Natural gas flow meter testing device and method

Abstract

The present application provides a natural gas flow meter testing device and method, which belongs to the field of natural gas flow metering technology. The technical solution provided in the embodiment of the present application uses a reference flow meter whose outflow coefficient can remain unchanged under different pressures to test the accuracy of the measured flow meter, and utilizes the characteristic that the accuracy of the reference flow meter is not affected under high pressure conditions, which not only ensures the accuracy of the reference flow meter under high pressure conditions, but also ensures that the measured flow meter is under high pressure conditions when being tested, so that the accuracy measured by the device is the actual accuracy of the measured flow meter under high pressure conditions, has a high reference value, and is suitable for flow metering when the measured flow meter is applied to the wellhead of a gas storage reservoir.

Description

Technical Field

[0001] The present application relates to the technical field of natural gas flow metering, and in particular to a natural gas flow meter testing device and method. Background Art

[0002] In the operation of natural gas storage, injection and production gas metering is an important process link. Accurate metering can effectively guide production, optimize operating parameters, scientifically evaluate injection and production effects, and improve natural gas injection and production rates. In the metering process, the accuracy of the flow meter plays a key role in the metering results. Therefore, it is necessary to test the accuracy of the flow meter, among which the accuracy test content includes indication error and repeatability.

[0003] However, the test of the flowmeter by the currently commonly used natural gas flowmeter testing device is usually a dry calibration performed under the conditions of a calibration pressure of less than 10MPa and when the gas is still and not flowing, by accurately measuring the various parameters in the flow equation. The accuracy of the flowmeter is only applicable to fluids with a pressure of less than 10MPa. When the above-mentioned flowmeter is applied to the wellhead of a gas storage reservoir, since the natural gas pressure at the wellhead of the gas storage reservoir may be as high as 16MPa-42MPa, under the conditions of high-pressure natural gas flow, the flowmeter probe signal, the dimensional deformation of the flowmeter body, etc. will have slight changes, which will cause the measurement accuracy of the on-site flowmeter to change. Therefore, the accuracy measured by the above-mentioned natural gas flowmeter testing device under the original test conditions will not be applicable to the high-pressure conditions at the wellhead of a gas storage reservoir. Summary of the invention

[0004] The embodiment of the present application provides a natural gas flow meter testing device and method. The accuracy measured by the device is the actual accuracy of the measured flow meter under high pressure conditions, which has a high reference value and is suitable for flow metering when the measured flow meter is applied at the wellhead of a gas storage reservoir. The technical solution is as follows:

[0005] In one aspect, a natural gas flow meter testing device is provided, the device comprising: a first branch and a second branch;

[0006] The first branch and the second branch are connected in parallel;

[0007] The first end of the first branch is connected to the first end of the second branch, and the first connection point formed is used to connect the booster unit or the natural gas pipeline network. The booster unit can provide a preset pressure for the first branch;

[0008] The second end of the first branch is connected to the second end of the second branch, and the formed second connection is used to connect to the wellhead of the gas storage reservoir, and the wellhead of the gas storage reservoir can provide a preset pressure for the first branch;

[0009] The first branch includes: a first valve group, a reference flow meter, a measured flow meter and a second valve group, which are sequentially connected through a pipeline from a first end to a second end of the first branch;

[0010] The second branch includes: a gas storage bidirectional flow meter connected to the first end and the second end of the second branch through a pipeline;

[0011] The outflow coefficient of the reference flow meter remains unchanged under different pressures. The reference flow meter comprises: a meter body and a flow blocker, wherein the flow blocker is in a spindle shape;

[0012] A flow channel is provided between the first port and the second port of the meter body, the flow blocking member is located in the flow channel, a first pressure port is provided on the side wall corresponding to the first port, and a second pressure port is provided on the side wall corresponding to the middle position of the flow channel.

[0013] In a possible design, the preset pressure is: 16MPa-42MPa.

[0014] In a possible design, the first valve group includes: at least two stages of valves connected in series, for adjusting the flow rate of the fluid in the first branch.

[0015] In a possible design, the second valve group includes: at least two stages of valves connected in series, for adjusting the flow rate of the fluid in the first branch.

[0016] In a possible design, the reference flow meter further includes: at least two groups of support plates, and each end of the flow blocking member is fixed to the inner wall of the meter body through a group of the support plates.

[0017] In a possible design, a temperature measuring port is also provided on the meter body.

[0018] In one possible design, the booster unit includes a compressor.

[0019] In one aspect, a natural gas flow meter testing method is provided, the method being applied to a natural gas flow meter testing device provided in any of the possible designs described above, the method comprising:

[0020] Install the flow meter to be measured between the reference flow meter and the second valve group;

[0021] opening the first valve group and the second valve group;

[0022] Adjusting the first valve group and the second valve group so that the fluid pressure in the first branch is a preset pressure;

[0023] Acquire first flow data of a reference flow meter and second flow data of a measured flow meter corresponding to the same moment for multiple times;

[0024] Based on the first flow data, the second flow data and the outflow coefficient of the reference flow meter, the flow indication error and repeatability of the measured flow meter relative to the reference flow meter are obtained.

[0025] In a possible implementation, the preset pressure is: 16MPa-42MPa.

[0026] In a possible implementation, adjusting the first valve group and the second valve group so that the fluid in the first branch has a preset pressure includes:

[0027] When the fluid flows from the first end to the second end of the first branch, the booster unit, the first valve unit and the second valve unit are adjusted so that the fluid in the first branch has a preset pressure;

[0028] When the fluid flows from the second end to the first end of the first branch, the first valve group and the second valve group are adjusted so that the fluid in the first branch has a preset pressure.

[0029] The technical solution provided in the embodiment of the present application tests the accuracy of the flow meter under test by using a reference flow meter whose outflow coefficient can remain unchanged under different pressures. It utilizes the characteristic that the accuracy of the reference flow meter is not affected under high pressure conditions, thereby ensuring the accuracy of the reference flow meter under high pressure conditions and ensuring that the flow meter under test is under high pressure conditions. Therefore, the accuracy measured by the device is the actual accuracy of the flow meter under high pressure conditions, has high reference value, and is suitable for flow metering when the flow meter under test is used at the wellhead of a gas storage reservoir. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0031] Figure 1 It is a structural schematic diagram of a natural gas flow meter testing device provided in an embodiment of the present application;

[0032] Figure 2 is a structural schematic diagram of a reference flow meter 12 provided in an embodiment of the present application;

[0033] Figure 3 It is a schematic diagram of the application structure of a natural gas flow meter testing device provided in an embodiment of the present application;

[0034] Figure 4 It is a schematic diagram of the application structure of another natural gas flow meter testing device provided in an embodiment of the present application;

[0035] Figure 5 is a flow chart of a natural gas flow meter testing method provided in an embodiment of the present application;

[0036] Figure 6 This is a flow chart of a natural gas flow meter testing method provided in an embodiment of the present application.

[0037] The reference numerals of the components in the accompanying drawings are as follows:

[0038] 1- First branch;

[0039] 11- first valve group;

[0040] 12- Reference flow meter;

[0041] 121-body;

[0042] 1211-first pressure port;

[0043] 1212- second pressure port;

[0044] 122- flow blocking member;

[0045] 123-first port;

[0046] 124 - second port;

[0047] 125-support sheet;

[0048] 126-temperature measuring port;

[0049] 13- Flow meter under test;

[0050] 14- second valve group;

[0051] 2- Second branch;

[0052] 21- Gas storage bidirectional flow meter;

[0053] 3- Booster unit;

[0054] 4-Natural gas pipeline network;

[0055] 5- Gas storage wellhead. DETAILED DESCRIPTION

[0056] In order to make the objectives, technical solutions and advantages of the present application clearer, the implementation methods of the present application will be further described in detail below in conjunction with the accompanying drawings.

[0057] In this application, unless otherwise clearly specified and limited, the terms such as "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0058] During the operation of the natural gas storage, a two-way flow meter 21 is installed at the wellhead 5 of the gas storage, so that the natural gas can flow into the gas storage through the two-way flow meter 21, and can also flow out of the gas storage through the two-way flow meter of the wellhead 5 of the gas storage. Since a large amount of natural gas is gathered in the gas storage, the fluid in the pipeline of the wellhead 5 of the gas storage has a relatively high pressure. At some wellheads 5 of the gas storage, the pressure can be 16MPa-42MPa.

[0059] The present application provides a natural gas flow meter testing device based on the original structure of the gas storage inlet, which can not only utilize the original conditions for testing and save the cost of building equipment, but also provide conditions for the test of the flow meter 13 to be tested that are completely consistent with the gas storage wellhead 5, including pressure conditions and the stability of natural gas flow, etc., so that the test process can completely simulate the actual use environment of the flow meter 13 to be tested, so that the obtained test results can completely match the use environment of the flow meter 13 to be tested.

[0060] Figure 1 This is a schematic diagram of the structure of a natural gas flow meter test device provided in an embodiment of the present application. Figure 1The device comprises: a first branch 1 and a second branch 2; the first branch 1 and the second branch 2 are connected in parallel; the first end of the first branch 1 is connected to the first end of the second branch 2, and the first connection formed is used to connect the booster unit 3 or the natural gas pipeline network 4, and the booster unit 3 can provide a preset pressure for the first branch 1; the second end of the first branch 1 is connected to the second end of the second branch 2, and the second connection formed is used to connect the gas storage wellhead 5, and the gas storage wellhead 5 can provide a preset pressure for the first branch 1; the first branch 1 comprises: a first valve group 11, a reference flow meter 12, which are sequentially connected from the first end of the first branch 1 to the second end through a pipeline. , a measured flow meter 13 and a second valve group 14; the second branch 2 includes: a gas storage reservoir bidirectional flow meter 21 respectively connected to the first end and the second end of the second branch 2 through a pipeline; the outflow coefficient of the reference flow meter 12 remains unchanged under different pressures, and the reference flow meter 12 includes: a meter body 121 and a baffle 122, and the baffle 122 is spindle-shaped; a flow channel is provided between the first port 123 and the second port 124 of the meter body 121, and the baffle 122 is located in the flow channel, and a first pressure port 1211 is provided on the side wall corresponding to the first port 123, and a second pressure port 1212 is provided on the side wall corresponding to the middle position of the flow channel.

[0061] The working principle of the device is described in detail below:

[0062] The reference flowmeter 12 is a differential pressure flowmeter, and its working principle is: to measure pressure based on the fluid continuity equation and the Bernoulli equation, and has the characteristic that the outflow coefficient remains unchanged under different pressures. Therefore, the reference flowmeter 12 can accurately measure the flow rate of the fluid and is suitable for testing the measured flowmeter 13. The structure and working principle of the reference flowmeter 12 are introduced below:

[0063] Figure 2 This is a schematic diagram of the structure of a reference flow meter 12 provided in an embodiment of the present application, see Figure 2For the reference flow meter 12, the first pressure port 1211 is connected to the first pressure gauge, and the second pressure port 1212 is connected to the second pressure gauge. By inserting a flow blocker 122 having a diameter smaller than the inner diameter of the flow channel, coaxial with the axis, and in the shape of a spindle in the meter body 121, when the fluid passes through the annular groove formed between the flow blocker 122 and the inner wall of the meter body 121, the boundary layers on both sides of the fluid are forced to be rebuilt, so that the flow state of the fluid in the annular groove is close to a uniform velocity distribution. Since the reference flow meter 12 is a bidirectional flow meter, the fluid can flow in both directions in the flow channel. Taking the process of the fluid flowing from the first port 123 to the second port 124 as an example, when the fluid flows from the first port 123 to the middle of the meter body 121, the flow velocity of the fluid is accelerated and the pressure is reduced, thereby forming a stable differential pressure between the first port 123 and the middle of the meter body 121, and then the flow rate can be calculated according to the functional relationship between the pressure difference and the flow rate.

[0064] The flow rate can be obtained based on the following equation 1 or equation 2:

[0065]

[0066] In the formula, q m is the mass flow rate;

[0067] Re is the Reynolds number;

[0068] D is the flow meter diameter;

[0069] d is the equivalent inner diameter of the flow meter;

[0070] β is the ratio of d to D;

[0071] Ma is the Mach number;

[0072] ρ 1 is the gas density;

[0073] Δp is the differential pressure;

[0074]

[0075] Where: q m is the mass flow rate;

[0076] D is the flow meter diameter;

[0077] d is the equivalent inner diameter of the flow meter;

[0078] ρ 1 is the gas density;

[0079] Δp is the differential pressure;

[0080] C is the flow meter discharge coefficient;

[0081] ε is the expansion coefficient.

[0082] The use of this spindle-shaped component fluid allows the reference flow meter 12 to have a self-rectifying effect, which can ensure that laboratory conditions and on-site high-pressure conditions have the same movement similarity.

[0083] In the above structure, the first connection point is used to connect the booster unit 3 or the natural gas pipeline network 4, and the booster unit 3 and the natural gas pipeline network 4 correspond to two different usage modes of the device.

[0084] Figure 3 This is a schematic diagram of the application structure of a natural gas flow meter test device provided in an embodiment of the present application. Figure 3 When the booster unit 3 is connected at the first connection point, high-pressure natural gas is introduced into the gas storage reservoir through the booster unit 3 along the first branch 1.

[0085] Figure 4 This is a schematic diagram of the application structure of another natural gas flow meter test device provided in the embodiment of the present application. Figure 4 , connected to the natural gas pipeline network 4 at the first connection point, and based on the pressure of the gas itself in the gas storage, natural gas is transported to the natural gas pipeline network 4 along the first branch 1.

[0086] In this embodiment, the use mode of introducing high-pressure natural gas into the gas storage reservoir through the booster unit 3 can be called forward use, and the use mode of transporting natural gas from the gas storage reservoir to the natural gas pipeline network 4 can be called reverse use. Through the use in both forward and reverse directions, the flow meter 13 under test is tested in both forward and reverse directions, thereby simulating its actual use state, which is conducive to accurate testing of its accuracy.

[0087] In the forward use process, the use steps can be:

[0088] Step 1: Connect the first end of the first branch 1 to the booster unit 3, and the second end to the gas storage wellhead 5.

[0089] Step 2: Install the measured flow meter 13 between the reference flow meter 12 and the second valve group 14 .

[0090] Step 3: Open the first valve group 11 and the second valve group 14.

[0091] Step 4: When the fluid flows from the first end to the second end of the first branch 1, the booster unit 3, the first valve group 11 and the second valve group 14 are adjusted so that the fluid in the first branch 1 has a preset pressure.

[0092] Step 5: Acquire the first flow data of the reference flow meter 12 and the second flow data of the measured flow meter 13 corresponding to the same moment for multiple times.

[0093] Step 6: Based on the first flow data, the second flow data and the outflow coefficient of the reference flow meter 12 , the flow indication error and repeatability of the measured flow meter 13 relative to the reference flow meter 12 are obtained.

[0094] In the reverse use process, the use steps can be:

[0095] Step 1: Connect the first end of the first branch 1 to the natural gas pipeline network 4, and the second end to the gas storage wellhead 5.

[0096] Step 2: Install the measured flow meter 13 between the reference flow meter 12 and the second valve group 14 .

[0097] Step 3: Open the first valve group 11 and the second valve group 14.

[0098] Step 4: When the fluid flows from the second end to the first end of the first branch 1, the first valve group 11 and the second valve group 14 are adjusted to make the fluid in the first branch 1 have a preset pressure.

[0099] Step 5: Acquire the first flow data of the reference flow meter 12 and the second flow data of the measured flow meter 13 corresponding to the same moment for multiple times.

[0100] Step 6: Based on the first flow data, the second flow data and the outflow coefficient of the reference flow meter 12 , the flow indication error and repeatability of the measured flow meter 13 relative to the reference flow meter 12 are obtained.

[0101] The device provided in the embodiment of the present application tests the accuracy of the measured flow meter 13 by using a reference flow meter 12 whose outflow coefficient can remain unchanged under different pressures. It utilizes the characteristic that the accuracy of the reference flow meter 12 is not affected under high pressure conditions, thereby ensuring the accuracy of the reference flow meter 12 under high pressure conditions and ensuring that the measured flow meter 13 is under high pressure conditions during the test. Therefore, the accuracy measured by the device is the actual accuracy of the measured flow meter 13 under high pressure conditions, has a high reference value, and is suitable for flow metering when the measured flow meter 13 is used at the wellhead 5 of a gas storage reservoir.

[0102] The following is a detailed description of the structure and working principle of each part of the device:

[0103] For the reference flow meter 12, in addition to the first pressure gauge and the second pressure gauge, a pressure transmitter and a flow integrator are also connected to automatically calculate the flow rate. The spindle-shaped flow blocker 122 can avoid flow separation and vortex generation, and minimize the resistance to the fluid. A uniform diameter section is provided at an appropriate position in the middle of the flow blocker 122, forming a uniform annular groove with the inner wall of the measuring tube.

[0104] At the baffle 122, the flow area of ​​the measuring tube becomes smaller. The fluid flow rate is low and the pressure is high where the cross-sectional area is large in the pipeline, and the flow rate is high and the pressure is low where the cross-sectional area is small. In other words, the flow area is large and the pressure is high where the high-pressure tube is located, and the flow area is small and the pressure is low where the low-pressure tube is located. In addition, the fluid is viscous, and the friction with the wall causes the total pressure of the fluid to decrease along the flow direction. The effects of these two aspects cause a differential pressure to be generated between the high-pressure hole and the low-pressure hole, and this differential pressure has a certain corresponding relationship with the flow rate. Therefore, the flow rate can be calculated by measuring the differential pressure. The measurement accuracy of the reference flowmeter 12 is largely limited by the accuracy of the differential pressure transmitter and the flow integrator.

[0105] Due to the similarity between the calibration flow field and the application flow field of the reference flow meter 12, the outflow coefficient of the reference flow meter 12 has a relatively unchanged characteristic under laboratory conditions and high pressure conditions when the Reynolds number is greater than 105, and the high pressure and low pressure metering indication errors are close. The outflow coefficients obtained by fitting using the coefficient verification method are 0.9051 and 0.9052 respectively.

[0106] Through the experimental data of high pressure, low pressure and factory test conditions, it can be known that when the flow rate is greater than 32m 3 / h, the reference flowmeter 12 is actually tested under the condition that the pressure at the wellhead 5 of the gas storage reservoir is 22MPa~25MPa. The deviation of the flow indication of the reference flowmeter 12 relative to the reference flow is about -0.43%. Using the laboratory outflow coefficient, the parameters under the field working conditions can be calculated to obtain the calculated flow indication error. The flow indication error calculated using the laboratory low-pressure outflow coefficient is very close to the relative deviation of the actual measured flow, and the entire average relative deviation is only -0.03%. Therefore, the test data of the reference flowmeter 12 in the gas injection stage shows that its relative deviation is consistent with the laboratory test data. Under low-pressure conditions less than 10MPa, high-pressure conditions higher than 20MPa, and when the Reynolds number is greater than 105, the outflow coefficient of the reference flowmeter 12 has a relatively unchanged characteristic.

[0107] In a possible design, the preset pressure is: 16MPa-42MPa, which is consistent with the pressure of the gas storage wellhead 5 during use, so that the device can simulate the actual working conditions of the measured flow meter 13.

[0108] In a possible design, the first valve group 11 includes: at least two stages of valves connected in series, which are used to adjust the flow rate of the fluid in the first branch 1. The at least two sets of valves are used to play a control role, and the flow rate of the fluid in the first branch 1 is adjusted by adjusting the opening of the two stages of valves, and the pressure of the fluid in the first branch 1 is adjusted to a preset pressure through the change of the flow rate.

[0109] In a possible design, the second valve group 14 includes: at least two stages of valves connected in series, which are used to adjust the flow rate of the fluid in the first branch 1. The at least two sets of valves are used to play a control role, and the flow rate of the fluid in the first branch 1 is adjusted by adjusting the opening of the two stages of valves, and the pressure of the fluid in the first branch 1 is adjusted to a preset pressure through the change of the flow rate.

[0110] In a possible design, the reference flow meter 12 further includes: at least two groups of support sheets 125, and each end of the flow blocker 122 is fixed to the inner wall of the meter body 121 through a group of the support sheets 125. The number of each group of support sheets 125 can be at least 3, and they are evenly distributed, so that the flow blocker 122 can be fixed at different angles in a circle, for example, there can be 4 sheets, and each two sheets form an angle of 90 degrees. The shape and inclination angle of the support sheet 125 can be set according to actual needs, and this embodiment does not limit this.

[0111] In a possible design, the meter body 121 is further provided with a temperature measuring port 126 for measuring the temperature of the fluid, so as to obtain more accurate flow information.

[0112] In a possible design, the booster unit 3 includes a compressor, which is used to pressurize the fluid so that the fluid can quickly reach a preset pressure.

[0113] All the above optional technical solutions can be arbitrarily combined to form optional embodiments of the present application, which will not be described one by one here.

[0114] The device provided in the embodiment of the present application tests the accuracy of the measured flow meter 13 by using a reference flow meter 12 whose outflow coefficient can remain unchanged under different pressures. It utilizes the characteristic that the accuracy of the reference flow meter 12 is not affected under high pressure conditions, thereby ensuring the accuracy of the reference flow meter 12 under high pressure conditions and ensuring that the measured flow meter 13 is under high pressure conditions during the test. Therefore, the accuracy measured by the device is the actual accuracy of the measured flow meter 13 under high pressure conditions, has a high reference value, and is suitable for flow metering when the measured flow meter 13 is used at the wellhead 5 of a gas storage reservoir.

[0115] In this embodiment, the use mode of introducing high-pressure natural gas into the gas storage reservoir through the booster unit 3 can be called forward use, and the use mode of transporting natural gas from the gas storage reservoir to the natural gas pipeline network 4 can be called reverse use. Through the use in both forward and reverse directions, the flow meter 13 under test is tested in both forward and reverse directions, thereby simulating its actual use state, which is conducive to accurately testing its accuracy. The two use cases are introduced respectively below.

[0116] Figure 5This is a flow chart of a natural gas flow meter testing method provided in an embodiment of the present application. Figure 5 The method is applied to a natural gas flow meter test device provided in any of the possible designs described above, and the method comprises:

[0117] In the forward use process, the use steps can be:

[0118] 501: Connect the first end of the first branch 1 to the booster unit 3, and the second end to the gas storage wellhead 5.

[0119] In this step, the first end is connected to the booster unit 3 to facilitate the introduction of high-pressure natural gas into the gas storage reservoir through the booster unit 3.

[0120] 502 : The measured flow meter 13 is installed between the reference flow meter 12 and the second valve group 14 .

[0121] In this step, the measured flow meter 13 and the reference flow meter 12 are placed adjacent to each other, thereby ensuring that the flow rates corresponding to the two are exactly the same.

[0122] 503 : Open the first valve group 11 and the second valve group 14 .

[0123] This step is used to start tapping.

[0124] 504: When the fluid flows from the first end to the second end of the first branch 1, the booster unit 3, the first valve group 11 and the second valve group 14 are adjusted so that the fluid in the first branch 1 has a preset pressure.

[0125] In a possible implementation, the preset pressure is: 16MPa-42MPa.

[0126] 505: Acquire the first flow data of the reference flow meter 12 and the second flow data of the measured flow meter 13 corresponding to the same moment for multiple times.

[0127] The first flow data can be obtained by calculating based on the function corresponding to the reference flow meter 12, and the second flow data can be obtained by calculating based on the function corresponding to the measured flow meter 13, or can be read out through the display corresponding to the measured flow meter 13, which is not limited in this embodiment.

[0128] 506: Based on the first flow data, the second flow data and the outflow coefficient of the reference flow meter 12, the flow indication error and repeatability of the measured flow meter 13 relative to the reference flow meter 12 are obtained.

[0129] The flow indication error relative to the reference flow meter 12 refers to the error size of the data after multiple tests, and repeatability refers to the degree of repetition of the data after multiple tests.

[0130] In this step, the indication error of the measured flow meter 13 can also be detected to serve as a reference for its accuracy test.

[0131] The method provided in the embodiment of the present application tests the accuracy of the measured flow meter 13 by using a reference flow meter 12 whose outflow coefficient can remain unchanged under different pressures. It utilizes the characteristic that the accuracy of the reference flow meter 12 is not affected under high pressure conditions, thereby ensuring the accuracy of the reference flow meter 12 under high pressure conditions and ensuring that the measured flow meter 13 is under high pressure conditions during the test. Therefore, the accuracy measured by the device is the actual accuracy of the measured flow meter 13 under high pressure conditions, has a high reference value, and is suitable for use in flow measurement when the measured flow meter 13 is used at the wellhead 5 of a gas storage reservoir.

[0132] Figure 6 This is a flow chart of a natural gas flow meter testing method provided in an embodiment of the present application. Figure 6 The method is applied to a natural gas flow meter test device provided in any of the possible designs described above, and the method comprises:

[0133] In the reverse use process, the use steps can be:

[0134] 601: Connect the first end of the first branch 1 to the natural gas pipeline 4, and connect the second end to the gas storage wellhead 5.

[0135] In this step, the first end is connected to the natural gas pipeline network 4 to facilitate the introduction of high-pressure natural gas into the natural gas pipeline network 4 through the gas storage wellhead 5 .

[0136] 602 : The measured flow meter 13 is installed between the reference flow meter 12 and the second valve group 14 .

[0137] In this step, the measured flow meter 13 and the reference flow meter 12 are placed adjacent to each other, thereby ensuring that the flow rates corresponding to the two are exactly the same.

[0138] 603 : Open the first valve group 11 and the second valve group 14 .

[0139] This step is used to start tapping.

[0140] 604: When the fluid flows from the second end to the first end of the first branch 1, the first valve group 11 and the second valve group 14 are adjusted so that the fluid in the first branch 1 has a preset pressure.

[0141] In a possible implementation, the preset pressure is: 16MPa-42MPa.

[0142] 605: Acquire the first flow data of the reference flow meter 12 and the second flow data of the measured flow meter 13 corresponding to the same moment for multiple times.

[0143] The first flow data can be obtained by calculating based on the function corresponding to the reference flow meter 12, and the second flow data can be obtained by calculating based on the function corresponding to the measured flow meter 13, or can be read out through the display corresponding to the measured flow meter 13, which is not limited in this embodiment.

[0144] 606: Based on the first flow data, the second flow data and the outflow coefficient of the reference flow meter 12, the flow indication error and repeatability of the measured flow meter 13 relative to the reference flow meter 12 are obtained.

[0145] The flow indication error relative to the reference flow meter 12 refers to the error size of the data after multiple tests, and repeatability refers to the degree of repetition of the data after multiple tests.

[0146] The method provided in the embodiment of the present application tests the accuracy of the measured flow meter 13 by using a reference flow meter 12 whose outflow coefficient can remain unchanged under different pressures. It utilizes the characteristic that the accuracy of the reference flow meter 12 is not affected under high pressure conditions, thereby ensuring the accuracy of the reference flow meter 12 under high pressure conditions and ensuring that the measured flow meter 13 is under high pressure conditions during the test. Therefore, the accuracy measured by the device is the actual accuracy of the measured flow meter 13 under high pressure conditions, has a high reference value, and is suitable for flow metering when the measured flow meter 13 is used at the wellhead 5 of a gas storage reservoir.

[0147] The above are only optional embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A natural gas flow meter testing method, characterized in that: The method is applied to a natural gas flow meter testing device, the device comprising: a first branch (1) and a second branch (2); The first branch (1) and the second branch (2) are connected in parallel; The first end of the first branch (1) and the first end of the second branch (2) are connected to form a first connection point for connecting a booster unit (3) or a natural gas pipeline network (4); the booster unit (3) can provide a preset pressure for the first branch (1); the booster unit (3) comprises a compressor; The second end of the first branch (1) is connected to the second end of the second branch (2), and the second connection point formed is used to connect to the gas storage wellhead (5). The gas storage wellhead (5) can provide a preset pressure for the first branch (1), and the preset pressure is: 16MPa-42MPa; The first branch (1) comprises: a first valve group (11), a reference flow meter (12), a measured flow meter (13) and a second valve group (14) which are sequentially connected through pipelines from a first end to a second end of the first branch (1); The second branch (2) comprises: a gas storage bidirectional flow meter (21) connected to the first end and the second end of the second branch (2) respectively through a pipeline; the gas storage bidirectional flow meter (21) allows the natural gas to flow into the gas storage through the gas storage bidirectional flow meter (21) and flow out of the gas storage through the gas storage bidirectional flow meter (21); The outflow coefficient of the reference flow meter (12) remains unchanged under different pressures. The reference flow meter (12) comprises: a meter body (121) and a flow blocker (122), wherein the flow blocker (122) is in the shape of a spindle; A circulation channel is provided between the first port (123) and the second port (124) of the meter body (121); the flow blocking member (122) is located in the circulation channel; a first pressure-taking port (1211) is provided on the side wall corresponding to the first port (123); and a second pressure-taking port (1212) is provided on the side wall corresponding to the middle position of the circulation channel; The first valve group (11) comprises: at least two stages of valves connected in series, used to adjust the flow rate of the fluid in the first branch (1); The second valve group (14) comprises: at least two stages of valves connected in series, used to adjust the flow rate of the fluid in the first branch (1); The reference flow meter (12) further comprises: at least two groups of support sheets (125), each end of the flow blocking element (122) being fixed to the inner wall of the meter body (121) via a group of the support sheets (125); the meter body (121) is also provided with a temperature measuring port (126); The method comprises: The measured flow meter (13) is installed between the reference flow meter (12) and the second valve group (14); Opening the first valve group (11) and the second valve group (14); When the fluid flows in a direction from the first end to the second end of the first branch (1), the booster unit (3), the first valve unit (11) and the second valve unit (14) are adjusted so that the pressure of the fluid in the first branch (1) is a preset pressure; when the fluid flows in a direction from the second end to the first end of the first branch (1), the first valve unit (11) and the second valve unit (14) are adjusted so that the pressure of the fluid in the first branch (1) is a preset pressure; Acquiring first flow data of a reference flow meter (12) and second flow data of a measured flow meter (13) corresponding to the same moment multiple times; Based on the first flow data, the second flow data and the outflow coefficient of the reference flow meter (12), the flow indication error and repeatability of the measured flow meter (13) relative to the reference flow meter (12) are obtained; when the first connection point is connected to the booster unit (3), high-pressure natural gas is introduced into the gas storage wellhead (5) along the first branch line (1) through the booster unit (3); when the first connection point is connected to the natural gas pipeline network (4), based on the pressure of the gas in the gas storage wellhead (5), the natural gas is transported to the natural gas pipeline network (4) along the first branch line (1); The first flow data of the reference flow meter (12) is obtained based on the following relational expression 1: Relation 1 In the formula, q m is the mass flow rate; Re is the Reynolds number; D is the flowmeter diameter; d is the equivalent inner diameter of the flowmeter; is the ratio of d to D; Ma is the Mach number; 1 is the gas density; is a differential pressure; the differential pressure is the differential pressure formed between the first port (123) and the middle part of the meter body (121).

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