Wellhead flowmeter adapter of oil (gas) well

Abstract

The utility model discloses an oil (gas) well mouth flowmeter adapter which comprises a first flow guide pipe, a first screwed plug, an oil return connector, a sampling valve and an isolating ring. The first screwed plug comprises a main body part and a first mounting part, one end of the main body part is in threaded connection with the mounting end of the wellhead sampler, and the other end of the main body part is fixedly connected with the first mounting part; at least two internal threaded holes are formed in the main body part in the circumferential direction, and the oil return joint and the sampling valve are in threaded connection with the internal threaded holes; one end of the first flow guide pipe is in threaded connection with an isolating ring, the other end of the first flow guide pipe penetrates through the first screwed plug and extends out of the first screwed plug, the first flow guide pipe is in threaded connection with the first mounting part, and the isolating ring is in close fit with the inner wall of the wellhead pipeline; the inner wall of the main body part and the outer wall of the first flow guide pipe form an annular space, and the inner threaded hole communicates with the annular space. According to the oil (gas) well mouth flow meter adapter, a flow meter can be installed on a well mouth on the premise that the original structure of the well mouth is not changed, and therefore real-time metering and monitoring are achieved.

Description

Technical Field

[0001] This utility model relates to the field of oilfield development technology, and in particular to an adapter for an oil (gas) wellhead flow meter. Background Technology

[0002] "Oil and gas well metering" is a crucial link in oil and gas field development and production. It plays a vital role in understanding reservoir geological conditions, assessing deep well pump operating conditions, adjusting oil (gas) well operating procedures, reducing energy consumption in oil production, determining well workover plans, and minimizing environmental pollution. Current metering methods rely on multi-way valves, metering separators, and flow meters at metering stations to calculate oil (gas) well production. The advantage is that it uses dedicated oil and gas separation and metering devices to separately meter oil and gas, resulting in high metering accuracy. However, the disadvantages include complex processes, significant infrastructure investment, and the inability to achieve real-time monitoring due to multiple wells being metered in a queue. While installing flow meters at the wellhead can achieve real-time metering and monitoring, the wellhead structure does not support non-destructive installation, requiring modifications to the wellhead process, which is labor-intensive, poses safety risks, and can disrupt subsequent special operations such as well washing, steam injection, well control, and well workover. Utility Model Content

[0003] In view of the above-mentioned technical deficiencies, the purpose of this utility model is to provide an oil (gas) wellhead flow meter adapter that allows the installation of a flow meter at the oil (gas) wellhead without altering the original structure of the wellhead, thereby solving the existing problems.

[0004] To achieve the above objectives, this utility model provides the following technical solution:

[0005] An adapter for an oil (gas) wellhead flow meter includes a first guide pipe, a first plug, a return oil connector, a sampling valve, and an isolation ring. The first plug comprises a main body and a first mounting portion. The outer and inner diameters of the main body are larger than those of the first mounting portion. One end of the main body is threaded to the mounting end of a wellhead sampler, and the other end of the main body is fixedly connected to the first mounting portion. The main body has at least two internally threaded holes circumferentially, and the return oil connector and sampling valve are threaded to these internally threaded holes. One end of the first guide pipe is threaded to the isolation ring, and the other end of the first guide pipe... One end of the first guide pipe passes through and extends out of the first threaded plug. The first guide pipe is threadedly connected to the first mounting part. The isolation ring is tightly fitted with the inner wall of the wellhead pipeline to isolate the inlet and outlet process pipelines of the flow meter. The inner wall of the main body and the outer wall of the first guide pipe form an annular space, and the internal threaded hole communicates with the annular space. The extended end of the first guide pipe is connected to the detection end of the flow meter, and the return oil connector is connected to the return end of the flow meter. The flow meter is a non-differential pressure flow meter. The isolation ring includes a rubber ring in the middle, and flat washers and locking nuts arranged sequentially on both sides of the rubber ring.

[0006] An adapter for an oil (gas) wellhead flow meter includes a second guide pipe, a first plug, a return oil connector, a sampling valve, and an isolation ring. The first plug comprises a main body and a first mounting part. The outer and inner diameters of the main body are larger than those of the first mounting part. One end of the main body is threaded to the mounting end of the wellhead sampler, and the other end is fixedly connected to the first mounting part. The main body has at least two internally threaded holes circumferentially, and the return oil connector and sampling valve are threaded to these holes. One end of the second guide pipe is threaded to an isolation ring, and the other end of the second guide pipe passes through the first plug. A plug extends from the first plug, the second guide pipe is threadedly connected to the first mounting part, the isolation ring 7 is tightly fitted to the inner wall of the wellhead pipeline, isolating the inlet and outlet process pipelines of the flow meter; the inner wall of the main body and the outer wall of the second guide pipe form an annular space, and the internal threaded hole communicates with the annular space; the second guide pipe is provided with a throttling hole at the position of the main body, the protruding end of the second guide pipe is connected to the high-pressure end of the differential pressure flow meter, and the return oil connector is connected to the low-pressure end of the differential pressure flow meter; the isolation ring includes a rubber ring located in the middle, and a flat washer and a locking nut arranged sequentially on both sides of the rubber ring.

[0007] An adapter for an oil (gas) wellhead flow meter includes a first guide pipe, a second plug, a return oil connector, and a sampling valve. The second plug comprises a main body and a second mounting part. The outer and inner diameters of the main body are larger than those of the second mounting part. One end of the main body is threaded to the mounting end of a wellhead sampler, and the other end of the main body is fixedly connected to the second mounting part. The main body has at least two internally threaded holes along its circumference, and the return oil connector and the sampling valve are threaded to these internally threaded holes. One end of the first guide pipe is threaded to an oil nozzle in the oil well pipeline, and the other end of the first guide pipe passes through and extends out of the second plug. The inner wall of the main body and the outer wall of the first guide pipe form an annular space, and the internally threaded holes communicate with the annular space. The extended end of the first guide pipe is connected to the detection end of the flow meter, and the return oil connector is connected to the return end of the flow meter. The flow meter is a non-differential pressure flow meter.

[0008] An adapter for an oil (gas) wellhead flowmeter includes a second guide pipe, a second plug, a return oil connector, and a sampling valve. The second plug comprises a main body and a second mounting part. The outer and inner diameters of the main body are larger than those of the second mounting part. One end of the main body is threaded to the mounting end of a wellhead sampler, and the other end of the main body is fixedly connected to the second mounting part. The main body has at least two internally threaded holes along its circumference, and the return oil connector and sampling valve are threaded to these internally threaded holes. One end of the second guide pipe is threaded to an oil nozzle in the oil well pipeline, and the other end of the second guide pipe passes through and extends out of the second plug. The inner wall of the main body and the outer wall of the second guide pipe form an annular space, and the internally threaded holes communicate with the annular space. The second guide pipe has a throttling orifice located at the position of the main body. The extended end of the second guide pipe is connected to the high-pressure end of a differential pressure flowmeter, and the return oil connector is connected to the low-pressure end of the differential pressure flowmeter.

[0009] The beneficial effects of this utility model are as follows: 1. Without modifying the original wellhead structure, the wellhead sampler is replaced by the oil (gas) wellhead flow meter adapter described in this utility model. The oil (gas) wellhead flow meter adapter is installed at the original sampler's installation position, allowing the flow meter to be installed on the wellhead. Users can choose any flow meter (differential pressure flow meter, gear flow meter, electromagnetic flow meter, vortex flow meter, turbine flow meter, etc.) that meets their needs (pressure, temperature, flow rate, water cut, sand content, gas content, and accuracy requirements) to achieve real-time metering and monitoring of oil and gas wells. 2. This utility model has a simple structure, is easy to install, has a wide range of applications, and is low in cost. 3. It allows for real-time monitoring of oil well production status, timely adjustment of work procedures, improved oil production speed, reduced oil production energy consumption, and reduced environmental pollution. 4. It provides accurate data for formulating production enhancement measures, reducing pump inspection frequency and well repair costs. 5. It reduces the labor intensity of oil production workers, decreasing the number of manual operations such as "well running," "pump stalling," and "sampling." 6. By installing a flow meter at the wellhead using this utility model, newly developed areas can save on the costs of building a metering station and purchasing metering equipment, thus significantly reducing the cost of oilfield infrastructure construction.

[0010] The above description is only an overview of the technical solution of this utility model. In order to better understand the technical means of this utility model and to implement it in accordance with the contents of the specification, the preferred embodiments of this utility model are described in detail below with reference to the accompanying drawings. Attached Figure Description

[0011] Figure 1 This is a schematic diagram of the integrated installation method of the oil (gas) wellhead flowmeter adapter of this utility model;

[0012] Figure 2 This is a schematic diagram of the structure of the split-type installation method of the oil (gas) wellhead flowmeter adapter of this utility model;

[0013] Figure 3 This is a schematic diagram of the structure of the No. 1 guide tube of this utility model;

[0014] Figure 4 This is a schematic diagram of the structure of the No. 2 guide tube of this utility model;

[0015] Figure 5 This is a schematic diagram of the No. 1 plug of this utility model;

[0016] Figure 6 This is a schematic diagram of the No. 2 plug of this utility model.

[0017] Explanation of reference numerals in the attached drawings: 1. No. 1 guide pipe; 2. No. 1 plug; 3. No. 2 guide pipe; 4. No. 2 plug; 5. Oil return connector; 6. Sampling valve; 7. Isolation ring; 8. Throttling orifice; 9. Main body; 10. First mounting part; 11. Internal threaded hole; 12. Second mounting part; 13. Annular space. Detailed Implementation

[0018] The technical solution of this utility model will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.

[0019] In the description of this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0020] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0021] Furthermore, the technical features involved in the different embodiments of this utility model described below can be combined with each other as long as they do not conflict with each other. Example 1

[0022] Please see Figure 1 , Figure 3 and Figure 5This application discloses an oil (gas) wellhead flow meter adapter, suitable for integrated installation in oil well pipelines without nozzles. It includes a first guide pipe 1, a first plug 2, a return oil connector 5, a sampling valve 6, and an isolation ring 7. The first guide pipe 1 is used to introduce the produced fluid from the oil (gas) well into the flow meter, and then the oil (gas) measured by the flow meter is led into the oil well pipeline through the return oil connector 5. The first plug 2, as the core component of the adapter, is used to connect the various components of the adapter to form the oil wellhead flow meter adapter and is threadedly connected to the installation end of the wellhead sampler. The sampling valve 6 is used to release the wellhead pressure and take oil samples; the sampling valve 6 is a standardized valve with pressure and temperature resistance levels meeting field requirements. The isolation ring is used to isolate the inlet and outlet process pipelines of the flow meter in the integrated installation mode.

[0023] The first plug 2 includes a main body 9 and a first mounting part 10. The outer diameter and inner diameter of the main body 9 are both larger than the outer diameter and inner diameter of the first mounting part 10. One end of the main body 9 is threadedly connected to the mounting end of the wellhead sampler, and the other end of the main body 9 is fixedly connected to the first mounting part 10. The main body 9 has at least two internal threaded holes 11 arranged circumferentially. The return oil connector 5 and the sampling valve 6 are threadedly connected to the internal threaded holes 11. There are four internal threaded holes 11, evenly arranged circumferentially along the main body 9. One hole is connected to the sampling valve 6, another to the return connector 5, and the remaining two are plugged. The specific two used are determined on-site according to the installation direction. One end of the first guide pipe 1 is threadedly connected to... The isolation ring 7 is provided. The other end of the first guide pipe 1 passes through the first plug 2 and extends out of the first plug 2. The first guide pipe 1 is threadedly connected to the first mounting part 10. The isolation ring 7 is tightly fitted with the inner wall of the wellhead pipeline to isolate the inlet and outlet process pipelines of the flow meter. The inner wall of the main body 9 and the outer wall of the first guide pipe 1 form an annular space 13. The internal threaded hole 11 is connected to the annular space 13. The extended end of the first guide pipe 1 is connected to the detection end of the flow meter. The return oil connector 5 is connected to the return end of the flow meter. The flow meter is a non-differential pressure flow meter. The isolation ring 7 includes a rubber ring located in the middle, and a flat washer and a locking nut arranged sequentially on both sides of the rubber ring. Example 2

[0024] Please see Figure 1 , Figure 4 and Figure 5This is an oil (gas) wellhead flow meter adapter, suitable for integrated installation of oil well pipelines without nozzles. It includes a second guide pipe 3, a first plug 2, a return oil connector 5, a sampling valve 6, and an isolation ring 7. The second guide pipe 3 is used to create a pressure differential through its own throttling orifice for pressure differential detection. The first plug 2, as the core component of the adapter, connects the various components to form the oil wellhead flow meter adapter and is threadedly connected to the wellhead sampler mounting end. The sampling valve 6 is used to release wellhead pressure and take oil samples; the sampling valve 6 is a standardized valve with pressure and temperature resistance ratings meeting field requirements. The isolation ring is used to isolate the flow meter inlet and outlet process pipelines in the integrated installation mode.

[0025] The first plug 2 includes a main body 9 and a first mounting part 10. The outer and inner diameters of the main body 9 are both larger than those of the first mounting part 10. One end of the main body 9 is threadedly connected to the wellhead sampler mounting end, and the other end of the main body 9 is fixedly connected to the first mounting part 10. The main body 9 has at least two internal threaded holes 11 arranged circumferentially. The return oil connector 5 and the sampling valve 6 are threadedly connected to the internal threaded holes 11. There are four internal threaded holes 11, evenly arranged circumferentially along the main body 9. One hole is connected to the sampling valve 6, another to the return connector 5, and the remaining two are plugged. The specific two used are determined on-site according to the installation direction. One end of the second guide pipe 3 is threadedly connected to an isolation ring 7. The other end of the second guide pipe 3 passes through and extends out of the first plug 2. The second guide pipe 3 is threadedly connected to the first mounting part 10. The isolation ring 7 is tightly fitted to the inner wall of the wellhead pipeline to isolate the inlet and outlet process pipelines of the flow meter. The inner wall of the main body 9 and the outer wall of the second guide pipe 3 form an annular space 13. The internal threaded hole 11 is connected to the annular space 13. The second guide pipe 3 is provided with a throttling hole 8 at the position of the main body 9. The extended end of the second guide pipe 3 is connected to the high-pressure end of the differential pressure flow meter. The return oil connector 5 is connected to the low-pressure end of the differential pressure flow meter. The isolation ring 7 includes a rubber ring in the middle, and a flat washer and a locking nut arranged sequentially on both sides of the rubber ring. Example 3

[0026] Please see Figure 2 , Figure 3 and Figure 6This is an oil (gas) wellhead flow meter adapter, suitable for split-type installation of oil well pipelines with nozzles. It includes a first guide pipe 1, a second plug 4, a return oil connector 5, and a sampling valve 6. The first guide pipe 1 is used to introduce the produced fluid from the oil (gas) well into the flow meter, and then the oil (gas) measured by the flow meter is led into the oil well pipeline through the return oil connector 5. One end of the first guide pipe 1 is threadedly connected to the oil nozzle of the oil well pipeline. The second plug 2, as the core component of the adapter, is used to connect the various components of the adapter to form the oil wellhead flow meter adapter and is threadedly connected to the wellhead sampler mounting end. The sampling valve 6 is used to release the wellhead pressure and take oil samples. The sampling valve 6 is a standardized valve with pressure and temperature resistance ratings that meet field requirements.

[0027] The second plug 4 includes a main body 9 and a second mounting part 12. The outer diameter and inner diameter of the main body 9 are both larger than the outer diameter and inner diameter of the second mounting part 12. One end of the main body 9 is threadedly connected to the wellhead sampler mounting end, and the other end of the main body 9 is fixedly connected to the second mounting part 12. The main body 9 is provided with at least two internal threaded holes 11 along the circumference. The return oil connector 5 and the sampling valve 6 are threadedly connected to the internal threaded holes 11. There are four internal threaded holes 11, which are evenly arranged along the circumference of the main body 9. One of them is connected to the sampling valve 6, and the other is connected to... The return connector 5 and the other two upper plugs will be used on-site based on the installation direction. One end of the first guide pipe 1 is threaded to the oil well pipeline nozzle, and the other end of the first guide pipe 1 passes through and extends out of the second threaded plug 4. The inner wall of the main body 9 and the outer wall of the first guide pipe 1 form an annular space 13, and the internal threaded hole 11 communicates with the annular space 13. The extended end of the first guide pipe 1 is connected to the detection end of the flow meter, and the return connector 5 is connected to the return end of the flow meter. The flow meter is a non-differential pressure flow meter. Example 4

[0028] Please see Figure 2 , Figure 4 and Figure 6 This is an oil (gas) wellhead flow meter adapter, suitable for split-type installation of oil well pipelines with nozzles. It includes a second guide pipe 3, a second plug 4, a return oil connector 5, and a sampling valve 6. The second guide pipe 3 is used to create a pressure differential through its own throttling orifice for pressure differential detection, and one end of the second guide pipe 3 is threadedly connected to the oil well pipeline nozzle. The second plug 2, as the core component of the adapter, connects the various components of the adapter to form the oil wellhead flow meter adapter and is threadedly connected to the wellhead sampler mounting end. The sampling valve 6 is used to release wellhead pressure and take oil samples; the sampling valve 6 is a standardized valve with pressure and temperature resistance ratings meeting field requirements.

[0029] The second plug 4 includes a main body 9 and a second mounting part 12. The outer and inner diameters of the main body 9 are both larger than those of the second mounting part 12. One end of the main body 9 is threadedly connected to the mounting end of the wellhead sampler, and the other end of the main body 9 is fixedly connected to the second mounting part 12. The main body 9 has at least two internal threaded holes 11 arranged circumferentially. The return oil connector 5 and the sampling valve 6 are threadedly connected to the internal threaded holes 11. There are four internal threaded holes 11, evenly arranged circumferentially along the main body 9. One of them is connected to the sampling valve 6, another to the return connector 5, and the rest... Two upper plugs are used; the specific two plugs will be determined on-site based on the installation direction. One end of the second guide pipe 3 is threaded to the oil well pipeline nozzle, and the other end of the second guide pipe 3 passes through and extends out of the second threaded plug 4. The inner wall of the main body 9 and the outer wall of the second guide pipe 3 form an annular space 13, and the internal threaded hole 11 communicates with the annular space 13. The second guide pipe 3 is provided with a throttling hole 8 at the position of the main body 9. The extended end of the second guide pipe 3 is connected to the high-pressure end of the differential pressure flow meter, and the return oil connector 5 is connected to the low-pressure end of the differential pressure flow meter.

[0030] This application relates to an oil (gas) wellhead flow meter adapter. Without altering the existing wellhead structure, the adapter is installed at the original sampler installation location. The adapter then mounts the flow meter onto the wellhead. Users can install any type of flow meter (differential pressure flow meter, gear flow meter, electromagnetic flow meter, vortex flow meter, turbine flow meter, etc.) that meets their specific needs (pressure, temperature, flow rate, water cut, sand content, gas content, and accuracy requirements), thereby achieving real-time metering and monitoring. This application features a simple structure and convenient installation. It features both integrated and split installation methods, making it widely applicable and cost-effective. It allows for real-time monitoring of oil well production status, enabling timely adjustments to work schedules, increasing oil production speed, reducing energy consumption, and minimizing environmental pollution. It provides more accurate data for formulating production enhancement measures, reducing pump inspections and well repair costs. It also reduces the labor intensity of oilfield workers, decreasing the frequency of manual operations such as well running, pump stalling, and sampling. Furthermore, by installing a flow meter at the wellhead using this invention, newly developed areas can eliminate the need for metering station construction and equipment procurement costs, significantly reducing oilfield infrastructure expenses.

[0031] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0032] The embodiments described above are merely illustrative of several implementations of this utility model, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the utility model patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this utility model, and these all fall within the protection scope of this utility model. Therefore, the protection scope of this utility model patent should be determined by the appended claims.

Claims

1. An adapter for an oil (gas) wellhead flowmeter, characterized in that, The system includes a No. 1 guide pipe (1), a No. 1 plug (2), a return oil connector (5), a sampling valve (6), and an isolation ring (7). The No. 1 plug (2) includes a main body (9) and a first mounting part (10). The outer diameter and inner diameter of the main body (9) are both larger than the outer diameter and inner diameter of the first mounting part (10). One end of the main body (9) is threadedly connected to the wellhead sampler mounting end, and the other end of the main body (9) is fixedly connected to the first mounting part (10). The main body (9) has at least two internal threaded holes (11) arranged circumferentially. The return oil connector (5) and the sampling valve (6) are threadedly connected to the internal threaded holes (11). One end of the No. 1 guide pipe (1) is threadedly connected to the isolation ring (7). (1) The other end is inserted through the first plug (2) and extends out of the first plug (2). The first guide pipe (1) is threadedly connected to the first mounting part (10). The isolation ring (7) is tightly fitted with the inner wall of the wellhead pipeline to isolate the inlet and outlet process pipelines of the flow meter. The inner wall of the main body (9) and the outer wall of the first guide pipe (1) form an annular space (13). The internal thread hole (11) is connected to the annular space (13). The extended end of the first guide pipe (1) is connected to the detection end of the flow meter. The return oil connector (5) is connected to the return end of the flow meter. The flow meter is a non-differential pressure flow meter. The isolation ring (7) includes a rubber ring in the middle and a flat washer and a locking nut arranged on both sides of the rubber ring in sequence.

2. An adapter for an oil (gas) wellhead flow meter, characterized in that, The system includes a No. 2 guide pipe (3), a No. 1 plug (2), a return oil connector (5), a sampling valve (6), and an isolation ring (7). The No. 1 plug (2) includes a main body (9) and a first mounting part (10). The outer diameter and inner diameter of the main body (9) are both larger than the outer diameter and inner diameter of the first mounting part (10). One end of the main body (9) is threaded to the wellhead sampler mounting end, and the other end of the main body (9) is fixedly connected to the first mounting part (10). The main body (9) has at least two internal threaded holes (11) arranged circumferentially. The return oil connector (5) and the sampling valve (6) are threaded to the internal threaded holes (11). One end of the No. 2 guide pipe (3) is threaded to an isolation ring (7), and the other end of the No. 2 guide pipe (3) passes through the isolation ring. The first plug (2) extends out of the first plug (2), the second guide pipe (3) is threadedly connected to the first mounting part (10), the isolation ring (7) is tightly fitted with the inner wall of the wellhead pipeline to isolate the inlet and outlet process pipelines of the flow meter; the inner wall of the main body (9) and the outer wall of the second guide pipe (3) form an annular space (13), the internal thread hole (11) is connected to the annular space (13); the second guide pipe (3) is provided with a throttling hole (8) at the position of the main body (9), the extended end of the second guide pipe (3) is connected to the high pressure end of the differential pressure flow meter, and the return oil connector (5) is connected to the low pressure end of the differential pressure flow meter; the isolation ring (7) includes a rubber ring in the middle, and a flat washer and a locking nut arranged sequentially on both sides of the rubber ring.

3. An adapter for an oil (gas) wellhead flow meter, characterized in that, The system includes a No. 1 guide pipe (1), a No. 2 plug (4), a return oil connector (5), and a sampling valve (6). The No. 2 plug (4) includes a main body (9) and a second mounting part (12). The outer diameter and inner diameter of the main body (9) are both larger than the outer diameter and inner diameter of the second mounting part (12). One end of the main body (9) is threadedly connected to the wellhead sampler mounting end, and the other end of the main body (9) is fixedly connected to the second mounting part (12). The main body (9) has at least two internal threaded holes (11) arranged circumferentially. The return oil connector (5) and the sampling valve (6) are connected to the wellhead sampler mounting end. The internal threaded hole (11) is threaded; one end of the first guide pipe (1) is threaded to the oil well pipeline nozzle, and the other end of the first guide pipe (1) is inserted through the second plug (4) and extends out of the second plug (4); the inner wall of the main body (9) and the outer wall of the first guide pipe (1) form an annular space (13), and the internal threaded hole (11) is connected to the annular space (13); the extended end of the first guide pipe (1) is connected to the detection end of the flow meter, and the return oil connector (5) is connected to the return end of the flow meter. The flow meter is a non-differential pressure flow meter.

4. An adapter for an oil (gas) wellhead flow meter, characterized in that, The system includes a No. 2 guide pipe (3), a No. 2 plug (4), a return oil connector (5), and a sampling valve (6). The No. 2 plug (4) includes a main body (9) and a second mounting part (12). The outer diameter and inner diameter of the main body (9) are both larger than the outer diameter and inner diameter of the second mounting part (12). One end of the main body (9) is threaded to the wellhead sampler mounting end, and the other end of the main body (9) is fixedly connected to the second mounting part (12). The main body (9) has at least two internal threaded holes (11) arranged circumferentially. The return oil connector (5) and the sampling valve (6) are threaded to the internal threaded holes (11). Connection; one end of the No. 2 guide pipe (3) is threaded to the oil well pipeline nozzle, and the other end of the No. 2 guide pipe (3) is inserted through the No. 2 plug (4) and extends out of the No. 2 plug (4); the inner wall of the main body (9) and the outer wall of the No. 2 guide pipe (3) form an annular space (13), and the internal thread hole (11) is connected to the annular space (13); the No. 2 guide pipe (3) is provided with a throttling hole (8) at the position of the main body (9), the extended end of the No. 2 guide pipe (3) is connected to the high pressure end of the differential pressure flow meter, and the return oil connector (5) is connected to the low pressure end of the differential pressure flow meter.

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