A continuous gas production pipe tail end multifunctional plugging device and use method

Abstract

This invention belongs to the field of oil and gas field development technology, and specifically relates to a multi-functional plugging device at the tail end of a continuous gas production pipe and its usage method. The multi-functional plugging device at the tail end of a continuous gas production pipe involves sealing the inside of the pipe string with a tail-end plug during the insertion of the continuous gas production pipe into the wellbore to achieve pressurized operation. After reaching the designed depth, the tail-end plug is removed to achieve drainage and gas production. During throttling gas production, a drop-and-retrieve throttle is set inside the tail-end plugging device to achieve downhole throttling production in the early stages of well production. Later, the drop-and-retrieve throttle is retrieved for liquid-carrying production. In the later stages of well production, a self-buffered plunger is placed into the pipe string at the wellhead to achieve plunger drainage and gas production during intermittent production periods. This invention combines a continuous gas production pipe with a multi-functional plugging device at the tail end to integrate downhole velocity pipe drainage and gas production, throttling gas production, and plunger drainage and gas production processes, forming a natural, continuous, and long-term production system for the gas well, ensuring the economical and efficient development of the gas field.

Description

Technical Field

[0001] This invention belongs to the field of oil and gas field development technology, and specifically relates to a multi-functional plugging device at the tail end of a continuous gas production pipe and its usage method. Background Technology

[0002] The Sulige gas field is characterized by low permeability and low production capacity. High-pressure gas gathering is costly and economically inefficient. It typically employs three production methods: initial pressure reduction and throttling at the wellhead, mid-term velocity tubing drainage, and late-stage plunger gas lift. Initial pressure reduction and throttling at the wellhead significantly reduces surface infrastructure costs and improves economic efficiency. However, these processes at the wellhead and surface can lead to hydrate formation, causing pipeline blockage and seriously jeopardizing gas well production.

[0003] The application of downhole choke technology has yielded significant results in improving hydrate formation conditions and reducing pipeline blockages. Currently, existing downhole choke tools are set at depths of 1500-2000 meters during production. At different production stages of the gas well, it is necessary to change the gas production method and constantly replace the downhole work string. This operation is time-consuming and labor-intensive. If the choke set in the well after the speed string has been drained and gas produced, and retrieval fails, subsequent plunger drainage and gas production cannot be carried out, and the gas well cannot achieve natural, continuous, long-term production, resulting in well shutdown. Summary of the Invention

[0004] To address the aforementioned problems, the purpose of this invention is to provide a multi-functional plugging device and its usage method at the tail end of a continuous gas production pipe. By using a continuous gas production pipe in conjunction with the multi-functional plugging device at the tail end, the downhole velocity tubing drainage gas production, throttling gas production, and plunger drainage gas production processes can be combined to form a natural, continuous, and long-term production of the gas well, ensuring the economical and efficient development of the gas field.

[0005] The technical solution of the present invention is: a multi-functional plugging device for the tail end of a continuous gas sampling pipe, comprising: a tail end plugger and a retrievable throttle valve set within the tail end plugger, wherein:

[0006] The tail end plug is located at the tail end of the continuous gas sampling pipe and includes a tail end plug body. The tail end plug body is hollow inside and has a plunger sitting working chamber, a positioning chamber, and a sealing chamber arranged sequentially from top to bottom. A screen tube is connected to the lower part of the tail end plug body, and a tail tube plug is provided in the upper part of the screen tube hole section inside the screen tube.

[0007] The retrievable throttle includes, from top to bottom, a delivery head, an upper rod, a lock core, an upper body, a sealing joint, and an air inlet pipe connected in sequence. The delivery head has a retrieval head on its outer side, and the lock core has a limiting spring and a tile on its outer side. The tile is fixedly connected to the upper rod through an upper pressure cap.

[0008] The upper part of the tail-end plug is provided with a compression cap and a slip. The compression cap is threaded to the upper part of the tail-end plug body. The slip is located in the annular space formed by the compression cap and the continuous gas sampling pipe. The tail-end plug body is fixedly connected to the continuous gas sampling pipe through the compression cap and the slip. The lower tail end of the screen tube is provided with a guide head.

[0009] The outer diameter of the continuous gas sampling pipe is 50.8 mm. The bottom of the gas inlet pipe is equipped with a sandproof cover. The tail pipe plug can be sheared and connected to the screen pipe. A sealing ring is provided between the tail pipe plug and the screen pipe.

[0010] The tailpipe plug and the screen pipe can be sheared together by a pin.

[0011] The guide head is frustum shaped.

[0012] The tailpipe plug includes a plug body, a groove at the front end of the plug body, a magnetic piece inside the groove, the magnetic piece being fixedly connected to the plug body by a fastening screw, a shearing groove at the lower side of the plug body, a sealing groove at the upper side of the plug body, and an O-ring sealing ring inside the sealing groove.

[0013] The outer diameter of the sealing joint is the same as the inner diameter of the sealing cavity.

[0014] A method for using a multi-functional plugging device at the tail end of a continuous gas sampling tube, using any of the multi-functional plugging devices at the tail end of a continuous gas sampling tube as described above, the specific process is as follows:

[0015] S1: Connect the tail end plug to the tail end of the continuous gas production pipe. The tail pipe plug will seal the tail end of the continuous pipe, enabling it to be run into the well under pressure.

[0016] S2: After the tail plug is lowered to the design position, the wellhead is pressurized, the tail plug is pressurized, the pin is sheared, the tail plug is pumped out into the screen pipe, and the tail plug sits on the bottom guide head of the screen pipe under the action of gravity and magnetic force. The air hole on the side of the screen pipe hole is connected to the internal channel of the continuous pipe to establish an air flow channel.

[0017] S3: The retrievable throttle is set inside the tail-end plug, and the gas well is put into production. The specific process is as follows:

[0018] When a gas well is put into production, the drop-and-retrieve throttle is inserted into the tail end plug. The throttle is positioned by the tiles on the outside of the lock core on the drop-and-retrieve throttle, which are then engaged in the positioning cavity of the tail end plug. The sealing joint of the drop-and-retrieve throttle forms a seal with the sealing cavity of the tail end plug. The gas flow is throttled and then flows out from the gas nozzle in the middle of the drop-and-retrieve throttle.

[0019] S4: In the later stage of production, a drop-out throttle is retrieved from the well, and continuous gas extraction pipe is used for drainage and gas extraction.

[0020] The number of pins can be installed as needed to control the differential pressure at the tailpipe plug pump outlet within 4±0.5MPa.

[0021] In step S4, when the production output drops again to the point that the continuous gas collection pipe can no longer continuously drain and collect gas in the later stage of production, a plunger is placed inside the pipe string and the plunger of the tail end plug is placed in the working chamber to carry out plunger gas lift drainage and gas collection.

[0022] The technical advantages of this invention are as follows: 1. The multi-functional plugging device at the tail end of the continuous gas production pipe of this invention can seal the inside of the pipe string during the process of placing the continuous gas production pipe into the wellbore, preventing high-pressure fluid in the wellbore from entering the continuous gas production pipe and realizing pressurized operation. After the pipe string is lowered to the designed depth, the tail end plug is removed to realize drainage and gas production from the pipe string; 2. The multi-functional plugging device at the tail end of the continuous gas production pipe of this invention uses a drop-and-retrieve choke to be set inside the tail end plug, realizing downhole choke production in the early stage of gas well production. In the later stage, the choke is retrieved, the continuous gas production pipe is unobstructed, and liquid-carrying production is carried out; 3. After the choke is retrieved, the multi-functional plugging device at the tail end of the continuous gas production pipe of this invention can place a self-buffered plunger into the pipe string at the wellhead, which can realize plunger drainage and gas production during the intermittent production period of the gas well.

[0023] The following will provide further explanation in conjunction with the accompanying drawings. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the structure of a multifunctional plugging device at the tail end of a continuous gas sampling pipe according to the present invention.

[0025] Figure 2 This is a schematic diagram of the tail-end plugging device of a multifunctional plugging device for the tail end of a continuous gas sampling pipe according to the present invention.

[0026] Figure 3 This is a schematic diagram of the tail pipe plug structure of the tail end plug of the multifunctional plugging device for the tail end of a continuous gas sampling pipe according to the present invention.

[0027] Figure 4 This is a schematic diagram of the retrievable throttle structure of a multifunctional blocking device at the tail end of a continuous gas sampling pipe according to the present invention.

[0028] Reference numerals: 1-Tail-end plug, 2-Retrievable throttle, 3-Continuous gas sampling pipe, 11-Compression cap, 12-Slipper, 13-Tail-end plug body, 14-Plug in working chamber, 15-Positioning chamber, 16-Sealing chamber, 17-Pin, 18-Tail pipe plug, 19-Screw pipe, 20-Guide head, 21-Feeding head, 22-Retrieving head, 23-Upper rod, 24-Upper pressure cap, 25-Limiting spring, 26-Lock core, 27-Roller, 28-Upper body, 29-Sealing joint, 210-Rubber ring escort sleeve, 211-Sand shield, 181-Plug body, 182-O-ring seal, 183-Scrapper groove, 184-Magnetic piece, 185-Fasting screw. Detailed Implementation

[0029] Example 1

[0030] To overcome the problems of existing low-permeability, low-productivity gas wells requiring changes in production methods and frequent replacement of downhole tubing during different production periods—problems that are time-consuming and labor-intensive—and the inability to retrieve the plunger-sealed choke after drainage production, which prevents subsequent plunger drainage production and the formation of a naturally continuous long-term production system, this invention provides a solution such as… Figure 1 The invention illustrates a multi-functional plugging device at the tail end of a continuous gas production pipe. By combining a continuous gas production pipe with a multi-functional plugging device at the tail end, the invention integrates downhole velocity tubing drainage gas production, throttling gas production, and plunger drainage gas production processes, thereby forming a natural, continuous, and long-term production of the gas well and ensuring the economical and efficient development of the gas field.

[0031] like Figure 1 , Figure 2 , Figure 3 As shown, a multi-functional plugging device for the tail end of a continuous gas sampling tube includes: a tail end plug 1 and a retrievable throttle 2 set within the tail end plug 1, wherein:

[0032] The tail end plug 1 is located at the tail end of the continuous gas sampling pipe 3 and includes a tail end plug body 13. The tail end plug body 13 is hollow inside and has a plunger sitting working chamber 14, a positioning chamber 15, and a sealing chamber 16 arranged sequentially from top to bottom. The lower part of the tail end plug body 13 is connected to a screen tube 19, and a tail tube plug 18 is provided inside the screen tube 19 at the upper part of the screen tube hole section.

[0033] The retrievable throttle 2 includes, from top to bottom, a delivery head 21, an upper rod 23, a lock core 26, an upper body 28, a sealing joint 29, and an air inlet pipe 210 connected in sequence. The delivery head 21 is provided with a retrieval head 22 on its outer side. The lock core 26 is provided with a limiting spring 25 and a tile 27 on its outer side. The tile 27 is fixedly connected to the upper rod 23 through an upper pressure cap 24.

[0034] During use, the multi-functional plugging device at the tail end of the continuous gas production pipe of this invention can seal the inside of the pipe string using the tail end plug 1 during the insertion of the continuous gas production pipe 3 into the wellbore, preventing high-pressure fluid from entering the continuous gas production pipe 3 and enabling pressurized operation. After the pipe string is lowered to the designed depth, the tail end plug 8 is removed to achieve drainage and gas production. During throttling gas production, a drop-and-retrieve throttle device 2 is set inside the tail end plug 1 to achieve downhole throttling production in the early stage of gas well production. Later, the drop-and-retrieve throttle device 2 is retrieved, and the continuous gas production pipe 3 is unobstructed for fluid-carrying production. In the later stage of gas well production, after retrieving the drop-and-retrieve throttle device 2, a self-buffered plunger is placed into the pipe string at the wellhead to achieve plunger drainage and gas production during the intermittent production period of the gas well. This invention, by using a continuous gas production pipe in conjunction with the multi-functional plugging device at the tail end, combines downhole velocity pipe drainage and gas production, throttling gas production, and plunger drainage and gas production processes to form a natural, continuous, and long-term production of the gas well, ensuring the economical and efficient development of the gas field.

[0035] Example 2

[0036] Preferably, based on Embodiment 1, in this embodiment, the upper part of the tail-end plug body 13 is provided with a compression cap 11 and a slip 12. The compression cap 11 is threadedly connected to the upper part of the tail-end plug body 13. The slip 12 is located in the annular space formed by the compression cap 11 and the continuous gas sampling pipe 3. The tail-end plug body 13 is fixedly connected to the continuous gas sampling pipe 3 through the compression cap 11 and the slip 12. The lower tail end of the screen pipe 19 is provided with a guide head 20. The outer diameter of the continuous gas sampling pipe 3 is 50.8 mm. The bottom of the air inlet pipe 210 is provided with a sandproof cover 211.

[0037] During use, the tail-end plug body 13 is fixedly connected to the continuous gas production pipe 3 via the clamping cap 11 and slip 12. When the continuous gas production pipe 3 is inserted into the wellbore, the tail-end plug 1 seals the inside of the pipe string, preventing high-pressure fluid from entering the continuous gas production pipe 3 and enabling pressurized operation. The outer diameter of the continuous gas production pipe 3 is 50.8 mm. A sand shield 211 is provided at the bottom of the inlet pipe 210. The sand shield 211 effectively prevents sand particles from the formation from entering the gas production pipe, preventing sand blockage.

[0038] Example 3

[0039] Preferably, based on Embodiment 1, in this embodiment, the outer diameter of the continuous gas sampling pipe 3 is 50.8 mm, the bottom of the air inlet pipe 210 is provided with a sandproof cover 211, the tail pipe plug 18 and the screen pipe 19 can be cut and connected, and a sealing ring is provided between the tail pipe plug 18 and the screen pipe 19.

[0040] During use, a sealing ring is provided between the tailpipe plug 18 and the screen pipe 19 to ensure the seal between the tailpipe plug 18 and the screen pipe 19. The continuous gas sampling pipe 3 can be lowered to the design depth under pressure. After reaching the design depth, the tailpipe plug 18 is sheared off from the screen pipe 19 by the pressure buildup inside the continuous gas sampling pipe 3, and the tailpipe plug 18 is knocked off to realize the drainage and gas sampling of the tubing.

[0041] Example 4

[0042] Preferably, based on Embodiment 3, in this embodiment, the tailpipe plug 18 and the screen tube 19 are shearably connected by a pin 17.

[0043] During use, the tailpipe plug 18 is sheared off from the screen pipe 19 by the pin 17, and the tailpipe plug 18 is knocked off to realize the drainage and gas collection of the tubing.

[0044] Example 5

[0045] Preferably, based on Embodiment 1, in this embodiment, the guide head 20 is frustum-shaped.

[0046] During use, the guide head 20 is frustum-shaped, which reduces the friction during the insertion of the continuous gas extraction pipe 3 into the wellbore.

[0047] Example 6

[0048] Preferably, based on Example 1, in this example, as Figure 4 As shown, the tailpipe plug 18 includes a plug body 181. The front end of the plug body 181 is provided with a groove, and a magnetic piece 184 is provided in the groove. The magnetic piece 184 is fixedly connected to the plug body 181 by a fastening screw 185. The lower side of the plug body 181 is provided with a shearing groove 183, and the upper side of the plug body 181 is provided with a sealing groove, and an O-ring 182 is provided in the sealing groove.

[0049] During use, the plug body 181 is made of easily magnetized carbon steel. The pump pressure difference of the plug is controlled. Once the plug is pumped out and falls into the bottom of the lower pocket of the screen tube 19, the magnet 184 attracts the tail tube plug 18 and the guide head 20 at the lower end of the screen tube 19 together to prevent back-blocking.

[0050] Example 7

[0051] Preferably, based on Embodiment 1, in this embodiment, the outer diameter of the sealing joint 29 is the same as the inner diameter of the sealing cavity 16.

[0052] During use, the outer diameter of the sealing joint 29 is the same as the inner diameter of the sealing cavity 16. When pressure is applied in the continuous gas sampling pipe 3, the rubber of the sealing joint 29 expands and can form a tight seal with the sealing cavity 16.

[0053] Example 8

[0054] A method for using a multi-functional plugging device at the tail end of a continuous gas sampling tube, using any of the multi-functional plugging devices at the tail end of a continuous gas sampling tube as described above, the specific process is as follows:

[0055] S1: Connect the tail end plug 1 to the tail end of the continuous gas production pipe 3. The tail pipe plug 18 will seal the tail end of the continuous pipe, thus enabling it to be lowered into the well under pressure.

[0056] S2: After the tail plug 1 is lowered to the design position, the wellhead is pressurized, the tail plug 1 is pressurized, the pin 17 is sheared, the tail tube plug 18 is pumped out into the screen tube 19, and the tail tube plug 18 is placed on the bottom guide head 20 of the screen tube 19 under the action of gravity and magnetic force. The air hole on the side of the screen tube hole is connected to the internal channel of the continuous tube to establish an airflow channel.

[0057] S3: The retrievable throttle device 2 is set inside the tail-end plug 1, and the gas well is put into production. The specific process is as follows:

[0058] When the gas well is put into production, the drop-and-retrieve throttle 2 is inserted into the tail end plug 1. The tile 27 on the outside of the lock core 26 of the drop-and-retrieve throttle 2 is inserted into the positioning cavity 15 of the tail end plug 1 to achieve positioning. The sealing joint 29 of the drop-and-retrieve throttle 2 and the sealing cavity 16 of the tail end plug 1 form a seal. The gas flow is throttled and flows out from the gas nozzle in the middle of the drop-and-retrieve throttle 2.

[0059] S4: In the later stage of production, the drop-out throttle device 2 is retrieved from the well, and the continuous gas extraction pipe 3 is used for drainage and gas extraction.

[0060] The number of pins 17 can be installed as needed to control the pump outlet pressure differential of the tailpipe plug 18 within 4 ± 0.5 MPa.

[0061] The tailpipe plug 18 is designed for unidirectional pumping and is connected using standard shear pins to ensure a reasonable shear pressure differential.

[0062] In step S4, when the production output drops again to the point that the continuous gas collection pipe 3 can no longer continuously drain and collect gas in the later stage of production, a plunger is placed inside the pipe column and the plunger of the tail end plug 1 is placed in the working chamber 14 to carry out plunger gas lift drainage and gas collection.

[0063] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A multi-functional plugging device at the tail end of a continuous gas sampling pipe, characterized in that: include: Tail-end plug (1), and a retrievable throttle (2) set within the tail-end plug (1), wherein: The tail-end plug (1) is located at the tail end of the continuous gas sampling pipe (3) and includes a tail-end plug body (13). The tail-end plug body (13) is hollow inside and has a plunger-sinking working chamber (14), a positioning chamber (15), and a sealing chamber (16) arranged sequentially from top to bottom. The upper part of the tail-end plug body (13) is provided with a compression cap (11) and a slip (12). The compression cap (11) is threadedly connected to the upper part of the tail-end plug body (13). The slip (12) is located in the annular space formed by the compression cap (11) and the continuous gas sampling pipe (3). The tail-end plug body (13) is fixedly connected to the continuous gas sampling pipe (3) through the compression cap (11) and the slip (12). The lower tail end of the screen pipe (19) A guide head (20) is provided. The lower part of the tail end plug body (13) is connected to a screen tube (19). The screen tube (19) has a tail tube plug (18) at the upper part of the screen tube hole section. The tail tube plug (18) includes a plug body (181). The plug body (181) is made of easily magnetized carbon steel to control the pump pressure difference of the plug. The front end of the plug body (181) is provided with a groove. A magnet (184) is provided in the groove. The magnet (184) is fixedly connected to the plug body (181) by a fastening screw (185). The lower side of the plug body (181) is provided with a shearing groove (183). The upper side of the plug body (181) is provided with a sealing groove. An O-ring (182) is provided in the sealing groove. The drop-out type throttle (2) includes, from top to bottom, a drop head (21), an upper rod (23), a lock core (26), an upper body (28), a sealing joint (29), and an air inlet pipe (210) connected in sequence. The drop head (21) is provided with a retrieval head (22) on the outside. The lock core (26) is provided with a limiting spring (25) and a tile (27) on the outside. The tile (27) is fixedly connected to the upper rod (23) through an upper pressure cap (24).

2. The multi-functional plugging device at the tail end of a continuous gas sampling pipe according to claim 1, characterized in that: The outer diameter of the continuous gas sampling pipe (3) is 50.8 mm. The bottom of the air inlet pipe (210) is provided with a sandproof cover (211). The tail pipe plug (18) and the screen pipe (19) can be cut and connected. A sealing ring is provided between the tail pipe plug (18) and the screen pipe (19).

3. The multi-functional plugging device at the tail end of a continuous gas sampling pipe according to claim 1, characterized in that: The tailpipe plug (18) and the screen pipe (19) can be sheared together by a pin (17).

4. The multi-functional plugging device at the tail end of a continuous gas sampling pipe according to claim 1, characterized in that: The guide head (20) is frustum-shaped.

5. The multi-functional plugging device at the tail end of a continuous gas sampling pipe according to claim 1, characterized in that: The outer diameter of the sealing joint (29) is the same as the inner diameter of the sealing cavity (16).

6. A method of using a multi-functional plugging device at the tail end of a continuous gas sampling pipe, comprising using any one of the multi-functional plugging devices at the tail end of a continuous gas sampling pipe as described in claims 1-5, characterized in that: Includes the following steps: S1: Connect the tail end plug (1) to the tail end of the continuous gas production pipe (3), and the tail pipe plug (18) will seal the tail end of the continuous pipe, so as to realize the pressurized entry into the well. S2: After the tail plug (1) is lowered to the design position, the wellhead is pressurized, the tail plug (1) is pressurized, the pin (17) is sheared, the tail plug (18) is pumped out into the screen pipe (19), and the tail plug (18) sits on the bottom guide head (20) of the screen pipe (19) under the action of gravity and magnetic force. The air hole on the side of the screen pipe hole is connected to the internal channel of the continuous pipe to establish an airflow channel. S3: The retrievable throttle (2) is set inside the tail-end plug (1), and the gas well is put into production. The specific process is as follows: When the gas well is put into production, the drop-able throttle (2) is inserted into the tail end plug (1). The tile (27) on the outside of the lock core (26) of the drop-able throttle (2) is inserted into the positioning cavity (15) of the tail end plug (1) to achieve positioning. The sealing joint (29) of the drop-able throttle (2) and the sealing cavity (16) of the tail end plug (1) form a seal. The gas flow flows out after being throttled from the gas nozzle in the middle of the drop-able throttle (2). S4: In the later stage of production, the drop-out throttle (2) is retrieved from the well, and the continuous gas extraction pipe (3) is used for drainage and gas extraction.

7. The method of using the multi-functional plugging device at the tail end of a continuous gas sampling pipe according to claim 6, characterized in that: The number of pins (17) can be installed as needed to control the pump pressure difference of the tailpipe plug (18) at 4±0.5MPa.

8. The method of using the multi-functional plugging device at the tail end of a continuous gas sampling pipe according to claim 6, characterized in that: In step S4, when the production output drops again to the point that the continuous gas collection pipe (3) cannot continuously drain and collect gas in the later stage of production, a plunger is placed inside the pipe column and the plunger of the tail end plug (1) is placed in the working chamber (14) to carry out plunger gas lift drainage and gas collection.

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