Gas-liquid separation device for natural gas

Abstract

According to the natural gas gas-liquid separation device, one end of an outer pipe is in threaded connection with an upper connector and coaxially sleeved with an inner pipe, and a cavity is formed between the inner pipe and the outer pipe; the floating valve assembly is installed in the middle of the cavity to divide the cavity into a cavity lower side close to the lower end cover and a cavity upper side close to the upper connector, a gas-liquid mixture from the valve body enters the cavity upper side through the cavity lower side, the valve body hole, the floating ring hole and the valve seat hole, and the multiple spiral baffling belts are arranged in the inner pipe and extend in the cavity upper side. After a gas-liquid mixture entering the upper side of the cavity encounters the spiral baffling belt, gas is separated in a baffling manner, upwards bypasses the baffling belt and is discharged through the exhaust hole, liquid flows to the lower side of the cavity along the outer wall of the inner pipe after encountering resistance, and when the liquid reaches the floating valve assembly along with continuous rising of the liquid level of the lower side of the cavity, the floating ring and the floating valve body form sealing under the action of buoyancy force, and the gas-liquid mixture is discharged. And the pressure of the sealed cavity continues to rise, and the liquid discharge valve assembly is opened to discharge liquid. The device performs gas-liquid separation by means of the energy of a gas well.

Description

Technical Field

[0001] The present invention relates to the technical field of downhole tools for gas drainage and gas production used in the development of natural gas and shale gas, and particularly relates to a natural gas gas-liquid separation device. Background Art

[0002] During the development of natural gas and shale gas, a downhole natural gas gas-liquid separation device is required. The existing downhole gas-liquid separators mainly utilize the organic combination of gravity separation and cyclone separation to make the oil flow containing dissolved gas generate effects such as stirring, turning, and sudden increase in speed, accelerating the precipitation of free gas and achieving efficient oil-gas separation. However, the existing technologies have the problems of requiring additional power and drive pipe strings, being inconvenient for fishing and having poor sand control effect, affecting the production cycle and being limited by the complex downhole application environment.

[0003] The above information disclosed in the background art section is only used to enhance the understanding of the background of the present invention, and thus may include information that does not constitute the prior art known to those of ordinary skill in the art. Summary of the Invention

[0004] The object of the present invention is to provide a natural gas gas-liquid separation device, which can preliminarily separate the gas-liquid mixed fluid in the well at the bottom of the well during the production of a natural gas well, and perform centralized lifting and discharging when the separated liquid reaches a certain amount. By this method, the liquid drainage efficiency during the production process of the gas well is improved, the normal production cycle of the gas well is extended, and thus the gas well output is increased.

[0005] In order to achieve the above object, the present invention provides the following technical solutions:

[0006] A natural gas gas-liquid separation device of the present invention includes:

[0007] An upper joint;

[0008] An inner pipe, one end of which is fixedly connected to the upper joint,

[0009] A lower end cover, which is fixedly connected to the other end of the inner pipe;

[0010] An outer pipe, one end of which is threadedly connected to the upper joint and coaxially sleeved with the inner pipe, and a cavity is formed between the inner pipe and the outer pipe;

[0011] A liquid inlet valve body assembly, which communicates with the cavity, and the liquid inlet valve body assembly includes,

[0012] A liquid inlet valve body, one end of which is sealingly connected to the outer pipe, and the other end is sealingly connected to the lower end cover,

[0013] At least one valve body, which is arranged at the other end of the liquid inlet valve body, and the valve body has a hollow fluid passage,

[0014] A sealed sphere movably disposed at one end of the valve body close to the outer pipe, the diameter of the sealed sphere being greater than the diameter of the fluid passage.

[0015] A spring pad having one end connected to the liquid inlet valve body and the other end connected to the sealed sphere, the spring pad applying a predetermined pressure to the sealed sphere to seal the valve body.

[0016] A floating valve assembly installed in the middle of the cavity to divide the cavity into a lower side of the cavity close to the lower end cover and an upper side of the cavity close to the upper joint. The floating valve assembly includes

[0017] A floating valve seat fixed in the cavity and provided with a valve seat hole.

[0018] A floating valve body sealingly connected to the floating valve seat, and the floating valve body and the floating valve seat enclose a floating chamber. The floating valve body is provided with a valve body hole communicating with the floating chamber, and the valve seat hole communicates with the floating chamber.

[0019] A floating ring floatingly disposed in the floating chamber. The floating ring is provided with a floating ring hole. The gas-liquid mixture from the valve body enters the upper side of the cavity through the valve body hole, the floating ring hole and the valve seat hole via the lower side of the cavity.

[0020] A plurality of spiral baffle strips disposed in the inner pipe and extending in the upper side of the cavity.

[0021] An exhaust hole penetrating through the inner pipe and located on the side of the spiral baffle strip away from the floating valve assembly.

[0022] A liquid discharge valve assembly penetrating through the inner pipe and located in communication with the lower side of the cavity. When the gas-liquid mixture entering the upper side of the cavity encounters the spiral baffle strip, the gas is deflected and separated, bypasses the baffle strip upward and is discharged through the exhaust hole, and the liquid is blocked and flows along the outer wall of the inner pipe to the lower side of the cavity. As the liquid level in the lower side of the cavity continues to rise and reaches the floating valve assembly, the floating ring forms a seal with the floating valve body under the action of buoyancy, and the pressure of the sealed cavity continues to rise, and the liquid discharge valve assembly opens to discharge the liquid.

[0023] In the described natural gas gas-liquid separation device, as the liquid discharge valve assembly discharges the liquid, the liquid level in the lower side of the cavity drops, the opening pressure of the floating valve channel drops, the liquid discharge valve assembly closes, and the gas-liquid mixture enters the lower side of the cavity through the liquid inlet valve assembly to enter a new round of gas-liquid separation process.

[0024] In the described natural gas gas-liquid separation device, the upper joint is a hollow pipe, and an inner shoulder is provided on the inner wall of the lower end of the hollow pipe. One end of the inner pipe is fixedly connected to the upper joint via the inner shoulder.

[0025] In the described natural gas gas-liquid separation device, the exhaust hole and the liquid discharge valve assembly are connected to the hollow pipeline, and the hollow pipeline is connected to the wellbore and extends out of the wellhead.

[0026] In the described natural gas gas-liquid separation device, a first sealing member for sealed connection is provided between the inner pipe and the upper joint. The floating valve assembly is sealedly connected to the outer pipe and the inner pipe via a second sealing member, and the liquid inlet valve body is sealedly connected to the inner pipe via a third sealing member.

[0027] In the described natural gas gas-liquid separation device, a sand control device is further included, which is fixed to the liquid inlet valve body and threadedly connected to the lower end cover to filter sand grains in the gas-liquid mixture. The sand control device includes,

[0028] A sand screen, which is arranged outside the valve body,

[0029] A sand retaining cover, which is arranged outside the sand screen,

[0030] A sand protection cover, which is arranged outside the sand retaining cover. The gas-liquid mixture sequentially flows through the sand protection cover, the sand retaining cover and the sand screen and enters the valve body.

[0031] In the described natural gas gas-liquid separation device, when the fluid pressure of the gas-liquid mixture from the fluid channel is greater than a predetermined pressure, the sealing sphere moves away from the valve body to release the sealing of the valve body.

[0032] In the described natural gas gas-liquid separation device, the floating valve seat is provided with a pin hole and is fixed to the inner pipe via a pin.

[0033] In the described natural gas gas-liquid separation device, a plurality of spiral baffle strips are arrayed on the inner pipe, and the spiral baffle strips extend obliquely in the upper side of the cavity.

[0034] In the described natural gas gas-liquid separation device, the floating ring hole does not overlap with the valve body hole in the fluid flow direction.

[0035] In the above technical solution, a natural gas gas-liquid separation device provided by the present invention has the following beneficial effects: The natural gas gas-liquid separation device is applied to a gas well with tubing completion. Without moving the tubing string, it can be lowered through the tubing and can be retrieved and fished. The existing production tubing string can be used, and it can be installed by the method of retrieving and fishing, and the effect of downhole gas-liquid separation can be achieved; Relying on the energy of the gas well itself, through baffle separation and centrifugal separation, the gas-liquid separation efficiency is improved. Relying on the energy of the gas well itself, the gas-liquid separator and lifting can be realized, and additional power is not required to realize the staged lifting of gas and liquid; After gas-liquid separation, gas production through the tubing can be realized, and the liquid will be automatically drained after accumulating to a certain amount, that is, the intermittent discharge of gas and liquid, improving the drainage efficiency; The natural gas gas-liquid separation device has a compact structure, high separation efficiency and improved sand control ability. Brief Description of the Drawings

[0036] To more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those of ordinary skill in the art, other drawings can also be obtained based on these drawings.

[0037] Figure 1 The structural schematic diagram of a natural gas gas-liquid separation device provided by an embodiment of the present invention.

[0038] Figure 2 The structural schematic diagram of a floating valve assembly of a natural gas gas-liquid separation device provided by an embodiment of the present invention. Detailed implementation manners

[0039] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention.

[0040] Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention.

[0041] It should be noted that: similar reference numerals and letters denote similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0042] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation of the present invention.

[0043] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, "a plurality of" means two or more unless otherwise specifically defined.

[0044] In the present invention, unless otherwise clearly specified and defined, terms such as "installed", "connected", "joined", "fixed", etc. shall be construed in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be directly connected or indirectly connected through an intermediate medium, and may be the communication inside two components or the interaction relationship between two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0045] In the present invention, unless otherwise clearly specified and defined, the first feature being "above" or "below" the second feature may include the direct contact between the first and second features, or may include the situation where the first and second features are not in direct contact but in contact through additional features therebetween. Moreover, the first feature being "above", "over" and "on top of" the second feature includes that the first feature is directly above and obliquely above the second feature, or merely means that the horizontal height of the first feature is higher than that of the second feature. The first feature being "under", "beneath" and "underneath" the second feature includes that the first feature is directly below and obliquely below the second feature, or merely means that the horizontal height of the first feature is lower than that of the second feature.

[0046] To enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings.

[0047] See Figure 1-2 As shown, in one embodiment, a natural gas gas-liquid separation device of the present invention includes

[0048] an upper joint 1;

[0049] an inner pipe 4, one end of which is fixedly connected to the upper joint 1,

[0050] a lower end cover 17, which is fixedly connected to the other end of the inner pipe 4;

[0051] an outer pipe 2, one end of which is threadedly connected to the upper joint 1 and coaxially sleeved with the inner pipe 4, and a cavity is formed between the inner pipe 4 and the outer pipe 2;

[0052] a liquid inlet valve body 10 assembly, which communicates with the cavity, and the liquid inlet valve body 10 assembly includes

[0053] The liquid inlet valve body 10 is hermetically connected to the outer pipe 2 at one end and hermetically connected to the lower end cover 17 at the other end.

[0054] At least one valve body 13 is provided at the other end of the liquid inlet valve body 10. The valve body 13 has a hollow fluid passage.

[0055] The sealing sphere 12 is movably provided at one end of the valve body 13 close to the outer pipe 2. The diameter of the sealing sphere 12 is larger than the diameter of the fluid passage.

[0056] The spring pad 11 is connected to the liquid inlet valve body 10 at one end and connected to the sealing sphere 12 at the other end. The spring pad 11 applies a predetermined pressure to the sealing sphere 12 to seal the valve body.

[0057] The floating valve assembly is installed in the middle of the cavity to divide the cavity into the lower side of the cavity close to the lower end cover 17 and the upper side of the cavity close to the upper joint 1. The floating valve assembly includes:

[0058] The floating valve seat 6 is fixed in the cavity and is provided with a valve seat hole 22.

[0059] The floating valve body 8 is hermetically connected to the floating valve seat 6. The floating valve body 8 and the floating valve seat 6 enclose a floating chamber. The floating valve body 8 is provided with a valve body hole 24 communicating with the floating chamber. The valve seat hole 22 communicates with the floating chamber.

[0060] The floating ring 7 floats in the floating chamber. The floating ring 7 is provided with a floating ring hole 23. The gas-liquid mixture from the valve body enters the upper side of the cavity through the valve body hole 24, the floating ring hole 23 and the valve seat hole 22 through the lower side of the cavity.

[0061] A plurality of spiral baffle strips 5 are provided on the inner pipe 4 and extend in the upper side of the cavity.

[0062] The exhaust hole 3 is penetrated through the inner pipe 4 and is located on the side of the spiral baffle strip 5 away from the floating valve assembly.

[0063] The drain valve assembly 9 is penetrated through the inner pipe 4 and is located in communication with the lower side of the cavity. When the gas-liquid mixture entering the upper side of the cavity encounters the spiral baffle strip 5, the gas is deflected and separated and bypasses the baffle strip upward and is discharged through the exhaust hole 3. The liquid is blocked and flows along the outer wall of the inner pipe 4 to the lower side of the cavity. As the liquid level on the lower side of the cavity continues to rise and then reaches the floating valve assembly, the floating ring 7 forms a seal with the floating valve body 8 under the action of buoyancy. The pressure of the sealed cavity continues to rise, and the drain valve assembly 9 opens to discharge the liquid.

[0064] In a preferred embodiment of the described natural gas gas-liquid separation device, as the liquid is discharged by the liquid discharge valve assembly 9, the liquid level on the lower side of the cavity drops, the opening pressure of the floating valve passage decreases, the liquid discharge valve assembly 9 closes, and the gas-liquid mixture enters the lower side of the cavity through the liquid inlet valve assembly to enter a new round of gas-liquid separation process.

[0065] In a preferred embodiment of the described natural gas gas-liquid separation device, the upper joint 1 is a hollow pipe, and an inner shoulder is provided on the inner wall of the lower end of the hollow pipe. One end of the inner pipe 4 is fixedly connected to the upper joint 1 via the inner shoulder.

[0066] In a preferred embodiment of the described natural gas gas-liquid separation device, the exhaust hole 3 and the liquid discharge valve assembly 9 communicate with the hollow pipe, and the hollow pipe communicates with the wellbore to lift it out of the wellhead.

[0067] In a preferred embodiment of the described natural gas gas-liquid separation device, a first seal 18 for sealed connection is provided between the inner pipe 4 and the upper joint 1. The floating valve assembly is sealedly connected to the outer pipe 2 and the inner pipe 4 via a second seal 19, and the liquid inlet valve body 10 is sealedly connected to the inner pipe 4 via a third seal 20.

[0068] In a preferred embodiment of the described natural gas gas-liquid separation device, it further includes a sand control device, which is fixed to the liquid inlet valve body 10 and threadedly connected to the lower end cover 17 to filter sand particles in the gas-liquid mixture. The sand control device includes,

[0069] A sand screen 14, which is provided on the outer side of the valve body,

[0070] A sand retaining cover 15, which is provided on the outer side of the sand screen 14,

[0071] A sand protection cover 16, which is provided on the outer side of the sand retaining cover 15. The gas-liquid mixture sequentially flows through the sand protection cover 16, the sand retaining cover 15 and the sand screen 14 and enters the valve body.

[0072] In a preferred embodiment of the described natural gas gas-liquid separation device, when the fluid pressure of the gas-liquid mixture from the fluid passage is greater than a predetermined pressure, the sealing sphere 12 moves away from the valve body to release the sealing of the valve body.

[0073] In a preferred embodiment of the described natural gas gas-liquid separation device, the floating valve seat 6 is provided with a pin hole 21 and is fixed to the inner pipe 4 via a pin.

[0074] In a preferred embodiment of the described natural gas gas-liquid separation device, a plurality of spiral baffle strips 5 are arranged in an array on the inner pipe 4, and the spiral baffle strips 5 extend obliquely in the upper side of the cavity.

[0075] In a preferred embodiment of the described natural gas gas-liquid separation device, the floating ring hole 23 does not overlap with the valve body hole 24 in the fluid flow direction.

[0076] In one embodiment, there is a gap between the spiral baffle strip 5 and the outer tube 2.

[0077] In one embodiment, the floating ring hole 23 does not overlap with the valve seat hole 22 in the fluid flow direction.

[0078] In one embodiment, a natural gas gas-liquid separation device includes

[0079] an upper joint 1, which is a hollow pipe, and an inner shoulder is provided on the inner wall of the lower end of the hollow pipe;

[0080] an inner tube 4, one end of which is fixedly connected to the upper joint 1 via the inner shoulder. Further, a first seal 18 for sealed connection is provided between the inner tube 4 and the upper joint 1.

[0081] a lower end cover 17, which is fixedly connected to the other end of the inner tube 4;

[0082] an outer tube 2, one end of which is threadedly connected to the upper joint 1 and coaxially sleeved with the inner tube 4, and a cavity is formed between the inner tube 4 and the outer tube 2;

[0083] a liquid inlet valve body 10 assembly, which communicates with the cavity. The liquid inlet valve body 10 assembly includes

[0084] a liquid inlet valve body 10, one end of which is sealed and connected to the outer tube 2, and the other end is sealed and connected to the lower end cover 17. Further, the liquid inlet valve body 10 is sealed and connected to the inner tube 4 via a third seal 20.

[0085] at least one valve 13, which is provided at the other end of the liquid inlet valve body 10. The valve body 13 has a hollow fluid passage.

[0086] a sealing sphere 12, which is movably provided at one end of the valve body 13 close to the outer tube 2. The diameter of the sealing sphere 12 is larger than the diameter of the fluid passage.

[0087] a spring pad 11, one end of which is connected to the liquid inlet valve body 10, and the other end is connected to the sealing sphere 12. The spring pad 11 applies a predetermined pressure to the sealing sphere 12 to seal the valve body.

[0088] a sand prevention device, which is fixed to the liquid inlet valve body 10 and threadedly connected to the lower end cover 17 to filter sand grains in the gas-liquid mixture. The sand prevention device includes

[0089] a sand screen 14, which is provided outside the valve body.

[0090] a sand retaining cover 15, which is provided outside the sand screen 14.

[0091] A sand control cover 16 is provided outside the sand retaining cover 15. The gas-liquid mixture sequentially flows through the sand control cover 16, the sand retaining cover 15, and the sand screen 14 and enters the valve body.

[0092] A floating valve assembly is installed in the middle of the cavity to divide the cavity into a lower side of the cavity close to the lower end cover 17 and an upper side of the cavity close to the upper joint 1. Further, the floating valve assembly is hermetically connected to the outer pipe 2 and the inner pipe 4 via a second seal 19. The floating valve assembly includes

[0093] A floating valve seat 6 is fixed in the cavity and is provided with a valve seat hole 22. Further, the floating valve seat 6 is provided with a pin hole 21 and is fixed to the inner pipe 4 via a pin.

[0094] A floating valve body 8 is hermetically connected to the floating valve seat 6, and the floating valve body 8 and the floating valve seat 6 enclose a floating chamber. The floating valve body 8 is provided with a valve body hole 24 communicating with the floating chamber.

[0095] A floating ring 7 is floatingly arranged in the floating chamber. The floating ring 7 is provided with a floating ring hole 23. The gas-liquid mixture from the valve body passes through the valve body hole 24, the floating ring hole 23, and the valve seat hole 22 through the lower side of the cavity and enters the upper side of the cavity.

[0096] A plurality of spiral baffle strips 5 are arranged on the inner pipe 4 and extend in the upper side of the cavity.

[0097] An exhaust hole 3 is penetratingly arranged on the inner pipe 4 and is located on the side of the spiral baffle strip 5 away from the floating valve assembly.

[0098] A liquid discharge valve assembly 9 is penetratingly arranged on the inner pipe 4 and is located in communication with the lower side of the cavity. After the gas-liquid mixture entering the upper side of the cavity encounters the spiral baffle strip 5, the gas is deflected and separated and bypasses the baffle strip upward and is discharged through the exhaust hole 3. The liquid is blocked and flows along the outer wall of the inner pipe 4 to the lower side of the cavity. As the liquid level on the lower side of the cavity continues to rise and reaches the floating valve assembly, the floating ring 7 forms a seal with the floating valve body 8 under the action of buoyancy. The pressure of the sealed cavity continues to rise, and the liquid discharge valve assembly 9 opens to discharge the liquid. At this time, the liquid level on the lower side of the cavity drops, the floating valve channel opens and the pressure drops, and the liquid discharge valve assembly 9 closes. The gas-liquid mixture enters the lower side of the cavity through the liquid inlet valve assembly and enters a new round of gas-liquid separation process.

[0099] In one embodiment, in the natural gas gas-liquid separation device, after the gas-liquid mixture passes through the sand prevention cover 16 and the liquid inlet valve, it enters the cavity between the inner pipe 4 and the outer pipe 2, then moves upward along the outer wall of the inner pipe 4, passes through the floating valve assembly, and enters the upper side of the cavity equipped with the spiral baffle strip 5. Gas-liquid separation is achieved under the combined action of centrifugal force and the baffle plate. The gas is discharged into the wellbore through the exhaust hole 3, and the liquid flows downward along the pipe wall back to the lower side of the cavity. As the liquid level in the lower side of the cavity gradually rises, the floating valve closes, the pressure in the cavity increases, the liquid discharge valve assembly 9 opens, and the liquid is quickly discharged into the wellbore. The liquid level drops and the pressure in the cavity decreases, causing the floating valve to open and the liquid discharge valve to close, and the gas-liquid mixture enters the next separation and liquid discharge cycle.

[0100] In one embodiment, the spiral baffle strip 5 is fixed to the upper outer wall of the inner pipe 4, and gas-liquid separation is achieved through two methods: baffle and centrifugation. The floating valve uses a floating ring 7 made of special material, and the valve body is sealed under the action of buoyancy to discharge the separated liquid into the wellbore.

[0101] In one embodiment, the outer pipe 2 is connected to the upper joint 1 and the liquid inlet valve assemblies 10, 11, 12, 13 through threads; the sand prevention devices 14, 15, 16 are connected to the lower end cover 17 through threads, and the lower end cover 17 is connected to the liquid inlet valve assemblies 10, 11, 12, 13 through threads; the inner pipe 4 is fixed by the inner shoulder of the upper joint 1 and the upper end face of the lower end cover 17. The upper part of the inner pipe 4 is also equipped with a spiral baffle strip 5 and has exhaust holes 3 on the inner wall, and a liquid discharge valve assembly 9 is installed on the inner wall of the lower part of the inner pipe; a cavity is formed between the inner pipe 4 and the outer pipe 2, and the floating valve assemblies 6, 7, 8 are installed in the middle of the cavity, fixed by pins and shoulders, and sealed with the outer pipe 2 and the inner pipe 4 through the second seal 19.

[0102] As Figure 1 shown, the device is lowered into the predetermined position in the wellbore through the tubing by the retrievable device and then set and released. The gas-liquid mixture in the well passes through the sand prevention devices 14, 15, 16 to filter the sand and then enters the cavity between the outer pipe 2 and the inner pipe 4 through the liquid inlet valve assemblies 10, 11, 12, 13. The gas-liquid mixture moves upward through the valve holes of the floating valve assemblies 6, 7, 8. After the gas-liquid mixture encounters the spiral baffle strip 5, the gas is deflected and separated, bypasses the baffle strip upward, and enters the wellbore through the exhaust hole 3 and is lifted out of the wellhead. The liquid flows back to the lower side of the cavity along the outer wall of the inner pipe after being blocked. As the liquid level in the lower side of the cavity continues to rise and reaches the floating valve assemblies 6, 7, 8, the floating ring 7 forms a seal with the floating valve body 8 under the action of buoyancy. The pressure in the sealed cavity continues to increase, and the liquid discharge valve assembly 9 opens, and the liquid quickly enters the wellbore and is further lifted out of the wellhead. At this time, the liquid level in the lower side of the cavity drops, the channels of the floating valve assemblies 6, 7, 8 open, the pressure drops, and the liquid discharge valve assembly 9 closes. The gas-liquid mixture enters the cavity between the outer pipe 2 and the inner pipe 4 through the liquid inlet valve assemblies 10, 11, 12, 13, and enters a new round of gas-liquid separation process.

[0103] In one embodiment, when the floating valve assembly is working, after the gas-liquid mixture enters the cavity, it successively passes through the valve body hole 24, the floating ring hole 23, and the valve seat hole 22 and enters the upper side of the cavity. After being separated by the spiral baffle strip, the gas is discharged and the liquid flows back. When the reflux liquid level reaches the floating ring 7, the floating ring 7 is pressed against the end face of the floating valve body 6 under the action of buoyancy to form a seal, and the floating valve closes; when the liquid in the lower part is discharged from the wellbore and the liquid level rapidly drops, the floating ring 7 is separated from the floating valve body 6, and the floating valve opens.

[0104] Finally, it should be noted that the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative efforts belong to the scope of protection of the present application.

[0105] Only some exemplary embodiments of the present invention have been described by way of illustration above. Undoubtedly, for those of ordinary skill in the art, the described embodiments can be modified in various different ways without departing from the spirit and scope of the present invention. Therefore, the above drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A natural gas gas-liquid separation device, It is characterized in that These include, Upper joint; An inner tube, one end of which is fixedly connected to the upper joint, A lower end cover fixedly connected to the other end of the inner tube; An outer tube, one end of which is threadedly connected to the upper joint and coaxially sleeved with the inner tube, forming a cavity between the inner tube and the outer tube; The liquid inlet valve body assembly is connected to the cavity, and the liquid inlet valve body assembly includes: The liquid inlet valve body has one end sealedly connected to the outer tube and the other end sealedly connected to the lower end cover. At least one valve body is disposed at the other end of the liquid inlet valve body, and the valve body has a hollow fluid passage. A sealing ball is movably arranged at one end of the valve body close to the outer tube, and the diameter of the sealing ball is larger than the diameter of the fluid channel. A spring washer, one end of which is connected to the liquid inlet valve body and the other end of which is connected to the sealing ball, wherein the spring washer applies a predetermined pressure to the sealing ball to seal the valve body; A floating valve assembly is installed in the middle of the cavity to separate the cavity into a lower side of the cavity close to the lower end cover and an upper side of the cavity close to the upper joint. The floating valve assembly includes: A floating valve seat, which is fixed in the cavity and provided with a valve seat hole, The floating valve body is sealed and connected to the floating valve seat. The floating valve body and the floating valve seat enclose a floating chamber. The floating valve body is provided with a valve body hole connected to the floating chamber. The valve seat hole is connected to the floating chamber. A floating ring is floated in the floating chamber, and the floating ring is provided with a floating ring hole. The gas-liquid mixture from the valve body enters the upper side of the cavity through the lower side of the cavity, the valve body hole, the floating ring hole and the valve seat hole. A plurality of spiral baffles are arranged on the inner tube and extend in the upper side of the cavity, The exhaust hole is arranged through the inner tube and is located on the side of the spiral baffle away from the floating valve assembly. The drain valve assembly is arranged through the inner tube and is located at the lower side of the cavity. After the gas-liquid mixture enters the upper side of the cavity and encounters the spiral baffle, the gas is baffled and separated, bypasses the baffle upward and is discharged through the exhaust hole. After encountering resistance, the liquid flows along the outer wall of the inner tube to the lower side of the cavity. As the liquid level on the lower side of the cavity continues to rise and reaches the floating valve assembly, the floating ring forms a seal with the floating valve body under the action of buoyancy, the sealed cavity pressure continues to rise, and the drain valve assembly opens to discharge the liquid.

2. A natural gas gas-liquid separation device according to claim 1, It is characterized in that As the discharge valve assembly discharges liquid, the liquid level at the lower side of the cavity drops, the floating valve channel opens and the pressure drops, the discharge valve assembly closes, and the gas-liquid mixture enters the lower side of the cavity through the inlet valve assembly to enter a new round of gas-liquid separation process.

3. A natural gas gas-liquid separation device according to claim 1, It is characterized in that The upper joint is a hollow pipe, the inner wall of the lower end of the hollow pipe is provided with an inner shoulder, and one end of the inner pipe is fixedly connected to the upper joint via the inner shoulder.

4. A natural gas gas-liquid separation device according to claim 1, It is characterized in that The exhaust hole and the drain valve assembly are connected to the hollow pipe, and the hollow pipe is connected to the wellbore to lift out the wellhead.

5. A natural gas gas-liquid separation device according to claim 1, It is characterized in that A first seal for sealed connection is provided between the inner pipe and the upper joint. The floating valve assembly seals and connects the outer pipe and the inner pipe via a second seal, and the liquid inlet valve body seals and connects to the inner pipe via a third seal.

6. A natural gas gas-liquid separation device according to claim 1, wherein, it further comprises a sand prevention device which is fixed to the liquid inlet valve body and threadedly connected to the lower end cover to filter sand grains in the gas-liquid mixture. The sand prevention device includes, a sand screen which is disposed outside the valve body, a sand retaining cover which is disposed outside the sand screen, a sand protection cover which is disposed outside the sand retaining cover. The gas-liquid mixture sequentially flows through the sand protection cover, the sand retaining cover and the sand screen and enters the valve body.

7. A natural gas gas-liquid separation device according to claim 1, wherein, when the fluid pressure of the gas-liquid mixture from the fluid passage is greater than a predetermined pressure, the sealing sphere moves away from the valve body to release the sealing of the valve body.

8. A natural gas gas-liquid separation device according to claim 1, wherein, the floating valve seat is provided with a pin hole and is fixed to the inner pipe via a pin.

9. A natural gas gas-liquid separation device according to claim 1, wherein, a plurality of spiral baffle strips are arrayed on the inner pipe, and the spiral baffle strips extend obliquely in the upper side of the cavity.

10. A natural gas gas-liquid separation device according to claim 1, wherein, the floating ring hole does not overlap with the valve body hole in the fluid flow direction.

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