A multifunctional gas production tool at the tail end of a coiled tubing

Abstract

The present application belongs to the technical field of oil and natural gas extraction, and specifically relates to a multifunctional gas extraction tool at the tail end of a continuous tubing. In natural gas extraction, in order to meet the needs of different gas extraction stages, it is often necessary to bring out continuous tubing, install and replace necessary tools, which is a complicated procedure and has poor reliability. In order to solve the aforementioned problems, the present application provides a multifunctional gas extraction tool at the tail end of a continuous tubing, including a buffer component, a throttling component and a plugging component. The plugging component adopts a water-soluble soluble cap, which can play a role of automatic release, and throttling gas extraction is achieved after release; a shear ring made of brittle material is used in the throttling component, and pressure is applied to break the shear ring, and the throttling component will also be released to achieve large-channel gas extraction; in addition, with the assistance of the buffer component, a plunger can be directly dropped from the wellhead to achieve plunger drainage and gas extraction. The present application can meet the gas extraction needs at different stages by going down the well once, without the need to lift and lower the tubing and replace tools multiple times, saving procedures and being economical and practical.

Description

Technical Field

[0001] The present application relates to the technical field of oil and natural gas extraction, and in particular to a multifunctional gas extraction tool at the tail end of a coiled tubing. Background Art

[0002] Similar to oil extraction, the use of coiled tubing to extract natural gas has been widely used. In the early stage of gas production, a throttle is installed at the tail end of the coiled tubing to control the natural gas pressure and flow, throttle and reduce the pressure, and achieve safe and stable production; after the underground production capacity continues to decrease, the coiled tubing is pulled out, the throttle at the tail end is removed, and the coiled tubing is then put into the well to achieve large-channel gas production. In the later stage of gas well production, the formation pressure is seriously insufficient and the wellbore is filled with liquid. The coiled tubing is pulled out again, a buffer mechanism is installed at its tail end, and then a plunger is placed in the coiled tubing to drain water and extract gas, thereby increasing natural gas production.

[0003] At present, the existing coiled tubing tail end gas production tools such as throttles are connected to the coiled tubing tail end through slips, the plugging cover is buckled on the outside of the slip sheath, and the throttle is installed in the slip sheath. The outer wall of the throttle is provided with a throttle sealing ring. When the coiled tubing increases the internal pressure, the plugging cover slides down and falls to the bottom of the well. When the internal pressure of the coiled tubing increases again, the throttle overcomes the friction of the sealing ring and slides to the bottom of the well. In the early stage, gas production is realized in the throttling state, and in the later stage, the throttle is knocked off by hydraulic force to realize full-bore gas production.

[0004] However, this coiled tubing tail end gas recovery tool still has the following disadvantages:

[0005] 1. After the wellbore is filled with liquid, the coiled tubing must be pulled out and a buffer tool must be installed at its tail end, otherwise the plunger cannot be deployed to achieve drainage and gas recovery;

[0006] Second, the plugging cover and throttle knocked off by hydraulic force fall to the bottom of the well, which will hinder the subsequent operation of the gas well. If the parts need to be salvaged or drilled out, the operation cost is high and the construction period is long;

[0007] 3. The throttle and the throttle seat are maintained by the friction of the rubber sealing ring. When the plugging cover is opened, the internal pressure may cause the throttle to fall prematurely and cause an operational accident.

[0008] In order to overcome the above shortcomings, a comprehensive tubing tail gas production tool is urgently needed to meet the needs of various gas production environments, so as to achieve the goal of efficient and safe gas production without removing the coiled tubing, installing or replacing tools during the production life cycle of the gas well. Summary of the invention

[0009] The present application provides a multifunctional gas production tool at the tail end of a coiled tubing to solve the problem that existing gas production tools cannot meet the requirements of different gas production environments and the gas production procedures are complicated.

[0010] The technical solutions adopted in this application are as follows:

[0011] A multifunctional gas recovery tool at the tail end of a coiled tubing, comprising:

[0012] An upper joint, an intermediate joint and a lower joint which are threadedly connected in sequence;

[0013] The upper joint, the middle joint and the lower joint are all tubular;

[0014] A buffer component is arranged in the upper joint, a throttling component is arranged in the middle joint, and a blocking component is arranged at the end of the throttling component;

[0015] The buffer assembly includes a buffer tube and a buffer spring, one end of the buffer tube is connected to one end of the buffer spring, the throttling assembly includes a preload spring and an inner tube, the buffer spring is arranged in the annular space between the inner tube and the upper joint, and the preload spring is arranged in the annular space between the inner tube and the middle joint;

[0016] The throttling assembly also includes a piston unit, a throttle, a shear ring and a pressure cap. The piston unit is sleeved between the outer wall of the throttle and the inner wall of the intermediate joint. One end of the piston unit is connected to the preload spring. Both ends of the piston unit are fixed by the inner tube and the shear ring. The throttle is a cylinder with upper and lower bottom surfaces passing through. The shear ring is a brittle ring. The outer circumference of the shear ring is embedded in the groove of the inner wall of the joint and fixed.

[0017] The pressing cap is an annular structure with a through hole in the shaft portion, the pressing cap is threadedly connected to the piston unit, and one end of the plugging assembly is embedded in the through hole of the pressing cap;

[0018] The plugging assembly includes a plug, a plugging spring, a soluble cap and a locking nut, wherein the plugging spring is arranged between the piston unit and the soluble cap, the soluble cap is sleeved on the plug, the soluble cap is threadedly connected to the pressure cap, and the locking nut is tightly attached to the soluble cap and threadedly connected to the plug;

[0019] The lower joint is a hollow cavity with a closed end, and a guide slit is arranged on the pipe wall of the lower joint.

[0020] Optionally, the piston unit also includes an inner piston unit and an outer piston unit, the inner piston unit is fixed by the inner cylinder and the inner shear ring, the inner shear ring is a brittle ring, and the outer piston unit is fixed by the inner cylinder and the shear ring, and the outer circumference of the inner shear ring is embedded in the annular groove of the outer piston unit.

[0021] Optionally, the passage opening of the piston unit facing one end of the coiled tubing is configured to be funnel-shaped.

[0022] Optionally, a sealing ball is further included, and the sealing ball is used to apply pressure to make the throttling assembly enter the cavity of the lower joint.

[0023] Optionally, it also includes a plunger, which is placed on the side of the buffer tube facing the coiled tubing.

[0024] Optionally, there are sealing gaskets between the throttle and the pressure cap, and between the pressure cap and the plug, and a circular baffle is arranged between the soluble cap and the locking nut.

[0025] Optionally, it also includes a rubber gasket, which is embedded in the interface of the threaded connection and on the side wall of the blocked end.

[0026] Optionally, the soluble cap has a porous structure, the pressing cap has a circular hole, and one end of the circular hole is the soluble cap.

[0027] Optionally, the multifunctional gas production tool at the tail end of the coiled tubing is connected to the coiled tubing by multiple U-grooves pressed tightly and provided with a sealing ring.

[0028] Optionally, the upper end of the buffer tube is connected to a buffer head with a conical inner hole, and the end of the lower joint is closed by a conical guide head.

[0029] The beneficial effects of adopting the above technical solution are:

[0030] The multifunctional gas extraction tool at the tail end of the coiled tubing of the present application is threadedly connected in sequence through the upper, middle and lower joints, and the throttling assembly is arranged inside the middle joint. The throttling assembly is fixed and blocked by a shear ring of brittle material. The throttling nozzle channel at the end of the throttling assembly is blocked by a blocking assembly, and the blocking assembly and the throttling assembly are threadedly connected through a soluble cap and a pressure cap. Due to the water solubility of the soluble cap, the soluble cap will gradually dissolve in water, and at the same time, the blocking assembly will be affected by the force of the blocking spring, and the blocking assembly will fall into the cavity of the lower joint. At this time, natural gas will enter the tubing from the throttling assembly and be mined, realizing throttling gas extraction. When the formation gas pressure is obviously insufficient, a blocking ball is put in to hit the throttling assembly, and the shear ring of the brittle material is broken by force, and the throttling assembly will fall into the cavity of the lower joint. At this time, natural gas realizes large-channel gas extraction. Later, when the formation pressure continues to drop and groundwater enters the coiled tubing to form liquid accumulation, a plunger is put in from the wellhead, and the plunger is taken over by the buffer assembly. When the pressure at the wellhead is released, the plunger will carry the accumulated liquid and natural gas upward and discharge the accumulated liquid and natural gas. The wellhead is closed and the plunger falls. This cycle can reduce the liquid accumulation in the wellbore and produce natural gas, realizing plunger drainage and gas production. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solution of the present application, the drawings required for use in the embodiments are briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0032] Figure 1 A schematic diagram of the structure of an embodiment of the present application;

[0033] Figure 2 This is a structural schematic diagram of another embodiment of the present application;

[0034] Figure 3 A schematic diagram of a local structure of an embodiment of the present application;

[0035] Figure 4 This is a schematic diagram of the local structure of a joint under an embodiment of the present application;

[0036] Figure 5 This is a schematic diagram of throttling gas production in an embodiment of the present application;

[0037] Figure 6 This is a schematic diagram of large channel gas collection in an embodiment of the present application;

[0038] Figure 7 This is a schematic diagram of plunger drainage and gas collection in an embodiment of the present application.

[0039] Explanation of the markings in the diagram: 1-upper joint, 11-buffer tube, 12-buffer spring, 2-middle joint, 21-inner tube, 22-preload spring, 23-piston unit, 231-outer piston unit, 232-inner piston unit, 24-throttle, 241-sealing gasket, 25-pressure cap, 26-shear ring, 261-inner shear ring, 3-lower joint, 31-blocking spring, 32-soluble cap, 33-baffle, 34-locking nut, 35-blocking, 36-rubber gasket, 4-sealing ball, 5-plunger. DETAILED DESCRIPTION

[0040] The following embodiments are described in detail, and examples thereof are shown in the accompanying drawings. When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The implementations described in the following embodiments do not represent all implementations consistent with the present application. They are only examples of systems and methods consistent with some aspects of the present application as detailed in the claims.

[0041] See also Figure 1 and Figure 4 , so as to facilitate understanding of the structure of an embodiment of the present application.

[0042] The present application provides a multifunctional gas production tool at the tail end of a coiled tubing, comprising:

[0043] An upper joint, an intermediate joint and a lower joint which are threadedly connected in sequence;

[0044] The upper joint, the middle joint and the lower joint are all tubular;

[0045] A buffer component is arranged in the upper joint, a throttling component is arranged in the middle joint, and a blocking component is arranged at the end of the throttling component;

[0046] The buffer assembly includes a buffer tube and a buffer spring, one end of the buffer tube is connected to one end of the buffer spring, the throttling assembly includes a preload spring and an inner tube, the buffer spring is arranged in the annular space between the inner tube and the upper joint, and the preload spring is arranged in the annular space between the inner tube and the middle joint;

[0047] The throttling assembly further comprises a piston unit, a throttle, a shear ring and a pressure cap. The piston unit is sleeved between the outer wall of the throttle and the inner wall of the intermediate joint. One end of the piston unit is connected to the preload spring. Both ends of the piston unit are fixed by the inner cylinder and the shear ring. The throttle is a cylinder with upper and lower bottom surfaces penetrating through it. The shear ring is a brittle ring. The outer circumference of the shear ring is embedded in the groove of the inner wall of the joint and fixed.

[0048] The above-mentioned pressing cap is an annular structure with a through hole in the shaft portion, the pressing cap is threadedly connected to the piston unit, and one end of the blocking component is embedded in the through hole of the pressing cap;

[0049] The plugging assembly comprises a plug, a plugging spring, a soluble cap and a locking nut. The plugging spring is arranged between the piston unit and the soluble cap. The soluble cap is sleeved on the plug. The soluble cap is threadedly connected with the pressure cap. The locking nut is tightly attached to the soluble cap and threadedly connected with the plug.

[0050] The lower joint is a hollow cavity with a closed end, and a guide slit is arranged on the pipe wall of the lower joint.

[0051] In the above embodiment, the part connected to the end of the continuous oil pipe adopts a three-section type, namely an upper joint, a middle joint and a lower joint. The three joints are all tubular in order to adapt to the oil pipes commonly used in natural gas extraction. Since the oil pipes are usually tubular, this embodiment adopts a tubular joint; the upper joint is threadedly connected to the continuous oil pipe, and a buffer component is provided in the internal cavity of the upper joint. The buffer component is used to alleviate the impact force of the plunger on the inside of the oil pipe and the gas extraction tool at the tail end of the oil pipe when the plunger is inserted into the oil pipe. Since the stratum for natural gas extraction often has a certain depth, the plunger falls sharply after being inserted, resulting in a large potential energy-kinetic energy conversion, which makes the plunger have a large impact force. The buffer component overcomes the influence of this impact on the oil pipe and the gas extraction tool to a certain extent.

[0052] In this application, the direction along the oil pipe toward the ground is called "up", and the direction downhole is called "down". The buffer assembly includes a buffer tube and a buffer spring. When installed, the buffer tube is arranged on the upper part of the buffer spring. When the plunger is released, the plunger falls onto the buffer tube under the action of gravity, compressing the buffer spring so that the plunger is released into place.

[0053] The throttling assembly is arranged in the inner cavity of the middle joint, and the throttling assembly includes: a preload spring, an inner tube, a piston unit, a throttle, a shear ring and a pressure cap. The preload spring is arranged to apply downward preload pressure to the piston unit, and the preload spring itself is in a compressed state. In this arrangement, since the shear ring has been subjected to a downward force, when the plugging ball is thrown, only a part of the original impact force is required to knock off the shear ring, making it easier for the piston unit to fall into the cavity of the lower joint.

[0054] The inner tube is a circular tubular structure, which is used to constrain the preload spring and the buffer spring in a certain space, so that the spring is not easy to deviate during expansion and contraction deformation, and the performance of the spring can be stably exerted.

[0055] The piston unit is sleeved outside the throttle, and the pressure cap is threadedly connected to the piston unit, so that the throttle is fixed by the pressure cap and confined in the through-channel of the piston unit. In addition, the pressure cap, the piston unit and the throttle all have through-channels on the upper and lower bottom surfaces, and the through-channel of the throttle has a smaller radial diameter. In throttling gas production, the natural gas production speed is directly affected by the diameter of the through-channel of the throttle. This will be conducive to the regulation of the production speed in throttling gas production.

[0056] The plug assembly includes a plug, a plug spring, a soluble cap and a locking nut. The plug is inserted into the through passage of the pressure cap to seal the rear end of the pressure cap. The soluble cap is sleeved on the plug and is tightened and fixed by the locking nut. Therefore, the plug, the soluble cap and the locking nut form a fastening whole. The soluble cap is threadedly connected to the pressure cap to fix the aforementioned fastening whole at the rear end of the pressure cap. The plug spring is arranged between the piston unit and the soluble cap and is in a compressed state, so as to apply a downward force to the soluble cap. See Figure 5 When the components of the present application are installed at the predetermined position underground, groundwater penetrates into the cavity of the lower joint. Due to the water solubility of the soluble cap, the contact edge seam between the soluble cap and the pressure cap also begins to dissolve, and the threaded connection between the soluble cap and the pressure cap fails. When the dissolution proceeds to a certain extent, the soluble cap and the pressure cap separate. At this time, the fixing of the fastening body and the pressure cap is released. Due to the elastic force of the blocking spring, the fastening body begins to separate from the pressure cap and falls into the cavity of the lower joint. At this time, the throttling channel is opened, and the conditions for throttling gas production are prepared.

[0057] The lower joint is a hollow cavity with a closed end. The hollow cavity is conducive to accommodating fallen plugging components and throttling components. Therefore, the length of the hollow cavity should meet the requirement of sufficient accommodation. A guide seam is provided on the pipe wall of the lower joint. The guide seam is a channel for underground fluid to enter the oil pipeline. The setting of the guide seam is to meet the needs of gas production.

[0058] Optionally, the piston unit further comprises an inner piston unit and an outer piston unit, the inner piston unit being fixed by an inner cylinder and an inner shear ring, the inner shear ring being a brittle circular ring, the outer piston unit being fixed by an inner cylinder and a shear ring, the outer circumference of the inner shear ring being embedded in the annular groove of the outer piston unit.

[0059] In this embodiment, the piston unit is divided into two parts, an inner piston unit and an outer piston unit, and the inner piston unit is fixed by an inner shear ring, while the outer piston unit is still fixed by a shear ring. Figure 6 When the throttling gas production is completed and the throttle needs to be removed to realize large-channel gas production, a blocking ball is placed into the coiled tubing through the wellhead, and the blocking ball will block the channel hole of the inner piston unit. Under pressure, the inner piston is pushed to cut off the inner shear ring, so that the throttle and the inner piston unit fall into the cavity of the lower joint. At this time, the entire inner diameter of the outer piston is unobstructed, and natural gas enters the coiled tubing through this channel, realizing large-channel gas production.

[0060] In addition, if the blocking ball exerts pressure on it to push the inner piston and is blocked, the pressure will continue to be increased, the outer piston unit will shear the shear ring and move downward, the preload spring will release the preload force, and the outer piston unit, the outer piston unit and the throttle will be pushed into the cavity of the lower joint, thus also realizing large-channel gas production.

[0061] Optionally, the passage opening of the piston unit facing one end of the coiled tubing is configured to be funnel-shaped.

[0062] See also Figure 2 and Figure 3 , which is convenient for understanding the specific structure of the piston unit in this embodiment. In this embodiment, the channel opening of the piston unit facing one end of the continuous oil pipe is set to a funnel shape in order to cooperate with the use of the blocking ball in this application. In the funnel-shaped structure, the caliber changes from large to small, and the blocking ball will naturally fall to the side with a small caliber to close the channel of the piston unit. At this time, a certain fluid pressure is applied to transmit the pressure to the blocking ball. Since the blocking ball closes the channel of the piston unit, the pressure will be directly transmitted to the piston unit, making it easier to control the piston unit and even the throttling assembly to overcome the resistance of the shear ring and enter the cavity of the lower joint. The funnel-shaped design is a double guarantee. When the blocking ball cannot directly impact the piston unit into the cavity of the lower joint, the fluid pressure transmission method is used to ensure that the piston unit smoothly enters the cavity of the lower joint. Effectively realize large channel gas production. The funnel shape described in this application means all structural shapes with calibers changing from large to small, and it is not mechanically considered to be only one funnel shape.

[0063] Optionally, a sealing ball is also included, and the sealing ball is used to apply pressure to make the throttling assembly enter the cavity of the lower joint.

[0064] See also Figure 6 In this embodiment, the sealing ball is used after the throttling gas production is completed and before entering the large channel gas production stage. A sealing ball is dropped into the continuous oil pipe, and the impact force of the falling sealing ball is used to hit the piston unit of the throttling assembly, so that the throttling assembly falls into the cavity of the lower joint. Of course, the above-mentioned throttling assembly does not include an inner cylinder, and the inner cylinder is always fixed with the middle joint. In this application, when describing the throttling assembly falling into the cavity of the lower joint, the inner cylinder is not included; if the impact force of the sealing ball is insufficient, the throttling assembly cannot break the shear ring, and the shear ring still blocks the throttling assembly from entering the cavity of the lower joint. At this time, a fluid is used to apply a certain pressure to the continuous oil pipe, and the pressure is transmitted to the sealing ball. Since the sealing ball blocks the channel opening of the piston unit, the pressure will be directly transmitted to the piston unit. When the pressure is increased to a certain level, the shear ring is broken, and the throttling assembly will eventually fall into the cavity of the lower joint to achieve large channel gas production.

[0065] Optionally, it also includes a plunger, which is placed on the side of the buffer tube facing the coiled tubing.

[0066] See also Figure 7 The plunger is a commonly used device in the natural gas extraction industry and is the key to the drainage and gas production stage. The plunger is dropped into the bottom of the well through the coiled tubing, and the plunger falls into the buffer tube, thereby compressing the buffer spring, achieving safe placement of the plunger and further reducing the damage to the plunger caused by the impact. Figure 7 As shown, when the wellhead is opened to release the pressure from the bottom of the well, the plunger will carry the accumulated liquid and natural gas upward and discharge the accumulated liquid and natural gas from the wellhead; when the wellhead is closed, the plunger falls back to the buffer tube. Such a reciprocating cycle can reduce the accumulation of liquid in the wellbore and produce natural gas. This is the plunger gas lift gas production process, which is also the plunger drainage gas production stage in this application.

[0067] Optionally, there are sealing gaskets between the throttle and the pressure cap, and between the pressure cap and the plug, and a circular baffle is arranged between the soluble cap and the locking nut.

[0068] In this embodiment, the sealing gasket has a completely sealed effect, avoiding the leakage of fluids, making natural gas extraction more controllable and efficient. A circular baffle is arranged between the soluble cap and the locking nut, which is conducive to the locking nut fixing the soluble cap and the plug more tightly. The force-bearing area of ​​the baffle is large. When the locking nut is tightened, the baffle is pushed to apply pressure to the soluble cap, and the soluble cap is more evenly stressed, and the tightening effect is better.

[0069] Optionally, it also includes a rubber gasket, which is embedded in the interface of the threaded connection and the side wall of the blocked end.

[0070] Threaded joints are usually prone to poor sealing due to long-term obvious or slight shaking. In the present application, rubber gaskets are installed at places where threaded connections appear, and even if there is a certain amount of shaking or looseness, sealing problems are not likely to occur. The rubber gasket itself has a certain elasticity. The rubber gasket is pressed to be embedded in the threaded joint, and the tension of the rubber gasket will form a self-sealing, which has a good sealing effect. Similarly, the blocked end is inserted into the hollow part of the pressure cap to play a sealing role, and the rubber gasket is embedded in the groove of the side wall of the blocked end. Because the rubber gasket is squeezed, it has expansion properties and fits tightly to the pressure cap, making the sealing effect better.

[0071] Optionally, the soluble cap has a porous structure, the pressing cap has a circular hole, and one end of the circular hole is the soluble cap.

[0072] In this embodiment, the void structure of the soluble cap is directly related to the dissolution time. By presetting the void structure, the staff can grasp the dissolution time of the soluble cap in water, which is very important in engineering installation and gas production process, and becomes a key link in whether the installation and gas production can be successfully carried out. The circular through hole on the pressure cap is conducive to the direct connection between groundwater and the soluble cap, accelerating the dissolution of the soluble cap. At the same time, since the circular through hole is set on the pressure cap, it can accelerate the failure of the threaded connection between the pressure cap and the soluble cap, thereby achieving the purpose of this application.

[0073] Optionally, the multifunctional gas production tool at the tail end of the coiled tubing is connected to the coiled tubing by compression with multiple U-shaped grooves and a sealing ring.

[0074] In this embodiment, the connection method between the multifunctional gas production tool at the tail end of the continuous oil pipe and the continuous oil pipe is set to be tightened by multiple U-shaped grooves to prevent loosening due to dynamic changes in fluid pressure, fluid type, etc. during natural gas extraction. Multiple U-shaped grooves are conducive to a tighter connection. At the same time, a sealing ring is set to effectively prevent fluid leakage or formation fluid infiltration.

[0075] Optionally, a buffer head with a conical inner hole is connected to the upper end of the buffer tube.

[0076] In this embodiment, a buffer head is provided on the buffer tube, which is conducive to receiving the impact force when the plunger falls, and further protecting the various parts of the present application from being damaged by impact. The buffer head is provided with a conical inner hole structure, so that the impact surface of the plunger when falling is an inclined groove, which further disperses the impact force, has a good effect in practical applications, prevents the shortening of component life due to impact damage, and saves economic costs.

[0077] Optionally, the end of the lower joint is closed by a conical guide head.

[0078] The conical guide head is conducive to the smooth installation of the multifunctional gas production tool at the tail end of the coiled tubing and the coiled tubing to the predetermined position during the oil production process. The conical design can prevent excessive resistance during the installation process, thereby preventing the multifunctional gas production tool at the tail end of the coiled tubing from being damaged.

[0079] The multifunctional gas extraction tool at the tail end of the continuous tubing of the present application is lowered to the bottom of the well at one time with the continuous tubing. The plugging component blocks the throttling component, the soluble cap reacts with the groundwater, and the connection between the soluble cap and the pressure cap dissolves. After dissolving for a certain period of time, under the elastic force of the plugging spring, the plugging component falls into the cavity of the lower joint. At this time, the gas extraction channel is opened, and the natural gas enters the cavity through the gap of the lower joint, and then enters the continuous tubing through the throttling component to achieve throttling gas extraction; after the formation pressure drops, the plugging ball is put in or even the inner piston or the outer piston is knocked out by hydraulic pressure to achieve large channel gas extraction; after the formation pressure drops further, the wellbore is filled with liquid and the plunger is put in from the wellhead to achieve intermittent drainage gas extraction. During the production life cycle of the gas well, the continuous tubing does not need to be taken out, the tools do not need to be replaced or installed, and there is no metal falling at the bottom of the well, which can achieve long-term, efficient and safe gas extraction production. The present application is put into the well once to achieve multiple functions, which can meet the needs of throttling gas extraction, large channel gas extraction, and plunger drainage gas extraction. There is no need to repeatedly trip the oil pipe and replace tools, saving operation time and cost. In addition, double protection structures are set for opening the plugging component and opening the large channel, which also solves the problem of blockage or failure of opening the large channel, and has high reliability. All fallen objects are stored in the cavity of the lower joint and do not fall to the bottom of the well, which is conducive to subsequent operations.

[0080] Similar parts between the embodiments provided in this application can be referenced to each other. The specific implementation methods provided above are only a few examples under the general concept of this application and do not constitute a limitation on the protection scope of this application. For those skilled in the art, any other implementation methods expanded based on the scheme of this application without creative work belong to the protection scope of this application.

Claims

1. A multifunctional gas production tool at the tail end of a coiled tubing, characterized in that: include: An upper joint (1), an intermediate joint (2) and a lower joint (3) which are threadedly connected in sequence; The upper joint (1), the middle joint (2) and the lower joint (3) are all tubular; A buffer component is arranged in the upper joint (1), a throttling component is arranged in the middle joint (2), and a blocking component is arranged at the end of the throttling component; The buffer assembly comprises a buffer tube (11) and a buffer spring (12), one end of the buffer tube (11) is connected to one end of the buffer spring (12), the throttling assembly comprises a preload spring (22) and an inner tube (21), the buffer spring (12) is arranged in an annular space between the inner tube (21) and the upper joint (1), and the preload spring (22) is arranged in an annular space between the inner tube (21) and the middle joint (2); The throttling assembly further comprises a piston unit (23), a throttle (24), a shear ring (26) and a pressure cap (25); the piston unit (23) is sleeved between the outer wall of the throttle (24) and the inner wall of the intermediate joint (2); one end of the piston unit (23) is connected to the preload spring (22); two ends of the piston unit (23) are fixed by the inner tube (21) and the shear ring (26); the throttle (24) is a cylinder with upper and lower bottom surfaces penetrating through it; the shear ring (26) is a brittle ring; the outer circumference of the shear ring (26) is embedded in a groove on the inner wall of the joint and fixed; The pressing cap (25) is an annular structure having a through hole in the shaft portion, the pressing cap (25) is threadedly connected to the piston unit (23), and one end of the plugging component is embedded in the through hole of the pressing cap (25); The plugging assembly comprises a plug (35), a plugging spring (31), a soluble cap (32) and a locking nut (34); the plugging spring (31) is arranged between the piston unit (23) and the soluble cap (32); the soluble cap (32) is sleeved on the plug (35); the soluble cap (32) is threadedly connected to the pressure cap (25); and the locking nut (34) is tightly attached to the soluble cap (32) and is threadedly connected to the plug (35); The lower joint (3) is a hollow cavity with a closed end, and a flow guide slit is provided on the tube wall of the lower joint (3); It also includes a blocking ball (4), which is used to apply pressure to make the throttling component enter the cavity of the lower joint (3); It also comprises a plunger (5), wherein the plunger (5) is placed on the side of the buffer tube (11) facing the coiled tubing.

2. The multifunctional gas production tool at the tail end of the coiled tubing according to claim 1, characterized in that: The piston unit (23) further comprises an inner piston unit (232) and an outer piston unit (231); the inner piston unit (232) is fixed by the inner cylinder (21) and an inner shear ring (261); the inner shear ring (261) is a brittle circular ring; the outer piston unit (231) is fixed by the inner cylinder (21) and the shear ring (26); the outer circumference of the inner shear ring (261) is embedded in the annular groove of the outer piston unit (231).

3. The multifunctional gas production tool at the tail end of the coiled tubing according to claim 1 or 2, characterized in that: The passage opening of the piston unit (23) facing one end of the coiled tubing is arranged in a funnel shape.

4. The multifunctional gas production tool at the tail end of the coiled tubing according to claim 1, characterized in that: There are sealing gaskets (241) between the throttle (24) and the pressure cap (25), and between the pressure cap (25) and the plug (35), and a circular baffle (33) is arranged between the soluble cap (32) and the locking nut (34).

5. The multifunctional gas production tool at the tail end of the coiled tubing according to claim 1, characterized in that: It also comprises a rubber gasket (36), wherein the rubber gasket (36) is embedded in the interface of the threaded connection and on the end side wall of the plug (35).

6. The multifunctional gas production tool at the tail end of the coiled tubing according to claim 1, characterized in that: The soluble cap (32) has a porous structure, the pressing cap (25) has a circular hole, and one end of the circular hole is the soluble cap (32).

7. The multifunctional gas production tool at the tail end of the coiled tubing according to claim 1, characterized in that: The connection method between the multifunctional gas production tool at the tail end of the coiled tubing and the coiled tubing is that multiple U-shaped grooves are pressed tightly and there is a sealing ring.

8. The multifunctional gas production tool at the tail end of the coiled tubing according to claim 1, characterized in that: The upper end of the buffer tube (11) is connected to a buffer head with a conical inner hole, and the end of the lower joint (3) is closed by a conical guide head.

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