Wellhead metering device

Abstract

The invention relates to the technical field of oil and gas well mouth metering, in particular to a well mouth metering device. The wellhead metering device comprises a central pipe and an outer pipe installed outside the central pipe, a liquid return cavity is defined between the central pipe and the outer pipe and connected with one end of the central pipe, the other end of the central pipe is a central pipe insertion end used for being inserted into a wellhead oil outlet pipe, and a sealing device is arranged at the central pipe insertion end. A wellhead connecting structure is arranged on the central pipe and / or the outer pipe, when the wellhead connecting structure is connected to a wellhead, the sealing device is located on the side, close to the wellhead, of the wellhead oil conveying pipe, an outlet of the liquid return cavity is located in an oil outlet pipe of the wellhead, and an output liquid metering assembly is arranged on the central pipe or between the central pipe and the liquid return cavity. The liquid inlet and the liquid outlet of the wellhead metering device are both arranged in the wellhead oil outlet pipe and are connected through the wellhead connecting structure, so that a worker only needs to carry out one-time connection work, and the wellhead metering device is convenient to install.

Description

Technical Field

[0001] This invention relates to the field of wellhead metering technology for oil and gas wells, and specifically to a wellhead metering device. Background Technology

[0002] Oil pumping units are used to extract oil from wells to the wellhead, and then the oil is transported to other places through pipelines installed at the wellhead. Generally, the oil is transported using the oil outlet pipe installed at the wellhead and the oil delivery pipe arranged perpendicular to it. One end of the oil outlet pipe is sealed with a plug to ensure that all the extracted oil can enter the oil delivery pipe.

[0003] To monitor the produced water volume of oil wells in real time and accurately determine their oil production, oilfields must periodically measure the water content of the produced fluids. Metering stations are crucial hubs connecting all oil wells and centrally measuring their oil and gas production sequentially. Generally, each well is metered at regular intervals, and the metered oil and gas are then mixed and transported to the oil station under wellhead pressure. Metering stations measure and record parameters such as flow rate, pressure, and temperature of the fluids produced by oil or gas wells, playing a vital role in oil and gas field development. They help to accurately obtain data such as the fluid production and oil-water ratio of each well, providing data references for oil production processes, assisting decision-making, and improving oil production efficiency.

[0004] Currently, due to digital transformation and aging equipment, metering stations in oilfields are gradually losing their metering function. Without accurate information on the production status of each pumping unit well, it's impossible to provide accurate data for adjusting oil and water well strategies, impacting block development and reducing ultimate recovery. However, installing a metering device for each pumping unit would be too costly.

[0005] In the prior art, Chinese invention patent with authorization announcement number CN114893170B and authorization announcement date of October 4, 2022 discloses an online detection device and method for wellhead fluid volume and water content. The online detection device includes an inlet pipe and an outlet pipe, and a measuring chamber is set between the inlet pipe and the outlet pipe. Various measuring instruments are set on the measuring chamber, which can detect the water content, temperature and flow rate of the liquid in the mixed fluid.

[0006] However, since its inlet and outlet pipes are located on both sides of the measuring chamber, it means that both ends of the online detection device need to be connected to pipes, which requires the staff to connect them twice, resulting in high labor intensity and inconvenience in installation. Summary of the Invention

[0007] The purpose of this invention is to provide a wellhead metering device to solve the problem of inconvenient installation of existing metering devices.

[0008] The technical solution of the wellhead metering device provided by the present invention is as follows: A wellhead metering device includes a central tube and an outer tube installed outside the central tube. A return fluid chamber is formed between the central tube and the outer tube. The return fluid chamber is connected to one end of the central tube. The other end of the central tube is a central tube insertion end for insertion into the wellhead oil outlet pipe. A sealing device for sealing and cooperating with the wellhead oil outlet pipe is provided at the central tube insertion end. A wellhead connection structure for connecting to and sealing the wellhead oil outlet pipe is provided on the central tube and / or the outer tube. When the wellhead connection structure is connected to the wellhead, the sealing device is located on the side of the wellhead oil delivery pipe closer to the wellhead. The outlet of the return fluid chamber is located in the wellhead oil outlet pipe. A produced fluid metering component is provided on the central tube or between the central tube and the return fluid chamber.

[0009] Beneficial Effects: This invention improves upon existing wellhead metering devices by placing both the inlet and outlet of the metering device inside the wellhead oil outlet pipe and connecting them via a wellhead connection structure. This eliminates the need for a single connection operation by the operator, simplifying installation. The central tube has an insertion end that inserts into the wellhead, and a sealing device at this insertion end seals the return fluid chamber between the central tube and the wellhead oil outlet pipe, preventing produced fluid from directly entering the return fluid chamber from the oil outlet pipe. Instead, all produced fluid enters the central tube, which forms a return fluid chamber between the central tube and the outer tube. This return fluid chamber is connected to one end of the central tube, allowing produced fluid entering from the central tube to flow into the return fluid chamber on its side. At this point, the produced fluid metering component located in the central tube or between the central tube and the return fluid chamber functions to measure the produced fluid. When the metering device is connected to the wellhead, the sealing device is located on the wellhead pipeline and close to the wellhead. At this point, the outlet of the return fluid chamber can connect to the pipeline, allowing the metered produced fluid to be transported to other locations via the pipeline. This invention places both the inlet and outlet of the metering device inside the production pipeline, specifically at the insertion end of the central tube and on the side of the central tube, rather than at both ends. Therefore, by simply fixing the metering device to the wellhead using the wellhead connection structure, metering of the produced fluid can be achieved. Furthermore, it only requires one connection by the operator, making installation convenient and solving the problem of inconvenient installation of metering devices in existing technologies.

[0010] As a further improvement, the central tube and the outer tube are telescopically fitted along the length direction, and a protruding retaining ring is provided at the insertion end of the central tube. The sealing device is a sealing rubber sleeve that is fitted on the central tube. The sealing rubber sleeve is located between the retaining ring and the corresponding end of the outer tube. A threaded sleeve that can be blocked by the outer tube is installed at the other end of the central tube.

[0011] As a further improvement, the retaining ring is threaded onto the central tube.

[0012] As a further improvement, the sealing tubes are provided in multiple units, and a pressure ring is provided between adjacent sealing tubes.

[0013] As a further improvement, the wellhead connection structure includes a wellhead connector, which includes a sleeve that is fitted outside the outer pipe, and a sleeve connector is provided on the sleeve, which communicates with the return fluid chamber.

[0014] As a further improvement, a pressure measuring device is installed on the sleeve.

[0015] As a further improvement, the sleeve and the outer tube are threaded together.

[0016] As a further improvement, a guide key is provided on one of the central tube and the outer tube, and a groove is provided on the other tube to guide and cooperate with the guide key. The inner and outer tubes are guided and cooperated with each other through the guide key and the groove.

[0017] As a further improvement, the output liquid metering component is installed at the corresponding end of the central tube and connected to the return liquid chamber through a corresponding pipeline.

[0018] As a further improvement, the outlet of the return chamber is formed by a sieve hole located at the corresponding position of the outer tube. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the overall structure of the wellhead metering device provided by the present invention.

[0020] Figure 2 This is a cross-sectional view of a portion of the structure of the wellhead metering device provided by the present invention.

[0021] Figure 3 for Figure 2 Enlarged view of the structure at point A in the middle;

[0022] Figure 4 This is a cross-sectional view of the central tube;

[0023] Figure 5 This is a cross-sectional view of the support pipe;

[0024] Figure 6 This is a cross-sectional view of the reflux pipe;

[0025] Figure 7 This is a cross-sectional view of the wellhead connector;

[0026] Figure 8 This is a schematic diagram showing the specific installation of the wellhead metering device provided by the present invention during use.

[0027] In the diagram: 1. Wellhead connector; 2. Return pipe; 3. Support pipe; 4. Center pipe; 5. Sealing sleeve; 6. Pressure ring; 7. Retaining ring; 8. Screw sleeve; 9. Groove; 10. Casing connector; 11. Sealing groove; 12. Oil delivery pipe; 13. Fluid inlet; 14. Seal; 15. Protrusion; 16. Cock; 17. Pressure gauge; 18. Produced fluid metering assembly; 19. High-pressure hose; 20. Outlet; 21. Production gate valve; 22. Back pressure gate valve; 23. Oil casing connection gate valve; 24. Oil delivery pipe. Detailed Implementation

[0028] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0029] In the existing technology, wellhead metering devices are installed between two pipelines, with the inlet and outlet located at both ends. When installing the metering device in the pipeline, the staff needs to perform two connection operations, which is inconvenient.

[0030] To address this issue, the present invention provides a wellhead metering device in which both the inlet and outlet are located inside the wellhead oil outlet pipe, rather than at both ends. This allows for easy installation by requiring only one connection by the operator, thus solving the problem of inconvenient installation in the prior art.

[0031] The overall design concept of the wellhead metering device provided by this invention is as follows:

[0032] like Figure 1-2 As shown, the wellhead metering device of the present invention includes a central tube 4 and an outer tube installed outside the central tube 4. A return fluid chamber is formed between the central tube 4 and the outer tube. The return fluid chamber is connected to one end of the central tube 4, and the other end of the central tube 4 is an insertion end for insertion into the wellhead oil outlet pipe 24. A sealing device is provided at the insertion end of the central tube 4 for sealing with the wellhead oil outlet pipe 24. When the central tube 4 is inserted into the wellhead oil outlet pipe 24, due to the sealing device sealing with the wellhead oil outlet pipe 24, all the produced fluid in the oil outlet pipe 24 enters the interior of the central tube 4, and the produced fluid enters the return fluid chamber from one end of the central tube 4. A wellhead connection structure is provided on the central tube 4 and / or the outer tube. The wellhead connection structure is connected to the wellhead oil outlet pipe 24 and seals the wellhead oil outlet pipe 24.

[0033] When the wellhead connection structure is connected to the wellhead, the attenuation is located on the side of the wellhead oil delivery pipe 12 closest to the wellhead. The outlet 20 of the return fluid chamber is located in the oil delivery pipe 24 of the wellhead. In effect, the wellhead connection structure and sealing device are used to block both sides of the return fluid chamber, so that the produced fluid can only enter the return fluid chamber from the central pipe 4, and then enter the oil delivery pipe 24 through the outlet 20. Due to the attenuation, the produced fluid can only flow out from the wellhead oil delivery pipe 12. A produced fluid metering component 18 is installed on the central pipe 4 or between the central pipe 4 and the return fluid chamber. The produced fluid metering component 18 can measure the produced fluid.

[0034] Based on the above overall description of the wellhead metering device of the present invention, a more specific embodiment is provided below:

[0035] In this embodiment, a wellhead connection structure is provided on the outer pipe, which connects to the wellhead oil outlet pipe 24 and can also seal the wellhead oil outlet pipe 24. In other embodiments, the wellhead connection structure can also be provided on the central pipe 4, or it can be provided on both the central pipe 4 and the outer pipe. A produced fluid metering component 18 is provided between the central pipe 4 and the return fluid chamber. In other embodiments, the produced fluid metering component 18 is provided on the central pipe 4.

[0036] The produced fluid metering component 18 can be one or a combination of several of the following: water cut tester, flow meter, thermometer, etc. It can measure the temperature, water cut and flow rate of the produced fluid, and the obtained data can provide a reference for subsequent oil production processes.

[0037] The central tube 4 and the outer tube have a telescopic fit along their length, allowing the central tube 4 to move axially within the outer tube. A protruding retaining ring 7 is provided at the insertion end of the central tube 4. The sealing device is a sealing rubber sleeve 5 fitted onto the central tube 4, positioned between the retaining ring 7 and the outer tube. Both ends of the sealing rubber sleeve 5 are blocked by the retaining ring 7 and the outer tube, respectively. When the central tube 4 moves away from its insertion end, the distance between the insertion end of the central tube 4 and one end of the outer tube decreases, compressing the sealing rubber sleeve 5. The expansion of the sealing rubber sleeve 5 seals the gap between the insertion end of the central tube 4 and the wellhead oil outlet pipe 24. In this embodiment, the retaining ring 7 is threaded onto the insertion end of the central tube 4. This threaded assembly facilitates adjustment of the position of the retaining ring 7 on the central tube 4 and allows for easy adjustment of the initial expansion of the sealing rubber sleeve 5. A sealing element 14 is also provided between the retaining ring 7 and the central tube 4 to prevent produced fluid from entering the threaded gap between the retaining ring 7 and the central tube 4.

[0038] In this embodiment, multiple sealing rubber sleeves 5 are provided, and a pressure ring 6 is provided between adjacent sealing rubber sleeves 5. Providing multiple sealing rubber sleeves 5 ensures better sealing performance between the central pipe 4 and the wellhead oil outlet pipe 24. The pressure ring 6 allows the force of one sealing rubber sleeve 5 to be stably applied to its adjacent sealing rubber sleeves 5, ensuring that each sleeve can expand and seal. In other embodiments, only one sealing rubber sleeve 5 is provided.

[0039] A threaded sleeve 8 is installed at the other end of the central tube 4, which can be stopped by the outer tube. The threaded sleeve 8 can stop the outer tube after the attenuation effect, preventing axial movement between the outer tube and the central tube 4 and thus preventing seal failure. A thread is provided at the position corresponding to the threaded sleeve 8 on the central tube 4. When the threaded sleeve 8 is rotated, the central tube 4 can move axially relative to the outer tube, which facilitates the movement of the central tube 4 and also facilitates installation and disassembly. At the same time, due to the self-locking force of the threaded engagement, the threaded sleeve 8 can stably stop the outer tube.

[0040] In this embodiment, the outer tube consists of a return pipe 2 and a support pipe 3 arranged sequentially along the axial direction of the central pipe 4. The support pipe 3 is located on the side near the insertion end of the central pipe 4. One end of the return pipe 2 is connected to the end of the central pipe 4 away from the insertion end, and the other end abuts against the support pipe 3. The return pipe 2 has radially extending sieve holes, which form the inlet hole 13 of the return liquid chamber. An annular groove is provided on the radially inner side of the return pipe 2 at a position corresponding to the inlet hole 13. The gap between the annular groove and the central pipe 4 forms part of the return liquid chamber. In other embodiments, the return pipe 2 and the support pipe 3 can be integrally formed.

[0041] A guide key is provided on the central tube 4, and a groove is provided on the outer tube to guide and cooperate with the guide key. The central tube 4 and the outer tube are guided and cooperated with each other through the guide key and the groove. Figure 2 , 4 As shown in Figure 5, a protrusion 15 is provided on the central tube 4, and the protrusion is in the shape of an "I". A groove 9, also in the shape of an "I", is provided on the support tube 3 at the end away from the central insertion tube. The outer diameter of the protrusion 15 is the same as the inner diameter of the groove 9 on the support tube 3, and the outer diameter of the central tube 4 is the same as the inner diameter of the central tube 4. At this time, the support tube 3 is supported by the protrusion 15 on the central tube 4. The protrusion 15 forms a guide key, and the groove 9 on the support tube 3 forms a groove. The central tube 4 can move axially within the outer tube, and the end face of the protrusion 15 and the groove 9 form a stop fit to prevent the central tube 4 from moving towards the wellhead oil outlet pipe 24 and falling into the oil outlet pipe 24. In other embodiments, a guide key can be provided on the outer tube, and a groove can be provided on the central tube 4.

[0042] like Figure 2 , 5As shown, the groove 9 of the support pipe 3 extends to one end facing the return pipe 2, and the gap between the groove 9 of the support pipe 3 and the central pipe 4 forms part of the return fluid chamber. A screen hole is provided radially on the support pipe 3, which forms the outlet 20 of the return fluid chamber, allowing the produced fluid in the return fluid chamber to be discharged into the wellhead oil outlet pipe 24.

[0043] like Figure 2 , 3 As shown in Figure 7, a wellhead connector 1 is provided on the outside of the return pipe 2 and the support pipe 3. The wellhead connector 1 includes a sleeve fitted over the outside of the return pipe 2 and the support pipe 3. The sleeve is threaded to the return pipe 2. A groove 9 is provided on the inner side of the sleeve, and a protrusion 15 is provided on the support pipe 3 at the corresponding position of the groove 9. The two parts are fitted together to secure the support pipe 3. A sleeve connector is provided on the sleeve, which communicates with the return fluid chamber. Two sleeve connectors are provided to form a four-way structure for the wellhead connector 1, and the two sleeve connectors are symmetrically arranged. One sleeve connector communicates with the produced fluid metering component 18, and the other sleeve connector is connected to a pressure detection device that monitors the wellhead pressure during the metering process. The pressure detection device is a pressure gauge 17, installed at one end of the casing connector 10. A cock 16 is also provided between the pressure gauge 17 and the casing connector 10 for opening or closing the casing connector 10. In other embodiments, the sleeve connectors may also be asymmetrically arranged. Alternatively, the pressure detection device may be omitted, in which case there may be only one sleeve connector connected to the produced liquid metering assembly 18.

[0044] In this embodiment, threads are provided on the return pipe 2 and the support pipe 3, respectively, and the inner side of the casing is provided with threads to connect with the support pipe 3 and the return pipe 2. A thread is provided on the outer side of the casing near the insertion end of the central pipe 4 to connect with the wellhead oil outlet pipe 24. The wellhead oil outlet pipe 24 is threadedly connected to the casing, so that the entire wellhead metering device is fixed on the wellhead oil outlet pipe 24, and the threaded connection is convenient and easy for the staff to install and remove.

[0045] like Figure 1 As shown, the produced liquid metering component 18 is connected to the end of the central tube 4 furthest from the insertion end of the central tube 4. The produced liquid in the central tube 4 enters the produced liquid metering component 18 for metering to obtain specific data. One end of the produced liquid metering component 18 is connected to the corresponding sleeve connector 10 through a high-pressure hose 19. Nuts are fixed at both ends of the high-pressure hose 19. The nuts are connected to the threads at the outlet 20 of the produced liquid metering component 18 and the threads on the sleeve connector 10, which allows the metered produced liquid to be input into the return liquid chamber.

[0046] like Figure 2 , 3As shown in Figures 5 and 6, to ensure sealing along the flow path of the produced fluid, sealing elements 14 are provided between the central pipe 4 and the support pipe 3, between the central pipe 4 and the return pipe 2, and between the return pipe 2 and the wellhead connector 1. A sealing groove 11 is provided on the inner side of the support pipe 3 away from the annular groove 9, and a sealing ring is filled in the sealing groove 11. Sealing grooves 11 are also provided on the outer and inner sides of the return pipe 2, and sealing rings are filled in the sealing grooves 11. In this embodiment, the sealing ring is an O-ring.

[0047] like Figure 1 , 2 As shown in Figure 8, when installing the wellhead metering assembly, first stop the pumping unit, close the wellhead production gate valve 21, back pressure gate valve 22, and oil casing connection gate valve 23, open the wellhead vent valve installed on the back of the oil delivery pipe 24 to release the residual pressure in the pipeline, then remove the plug on the wellhead oil delivery pipe 24, and then install the wellhead metering device. Insert the center tube 4 of the wellhead metering device into the wellhead oil delivery pipe 24, then connect the wellhead connector 1 to the wellhead oil delivery pipe 24, and then rotate the screw sleeve 8 to guide the center tube 4 within the return pipe 2 and support pipe 3, thereby sealing the sealing sleeve 5. After sealing, check whether the other components of the wellhead metering device are fixed. After fixing, close the wellhead vent valve, open the wellhead back pressure gate valve 22 and the production gate valve 21 in sequence, and start the pumping unit.

[0048] After the pumping unit is turned on, the produced fluid enters the central tube 4 and flows sequentially through the produced fluid metering assembly 18, high-pressure hose 19, sleeve connector, inlet port 13, return chamber, and outlet 20 into the wellhead oil delivery pipe 24, i.e., the side of the central tube 4. However, due to the obstruction of the sealing sleeve 5, the produced fluid only enters the wellhead oil delivery pipe 12 and is transported to other locations by the oil delivery pipe 12. When it is necessary to measure the wellhead produced fluid pressure, the cock 16 is opened, and the pressure gauge 17 is used for measurement.

[0049] When it is necessary to remove the wellhead metering device to meter another well, first shut down the pumping unit, wellhead backpressure gate 22 and production gate 21, open the wellhead vent gate to release the residual pressure in the pipeline, then rotate the screw sleeve 8 of the wellhead metering device in the reverse direction to shrink the sealing sleeve 5 and release the seal on the oil outlet pipe 24. After that, remove the wellhead metering device and install the plug.

[0050] It should be noted that the various specific technical features described in the above embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0051] Furthermore, various embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.

[0052] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. The scope of patent protection of the present invention shall be determined by the claims. Similarly, any equivalent structural changes made based on the description and drawings of the present invention shall also be included within the scope of protection of the present invention.

Claims

1. A wellhead metering device, characterized in that, The device includes a central tube and an outer tube installed outside the central tube. A return fluid chamber is formed between the central tube and the outer tube. The return fluid chamber is connected to one end of the central tube. The other end of the central tube is a central tube insertion end for insertion into the wellhead oil outlet pipe. A sealing device is provided at the central tube insertion end for sealing and cooperating with the wellhead oil outlet pipe. The central tube and / or the outer tube are provided with a wellhead connection structure for connecting to and sealing the wellhead oil outlet pipe. When the wellhead connection structure is connected to the wellhead, the sealing device is located on the side of the wellhead oil delivery pipe closer to the wellhead. The outlet of the return fluid chamber is located in the wellhead oil outlet pipe. A produced fluid metering component is provided on the central tube or between the central tube and the return fluid chamber.

2. The wellhead metering device according to claim 1, characterized in that, The central tube and the outer tube are telescopically fitted along the length direction. A protruding retaining ring is provided at the insertion end of the central tube. The sealing device is a sealing rubber sleeve fitted on the central tube. The sealing rubber sleeve is located between the retaining ring and the corresponding end of the outer tube. A threaded sleeve that can be blocked by the outer tube is installed at the other end of the central tube.

3. The wellhead metering device according to claim 2, characterized in that, The retaining ring is threaded onto the central tube.

4. The wellhead metering device according to claim 2, characterized in that, The sealing tubes are provided in multiple ways, and a pressure ring is provided between adjacent sealing tubes.

5. The wellhead metering device according to claim 1, characterized in that, The wellhead connection structure includes a wellhead connector, which includes a sleeve that is fitted outside the outer pipe. A sleeve connector is provided on the sleeve and the sleeve connector is in communication with the return fluid chamber.

6. The wellhead metering device according to claim 5, characterized in that, A pressure measuring device is installed on the sleeve.

7. The wellhead metering device according to claim 5, characterized in that, The sleeve and the outer tube are threaded together.

8. The wellhead metering device according to claim 2, characterized in that, A guide key is provided on one of the central tube and the outer tube, and a groove is provided on the other tube to guide and cooperate with the guide key. The inner and outer tubes are guided and cooperated with each other through the guide key and the groove.

9. The wellhead metering device according to any one of claims 1-8, characterized in that, The output liquid metering component is installed at the corresponding end of the central tube and connected to the return liquid chamber through a corresponding pipeline.

10. The wellhead metering device according to any one of claims 1-8, characterized in that, The outlet of the return chamber is formed by a sieve hole located at the corresponding position on the outer tube.

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