Oil gas collecting device with bottom hole pressure compensation and backflow control functions

Abstract

The invention discloses an oil and gas collecting device with bottom hole pressure compensation and backflow control functions, which is applied to the technical field of oil and gas collection, and comprises a large four-way joint, an operation shut-in valve, a first small four-way joint, an operation heightening flange and a small annular communicating pipe, the lower end of the large four-way joint is connected with an outer layer pipe, and the upper end of the large four-way joint is connected with the operation shut-in valve; the upper end of the operation well shut-in valve is connected with a first small four-way joint, the upper end of the first small four-way joint is connected with an operation heightening flange, the upper end of the operation heightening flange is connected with a third gate valve, the side face of the large four-way joint is communicated with one end of a small annular communicating pipe, and the other end of the small annular communicating pipe is communicated with the side face of the first small four-way joint. And the outer-layer pipe, the middle pipe, the small-diameter pipe and the bottom hole pressure control assembly are arranged underground from outside to inside. According to the invention, the problem of flooding of deep-sea oil and gas wells, ultra-deep wells and low-pressure wells and the problem of long-term effective drainage and production of liquid producing wells can be solved.

Description

Technical Field

[0001] This invention relates to the field of oil and gas extraction technology, specifically to an oil and gas extraction device with bottom hole pressure compensation and backflow control functions. Background Technology

[0002] In the extraction of oil and gas fields and coalbed methane, wellbore fluid accumulation is one of the main problems restricting stable and high production of oil and gas wells. To ensure normal production of oil and gas wells, especially for high-yield fluid wells, it is essential to promptly drain the accumulated fluid from the wellbore. If the fluid remains, it will severely inhibit oil and gas production, leading to a decrease in the production ratio and economic benefits. Therefore, appropriate methods are needed to effectively drain the accumulated fluid from the wellbore.

[0003] Currently used liquid drainage and gas production technologies include bubble drainage and plunger drainage, but these methods have limited liquid carrying capacity and are only suitable for gas wells with low liquid production. For high-yield gas wells, mechanical pumping, electric submersible pumping, and jet pumping are commonly used, but these technologies have disadvantages such as high cost and high energy consumption, and the maintenance process can cause significant damage to the oil and gas reservoir, seriously affecting the economic benefits of the gas well. This problem is particularly prominent in deep-sea oil and gas wells and offshore oil and gas fields due to the large liquid volume and complex operating conditions.

[0004] Especially for water-flooded deep-sea oil and gas wells, ultra-deep wells, and low-pressure wells, well recovery is extremely difficult. Conventional drainage methods struggle to establish an effective lift pressure differential, and the back pressure of the liquid column suppresses formation productivity release for extended periods. Existing equipment requires multiple gas lifts and prolonged well shut-ins during the high-cost liquid nitrogen lift process, with some shut-ins lasting up to a year before attempting to reopen the well. This cycle not only prolongs the recovery period but also easily induces reservoir clay swelling and water-sensitive damage, further deteriorating the seepage channels and severely restricting the recovery and efficient production of oil and gas wells.

[0005] The aforementioned phenomena and difficulties are due to the accumulated pressure drop of the liquid column slug and the pressure drop caused by the accumulation of liquid in oil and gas wells. Therefore, it is necessary to provide an oil and gas collection device with bottom hole pressure compensation and backflow control functions to solve the above problems. Summary of the Invention

[0006] The purpose of this invention is to provide an oil and gas extraction device with bottomhole pressure compensation and backflow control functions. This device solves the problems of excessive pressure drop and high operating resistance caused by liquid column slugging in existing oil and gas well drainage technologies. By breaking down the liquid column slugging into a gas column flow, it fundamentally reduces the pressure drop during the drainage process, achieving unobstructed tubing and low-pressure fluid-carrying drainage. Therefore, this invention can effectively solve the water flooding problem in deep-sea oil and gas wells, ultra-deep wells, and low-pressure wells, and meet the long-term effective drainage requirements of producing wells, thus solving the problems mentioned in the background art.

[0007] To solve the above-mentioned technical problems, the present invention provides the following technical solution: an oil and gas collection device with bottomhole pressure compensation and backflow control functions, which is installed through the ground and includes a collection tree located on the upper part of the ground. The collection tree includes a large four-way valve, a work stop valve, a first small four-way valve, a work elevation flange, and a small annulus connecting pipe. The upper end of the large four-way valve is connected to the work stop valve, the upper end of the work stop valve is connected to the first small four-way valve, the upper end of the first small four-way valve is connected to the work elevation flange, and a third gate valve is connected to the upper end of the work elevation flange. The side of the large four-way valve is connected to one end of the small annulus connecting pipe, and the other end of the small annulus connecting pipe is connected to the side of the first small four-way valve; and The downhole section, located below the surface, includes an outer tube, an intermediate tube, a small-diameter tube, and a bottomhole pressure control assembly arranged from the outside in. The lower end of the large four-way connector is connected to the outer tube. A large annulus is formed between the inner side of the outer tube and the outer side of the intermediate tube. Gas and liquid produced from the oil and gas reservoir accumulate in the large annulus, forming downhole gas-liquid separation. A small annulus is formed between the inner side of the intermediate tube and the outer side of the small-diameter tube. A liquid-carrying chamber is formed inside the small-diameter tube. The small annular connecting pipe connects the large annular space and the small annular space. The small annular connecting pipe is also equipped with a horizontal connecting device, a vertical connecting device, and a connecting tee.

[0008] According to the above technical solution, the bottom hole pressure control component includes a flow guiding device, a collection device, and a multi-chamber pressure transmitter. The flow guiding device is connected to the lower end of the small-diameter pipe. A gas phase flow channel is provided on the flow guiding device. The small annulus is connected to the liquid carrying chamber through the gas phase flow channel. A flow guiding device flow channel is provided on the lower side of the gas phase flow channel. A flow guiding device lower end seal is provided at the lower end of the flow guiding device. The collecting device is sealed to the lower end of the intermediate tube. The upper inner side of the collecting device is provided with a sealing surface that seals with the lower end of the flow guiding device. The collecting device has a flow passage in the middle and a collecting inner cavity on the lower side of the flow passage.

[0009] According to the above technical solution, the flow channel of the flow guiding device is a throttling channel, and the flow channel of the flow guiding device is a throttling channel, and a certain throttling pressure difference will be formed when the fluid passes through it; The flow channel of the collection device is a throttling channel, and a certain throttling pressure difference will be formed when the fluid passes through it. According to the above technical solution, a large four-way suspension device is connected to the inner side of the upper end of the large four-way, and a middle pipe connecting pipe is connected to the lower end of the large four-way suspension device. The lower end of the middle pipe connecting pipe is connected to the middle pipe. The upper inner side of the first small four-way is connected to a small four-way suspension device, and the lower end of the small four-way suspension device is connected to a small diameter pipe connecting pipe, and the lower end of the small diameter pipe connecting pipe is connected to a small diameter pipe.

[0010] According to the above technical solution, a first gate valve is provided on the small annular connecting pipe. The first gate valve is located at the front end of the small annular connecting pipe and is connected to the side interface of the large four-way valve. The small annular connecting pipe is connected to the large annular space by the first gate valve. The horizontal connecting device includes a horizontal connecting pipe, a connecting device fixing nut, a first sealing push ring, a first sealing assembly, and a horizontal fixing pipe. The horizontal connecting pipe is connected to a first gate valve. The connecting device fixing nut, the first sealing push ring, the first sealing assembly, and the horizontal fixing pipe are located on the outside of the horizontal connecting pipe. The inner and outer sides of the connecting device fixing nut are threadedly connected to the horizontal connecting pipe and the horizontal fixing pipe, respectively, to ensure that the horizontal connecting pipe remains fixed after axial expansion and contraction. The first sealing push ring and the first sealing assembly are located between the connecting device fixing nut and the horizontal fixing pipe. The horizontal connecting pipe can be horizontally displaced and can adaptably expand and contract during installation, giving the horizontal connecting device a telescopic installation function, which can effectively eliminate on-site installation connection stress. According to the above technical solution, the vertical connection device includes a vertical fixed pipe, a second sealing assembly, a second sealing push ring, a vertical connection pipe, a second connection device fixing nut, and a one-way device. The one-way device is located on the bottom inner side of the vertical fixed pipe to ensure that the fluid flows only in one direction from the large annulus to the small annulus. The vertical connecting device is similar in structure and connection method to the horizontal connecting device, and has the same function as the horizontal connecting device. An extension connecting pipe is connected to the top of the vertical connecting pipe. The vertical connecting device has a telescopic installation function, which can effectively eliminate on-site installation connection stress.

[0011] According to the above technical solution, the connecting tee is located between the horizontal connecting device and the vertical connecting device. Two ports of the connecting tee are connected to the horizontal fixed pipe and the vertical fixed pipe, respectively. The other port of the connecting tee is connected to a plug. The plug is connected to an external filling port one. The external filling port one is connected to an external gas source one or other sources.

[0012] According to the above technical solution, the small annular connecting pipe is also provided with a second gate valve and a first angle valve. The second gate valve is located at the end of the small annular connecting pipe and is connected to the first small four-way side interface. The small annular connecting pipe is controlled by the second gate valve to connect to the small annular space. The control end of the first angle valve is equipped with an angle valve electric control head. The first angle valve is used to divert or regulate the fluid in the large annulus into the small annulus, in accordance with the system pressure field requirements, to achieve balanced fluid carrying and long-term drainage of oil and gas wells. The extended connecting pipe is connected to the first angle valve.

[0013] According to the above technical solution, the area below the ground also includes, from top to bottom, the upper boundary of the producing layer, the lower boundary of the producing layer, and the artificial well bottom; The angle valve control head is electrically connected to the multi-chamber pressure transmitter. The multi-chamber pressure transmitter includes a large annulus pressure transmitter, a small annulus pressure transmitter, and a fluid-carrying chamber pressure transmitter, all located at the bottom of the well. These transmitters are installed at the corresponding annulus or chamber connection points and are used to monitor and feedback the pressure data in the large annulus, small annulus, and fluid-carrying chamber, respectively, to achieve automatic bottom-hole pressure compensation and backflow control.

[0014] According to the above technical solution, the upper end of the third gate valve is connected to an external production device, which includes a second small four-way valve, a production connecting pipe, and a second angle valve. The second small four-way valve is connected to the top of the third gate valve, and the production connecting pipe is connected to the second small four-way valve and the large annulus. The top and the other side interface of the second small four-way valve are both connected to a sixth gate valve. The other side interface of the second small four-way valve is connected to an external filling port two through the sixth gate valve. The external filling port two is connected to an external gas source two or other sources. The second angle valve is installed on the production connecting pipe. The second angle valve is used to dynamically correct the throttling pressure difference so that the gas phase energy is accurately matched with the liquid phase load.

[0015] Compared with existing technologies, current oil and gas well drainage technologies rely on pushing liquid slugs in the wellbore for production, which results in significant pressure drop from the liquid slugs and pressure drop due to operating resistance. This invention, however, primarily solves the problem of significant pressure drop during drainage by breaking down the liquid slugs into a gas column flow. Through large-ring air-liquid separation, bottom-hole pressure control components for liquid inlet throttling control, and electrically connected pressure field control of the gas and liquid phases, a gas column flow is achieved, ensuring smooth tubing flow and facilitating liquid drainage. Specifically, a pressure gradient drive system is constructed by setting up a throttling channel, an angle valve electric control head, a large annulus, a small annulus, a liquid carrying chamber, and a small annulus connecting pipe. This system enables efficient lifting and stable transport of the gas-liquid mixture in the liquid carrying chamber. It monitors the bottom hole pressure, gas-liquid ratio, and liquid carrying chamber flow velocity in real time, and dynamically adjusts the angle valve opening to ensure that the flow velocity in the liquid carrying chamber is always maintained above the critical liquid carrying velocity. This ensures that the flow stability in the liquid carrying chamber can still be maintained under complex conditions such as low-pressure wells, high liquid-to-gas ratios, or intermittent liquid production, effectively suppressing the risks of slug flow and liquid accumulation. Attached Figure Description

[0016] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings: Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is the invention Figure 1 Enlarged structural diagram of region A in the middle; Figure 3 This is the invention Figure 1 Enlarged structural diagram of region B in the middle; Figure 4 This is the invention Figure 1 Enlarged structural diagram of region C in the middle; Figure 5 This is the invention Figure 1 A magnified structural diagram of region D in the middle; In the diagram: 1. Large four-way valve; 2. Intermediate pipe connecting pipe; 3. Large four-way valve suspension device; 4. Large four-way valve reducer; 5. Operation shut-off valve; 6. First small four-way valve; 7. First gate valve; 8. Horizontal connecting pipe; 9. Connecting device fixing nut one; 10. First sealing push ring; 11. First sealing assembly; 12. Horizontal fixed pipe; 13. Connecting tee; 14. Plug; 15. One-way device; 16. Vertical fixed pipe; 17. Second sealing assembly; 18. Second sealing push ring; 19. Vertical connecting pipe; 20. Extended connecting pipe; 21. First angle valve; 22. Angle valve solenoid; 23. Second gate valve; 24. Small diameter pipe connecting pipe; 25. Small four-way valve suspension device; 26. Operation heightening flange; 27. Third gate valve; 28. Fourth gate valve; 29. ​​Second angle valve; 30. Second small four-way valve; 31. Outer tube; 32. Intermediate tube; 33. Small-diameter tube; 34. Large annulus; 35. Small annulus; 36. Liquid-carrying chamber; 40. Formation produced fluid; 41. Collection chamber; 42. Collection device; 43. Collection device flow passage; 44. Lower seal of the flow guiding device; 45. Flow guiding device flow passage; 46. Gas phase flow passage; 47. Flow guiding device; W11, External Air 1; W12, External Air 2; W13, External Air 3; M, upper boundary of the producing layer; N, lower boundary of the producing layer; H, artificial well bottom; DM, surface. Detailed Implementation

[0017] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] Please see Figure 1-5The present invention provides a technical solution: an oil and gas collection device with bottom hole pressure compensation and backflow control functions, including a collection tree, a downhole part, and a surface DM. The main body of the collection tree is located above the surface DM, and the downhole part is located below the surface DM. Below the surface DM, there are also the upper boundary M of the production layer, the lower boundary N of the production layer, and the artificial bottom hole H, which are presented from top to bottom.

[0019] Specifically, such as Figures 1-3 As shown, the acquisition tree includes a large four-way valve 1, a work shut-in valve 5, a first small four-way valve 6, a work heightening flange 26, and a small annulus connecting pipe. The downhole part includes an outer layer pipe 31, an intermediate pipe 32, a small diameter pipe 33 arranged from the outside to the inside, and a bottom hole pressure control assembly. The bottom hole pressure control assembly includes a flow guiding device 47, a collection device 42, and a multi-chamber pressure transmitter.

[0020] It should be noted that, Figure 1 The diagram illustrates the underground section in a simplified manner and does not represent the actual proportions of the data collection tree and the underground section. In reality, the underground section may extend hundreds or thousands of meters below the ground surface. Vertically, the underground section can be formed by multiple sections connected by appropriate pipe joints; or by connecting or linking metal or non-metal pipes using existing methods. The underground section can also be formed as a continuous pipeline. Specifically, the intermediate pipe 32 and the small-diameter pipe 33 can be a single, continuous pipeline.

[0021] Specifically, such as Figures 1-3 As shown, the lower end of the large cross-connector 1 is connected to the outer tube 31, the upper end of the large cross-connector 1 is connected to the large cross-connector reducer 4, the upper end of the large cross-connector reducer 4 is connected to the working shut-in valve 5, the upper end of the working shut-in valve 5 is connected to the first small cross-connector 6, the upper end of the first small cross-connector 6 is connected to the working heightening flange 26, the upper end of the working heightening flange 26 is connected to the third gate valve 27, the working heightening flange 26 is used to raise the installation height of the first small cross-connector 6, and the large cross-connector reducer 4 is used to adapt to different wellhead device interface sizes; The side of the large four-way connector 1 is connected to one end of the small annular connecting pipe, and the other end of the small annular connecting pipe is connected to the side of the first small four-way connector 6.

[0022] Furthermore, such as Figure 1 As shown, the shut-in valve 5 is connected in series between the first small four-way valve 6 and the large four-way valve 1. It is used for controllable shut-off during operation, and also facilitates shut-in for both well control and non-well control operations. At the same time, it is also a safety precaution for operation.

[0023] It should be noted that the working heightening flange 26 is used in the later stages of well control or non-well control operations to facilitate the fixing of the small-diameter pipe suspension device 25 and provide reliable safety assurance.

[0024] Specifically, such as Figure 2 and Figure 3As shown, the upper inner side of the large four-way 1 is connected to the large four-way suspension device 3, and the lower end of the large four-way suspension device 3 is connected to the intermediate pipe connecting pipe 2. The lower end of the intermediate pipe connecting pipe 2 is connected to the intermediate pipe 32. A large annulus 34 is formed between the inner side of the outer pipe 31 and the outer side of the intermediate pipe 32. The gas and liquid produced by the oil and gas reservoir accumulate in the large annulus 34. The depth of the large annulus 34 is hundreds or thousands of meters, which forms a large space. Due to the large difference in density between gas and liquid, gas moves upward and liquid is deposited at the bottom, forming gas-liquid separation. Therefore, the large annulus 34 is also equivalent to a downhole gas-liquid separator, realizing downhole gas-liquid separation. The upper inner side of the first small four-way connector 6 is connected to a small four-way suspension device 25. The lower end of the small four-way suspension device 25 is connected to a small diameter pipe connecting pipe 24. The lower end of the small diameter pipe connecting pipe 24 is connected to a small diameter pipe 33. A connecting cavity is formed between the inner side of the intermediate pipe 32 and the outer side of the small diameter pipe 33. The connecting cavity is a small annulus 35. A liquid carrying cavity 36 is formed inside the small diameter pipe 33. The small annulus 35 is connected to the liquid carrying cavity 36 through the gas phase flow channel 46.

[0025] It should be noted that the small four-way suspension device 25 can also be connected to the inner side of the upper end face of the working heightening flange 26; the absence of the working well shut-off valve 5 or the working heightening flange 26 does not affect the completion of the invention or the invention effect.

[0026] Furthermore, such as Figure 1 and Figure 4 As shown, the small annulus connecting pipe connects the large annulus 34 and the small annulus 35. The small annulus connecting pipe is equipped with a first gate valve 7 and a second gate valve 23. The first gate valve 7 is located at the front end of the small annulus connecting pipe and is connected to the side interface of the large four-way valve 1. The second gate valve 23 is located at the end of the small annulus connecting pipe and is connected to the side interface of the first small four-way valve 6. The first gate valve 7 and the second gate valve 23 are used to regulate the flow between the large annulus 34 and the small annulus 35. At the same time, the first gate valve 7 and the second gate valve 23 are closed during operation or other operations, which facilitates operation, maintenance or other operations.

[0027] It should be noted that the first gate valve 7 and the second gate valve 23 can be in two or more sets to adapt to different wellbore working conditions.

[0028] Furthermore, such as Figure 1 and Figure 4 As shown, a first angle valve 21 is installed on the small annulus connecting pipe, and an angle valve electric control head 22 is installed at the control end of the first angle valve 21. The first angle valve 21 is used to divert or regulate the fluid in the large annulus 34 into the small annulus 35, in accordance with the system pressure field requirements, to achieve balanced fluid carrying and long-term drainage of oil and gas wells. The angle valve electric control head 22 is electrically connected to the multi-chamber pressure transmitter. The multi-chamber pressure transmitter includes a large annulus pressure transmitter, a small annulus pressure transmitter, and a liquid-carrying chamber pressure transmitter, all equipped with an artificial well bottom H. The large annulus pressure transmitter monitors and provides feedback on the pressure inside the large annulus 34, the small annulus pressure transmitter monitors and provides feedback on the pressure inside the small annulus 35, and the liquid-carrying chamber pressure transmitter monitors and provides feedback on the pressure inside the liquid-carrying chamber 36. These transmitters are installed at suitable connection points in their respective annulus or chambers. Therefore, the angle valve control head 22, together with the pressure transmitters at the bottom of the well, annulus, and chamber pressure, forms a closed-loop feedback system. This system senses micro-pressure changes at the bottom of the well in real time. Combined with the flow recognition model embedded in the edge computing unit, it dynamically calculates the backflow threshold, automatically identifies the water flooding stage and the lifting critical point, and dynamically adjusts the opening of the first angle valve 21 to maintain the optimal backflow ratio. The system drives the angle valve opening to respond in the hundreds of milliseconds between 0.5% and 100%. When liquid column fall or gas-liquid interface fluctuation is detected, the system completes the compensation response within hundreds of milliseconds. This closed-loop control mechanism significantly improves the adaptive capability of the drainage system.

[0029] It should be noted that the suitable connection position between the large annular pressure transmitter and the corresponding annular space or chamber can be the right side of the first gate valve 7, the suitable connection position between the small annular pressure transmitter and the corresponding annular space or chamber can be the right side of the second gate valve 23, and the suitable connection position between the liquid-carrying chamber pressure transmitter and the corresponding annular space or chamber can be the top of the liquid-carrying chamber 36.

[0030] Furthermore, such as Figure 4 As shown, the small annular connecting pipe is equipped with a horizontal connecting device, a vertical connecting device, and a connecting tee 13. The horizontal connecting device includes a horizontal connecting pipe 8, a connecting device fixing nut 9, a first sealing push ring 10, a first sealing assembly 11, and a horizontal fixing pipe 12. The horizontal connecting pipe 8 is connected to the first gate valve 7. The connecting device fixing nut 9, the first sealing push ring 10, the first sealing assembly 11, and the horizontal fixing pipe 12 are located on the outside of the horizontal connecting pipe 8. The inner and outer sides of the connecting device fixing nut 9 are threadedly connected to the horizontal connecting pipe and the horizontal fixing pipe, respectively, to ensure that the horizontal connecting pipe 8 can still maintain its position after axial expansion and contraction. The first sealing push ring 10 and the first sealing assembly 11 are located between the connecting device fixing nut 9 and the horizontal fixing pipe 12. The field oil and gas well sampling tree has been installed for many years, and different wellheads have different installation errors. The horizontal connecting pipe 8 can be horizontally displaced and can be adaptively expanded and contracted during installation, so that the horizontal connecting device has a telescopic installation function, which can effectively eliminate the on-site installation connection stress. At the same time, the first sealing push ring 10 and the filling first sealing assembly 11 set between the connecting device fixing nut 9 and the horizontal fixing pipe 12 can ensure the high pressure sealing requirements.

[0031] The vertical connection device includes a vertical fixed pipe 16, a second sealing component 17, a second sealing push ring 18, a vertical connection pipe 19, and a connection device fixing nut 2. The vertical connection device is similar to the horizontal connection device in structure and connection method, and has the same function as the horizontal connection device. An extension connection pipe 20 is connected to the top of the vertical connection pipe 19. The extension connection pipe 20 is connected to the first angle valve 21. The vertical connection pipe 19 can be vertically displaced. The vertical connection device has a telescopic installation function, which can effectively eliminate on-site installation connection stress. The vertical connection device also includes a one-way device 15, which is located inside the bottom of the vertical fixed pipe 16. The one-way device 15 is used to ensure that the fluid flows unidirectionally from the large annulus 34 to the small annulus 35. In a preferred embodiment, the one-way device 15 is provided with a one-way valve core assembly, which is made of alloy. Furthermore, such as Figure 4 As shown, the connecting tee 13 is located between the horizontal connecting device and the vertical connecting device. Two ports of the connecting tee 13 are connected to the horizontal fixed pipe 12 and the vertical fixed pipe 16 respectively. The other port of the connecting tee 13 is connected to a plug 14. The plug 14 is connected to an external filling port 1. The external filling port 1 is connected to an external gas W11 or other. Furthermore, such as Figure 1 As shown, the top of the third gate valve 27 is connected to an external production device, which includes a second small four-way valve 30, a production connecting pipe, and a second angle valve 29. The second small four-way valve 30 is connected to the top of the third gate valve 27. The production connecting pipe connects the second small four-way valve 30 and the large annulus 34. A fourth gate valve 28 and a fifth gate valve are installed on the production connecting pipe. The fourth gate valve 28 is located at the upper end of the production connecting pipe and is connected to the side interface of the second small four-way valve 30. The fifth gate valve is located at the lower end of the production connecting pipe and is connected to the other side interface of the large four-way valve 1. The fourth gate valve 28 and the fifth gate valve are used to regulate the flow between the large annulus 34 and the liquid carrying chamber 36. The fourth gate valve 28 and the fifth gate valve open and close under appropriate working conditions, which is convenient for production, operation, maintenance or other operations. The top and other side interfaces of the second small four-way valve 30 are both connected to a sixth gate valve. The other side interface of the second small four-way valve 30 is connected to an external filling port 2 through the sixth gate valve. The external filling port 2 is connected to an external gas supply 2 W12 or other gas.

[0032] Furthermore, such as Figure 1 As shown, the second angle valve 29 is installed on the production connecting pipe. The second angle valve 29 is used to dynamically correct the throttling pressure difference so that the gas phase energy is accurately matched with the liquid phase load.

[0033] It should be noted that the other side interface of the first small four-way valve 6 is connected to the seventh gate valve. The first small four-way valve 6 is connected to the external injection port 3 through the seventh gate valve. The external injection port 3 is connected to the external gas port 3 W13 or other ports. The external gas port 3 W13 is another spare port. External injection ports 1, 2, and 3 are all used to inject low-density fluids such as nitrogen to work with the bottom hole pressure control components to build a dynamic micro-positive pressure field, or other injection agents required in the wellbore.

[0034] Furthermore, such as Figure 5 As shown, the flow guiding device 47 is connected to the lower end of the small diameter pipe 33. A gas phase flow channel 46 is provided on the flow guiding device 47, and a flow guiding device flow channel 45 is provided on the lower side of the gas phase flow channel 46. A flow guiding device lower end seal 44 is provided at the lower end of the flow guiding device 47.

[0035] It should be noted that the lower end seal 44 of the flow guiding device can be a conical seal or other sealing forms.

[0036] Furthermore, such as Figure 5 As shown, the collecting device 42 is sealed to the lower end of the intermediate pipe 32. The inner side of the upper end of the collecting device 42 is provided with a sealing surface that cooperates with the lower end seal 44 of the flow guiding device. The collecting device 42 is provided with a collecting device flow passage 43 in the middle. The collecting device flow passage 43 is provided with a collecting inner cavity 41 on the lower side. The collecting inner cavity 41 is an enlarged shape with a small opening at the top and a large opening at the bottom. The collecting inner cavity 41 collects the formation fluid after it is produced. This fluid becomes the formation produced fluid 40. The remaining part of the formation produced fluid 40 enters the large annulus 34. This structure provides the basic conditions for gas-liquid fluid diversion, distribution and pressure control.

[0037] Furthermore, such as Figure 5 As shown, the flow channel 45 of the flow guiding device is a throttling channel, and a certain throttling pressure difference will be formed when the fluid passes through it. Alternatively, the flow channel 43 of the collection device can be set as a throttling channel. Since the liquid phase after gas-liquid separation is located in the throttling channel, or the throttling channel is submerged in the liquid phase, the opening of the angle valve solenoid 22 is precisely executed. The pressure difference in the throttling channel changes with the opening of the angle valve solenoid 22. The throttling pressure difference, together with the separated gas phase fluid, flows controllably from the large annulus 34 to the small annulus 35, and then enters the liquid-carrying chamber 36, so that the gas-liquid mixture in the liquid-carrying chamber 36 continuously receives a suitable kinetic energy boost. This kinetic energy boosting mechanism significantly enhances the gas-liquid mixing and transport efficiency in the small-diameter pipe 33, ideally in the form of a mist-like gas column, avoiding liquid carry-over failure caused by liquid fallback. At the same time, water flooding combined with nitrogen gas lift-assisted drainage forms a strong positive pressure field, further improving the liquid carry-over effect and achieving rapid drainage, thus solving the economic losses of high investment costs in water flooding wells and long-term well closure.

[0038] Furthermore, such as Figure 5As shown, the bottom of the outer tube 31 is located at the bottom of the artificial well H. The lower end face of the collecting inner cavity 41 of the collecting device 42 is located at a certain position above the upper boundary M of the production layer. When the distance between the upper boundary M and the lower boundary N of the production layer is large, the lower end face of the collecting inner cavity 41 can also be set at a specific position between the upper boundary M and the lower boundary N of the production layer. This position is set by the staff according to the actual situation to ensure that after the liquid phase fluid and part of the gas phase enter the collecting inner cavity 41, they enter the liquid carrying chamber 36 and are transported to the wellhead.

[0039] In the oil and gas extraction device, after gas-liquid separation, the gas phase enters the large annulus 34 under ideal conditions. The gas flow from the large annulus 34 enters the small annulus 35 through the first angle valve 21 and enters the liquid-carrying chamber 36 through the gas phase flow channel 46. The liquid phase and part of the gas phase at the bottom of the well enter the liquid-carrying chamber 36 through the throttling channel. After the gas and liquid phases mix, they form a gas mist column under the action of the flow rate, which unblocks the oil pipe and carries the liquid upward in a balanced manner.

[0040] In actual working conditions, due to the interference of factors such as uneven formation gas-liquid production, pressure fluctuations in surface output pipelines, and the complexity of the wellbore itself, the gas-liquid two-phase flow state undergoes dynamic changes. At this time, the system uses the electronic control head to sense the pressure gradient of the liquid-carrying chamber 36 and the opening of the second angle valve 29 in real time, dynamically corrects the throttling pressure difference, and makes the gas phase energy accurately match the liquid phase load. When the gas column has a higher proportion of liquid phase, the gas phase in the large annulus 34 is controlled by the angle valve control head 22 and the first angle valve 21 to automatically compensate and divert the gas phase to the small annulus 35. The gas phase flows through the gas phase flow channel 46 to the liquid carrying chamber 36 to form compensated liquid carrying energy, maintaining the continuous upward flow of the liquid phase. At the same time, due to the large amount of compensated gas, the pressure difference in the throttling channel (flow channel 45 of the guide device or flow channel 43 of the collection device) decreases, and the amount of liquid entering decreases accordingly. After a certain period of time, when the system detects overcompensation, the system limits compensation through the angle valve control head 22 to save wellbore gas and cooperate with long-term effective liquid production. At the same time, after limiting compensation, the amount of compensated gas decreases, the pressure difference in the throttling channel (flow channel 45 of the guide device or flow channel 43 of the collection device) increases, and the amount of liquid entering increases accordingly. This cycle repeats, constantly correcting and continuously carrying liquid for production, automatically adapting to well conditions. This situation is the self-producing gas-driven mode. Through structural and system control, automatic bottomhole pressure compensation and reflux control enable long-term and effective fluid production from oil and gas wells. This closed-loop control mechanism allows the unit to maintain stable fluid carrying capacity even under complex operating conditions such as low gas production, high water cut, and variable well inclination. It truly achieves a dynamic balance of "using gas to guide fluid and using fluid to promote stability."

[0041] When a well is flooded or has a large volume of fluid in the early stages of well opening, nitrogen gas lift is used to assist in fluid removal, creating a strong positive pressure field that quickly displaces the fluid in the wellbore and significantly shortens the gas-seeping period. First, external gas W12 is introduced to displace the fluid level in the small-diameter pipe 33 to the bottom of the pipe. Then, external gas W11 is switched to reverse displacement, forcibly pushing the fluid from the annulus into the small-diameter pipe 33. Nitrogen is continuously injected to maintain the positive pressure gradient at the bottom of the well, pushing the fluid rapidly upward along the fluid-carrying chamber 36 of the small-diameter pipe 33 to the wellhead, suppressing gas-liquid slippage and slug accumulation throughout the process. After gas is seen at the wellhead, the amount of fluid in the wellbore is calculated to be emptied, and the nitrogen injection rate is gradually reduced until injection stops. The system switches to a self-generated gas-driven mode to achieve efficient fluid-carrying. At this time, the bottom-hole pressure field smoothly transitions from external drive to endogenous maintenance. When nitrogen injection stops, the self-generated gas fluid-carrying capacity has simultaneously jumped to the critical threshold, avoiding pressure collapse and fluid re-aggregation.

[0042] Based on the above-described oil and gas collection device, the oil and gas collection method provided in this embodiment of the invention includes the following steps: Step 1: Utilize the density difference between air and liquid in the large ring to achieve natural gas-liquid separation downhole.

[0043] Step 2: In the self-generated gas drive mode, the gas and liquid are mixed and lifted to the wellhead through the throttling channel and the gas phase flow channel.

[0044] Step 3: Based on the feedback from the multi-chamber pressure transmitter, the opening of the angle valve is dynamically adjusted to achieve automatic compensation and backflow control of the bottom hole pressure.

[0045] Step 4: In the initial stage of well flooding or well opening, nitrogen gas is used for forced drainage through positive and negative displacement to quickly establish a positive pressure field.

[0046] Step 5: After nitrogen injection is stopped, smoothly switch to self-generated gas-driven mode to maintain long-term stable liquid-carrying and drainage.

[0047] The above methods can solve the water flooding problems of deep-sea oil and gas wells, ultra-deep wells, and low-pressure wells, as well as the long-term effective drainage problem of producing wells. Given the characteristics of deep-sea oil and gas wells—large fluid volumes and a tendency to form liquid slugs—the pressure field control of this invention plays a particularly prominent role under these conditions. Furthermore, this technology provides a new path to solving the current challenges of continuous development of combustible ice.

[0048] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0049] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An oil and gas harvesting device with bottom hole pressure compensation and backflow control functions, which is installed through the surface (DM), characterized in that, include: A data collection tree, located above the ground (DM), includes a large four-way valve (1), a working shut-off valve (5), a first small four-way valve (6), a working elevation flange (26), and a small annulus connecting pipe. The upper end of the large four-way valve (1) is connected to the working shut-off valve (5), the upper end of the working shut-off valve (5) is connected to the first small four-way valve (6), the upper end of the first small four-way valve (6) is connected to the working elevation flange (26), and a third gate valve (27) is connected to the upper end of the working elevation flange (26). The side of the large four-way valve (1) is connected to one end of the small annulus connecting pipe, and the other end of the small annulus connecting pipe is connected to the side of the first small four-way valve (6). The downhole section is located below the surface (DM). The downhole section includes an outer tube (31), an intermediate tube (32), a small diameter tube (33), and a bottom hole pressure control assembly arranged from the outside to the inside. The lower end of the large four-way connector (1) is connected to the outer tube (31). A large annulus (34) is formed between the inner side of the outer tube (31) and the outer side of the intermediate tube (32). Gas and liquid produced by the oil and gas reservoir accumulate in the large annulus (34), forming downhole gas-liquid separation. A small annulus (35) is formed between the inner side of the intermediate tube (32) and the outer side of the small diameter tube (33). A liquid-carrying chamber (36) is formed inside the small diameter tube (33). The small annular connecting pipe connects the large annular space (34) and the small annular space (35). The small annular connecting pipe is also equipped with a horizontal connecting device, a vertical connecting device and a connecting tee (13).

2. The oil and gas collection device with bottom hole pressure compensation and backflow control functions according to claim 1, characterized in that, The bottom hole pressure control assembly includes a flow guiding device (47) and a collection device (42). The flow guiding device (47) is connected to the lower end of the small diameter pipe (33). A gas phase flow passage (46) is provided on the flow guiding device (47). The small annulus (35) is connected to the liquid carrying chamber (36) through the gas phase flow passage (46). A flow guiding device flow passage (45) is provided on the lower side of the gas phase flow passage (46). A flow guiding device lower end seal (44) is provided at the lower end of the flow guiding device (47). The collecting device (42) is sealed to the lower end of the intermediate tube (32). The upper inner side of the collecting device (42) is provided with a sealing surface that cooperates with the lower sealing (44) of the flow guiding device. The collecting device (42) is provided with a collecting device flow passage (43) in the middle. The collecting device flow passage (43) has a collecting inner cavity (41) on the lower side.

3. The oil and gas collection device with bottom hole pressure compensation and backflow control functions according to claim 2, characterized in that, The flow channel (45) of the flow guiding device is a throttling channel and a certain throttling pressure difference will be formed when the fluid passes through it; The flow channel (43) of the collection device is a throttling channel, and a certain throttling pressure difference will be formed when the fluid passes through it.

4. The oil and gas collection device with bottom hole pressure compensation and backflow control functions according to claim 1, characterized in that, The upper inner side of the large four-way connector (1) is connected to a large four-way suspension device (3), and the lower end of the large four-way suspension device (3) is connected to an intermediate pipe connecting pipe (2). The lower end of the intermediate pipe connecting pipe (2) is connected to the intermediate pipe (32). The upper inner side of the first small four-way connector (6) is connected to a small four-way suspension device (25), and the lower end of the small four-way suspension device (25) is connected to a small diameter pipe connecting pipe (24), and the lower end of the small diameter pipe connecting pipe (24) is connected to a small diameter pipe (33).

5. The oil and gas collection device with bottom hole pressure compensation and backflow control functions according to claim 1, characterized in that, A first gate valve (7) is provided on the small annular connecting pipe. The first gate valve (7) is located at the front end of the small annular connecting pipe and is connected to the side interface of the large four-way connector (1). The small annular connecting pipe is controlled by the first gate valve (7) to connect to the large annular space (34). The horizontal connecting device includes a horizontal connecting pipe (8), a connecting device fixing nut (9), a first sealing push ring (10), a first sealing assembly (11), and a horizontal fixing pipe (12). The horizontal connecting pipe (8) is connected to the first gate valve (7). The connecting device fixing nut (9), the first sealing push ring (10), the first sealing assembly (11), and the horizontal fixing pipe (12) are arranged on the outside of the horizontal connecting pipe (8). The inner and outer sides of the connecting device fixing nut (9) are threadedly connected to the horizontal connecting pipe (8) and the horizontal fixing pipe (12), respectively. The first sealing push ring (10) and the first sealing assembly (11) are located between the connecting device fixing nut (9) and the horizontal fixing pipe (12).

6. The oil and gas collection device with bottom hole pressure compensation and backflow control functions according to claim 5, characterized in that, The vertical connection device includes a vertical fixed pipe (16), a second sealing assembly (17), a second sealing push ring (18), a vertical connection pipe (19), a connection device fixing nut, and a one-way device (15). The one-way device (15) is located inside the bottom of the vertical fixed pipe (16) to ensure that the fluid flows only in one direction from the large annulus (34) to the small annulus (35). The vertical connecting device is similar in structure and connection method to the horizontal connecting device, and has the same function as the horizontal connecting device. An extended connecting pipe (20) is connected to the top of the vertical connecting pipe (19).

7. An oil and gas extraction device with bottom hole pressure compensation and backflow control functions according to claim 6, characterized in that, The connecting tee (13) is located between the horizontal connecting device and the vertical connecting device. Two ports of the connecting tee (13) are connected to the horizontal fixed pipe (12) and the vertical fixed pipe (16) respectively. The other port of the connecting tee (13) is connected to a plug (14). The plug (14) is connected to an external filling port one, and the external filling port one is connected to an external gas port one (W11).

8. An oil and gas extraction device with bottom hole pressure compensation and backflow control functions according to claim 7, characterized in that, The small annular connecting pipe is also equipped with a second gate valve (23) and a first angle valve (21). The second gate valve (23) is located at the end of the small annular connecting pipe and is connected to the side interface of the first small four-way valve (6). The small annular connecting pipe is controlled by the second gate valve (23) to connect to the small annular space (35). The control end of the first angle valve (21) is equipped with an angle valve electric control head (22). The first angle valve (21) is used to divert or regulate the fluid in the large annulus (34) into the small annulus (35) in accordance with the system pressure field requirements, so as to realize the balanced fluid carrying and long-term drainage of oil and gas wells. The extended connecting pipe (20) is connected to the first angle valve (21).

9. An oil and gas extraction device with bottom hole pressure compensation and backflow control functions according to any one of claims 1-8, characterized in that, Below the surface (DM) are, from top to bottom, the upper boundary of the producing layer (M), the lower boundary of the producing layer (N), and the artificial well bottom (H). The angle valve control head (22) is electrically connected to the multi-chamber pressure transmitter. The bottom hole pressure control assembly also includes a multi-chamber pressure transmitter. The multi-chamber pressure transmitter includes a large annulus pressure transmitter, a small annulus pressure transmitter, and a liquid-carrying chamber pressure transmitter, which are equipped with an artificial bottom hole (H). The large annulus pressure transmitter, the small annulus pressure transmitter, and the liquid-carrying chamber pressure transmitter are respectively installed at the connection position of the corresponding annulus or chamber, and are used to monitor and feedback the pressure data in the large annulus (34), the small annulus (35), and the liquid-carrying chamber (36) to realize automatic bottom hole pressure compensation and backflow control.

10. An oil and gas extraction device with bottom hole pressure compensation and backflow control functions according to claim 1, characterized in that, The upper end of the third gate valve (27) is connected to an external production device, which includes a second small four-way valve (30), a production connecting pipe and a second angle valve (29). The second small four-way valve (30) is connected to the top of the third gate valve (27), and the production connecting pipe is connected to the second small four-way valve (30) and the large annulus (34). The top and the other side interface of the second small four-way (30) are both connected to a sixth gate valve, wherein the other side interface of the second small four-way (30) is connected to an external filling port two through the sixth gate valve, and the external filling port two is connected to an external gas two (W12). The second angle valve (29) is installed on the production connecting pipe. The second angle valve (29) is used to dynamically correct the throttling pressure difference so that the gas phase energy is accurately matched with the liquid phase load.

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