Downhole flow channel conversion device and downhole drainage equipment

Abstract

The present application belongs to the technical field of gas well drainage and production, and specifically relates to a downhole flow channel conversion device and downhole drainage and production equipment. The downhole flow channel conversion device includes a shell and a piston, a fluid flow channel is provided in the shell, the first end of the shell is the inlet end, and the second end of the shell is the outlet end. The piston is slidably sleeved in the shell along the axial direction of the shell, and the piston separates the fluid flow channel into a first flow channel and a second flow channel. The opening of the first flow channel is located at the inlet end, and the opening of the second flow channel is located at the outlet end. The shell is provided with a third flow channel and a fourth flow channel. The outside of the shell is connected to the second flow channel through the third flow channel, and the first flow channel and the second flow channel are connected through the fourth flow channel. The piston can slide between a first position and a second position. When the piston is in the first position, the third flow channel is connected and the fourth flow channel is cut off; when the piston is in the second position, the third flow channel is cut off and the fourth flow channel is connected. The present application can shorten the construction period and reduce the construction risk.

Description

Technical Field

[0001] The present application belongs to the technical field of gas well drainage and production, and specifically relates to a downhole flow channel conversion device and downhole drainage and production equipment. Background Art

[0002] Existing shale gas well drainage is divided into early drainage, mid-term drainage and late-term drainage. In the early stage, the gas pressure in the gas well is relatively high, and casing self-flowing production can be directly adopted; in the mid-term of exploitation, the gas pressure in the gas well decreases, and the gas liquid carrying capacity is weakened. If a casing with a larger inner diameter is used, the gas in the gas well cannot be drained out, causing liquid accumulation in the well, affecting the gas well production. Therefore, in the mid-term of gas well exploitation, a tubing with a smaller inner diameter can be lowered into the casing to increase the gas flow rate in the tubing, increase the gas liquid carrying capacity, prevent liquid accumulation in the well, and realize tubing self-flowing production; in the late stage of exploitation, a large amount of water is discharged from the gas well, and the reservoir gas is blocked by the liquid in the well and cannot effectively enter the wellbore. At this time, artificial lifting technology is required for drainage, such as connecting one end of the tubing to a downhole pump, and the downhole pump can discharge the liquid in the gas well through the tubing. After the liquid in the well is discharged, the reservoir gas can smoothly enter the wellbore, and then be discharged through the oil casing annulus between the tubing and the casing.

[0003] In the process of gas extraction by artificial lift technology, when the amount of liquid produced in the formation is small, the downhole pump cannot operate normally. At this time, it is necessary to change the flow path of liquid and gas, use oil pipe to extract gas, and realize gas-liquid production through oil pipe. In the process of changing the flow path of liquid and gas, it is usually necessary to lift the pipe string under pressure, which has the problems of long construction period, high operation cost and high construction risk. Summary of the invention

[0004] The purpose of the embodiments of the present application is to provide a downhole flow channel conversion device and downhole production equipment, which can solve the problems of long construction period, high operation cost and high construction risk of lifting the pipe under pressure.

[0005] In order to solve the above technical problems, this application is implemented as follows:

[0006] In a first aspect, an embodiment of the present application provides a downhole flow channel conversion device, including a shell and a piston, wherein a fluid flow channel is provided in the shell, wherein the first end of the shell is an inlet end, and the second end of the shell is an outlet end.

[0007] The piston is slidably sleeved in the housing along the axial direction of the housing. The piston divides the fluid flow channel into a first flow channel and a second flow channel. The opening of the first flow channel is located at the inlet end, and the opening of the second flow channel is located at the outlet end.

[0008] The shell body is provided with a third flow channel and a fourth flow channel at intervals. The outside of the shell body is connected with the second flow channel through the third flow channel, and the first flow channel and the second flow channel are connected with each other through the fourth flow channel.

[0009] The piston can slide between a first position and a second position. When the piston is at the first position, the third flow channel is connected and the fourth flow channel is cut off; when the piston is at the second position, the third flow channel is cut off and the fourth flow channel is connected.

[0010] In the second aspect, an embodiment of the present application provides a downhole production and drainage equipment, including a casing and the downhole flow path conversion device recorded above, the downhole flow path conversion device is arranged in the casing, and an oil-casing annulus is formed between the inner wall of the casing and the outer wall of the shell, and the flow area of ​​the fluid flow path is smaller than the flow area of ​​the oil-casing annulus.

[0011] When the piston is in the first position, the oil casing annulus and the fluid flow channel are both gas drainage channels; when the piston is in the second position, the oil casing annulus is the gas drainage channel, and the fluid flow channel is the liquid drainage channel.

[0012] In the embodiment of the present application, the inlet end of the shell can be connected to the outlet of the drainage pump, and the outlet end of the shell can be connected to the upper drainage device. When in use, the downhole flow channel conversion device can be set in the casing, and the flow area of ​​the fluid flow channel is smaller than the flow area of ​​the oil casing annulus between the casing and the shell. When the pressure of the gas in the gas well is relatively high, the piston is placed in the first position, at which time the third flow channel is connected and the fourth flow channel is cut off, and the gas in the gas well can be discharged from the second flow channel through the third flow channel, and the gas can be discharged from the oil casing annulus; when the gas in the gas well is covered by liquid, the drainage pump can be started, and the gas can be discharged from the second flow channel through the third flow channel. When the gas in the gas well is covered by liquid, the drainage pump can be turned on, and the drainage pump pumps the liquid in the gas well into the inlet of the shell. Under the impact of the liquid, the piston slides from the first position to the second position. At this time, the third flow channel is cut off and the fourth flow channel is connected. After the liquid in the gas well enters the first flow channel, it is discharged through the fourth flow channel and the second flow channel. Since the third flow channel is cut off, the gas is discharged through the oil casing annulus; in this process, if the formation liquid output is small, the drainage pump can be turned off so that the piston is in the first position. At this time, the gas can be discharged from the second flow channel through the third flow channel. It can be seen that the embodiment of the present application can switch the state of the second flow channel by adjusting the position of the piston, thereby changing the medium transported in the second flow channel. Therefore, the downhole flow channel conversion device of the present application can realize the flow channel of liquid and gas without lifting the lower pipe string with pressure, which can shorten the construction period, reduce operating costs and reduce construction risks. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a schematic diagram of the structure of the underground production equipment disclosed in the embodiment of the present application in the first state;

[0014] Figure 2 It is a schematic diagram of the structure of the underground production equipment disclosed in the embodiment of the present application in the second state;

[0015] Figure 3 A cross-sectional view of a valve body disclosed in an embodiment of the present application;

[0016] Figure 4 A side view of a valve body disclosed in an embodiment of the present application;

[0017] Figure 5 A schematic diagram of the flow of fluid in the annulus of the oil pipe when the downhole production and drainage equipment disclosed in the embodiment of the present application is in the first state;

[0018] Figure 6 This is a schematic diagram of the flow of fluid in the annulus of the oil pipe when the downhole production equipment disclosed in the embodiment of the present application is in the second state.

[0019] Description of reference numerals:

[0020] 100-shell, 110-first flow channel, 120-second flow channel, 130-third flow channel, 140-fourth flow channel, 150-shell body, 160-valve body, 170-first joint, 180-first through hole, 200-piston, 300-elastic reset member, 400-guide tube, 410-fifth flow channel, 420-guide hole, 430-limiting part, 510-first sealing ring, 520-second sealing ring, 530-second joint, 600-casing, 700-casing annulus, 800-oil pipe, 910-oil pipe annulus. DETAILED DESCRIPTION

[0021] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0022] The terms "first", "second", etc. in the specification and claims of the present application are used to distinguish similar objects, and are not used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable under appropriate circumstances, so that the embodiments of the present application can be implemented in an order other than those illustrated or described here, and the objects distinguished by "first", "second", etc. are generally of one type, and the number of objects is not limited. For example, the first object can be one or more. In addition, "and / or" in the specification and claims represents at least one of the connected objects, and the character " / " generally indicates that the objects associated with each other are in an "or" relationship.

[0023] The downhole flow channel conversion device and downhole production equipment provided in the embodiments of the present application are described in detail below with reference to the accompanying drawings through specific embodiments and their application scenarios.

[0024] like Figures 1 to 6 As shown, an embodiment of the present application discloses a downhole flow channel conversion device, including a shell 100 and a piston 200. A fluid flow channel is provided in the shell 100. The first end of the shell 100 is an inlet end, and the second end of the shell 100 is an outlet end.

[0025] The piston 200 is slidably mounted in the shell 100 along the axial direction of the shell 100. The piston 200 divides the fluid flow channel into a first flow channel 110 and a second flow channel 120. That is, the first flow channel 110 and the second flow channel 120 are located on both sides of the piston 200. In addition to the first flow channel 110 and the second flow channel 120, the fluid flow channel may also include other flow channels. The opening of the first flow channel 110 is located at the inlet end, and the opening of the second flow channel 120 is located at the outlet end. That is to say, the other end of the first flow channel 110 opposite to its opening is closed by the piston 200, and the other end of the second flow channel 120 opposite to its opening is closed by the piston 200.

[0026] The shell 100 is provided with a third flow channel 130 and a fourth flow channel 140 at intervals. The outside of the shell 100 is connected to the second flow channel 120 through the third flow channel 130, and the first flow channel 110 and the second flow channel 120 are connected through the fourth flow channel 140. The piston 200 can slide between the first position and the second position. When the piston 200 is in the first position, the third flow channel 130 is connected and the fourth flow channel 140 is cut off; when the piston 200 is in the second position, the third flow channel 130 is cut off and the fourth flow channel 140 is connected. In the embodiment of the present application, the inlet end of the shell 100 can be connected to the outlet of the drainage pump, and the outlet end of the shell 100 can be connected to the upper drainage device. When in use, the downhole flow channel conversion device can be arranged in the casing 600, and the flow area of ​​the fluid flow channel is made smaller than the flow area of ​​the oil casing annulus 700 between the casing 600 and the shell 100. When the pressure of the gas in the gas well is relatively high, the piston 200 is located in the first position. At this time, the third flow channel 130 is connected and the fourth flow channel 140 is cut off. The gas in the gas well can be discharged from the second flow channel 120 through the third flow channel 130, and the gas can be discharged from the casing annulus 700 at the same time. When the gas in the gas well is covered by liquid, the drainage pump can be started, and the gas can be discharged from the second flow channel 120 through the third flow channel 130. When the gas in the gas well is covered by liquid, the drainage pump can be turned on, and the drainage pump pumps the liquid in the gas well into the inlet of the housing 100. Under the impact of the liquid, the piston 200 slides from the first position to the second position. At this time, the third flow channel 130 is cut off, and the fourth flow channel 140 is connected. After the liquid in the gas well enters the first flow channel 110, it is discharged through the fourth flow channel 140 and the second flow channel 120. Since the third flow channel 130 is cut off, the gas is discharged through the oil casing annulus 700; in this process, if the formation liquid output is small, the drainage pump can be turned off, so that the piston 200 is located in the first position, and the gas can be discharged from the second flow channel 120 through the third flow channel 130. It can be seen that the embodiment of the present application can switch the state of the second flow channel 120 by adjusting the position of the piston 200, thereby changing the medium transported in the second flow channel 120. Therefore, the downhole flow channel conversion device of the present application can realize the flow channel of liquid and gas without lifting the lower pipe string with pressure, which can shorten the construction period, reduce the operation cost and reduce the construction risk.

[0027] Optionally, the downhole flow channel conversion device of the embodiment of the present application can be placed vertically when in use. When liquid is introduced into the inlet end of the housing 100, the piston 200 slides from the first position to the second position under the impact of the liquid; when liquid is not introduced into the inlet end of the housing 100, the piston 200 slides from the second position to the first position by its own weight. In addition, the piston 200 can also be driven to slide between the first position and the second position by an external driving device, such as a hydraulic cylinder, a cylinder, etc. In an optional embodiment, the downhole flow channel conversion device also includes an elastic reset member 300, the first end of the elastic reset member 300 is connected to the piston 200, and the second end of the elastic reset member 300 is connected to the housing 100. Under the action of the liquid at the inlet end, the piston 200 slides from the first position to the second position; under the action of the elastic reset member 300, the piston 200 slides from the second position to the first position. In addition, the elastic reset member 300 can also be replaced by hydraulic cylinders, air cylinders, motors, screw nut pairs and other components, but the above reset member needs to be driven by an external power source to reset the piston 200, which will make the structure of the downhole flow channel conversion device complex and difficult to assemble; in addition, the above reset member needs to monitor whether the inlet end of the housing 100 is passed through liquid. When the inlet end of the housing 100 is passed through liquid, the reset member needs to be used to drive the piston 200 from the first position to the second position; when the inlet end of the housing 100 is not passed through liquid, the reset member needs to be used to drive the piston 200 from the second position to the first position, which will make the position of the control piston 200 more complicated. The embodiment of the present application adopts an elastic reset member 300. When liquid is passed through the inlet end of the housing 100, the piston 200 slides from the first position to the second position under the impact of the liquid, and the elastic reset member 300 undergoes elastic deformation. When the inlet end of the housing 100 is not fed with liquid, the piston 200 is no longer subjected to the impact force of the liquid, and the elastic reset member 300 restores its elastic deformation, thereby causing the piston 200 to slide from the second position to the first position. The piston 200 is driven to move by the downhole liquid and the elastic reset member 300, and the position of the piston 200 can change according to whether liquid is fed into the inlet end of the housing 100. Therefore, it is relatively simple to control the position of the piston 200 in the embodiment of the present application. In addition, after using the elastic reset member 300, there is no need to set up an additional external power source, so the downhole flow channel conversion device can be simple in structure and easier to assemble. Optionally, the elastic reset member 300 can be a spring, a shrapnel, an elastic sleeve or other elastic component.

[0028] In an optional embodiment, the shell 100 includes a shell body 150 and a valve body 160, the first end of the valve body 160 is detachably connected to the first end of the shell body 150, the second end of the valve body 160 is an inlet end, the second flow channel 120 is formed in the shell body 150, the third flow channel 130 and the fourth flow channel 140 are arranged at intervals in the valve body 160, and the piston 200 is slidably arranged in the valve body 160.

[0029] The shell body 150 and the valve body 160 may also be an integrally formed part. The shell body 150 and the valve body 160 of the embodiment of the present application may be detachably connected by threaded connection, clamping, etc. The shell body 150 and the valve body 160 may be detachably connected to each other so that different valve bodies 160 can be replaced, and different valve bodies 160 may have different flow areas of the third flow channel 130 and / or different flow areas of the fourth flow channel 140; in this way, only by replacing different valve bodies 160, the flow area of ​​the third flow channel 130 and / or the flow area of ​​the fourth flow channel 140 may be changed; after changing the flow area of ​​the third flow channel 130, the flow rate of the gas entering the third flow channel 130 may be changed, thereby changing the amount of liquid carried by the entering gas, that is, the amount of liquid carried by the gas. In addition, before processing the third flow channel 130 and the fourth flow channel 140, the valve body 160 can be disconnected from the shell body 150, and then the third flow channel 130 and the fourth flow channel 140 can be processed on the valve body 160, which is more convenient for processing the third flow channel 130 and the fourth flow channel 140. If the shell body 150 and the valve body 160 are an integrally formed part, the shell body 150 and the valve body 160 need to be replaced as a whole, which will increase the cost and is not convenient for processing the third flow channel 130 and the fourth flow channel 140. Optionally, a third sealing ring is provided at the connection between the shell body 150 and the valve body 160, and the third sealing ring can prevent the fluid in the fluid flow channel from leaking from the connection between the shell body 150 and the valve body 160.

[0030] In an optional embodiment, the housing 100 also includes a first connector 170, a first through hole 180 is provided in the first connector 170 for fluid to pass through, the first flow channel 110 includes the first through hole 180, the first end of the first connector 170 is detachably provided inside the second end of the valve body 160, the second end of the first connector 170 is the inlet end, and the end face of the first end of the first connector 170 cooperates with the upper limit position of the piston 200 in the first direction, wherein the first direction is the moving direction of the piston 200 when sliding from the second position to the first position. The first connector 170 of the embodiment of the present application is used to be connected to the outlet of the drainage pump, the first connector 170 is detachably connected to the second end of the valve body 160, and first connectors 170 of different sizes can be replaced according to different models of drainage pumps, so that the downhole flow channel conversion device can adapt to different models of drainage pumps. And the end surface of the first end of the first joint 170 cooperates with the upper limit position of the piston 200 in the first direction, so that the piston 200 can be prevented from being separated from the inlet end of the housing 100 from the fluid flow channel under the action of the elastic reset member 300; the embodiment of the present application limits the piston 200 in the first direction through the first joint 170, and there is no need to set other limiting components to limit the piston 200, so that the limiting components can be prevented from occupying the fluid flow channel. Further, when the piston 200 is in the first position, the end surface of the first end of the first joint 170 cooperates with the upper limit position of the piston 200 in the first direction. The embodiment of the present application can make the piston 200 in the first position through the limiting cooperation between the piston 200 and the first joint 170, so as to ensure that the third flow channel 130 is connected and the fourth flow channel 140 is cut off. In addition, the piston 200 can be placed in the first position by controlling the deformation amount of the elastic deformable member itself, but the deformation amount of the elastic deformable member may change during use, so that the piston 200 cannot be stably placed in the first position.

[0031] In an optional embodiment, the downhole flow channel conversion device further includes a guide tube 400 , which is disposed in the second flow channel 120 , with the first end of the guide tube 400 facing the outlet end and sealedly connected to the housing 100 .

[0032] A fifth flow channel 410 is provided in the guide tube 400. The fifth flow channel 410 extends from the end surface of the first end of the guide tube 400 to the second end of the guide tube 400. A plurality of guide holes 420 are provided at intervals on the outer peripheral surface of the guide tube 400. The fifth flow channel 410 is connected to the second flow channel 120 through the guide holes 420.

[0033] It should be noted that, when the downhole flow channel conversion device is not used together with the oil pipe 800 described below, the second end of the flow guide tube 400 is a closed structure, thereby preventing the fluid in the fluid flow channel from entering the fifth flow channel 410 from the second end of the flow guide tube 400. When the downhole flow channel conversion device is used together with the oil pipe 800 described below, the oil pipe 800 penetrates the flow guide tube 400 through the fifth flow channel 410, and the second end of the flow guide tube 400 is combined with the fifth flow channel 410 to form a closed structure.

[0034] In an optional embodiment, the downhole flow channel conversion device also includes a second joint 530, the first end of the second joint 530 is detachably connected to the second end of the shell body 150, the second joint 530 is provided with a second through hole for fluid to pass through, and the second end of the second joint 530 is the outlet end of the shell 100. The second joint 530 can be connected to the upper drainage equipment, and the upper drainage equipment of different specifications can be adapted by replacing the second joints 530 of different specifications. In addition, this embodiment can be combined with the guide tube 400, at which time the first end of the second joint 530 is located in the shell body 150, and the guide tube 400 is connected to the first end of the second joint 530. Furthermore, a fourth sealing ring is provided at the place where the second joint 530 is connected to the shell body 150, so as to prevent leakage of the fluid in the fluid flow channel.

[0035] Optionally, the piston 200 can be located in the second position by controlling the pressure of the liquid entering from the inlet end of the housing 100, but when the pressure of the liquid entering the inlet end of the housing 100 is too high, the piston 200 cannot be stably located in the second position. In an optional embodiment, the guide tube 400 is also provided with a limit portion 430, and the limit portion 430 cooperates with the piston 200 to limit the position in the second direction, and the second direction is the movement direction of the piston 200 when sliding from the first position to the second position. The limit portion 430 of the embodiment of the present application can prevent the piston 200 from detaching from the fluid flow channel from the outlet end of the housing 100 under the impact of the liquid entering the inlet end of the housing 100. Optionally, the limit portion can be provided at the second end of the guide tube 400.

[0036] In an optional embodiment, the limiting portion 430 has a first limiting surface, and the piston 200 has a second limiting surface, the first limiting surface and the second limiting surface cooperate in limiting in the second direction, and the distance between the first limiting surface and the second limiting surface in the second direction is less than the limit deformation distance of the elastic return member 300. The first limiting surface of the limiting portion 430 of the embodiment of the present application is: when the limiting portion 430 and the piston 200 are limited, the limiting surface of the piston 200 is: when the limiting portion 430 and the piston 200 are limited, the piston 200 and the limiting portion 430 contact the surface; the limit deformation distance is the maximum distance that the elastic return member 300 can deform when the elastic return member 300 is elastically deformed, so that the piston 200 can be prevented from sliding too far in the second direction when the pressure of the liquid entering the inlet end of the housing 100 is too large, thereby preventing the elastic return member 300 from being elastically deformed by a distance greater than the limit deformation distance, so that the elastic return member 300 can be prevented from being damaged.

[0037] In an optional embodiment, the outer circumferential surface of the piston 200 is provided with a first sealing ring 510 and a second sealing ring 520 at intervals, and the housing 100 and the piston 200 are sealed and connected through the first sealing ring 510 and the second sealing ring 520. When the piston 200 is in the first position, the piston 200 blocks the fourth flow channel 140, and the first sealing ring 510 and the second sealing ring 520 are both located between the third flow channel 130 and the inlet end, and at least one of the first sealing ring 510 and the second sealing ring 520 is located between the inlet of the fourth flow channel 140 and the inlet end. When the piston 200 is in the first position, the gas can enter the third flow channel 130 from the oil casing annulus 700. If the first sealing ring 510 and the second sealing ring 520 are not provided, the gas may flow out from the inlet end of the housing 100 through the gap between the fourth flow channel 140 and the inner wall of the piston 200 and the housing 100; after the first sealing ring 510 and the second sealing ring 520 are provided, the gas can be prevented from flowing out from the inlet end of the housing 100. Optionally, the first sealing ring 510 and the second sealing ring 520 may be located at both sides of the inlet of the fourth flow channel 140, or the first sealing ring 510 and the second sealing ring 520 may be located between the inlet and the inlet end of the fourth flow channel 140. It should be noted that the inlet of the fourth flow channel 140 faces the first flow channel 110.

[0038] When the piston 200 is located at the second position, the piston 200 blocks the third flow channel 130, and the outlet of the third flow channel 130 is located between the first sealing ring 510 and the second sealing ring 520. The first sealing ring 510 and the second sealing ring 520 can prevent the gas in the oil casing annulus 700 from leaking from the gap between the piston 200 and the inner wall of the housing 100 through the outlet of the third flow channel 130. The outlet of the third flow channel 130 is located at the junction of the third flow channel 130 and the inner wall of the housing 100.

[0039] In an optional embodiment, the third flow channel 130 has a first inlet and a first outlet, the first inlet is located at the outer peripheral wall of the shell 100, and the first outlet is located at the inner peripheral wall of the shell 100, and the fourth flow channel 140 has a second inlet and a second outlet, the second inlet is located at the inner peripheral wall of the shell 100, the second outlet is located at the side wall of the shell 100, and the second inlet faces the first flow channel 110. Of course, the first outlet can also be located at the side wall of the shell 100, and the third flow channel 130 can be L-shaped, which will make the pressure drop of the gas when passing through the third flow channel 130 larger; while the first inlet of the embodiment of the present application is located at the outer peripheral wall of the shell 100, and the first outlet is located at the inner peripheral wall of the shell 100, then the third flow channel 130 can be linear, which can reduce the pressure drop of the gas compared with the previous embodiment. In addition, the second outlet may also be located on the inner wall of the housing 100, and the fourth flow channel 140 may be U-shaped, which will result in a greater pressure drop of the gas when passing through the third flow channel 130; while the second outlet of the embodiment of the present application is located on the side wall of the housing 100, and the fourth flow channel 140 may be L-shaped, which can reduce the pressure drop of the gas compared with the previous embodiment. This embodiment can be combined with an embodiment in which the housing 100 includes a shell body 150 and a valve body 160, and the side wall of the housing 100 is the end face of the valve body 160 away from the inlet end of the housing 100.

[0040] A downhole drainage and production device comprises a casing 600 and a downhole flow channel conversion device according to any one of the above embodiments, wherein the downhole flow channel conversion device is arranged in the casing 600, and an oil-casing annulus 700 is formed between the inner wall of the casing 600 and the outer wall of the housing 100, and the flow area of ​​the fluid flow channel is smaller than the flow area of ​​the oil-casing annulus 700.

[0041] When the piston 200 is in the first position, the oil casing annulus 700 and the fluid flow channel are both gas drainage channels; when the piston 200 is in the second position, the oil casing annulus 700 is a gas drainage channel, and the fluid flow channel is a liquid drainage channel. In the embodiment of the present application, the inlet end of the shell 100 can be connected to the outlet of the drainage pump, and the outlet end of the shell 100 can be connected to the upper drainage device. When the pressure of the gas in the gas well is relatively high, the piston 200 is located in the first position, at which time the third flow channel 130 is connected and the fourth flow channel 140 is cut off, and the gas in the gas well can be discharged from the second flow channel 120 through the third flow channel 130, and the gas can be discharged from the oil casing annulus 700 at the same time; when the gas in the gas well is covered by liquid, the drainage pump can be started, and the gas can be discharged from the second flow channel 120 through the third flow channel 130. When the gas in the gas well is covered by liquid, the drainage pump can be turned on, and the drainage pump pumps the liquid in the gas well into the inlet of the housing 100. Under the impact of the liquid, the piston 200 slides from the first position to the second position. At this time, the third flow channel 130 is cut off, and the fourth flow channel 140 is connected. After the liquid in the gas well enters the first flow channel 110, it is discharged through the fourth flow channel 140 and the second flow channel 120. Since the third flow channel 130 is cut off, the gas is discharged through the oil casing annulus 700; in this process, if the formation liquid output is small, the drainage pump can be turned off, so that the piston 200 is located in the first position, and the gas can be discharged from the second flow channel 120 through the third flow channel 130. It can be seen that the embodiment of the present application can switch the state of the second flow channel 120 by adjusting the position of the piston 200, thereby changing the medium transported in the second flow channel 120. Therefore, the downhole flow channel conversion device of the present application can realize the flow channel of liquid and gas without lifting the lower pipe string with pressure, which can shorten the construction period, reduce the operation cost and reduce the construction risk.

[0042] Optionally, the drainage pump can be driven by setting a cable, but the cable is prone to wear and breakage during use, which may cause the liquid in the gas well to conduct electricity, posing a greater safety hazard; and the cable needs to be replaced after wear and breakage, which is costly. In addition, when lowering or lifting the cable, the cable is prone to jamming, which will cause construction difficulties. In an optional embodiment, the downhole drainage equipment also includes an oil pipe 800, a portion of which is located in the fluid flow channel, one end of the oil pipe 800 is used to connect to the drainage pump, the oil pipe 800 passes through the piston 200, and an oil pipe annulus 910 is formed between the outer wall of the oil pipe 800 and the inner wall of the housing 100. When the piston 200 is in the first position, the oil casing annulus 700 and the oil pipe annulus 910 are both gas drainage channels; when the piston 200 is in the second position, the oil casing annulus 700 is a gas drainage channel, and the oil pipe annulus 910 is a liquid drainage channel. In the embodiment of the present application, liquid can be injected into the oil pipe 800 to drive the operation of the drainage pump, thereby avoiding the problem of liquid conductivity in the gas well caused by cable wear and breakage, thereby reducing safety hazards and costs; in addition, the solution of this embodiment does not need to configure cables for the drainage pump, so the problem of cable jamming during the process of lowering or lifting the cable can be avoided, thereby reducing the difficulty of construction. Furthermore, in this embodiment, an ordinary centrifugal pump or plunger pump can be used to inject liquid into the oil pipe 800 to drive the operation of the drainage pump. Compared with the cable-driven submersible electric pump, the power consumption of the centrifugal pump or plunger pump is relatively small, that is, the power consumption of the solution of this embodiment is relatively small. Furthermore, a fifth sealing ring is provided between the outer wall of the oil pipe 800 and the inner circumferential wall of the piston 200.

[0043] The above embodiments of the present invention focus on the differences between the various embodiments. As long as the different optimization features between the various embodiments are not contradictory, they can be combined to form a better embodiment. Considering the simplicity of the text, they will not be repeated here.

[0044] The above description is only an embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent substitution, improvement, etc. made within the spirit and principle of the present invention should be included in the scope of the claims of the present invention.

Claims

1. A downhole flow channel conversion device, characterized in that: The invention comprises a housing (100) and a piston (200), wherein a fluid flow channel is provided in the housing (100), a first end of the housing (100) is an inlet end, and a second end of the housing (100) is an outlet end. The piston (200) is slidably sleeved in the housing (100) along the axial direction of the housing (100), and the piston (200) divides the fluid flow channel into a first flow channel (110) and a second flow channel (120). The opening of the first flow channel (110) is located at the inlet end, and the opening of the second flow channel (120) is located at the outlet end. The shell (100) is provided with a third flow channel (130) and a fourth flow channel (140) at intervals; the outside of the shell (100) is connected to the second flow channel (120) via the third flow channel (130); the first flow channel (110) and the second flow channel (120) are connected via the fourth flow channel (140); The piston (200) can slide between a first position and a second position. When the piston (200) is located at the first position, the third flow channel (130) is connected and the fourth flow channel (140) is cut off; when the piston (200) is located at the second position, the third flow channel (130) is cut off and the fourth flow channel (140) is connected.

2. The downhole flow channel conversion device according to claim 1, characterized in that: The shell (100) includes a shell body (150) and a valve body (160), the first end of the valve body (160) is detachably connected to the first end of the shell body (150), the second end of the valve body (160) is the inlet end, the second flow channel (120) is formed in the shell body (150), the third flow channel (130) and the fourth flow channel (140) are arranged in the valve body (160) at intervals, and the piston (200) is slidably arranged in the valve body (160).

3. The downhole flow channel conversion device according to claim 2, characterized in that: The housing (100) further comprises a first joint (170), wherein a first through hole (180) is provided in the first joint (170) for fluid to pass through, the first flow channel (110) comprises the first through hole (180), a first end of the first joint (170) is detachably arranged inside the second end of the valve body (160), the second end of the first joint (170) is the inlet end, and an end surface of the first end of the first joint (170) cooperates with the piston (200) in a first direction limit position. The first direction is the moving direction of the piston (200) when it slides from the second position to the first position.

4. The downhole flow channel conversion device according to claim 1, characterized in that: The downhole flow channel conversion device further comprises an elastic reset member (300), wherein a first end of the elastic reset member (300) is connected to the piston (200), and a second end of the elastic reset member (300) is connected to the housing (100). Under the action of the liquid at the inlet end, the piston (200) slides from the first position to the second position; Under the action of the elastic return member (300), the piston (200) slides from the second position to the first position.

5. The downhole flow channel conversion device according to claim 4, characterized in that: The downhole flow channel conversion device further comprises a flow guide tube (400), wherein the flow guide tube (400) is arranged in the second flow channel (120), wherein the first end of the flow guide tube (400) faces the outlet end, and the first end of the flow guide tube (400) is sealedly connected to the housing (100). A fifth flow channel (410) is provided in the guide tube (400), and the fifth flow channel (410) extends from the end surface of the first end of the guide tube (400) to the second end of the guide tube (400). A plurality of guide holes (420) are provided at intervals on the outer peripheral surface of the guide tube (400), and the fifth flow channel (410) is connected to the second flow channel (120) through the guide holes (420).

6. The downhole flow channel conversion device according to claim 5, characterized in that: The guide tube (400) is further provided with a limiting portion (430), and the limiting portion (430) cooperates with the piston (200) to limit the position in the second direction. The second direction is the moving direction of the piston (200) when it slides from the first position to the second position.

7. The downhole flow channel conversion device according to claim 6, characterized in that: The limiting portion (430) has a first limiting surface, and the piston (200) has a second limiting surface. The first limiting surface and the second limiting surface cooperate with each other in limiting position in the second direction, and the distance between the first limiting surface and the second limiting surface in the second direction is less than the limit deformation distance of the elastic return member (300).

8. The downhole flow channel conversion device according to claim 1, characterized in that: A first sealing ring (510) and a second sealing ring (520) are provided at intervals on the outer peripheral surface of the piston (200); the housing (100) and the piston (200) are sealed and connected via the first sealing ring (510) and the second sealing ring (520); When the piston (200) is located in the first position, the piston (200) blocks the fourth flow channel (140), the first sealing ring (510) and the second sealing ring (520) are both located between the third flow channel (130) and the inlet end, and at least one of the first sealing ring (510) and the second sealing ring (520) is located between the inlet of the fourth flow channel (140) and the inlet end; when the piston (200) is located in the second position, the piston (200) blocks the third flow channel (130), and the outlet of the third flow channel (130) is located between the first sealing ring (510) and the second sealing ring (520).

9. The downhole flow channel conversion device according to claim 1, characterized in that: The third flow channel (130) has a first inlet and a first outlet, wherein the first inlet is located on the outer peripheral wall of the shell (100), and the first outlet is located on the inner peripheral wall of the shell (100). The fourth flow channel (140) has a second inlet and a second outlet, wherein the second inlet is located on the inner peripheral wall of the shell (100), and the second outlet is located on the side wall of the shell (100), and the second inlet faces the first flow channel (110).

10. An underground drainage equipment, characterized in that: The invention comprises a casing (600) and a downhole flow channel conversion device according to any one of claims 1 to 9, wherein the downhole flow channel conversion device is arranged in the casing (600), and an oil-casing annulus (700) is formed between the inner wall of the casing (600) and the outer wall of the shell (100), and the flow area of ​​the fluid flow channel is smaller than the flow area of ​​the oil-casing annulus (700), When the piston (200) is located at the first position, the oil casing annulus (700) and the fluid flow channel are both gas drainage channels; when the piston (200) is located at the second position, the oil casing annulus (700) is a gas drainage channel, and the fluid flow channel is a liquid drainage channel.

11. The underground drainage equipment according to claim 10, characterized in that: The downhole drainage equipment further comprises an oil pipe (800), a portion of which is located in the fluid flow channel, one end of which is used to be connected to a drainage pump, the oil pipe (800) passes through the piston (200), and an oil pipe annulus (910) is formed between the outer wall of the oil pipe (800) and the inner wall of the housing (100). When the piston (200) is located at the first position, the casing annulus (700) and the tubing annulus (910) are both gas drainage passages; when the piston (200) is located at the second position, the casing annulus (700) is a gas drainage passage, and the tubing annulus (910) is a liquid drainage passage.

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