnetic resonance flowmeter 动 Calculated according to the following formula 5) and formula 6): T 动 =T1×FN+FN×RT 动 =N3×T 往 Formula 5); T1=ET 动 ×EC 动 ×Sc 动 +Sc 动 ×FS≤T 单 Formula 6); In formula 5) and formula 6), T1 is the time required for each flow measurement, in seconds, FN is the number of measurements, and T 往 is the time it takes for the pumping unit to reciprocate once, in seconds; N3 is an integer, in times; ET 动 is the echo interval, RT 动 is the sampling interval, EC 动 is the number of echoes, Sc 动 is the number of superpositions, FS is the superposition interval; T 单 is the minimum one-way time of the pumping unit, in seconds, which is calculated according to the following formula 7); In formula 7), S is the stroke count, which represents the number of reciprocating motions of the sucker rod of the pumping unit in 1 minute. One stroke count means that the sucker rod of the pumping unit moves up and down once per minute.

6. The method according to claim 1, wherein A pressure gauge is provided on the inlet pipeline between the sand settling tank and the sampling port.

7. The method according to claim 1, characterized in that The sampling port is provided with a manual sampling port valve.

8. The method according to claim 1 or 7, characterized in that The pressure relief port is provided with a manual unloading valve for the pressure relief port.

9. The method according to claim 1, characterized in that The outlet valve and the inlet valve are both electric valves.

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