CN102296943B - Plunger tool for gas well drainage and gas recovery - Google Patents

Abstract

The invention discloses a plunger tool for liquid drainage and gas production of a gas well, which has flexibility, and particularly comprises a flexible plunger assembly, wherein the flexible plunger assembly comprises a flexible central body, a plurality of plunger unit bodies connected in series are sleeved on the periphery of the flexible central body, and each adjacent plunger unit body is in spherical contact with the other plunger unit body; when the flexible plunger assembly passes through the inclined shaft section, the flexible central body is bent, each plunger unit body is relatively displaced, and the plunger unit bodies still keep spherical contact. When the flexible plunger (12) runs in a well section with a large dog-leg degree, the flexible plunger tool (12) is acted by the transverse force of the inner wall of the oil pipe, the length of the flexible central body (13) is changed, and the floating mechanism at the top of the plunger tool (12) compensates the extension and retraction of the flexible central body (13) to prevent the flexible central body (13) from being damaged. The invention overcomes the defects of the traditional rigid plunger and improves the adaptability of the plunger gas lift process in the application of the large-inclination directional well.

Description

Plunger tool for gas well drainage and gas recovery

technical field

The invention relates to a plunger tool, in particular to a novel gas-lift plunger tool used in the liquid drainage and gas recovery process of a high-inclination natural gas directional development well.

Background technique

In recent years, the development and utilization of natural gas has achieved rapid development. With the improvement of gas field recovery, many gas wells have entered the stage of low pressure and low production. The flow rate of the gas well is too low to reach the critical liquid-carrying flow rate of the gas well. Liquid accumulation gradually occurs at the bottom of the well, and the pressure of the wellbore increases, which eventually leads to the well being crushed to death and unable to produce. Therefore, it is necessary to adopt an effective liquid removal process to ensure the long-term stable production of gas wells.

At present, a variety of liquid drainage and gas recovery processes are used on site. Plunger gas lift is an intermittent lifting method that uses the energy of the reservoir itself to carry liquid (as shown in Figure 1). The plunger is a piston that matches the oil pipe and can move freely in the oil pipe. When working, first close the well to increase the bottom hole pressure, and then open the well when the pressure rises to meet the lifting requirements. The switch of the pipeline is controlled by the electric on-off valve 3 and the electronic controller 4. The plunger arrival sensor 9 is located above the main valve 8. When the plunger 5 passes through the plunger and reaches the sensor 9, the plunger arrival sensor 9 reports to the electronic controller. 4 sends a signal, the electronic controller 4 opens the electric switch valve 3, the liquid is discharged from the pipeline tee 2, and the natural gas is output from the oil jacket annulus. With the continuous production of natural gas, the wellbore pressure drops, the electric on-off valve 3 closes the well again, and the plunger 5 falls to the bottom of the well by its own gravity to start the next pressure recovery process. There is a bottom shock absorber 6 at the bottom of the shaft to prevent the plunger 5 from falling and being damaged. The opening and closing of the gas well forms a working cycle of plunger gas lift, and the cyclical repetition of this periodic action can continuously produce the bottom liquid and natural gas. Through the gas lift of the plunger, a fixed interface is formed between the gas and the produced liquid, which can effectively prevent the liquid from falling back. Compared with other liquid drainage gas recovery processes, the plunger gas lift fully utilizes the energy of the reservoir to work, the overall structure of the system is simple, and the cost is only about 1/5-1/4 of the rod pump, which is very suitable for the needs of mid-to-late production of gas fields .

At present, in addition to traditional vertical wells, directional wells are commonly used to develop natural gas resources. By increasing the contact area between the wellbore and the gas reservoir, the production of a single well can be effectively increased, and the recovery rate of the gas field can be improved. Traditional plunger gas lift tools can work effectively in vertical wells, but when running in directional wells, because the plunger itself is a rigid assembly, the frictional resistance is relatively large when passing through the build-up section or the well section with a large dogleg , may lead to a decrease in the up and down speed, serious wear of the plunger body, and the loss of liquid on the upper part of the plunger, the system cannot work normally, and the work efficiency will decrease.

At present, there are many patents for plunger gas lift. The patented technologies applied for protection can only be used in vertical wells, and there are no public reports on special plunger tools that can adapt to highly deviated directional wells.

The utility model with the patent number CN200971772 relates to a relay type plunger gas lift oil and gas recovery device used in the field of oil and natural gas exploitation, especially for high gas-liquid ratio wells. It is suitable for the plunger gas lift of combined oil pipes with two diameters, the upper diameter and the lower diameter, which expands the application range of the plunger gas lift process. It is mainly composed of three parts: the wellhead part, the downhole part and the plunger. Its characteristics are: the oil pipe is a combined oil pipe string with a large inner diameter and a small bottom. The buffer spring and the oil pipe retainer of the downhole part are installed in the lower small oil pipe; The plunger is connected by a petal spring claw between the large plunger and the small plunger. The large plunger is installed in the upper large oil pipe. The large plunger is hollow and can be automatically disconnected and connected to the butt joint on the small plunger. The small plunger The plug is installed in the lower small oil pipe. The small plunger is lifted in the small tubing, and the small plunger is lifted in the large-diameter tubing after docking with the large plunger. The disconnection and connection of the small and large plungers is automatically realized by inertial force, and the gas produced in the formation is fully used to push the column. Plug movement for oil recovery or drainage for gas recovery.

The patent No. 2010201230050 relates to a two-element split plunger gas lift tool, which is mainly composed of a plunger, a plunger body and a steel ball. The outer diameter of the plunger body is the same as the diameter of the downhole tubing. The plunger body is in the shape of a cylinder. The plunger body has a central hole. For the valve seat of the ball valve, the diameter of the steel ball is 2-30mm larger than the diameter of the center hole of the plunger body, and the outer wall of the plunger body is evenly distributed with annular grooves.

The patent No. 200310111081 relates to a temperature-controlled umbrella-type gas-lift plunger. The tool is characterized by using the principle that the opening and closing of the umbrella can greatly change its shielding area to change the working conditions of the gas-lift plunger, and to control the opening and closing of the umbrella. and energy is temperature. This is a gas-lift plunger that can be used for continuous production (without shutting down the well and stopping production). The temperature and heat energy in the well can be used to cause thermal deformation of the material or magnetic changes of the magnetic-temperature material to cause displacement of the mechanism on the gas-lift plunger. Control the opening and closing of the umbrella. The plunger keeps closed when going down until the temperature section is opened downhole, and keeps open until the wellhead when going up. Because the cross-sectional area of the plunger is only about 1/3 of the internal cross-sectional area of the tubing when the umbrella piece is closed, it falls to the bottom of the well by its own weight under normal production conditions.

Contents of the invention

The technical problem solved by the present invention is to provide a plunger tool for gas well drainage and gas recovery, so as to improve or overcome the disadvantage of poor adaptability of existing plunger gas lift tools in high-inclination natural gas directional development wells.

The technical solution of the present invention is: a plunger tool for gas well drainage and gas recovery, characterized in that the plunger tool is flexible, and the plunger tool includes a flexible plunger assembly, and the flexible plunger assembly It consists of a flexible central body, and the periphery of the flexible central body is provided with a plurality of series-connected plunger units; when the flexible plunger assembly passes through the inclined well section, the flexible central body bends, and each plunger unit The relative displacement of the body occurs, and the tight contact between the plunger unit bodies is still maintained.

Features and advantages of the present invention are as follows:

The invention provides a flexible plunger tool, which can extend the application of the plunger liquid drainage and gas recovery technology to high-inclination directional wells. This technology has the following characteristics: (1) Flexible parts: this part constitutes the core of the plunger, and when the plunger passes through the inclined well section, it is automatically deformed and bent under the lateral external force of the tubing wall, driving the plunger to pass smoothly as a whole In the inclined well section, avoid the liquid slippage caused by the serious wear of the plunger, which will lead to the decrease of the working efficiency of the system; (2) The overall structure is compact: the mechanical structure is relatively simple, the work reliability is high, and it has the ability of automatic expansion and contraction compensation; (3) The system Easy maintenance: Except for the plunger itself, other supporting equipment, such as wellhead lubricator, capture device, bottom hole device, etc., are the same as the existing technology; (4) On-line monitoring is possible: the sensor carried by the plunger can Carry out wellbore data sampling during operation, open the wellhead blowout preventer 1, take out the instrument mandrel, and connect it to a computer to read and analyze the data; (5) Automatically remove sand, wax, and scale on the inner wall of the tubing: when working through the plunger The up and down reciprocating movement in the tubing can effectively remove the grit, scaling and wax in the tubing, eliminating the need to run a separate trip to clean the tubing string, and the work efficiency is significantly improved.

This technology overcomes the disadvantage that the existing rigid plunger can only be used in vertical wells, and ensures the smooth implementation of liquid drainage and gas recovery operations in highly inclined directional wells. In today's era of rapid development of natural gas development, this technology has a very good market prospect.

Description of drawings

Fig. 1 is a structural schematic diagram of an existing plunger liquid drainage gas recovery system.

2A and 2B are a cross-sectional view and a schematic appearance diagram of a flexible plunger tool assembly according to a specific embodiment of the present invention.

Fig. 3 is an enlarged view of the top structure of the plunger tool shown in Fig. 2A and Fig. 2B.

Fig. 4 is an enlarged view of the bottom structure of the plunger tool shown in Fig. 2A and Fig. 2B.

Fig. 5 is a cross-sectional view of the top sliding sleeve of the plunger tool shown in Fig. 2A and Fig. 2B.

Fig. 6 is a cross-sectional view of the structure of the instrument mandrel assembly used in the plunger tool shown in Fig. 2A and Fig. 2B.

Explanation of the main symbols of the accompanying drawings:

1-Nozzle assembly; 2-Pipeline tee; 3-Electric switch valve;

4-electronic controller; 5-rigid plunger; 6-bottom shock absorber;

7-oil pipe limiter; 8-main valve; 9-plunger arrival sensor;

10-Plunger catcher; 11-Instrument mandrel assembly; 12-Flexible plunger assembly;

13-Flexible central body; 14-Plunger unit body; 15-Top limit cylinder;

16-Flexible body positioning joint; 17-Top sliding sleeve; 18-Top ferrule;

19-top ferrule joint; 20-compression spring; 21-spring preloaded joint;

22-bottom ferrule joint; 23-bottom connecting sleeve; 24-bottom ferrule;

25-bottom plug; 26-fishing head; 27-shock-absorbing spring;

28-pressure cap; 29-instrument mandrel body; 30-wellbore measuring instrument;

31-working barrel sealing ring.

Detailed ways

The invention provides a plunger tool for gas well drainage and gas recovery, and the plunger tool is flexible.

As shown in Figures 2A to 6, in a specific embodiment of the present invention, the plunger tool includes a flexible plunger assembly 12, the flexible plunger assembly includes a cylindrical flexible central body 13, and the flexible central body 13 The outer circumference is provided with a plurality of plunger unit bodies 14 connected in series up and down, and all the plunger unit bodies 14 are connected in series through the flexible central body 13, and each adjacent plunger unit body 14 is in close contact with each other. It is preferable to adopt a spherical (or arc surface) contact so that the two can always maintain a reliable contact state; when the flexible plunger assembly 12 passes through the inclined well section, the flexible central body 13 bends, and each column The plug unit bodies 14 are relatively displaced, and the plunger unit bodies 14 still maintain spherical close contact.

The plunger tool of the present invention has a flexible part, which constitutes the core of the plunger. When the plunger passes through the inclined well section, it is automatically deformed and bent under the lateral external force of the tubing wall, driving the plunger as a whole to pass through the inclined well section smoothly. , to avoid the slippage of the liquid caused by the serious wear of the plunger, which will lead to a decrease in the working efficiency of the system.

Preferably, the main material of the flexible central body 13 is a reinforced thermoplastic (RTP) with certain flexibility. Further, the flexible central body 13 can be made of high-density polyethylene, so that the flexible central body 13 has Good corrosion resistance, longer downhole working life.

As shown in Fig. 2A, Fig. 3 and Fig. 4, the upper part of each plunger unit body 14 is provided with a convex convex spherical surface 141, and the lower part is provided with a concave concave spherical surface 143, so that the two are connected in series to maintain close contact. state; preferably, after the installation is completed, an annular groove 145 is formed between adjacent plunger unit bodies 14, so that the sand, wax, scale, etc. The operation string has significantly improved the work efficiency.

As shown in Fig. 2A, Fig. 2B and Fig. 3, the flexible plunger assembly 12 also includes a limit tube 15 on the top of the flexible center body and a stopper 15 which is relatively fixed with the flexible center body 13 and can slide in the limit tube 15. For the floating mechanism, when the flexible plunger assembly 12 receives a lateral force from the inner wall of the oil pipe in the wellbore, the flexible central body 13 bends, and its length changes to a certain extent at the same time, and the floating mechanism slides in the limit cylinder 15.

In a specific embodiment of the present invention, please refer to FIG. 3 , the floating mechanism includes a flexible body positioning joint 16 , a top sliding sleeve 17 , a top ferrule 18 and a top ferrule joint 19 .

Specifically, the flexible body positioning joint 16 has external threads, and the two ends of the top sliding sleeve 17 have internal threads, and the flexible body positioning joint 16 is screwed into the top sliding sleeve 17 from the first end of the top sliding sleeve 17, The cone at its end bears against the flexible central body 13 to limit its position.

Further, according to the size of the inner diameter, the top sliding sleeve 17 has a first large-diameter portion, a small-diameter portion 173 and a second large-diameter portion 175, wherein the inner diameter of the small-diameter portion 173 is slightly larger than the outer diameter of the flexible central body 13, The inner wall between the second large-diameter portion 175 and the small-diameter portion 173 is formed with a tapered transition portion 174; the first large-diameter portion 171 of the top sliding sleeve 17 is in contact with the flexible body positioning joint 16 on the upper end of the corresponding flexible central body 13 Cooperating with screw connection, the second large diameter portion 175 of the top sliding sleeve 17 is cooperating with the upper part of the top ferrule joint 19 for screw connection.

The top ferrule 18 is arranged in the space formed by the top sliding sleeve 17, the flexible central body 13 and the top ferrule joint 19, and its upper end is formed with a tapered protruding portion 181, and the conical protruding portion 181 is connected to the aforementioned top sliding sleeve. The tapered transition part 174 (taper surface) of 17 cooperates and can extend into the gap between the small-diameter part 173 of the top sliding sleeve 17 and the flexible central body 13. The top ferrule joint 19 has an external thread, and the The other end is screwed into the top sliding sleeve 17, and the end bears against the top ferrule 18, so that the top ferrule 18 can hug the upper part of the flexible central body 13 by applying a load.

Utilizing the above-mentioned floating mechanism, the plunger tool of the present invention has the ability of automatic expansion and contraction compensation. When the flexible plunger 12 is running in a well section with a large dogleg degree, the flexible plunger tool 12 is subjected to the lateral force of the inner wall of the tubing, the length of the flexible central body 13 changes, and the floating mechanism on the top of the plunger tool 12 counteracts the The expansion and contraction of the flexible central body 13 is compensated to prevent the flexible central body 13 from being damaged.

Further, the flexible plunger assembly 12 also includes a compression spring 20 and a spring preload joint 21 arranged under the floating mechanism. The upper end of the compression spring 20 is close to the bottom of the top ferrule joint 19. thread, the top limit cylinder 15 is provided with internal thread, the spring preload joint 21 is screwed into the top limit cylinder 15, and the compression spring 20 is preloaded; the limit cylinder 15 has an internal thread, and the spring preload joint 21 is screwed into the limit The barrel 15 preloads the compression spring 20 . Preferably, the head of the spring preload joint 21 is milled into a flat square, which is convenient for tools such as wrenches to assemble. When the floating mechanism slides in the top limiting cylinder 15 , its sliding distance is limited by the compression spring 20 and the spring preload joint 21 .

In a specific embodiment of the present invention, please refer to FIG. 4, the plunger tool assembly 12 also includes a bottom positioning mechanism located at the bottom of the flexible central body 13, so that the spring preload joint 21, the compression spring 20 and the bottom positioning mechanism mechanism to jointly adjust the degree of expansion and contraction of the flexible central body 13 in the top limiting cylinder 15 to achieve a better adjustment effect.

As shown in the figure, the bottom positioning mechanism includes a bottom ferrule joint 22, a bottom connecting sleeve 23, a bottom ferrule 24 and a bottom plug 25. Both ends of the bottom connecting sleeve 23 are provided with internal threads, and the bottom ferrule joint 22 and the bottom plug 25 are provided with There are external threads, which are respectively screwed in from the two ends of the bottom connecting sleeve 23; the cone 251 at the upper end of the bottom plug 25 withstands the flexible central body 13 and limits its position. Preferably, the heads of the bottom ferrule joint 22 and the bottom plug 25 are milled into a flat square, which is convenient for tools such as wrenches to assemble.

In a specific embodiment of the present invention, the bottom connecting sleeve 23 has the same shape and structure as the top sliding sleeve 17, and has a first large-diameter portion, a small-diameter portion and a second large-diameter portion, and the inner diameter of the small-diameter portion is slightly larger than the flexible center The outer diameter of the body 13, and the inner wall between the second large diameter portion and the small diameter portion forms a tapered transition portion; the first large diameter portion of the bottom connecting sleeve is screwed to the bottom plug 25 at the lower end of the corresponding flexible central body 13, Its second large-diameter part is threadedly connected with the bottom ferrule joint 22, and the bottom ferrule 24 is arranged in the space formed by the bottom connecting sleeve 23, the flexible central body 13 and the bottom ferrule joint 22, and its lower end is formed with a tapered protruding part 241, the conical protruding part 241 cooperates with the tapered transition part of the bottom connecting sleeve 23 and can extend into the gap between the small diameter part of the bottom connecting sleeve and the flexible central body 13, and the bottom ferrule joint 22 is provided with an outer The thread is screwed into the bottom connecting sleeve 23 from the upper end of the bottom connecting sleeve 23, and its lower end withstands the upper end of the bottom ferrule 24, so that the bottom ferrule 24 can hug the bottom of the flexible central body 13 by applying a load.

As shown in FIG. 2A , FIG. 2B and FIG. 6 , the plunger tool can also include an instrument mandrel assembly 11 , and the instrument mandrel assembly 11 is screwed to the upper end of the flexible plunger assembly 12 . As shown in FIG. 6 , the instrument mandrel assembly 11 includes a fishing head 26 and a hollow mandrel body 29 , and the inner space of the mandrel body 29 is used for installing a wellbore surveying instrument 30 .

Specifically, the fishing head 26 can adopt a structure conforming to industry standards, and the outer surface of the working cylinder body 29 has a liquid inlet hole (not shown in the figure), which communicates the inside and outside of the working cylinder to provide measurement samples for the pressure sensor. The wellbore surveying instrument 30 mainly contains various sensors, power supplies and the like. There is a fluid inlet hole (not shown) in the bottom of the wellbore measuring instrument 30, and there is a working cylinder sealing ring 31 in the middle part of the working cylinder body 29, which is used to prevent the wellbore fluid of the bottom from scurrying to the electronic instrument on the top. The shock absorbing springs 27 and pressure caps 28 at both ends of the wellbore measuring instrument 30 are used to limit, fix and buffer the wellbore measuring instrument 30, so as to prevent the internal instruments from being damaged by various impacts when the flexible plunger 12 is running in the wellbore. invalidated. The instrument mandrel assembly 11 is connected together with the flexible plunger 12 through threads. There is a conventional data interface inside the plunger instrument working cylinder 11, the plunger 12 can be taken out from the blowout preventer 1, and the data stored in the plunger instrument working cylinder 11 can be read and downloaded by wired or wireless connection. If the plunger tool needs to be maintained and repaired, it can be salvaged, and the plunger tool can be taken out as a whole by entering the fishing tool and acting on the fishing head 26 .

Example 1

A certain flexible plunger tool for 31/2" tubing (as shown in Fig. 2A and Fig. 2B) works in natural gas directional wells. The tool consists of an instrument mandrel assembly 11 and a flexible plunger assembly 12. The overall length is 1630mm, and the maximum outer diameter is 72mm. Among them, the flexible plunger assembly 12 is mainly composed of a flexible central body 13, a plunger unit body 14, a top limit cylinder 15, a flexible body positioning joint 16, a top sliding sleeve 17, Top ferrule 18, top ferrule joint 19, compression spring 20, spring preload joint 21, bottom ferrule joint 22, bottom connecting sleeve 23, bottom ferrule 24 and bottom plug 25. The thermoplastic used in the flexible central body 13 The plastic is high-density polyethylene, and the structure is reinforced by winding metal wires. The flexible central body 13 has a diameter of 30mm and a length of 960mm.

The top limiting cylinder 15 has an outer diameter of 68mm and a length of 240mm. The flexible body positioning joint 16 has external threads, and the two ends of the top sliding sleeve 17 have internal threads. The flexible body positioning joint 16 is screwed into the top sliding sleeve 17 from one end of the top sliding sleeve 17, and its cone withstands the flexible central body 13 , its limit. The top ferrule 18 fits with the tapered surface in the middle of the top sliding sleeve 17. The top ferrule joint 19 has an external thread, which is screwed into the top sliding sleeve 17 from the other end, and the end withstands the top ferrule 18. By applying a load, the top ferrule 18 hugs the flexible central body 13 tightly. The compression spring 20 is close to the top ferrule joint 19, and the spring preload joint 21 has an external thread, and the head is milled into a flat square. The spring pre-tightening joint 21 is screwed into the top limit cylinder 15 to pre-tighten the compression spring 20 . After the installation is completed, the flexible body positioning joint 16, the top sliding sleeve 17, the top ferrule 18 and the top ferrule joint 19 together constitute the floating mechanism of the flexible plunger assembly 12 (as shown in FIG. 3 ). The top sliding sleeve 17 has a length of 84mm, a maximum outer diameter of 60mm, a minimum inner diameter of 38mm, and M48 fine thread internal threads at both ends.

The bottom ferrule joint 22 , the bottom connecting sleeve 23 , the bottom ferrule 24 and the bottom plug 25 together constitute the bottom positioning mechanism of the flexible plunger assembly 12 (as shown in FIG. 4 ). Both ends of the bottom connecting sleeve 23 have internal threads, and the bottom ferrule joint 22 and the bottom plug 25 have external threads, which are screwed in from the two ends of the bottom connecting sleeve 23 respectively. The cone of the bottom plug 25 bears against the flexible central body 13 and limits its position. The heads of the bottom ferrule joint 22 and the bottom plug 25 are milled into flat squares.

The body of the flexible plunger assembly 12 is composed of a plurality of plunger unit bodies 14 connected in series through a flexible central body 13 . The plunger unit body 14 is 52mm long, the maximum outer diameter is 72mm, the inner diameter is 32mm, and the upper diameter of the unit body is 66mm. The upper part of each plunger unit body 14 has a convex convex spherical surface, and the lower part has a concave concave spherical surface. After the flexible plunger assembly 12 is assembled, the plunger unit bodies 14 are in spherical contact and fit closely. After the installation is completed, an annular groove structure is formed between each plunger unit body 14 .

The instrument mandrel assembly 11 (as shown in FIG. 6 ) is made up of a fishing head 26 , a damping spring 27 , a pressure cap 28 , a mandrel body 29 , a wellbore measuring instrument 30 and a mandrel sealing ring 31 . The instrument mandrel assembly 11 is connected together with the flexible plunger 12 through threads. The wellbore measuring instrument 30 is a pressure sensor with a maximum measurement value of 3000psi, and the power supply is a rechargeable lithium-ion power supply with a rated voltage of 3.6v. There is a conventional data interface inside the plunger instrument work cylinder 11, the plunger 12 can be taken out from the blowout preventer 1, and the data stored in the plunger instrument work cylinder 11 can be read and downloaded by means of a wired connection.

To sum up, the present invention proposes a flexible plunger tool 12 (as shown in FIGS. 2A and 2B ) dedicated to high-inclination directional wells. The tool adopts a flexible central body 13 made of reinforced thermoplastics (RTP) as a core component, and a floating mechanism is arranged on the top of the plunger tool 12. The plunger body is connected in series with a plurality of plunger unit bodies 14, and between the plunger unit bodies 14 is Close spherical contact. When the flexible plunger 12 is running in a well section with a large dogleg degree, the flexible plunger tool 12 is subjected to the lateral force of the inner wall of the tubing, the length of the flexible central body 13 changes, and the floating mechanism on the top of the plunger tool 12 counteracts the The expansion and contraction of the flexible central body 13 is compensated to prevent the flexible central body 13 from being damaged. At the same time, an instrument mandrel 11 is connected to the top of the plunger tool 12 to measure the production dynamics of the wellbore while draining liquid and producing gas. When the plunger tool of the present invention is in operation, it can smoothly pass through the build-up section or the well section with a relatively large dogleg degree, and lift the bottom fluid accumulation out of the wellbore, so as to maintain the stable production of the gas well. The technology is compact in structure, high in operating efficiency, and the tool has the ability of self-adaptive adjustment. It can be used for liquid drainage and gas recovery operations of various high-inclination natural gas directional development wells, including low-production gas wells, gas wells with depleted gas reservoir pressure, and condensate production in the later stage of production. Gas wells, tight gas wells, shale gas wells, coalbed methane wells and other conventional and unconventional gas reservoir development wells. Therefore, the flexible plunger technology proposed by the present invention overcomes the shortcomings of traditional rigid plungers such as poor adaptability, serious wear, and low work efficiency, and improves the adaptability of the plunger gas lift process in high-inclination directional wells. The new tool simultaneously Taking into account the online measurement technology, the operating efficiency is significantly improved, which is conducive to improving the single well production of gas wells, and is conducive to the stable production of gas fields and the improvement of economic benefits.

Although the present invention has been disclosed with specific embodiments, it is not intended to limit the present invention. Any person skilled in the art can make replacements of equivalent components without departing from the concept and scope of the present invention, or replace them according to the present invention. The equivalent changes and modifications made in the scope of patent protection should still fall within the scope of this patent.

Claims (12)

1. a gas well liquid discharging gas producing piston tool, it is characterized in that, this piston tool has flexible, this piston tool comprises flexible assembly for plunger (12), described flexible assembly for plunger comprises flexible centerbody (13), described flexible centerbody (13) periphery is arranged with the plunger unit body (14) of a plurality of series connection, between each adjacent plunger unit body (14), is sphere-contact; Described flexible assembly for plunger (12) also comprises position-limiting drum (15) and the fixing relocation mechanism that also can described position-limiting drum (15) in slide relative to described flexible centerbody at flexible centerbody top; Described relocation mechanism comprises flexible body landing nipple (16), top slide cover (17), top cutting ferrule (18) and top card bell and spigot joint (19); Described flexible body landing nipple (16) has external screw thread, described top slide cover (17) two ends have internal thread, described flexible body landing nipple (16) is screwed into top slide cover (17) from the first end of top slide cover (17), the cone of its end is withstood flexible centerbody (13), spacing to it; Described top cutting ferrule (18) is arranged in the space of top slide cover (17), flexible centerbody (13) and top card bell and spigot joint (19) formation, can make top cutting ferrule (18) hold the top of this flexible centerbody (13) tightly by imposed load; When described flexible assembly for plunger (12) is subject to tube inner wall to its lateral force in pit shaft, described flexible centerbody (13) bends, and its length changes a lot simultaneously, and relocation mechanism can slide in the described position-limiting drum (15) at top; When flexible assembly for plunger (12) passes through lower curved section, flexible centerbody (13) bends, and relative displacement occurs each plunger unit body (14), between adjacent plunger unit body (14), still keeps sphere-contact.

2. gas well liquid discharging gas producing piston tool as claimed in claim 1, is characterized in that, described flexible centerbody (13) is to make by having flexible reinforced thermoplastics.

3. gas well liquid discharging gas producing piston tool as claimed in claim 1, is characterized in that, described flexible centerbody (13) is to adopt high density polyethylene (HDPE) to make.

4. gas well liquid discharging gas producing piston tool as claimed in claim 1, is characterized in that, each plunger unit body (14) top is provided with the protruding sphere of protrusion, and bottom is provided with recessed concave spherical surface; Between adjacent plunger unit body (14), form annular groove, be used for removing the impurity in pit shaft.

5. gas well liquid discharging gas producing piston tool as claimed in claim 1, it is characterized in that, described top slide cover has first footpath portion (171), minor diameter part (173) and the second large-diameter portion (175), the internal diameter of described minor diameter part (173) is slightly larger than the external diameter of flexible centerbody (13), and the inwall between described the second large-diameter portion (175) and described minor diameter part (173) forms tapering transition portion (174), first large-diameter portion (171) of described top slide cover (17) matches with the flexible body landing nipple (16) of corresponding flexible centerbody (13) upper end, second large-diameter portion (175) of described top slide cover (17) matches with top card bell and spigot joint (19), described top cutting ferrule (18) upper end is formed with taper and stretches into portion (181), this taper is stretched into portion (181) and is coordinated and can stretch into the minor diameter part (173) of top slide cover (17) and the space between flexible centerbody (13) with aforementioned tapering transition portion (174), thereby hold this flexible centerbody (13) top tightly.

6. gas well liquid discharging gas producing piston tool as claimed in claim 1, it is characterized in that, described flexible assembly for plunger also comprises Compress Spring (20) and the spring pre-tightening joint (21) that is arranged at described relocation mechanism below, top card bell and spigot joint (19) bottom is close in the upper end of Compress Spring (20), described spring pre-tightening joint (21) is provided with external screw thread, described position-limiting drum (15) is provided with internal thread, described spring pre-tightening joint (21) is screwed into described position-limiting drum (15), and described Compress Spring (20) is carried out to pretension; When relocation mechanism slides in described position-limiting drum (15), its sliding distance is subject to the restriction of described Compress Spring (20) and described spring pre-tightening joint (21).

7. gas well liquid discharging gas producing piston tool as claimed in claim 6, it is characterized in that, described flexible assembly for plunger (12) also comprises the bottom detent mechanism that is positioned at described flexible centerbody (13) bottom, by described spring pre-tightening joint (21), described Compress Spring (20) and described bottom detent mechanism, jointly regulates the telescopic level of flexible centerbody (13) in position-limiting drum (15).

8. gas well liquid discharging gas producing piston tool as claimed in claim 7, it is characterized in that, bottom described bottom detent mechanism comprises ferrule fitting (22), bottom adapter sleeve (23), bottom cutting ferrule (24) and the end stifled (25), described bottom adapter sleeve (23) two ends are provided with internal thread, described bottom ferrule fitting (22) and the described end,, stifled (25) were provided with external screw thread, were screwed into respectively from the two ends of described bottom adapter sleeve (23); The cone of stifled (25) of the described end is withstood described flexible centerbody (13), spacing to it; Described bottom cutting ferrule (24) is arranged in the space of bottom adapter sleeve (23), flexible centerbody (13) and bottom ferrule fitting (22) formation, the bottom that can make bottom cutting ferrule (24) hold this flexible centerbody (13) tightly by imposed load.

9. gas well liquid discharging gas producing piston tool as claimed in claim 8, it is characterized in that, described bottom adapter sleeve (23) has the first large-diameter portion, minor diameter part and the second large-diameter portion, the internal diameter of described minor diameter part is slightly larger than the external diameter of flexible centerbody, and the inwall between described the second large-diameter portion and described minor diameter part forms tapering transition portion; The first large-diameter portion of described bottom adapter sleeve (23) was threaded with the end stifled (25) of corresponding flexible centerbody lower end, its second large-diameter portion is threaded with bottom ferrule fitting (22), described bottom cutting ferrule (24) one end is formed with taper and stretches into portion, this taper is stretched into portion and is coordinated with the tapering transition portion of bottom adapter sleeve (23) and can stretch into the space between bottom adapter sleeve minor diameter part and flexible centerbody, thereby can when imposed load, hold the bottom of this flexible centerbody tightly.

10. gas well liquid discharging gas producing piston tool as claimed in claim 1, it is characterized in that, this piston tool also comprises instrument seating nipple assembly (11), and described instrument seating nipple assembly (11) is threaded in the upper end of described flexible assembly for plunger (12), described instrument seating nipple assembly (11) comprises the seating nipple body (29) of fishing head (26) and inner hollow, and the inner space of described seating nipple body (29) is used for installing pit shaft measuring apparatus (30).

11. gas well liquid discharging gas producing piston tools as claimed in claim 10, it is characterized in that, the two ends of described pit shaft measuring apparatus (30) are equipped with damping spring (27) and pressure cap (28), spacing so that described pit shaft measuring apparatus (30) is carried out, fixing and bumper and absorbing shock, lost efficacy because various shocks cause interior instrument while avoiding flexible assembly for plunger (12) to move in pit shaft; Described seating nipple body middle part is provided with seating nipple sealing ring.

12. gas well liquid discharging gas producing piston tools as claimed in claim 10, it is characterized in that, described instrument seating nipple assembly (11) inside is provided with data-interface, can adopt the mode of wireless or wired connection to read and download the data of storage in plunger instrument seating nipple assembly (11).

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