Gas lift valve in concentric double-tube small tube for concentric double-tube gas jet pump

Abstract

The invention relates to a gas lift valve in a concentric double-tube small pipe for a concentric double-tube gas jet pump. The upper end of a tubing coupling is connected with a liquid discharge tubing string, the lower end of the tubing coupling is connected with a main body, a central hole of the main body is connected with a gas nozzle, the middle of the main body is provided with a gas inlet channel, and the axial outer ring of the main body is provided with an upper liquid-gas channel and a lower liquid-gas channel; a small plunger valve rod and a large plunger valve rod are arranged in the main body; the lower part of the main body is provided with an air bag protection cylinder, the inner diameter of the air bag protection cylinder forms an air bag expanding chamber, and a pressurizable air bag is arranged in the air bag expanding chamber. The small annulus injection air pressure in the initial stage of the drainage gas recovery process of the concentric double-pipe gas jet pump is greatly reduced, a liquid column in a small pipe on the upper portion of the concentric double-pipe gas jet pump is automatically and smoothly discharged in a segmented mode, and liquid is pushed to be continuously and smoothly discharged to the ground to be output for the smooth input of the gas jet pump to jet, atomize, suck and expand accumulated water in the small pipe. Accumulated water in a gas (oil) well is discharged, gas is discharged at the same time, and the purposes of high yield and stable continuous production of the self-injection gas (oil) well are achieved.

Description

Technical Field

[0001] This invention belongs to the field of oil and gas field development technology, and relates to a gas lift valve used in oil and gas field development for restoring normal gas (oil) production by draining water from self-flowing gas (oil) wells that have stopped flowing due to water accumulation in the well. In particular, it relates to a concentric double-tube small-tube gas lift valve for a concentric double-tube gas jet pump. Background Technology

[0002] As the development and production time of gas (oil) wells increases, the formation water cut rises, and water production from the gas (oil) producing layer intensifies. When the gas velocity in the production tubing falls below the critical fluid-carrying velocity, the fluid in the well cannot be effectively carried out of the wellbore at any time. Over time, fluid accumulates at the bottom of the well, causing increased back pressure. This not only affects the production capacity of the gas (oil) well but also shortens the normal self-flowing production time, and may even cause the gas (oil) well to stop flowing. Therefore, draining the accumulated fluid in the gas (oil) well to the surface as soon as possible, effectively reducing the back pressure in the near-well producing zone, and providing a good unobstructed channel for gas (oil) production, thereby restoring normal self-flowing production and maintaining vigorous self-flowing production, is the most economically efficient approach in gas (oil) well development and production.

[0003] Currently, existing technologies for gas (oil) well drainage and gas (oil) production include: conventional casing gas injection + multi-stage gas lift valve drainage, foam drainage, plunger gas lift, conventional oil pump drainage, submersible electric pump drainage, screw pump drainage, and concentric double-tube hydraulic jet pump drainage and gas production. These drainage technologies are not only ineffective for gas (oil) wells with high formation water production, but also have high production costs and management expenses. Although the newly developed concentric double-tube gas jet pump drainage and gas production technology has achieved good results in recent years, its application is limited by the need for high injection pressure in the small annulus during initial production (drainage) due to the depth of the gas jet pump and the high liquid level.

[0004] To broaden the application of the concentric double-tube gas jet pump drainage and gas production technology for gas (oil) well development and to further improve economic benefits, this invention has developed and designed a concentric double-tube small tube internal gas lift valve for the concentric double-tube gas jet pump. Summary of the Invention

[0005] The purpose of this invention is to address the deficiencies and shortcomings of existing technologies by providing a concentric double-tube gas lift valve for a concentric double-tube gas jet pump. This valve significantly reduces the initial annular injection pressure in the drainage and gas production process of the concentric double-tube gas jet pump. It enables the automatic segmented and smooth discharge of the liquid column in the upper small tube of the concentric double-tube gas jet pump, facilitating the smooth operation of the gas jet pump in jetting, atomizing, sucking, and expanding the water accumulated in the small tube to continuously and smoothly discharge the liquid to the surface for external transport. This achieves the goal of quickly draining the water accumulated in the gas (oil) well and simultaneously draining the gas and liquid, avoiding water accumulation in the well, and achieving the goal of maintaining high and stable production in the gas (oil) well.

[0006] The technical problem solved by this invention is achieved through the following technical solution: A concentric double-tube gas jet pump uses a concentric double-tube small-tube internal air lift valve, comprising an oil pipe coupling, an air nozzle, a main body, a small plunger valve stem, a large plunger valve stem, an airbag protection cylinder, an inflatable airbag, and a flow guide cover. The upper end of the oil pipe coupling is connected to a drain oil pipe column, and the lower end of the oil pipe coupling is connected to the main body. The air nozzle is connected to the central hole of the main body. An air inlet channel is provided in the middle of the main body, and upper and lower liquid-gas channels are provided on the outer axial ring of the main body. A small plunger valve stem and a large plunger valve stem are provided inside the main body to switch the air inlet channel. One end of the small plunger valve stem is a plunger, and the lower end of the plunger is... The spindle is equipped with a female thread for connecting to the large plunger valve stem. The other end of the small plunger valve stem is a long valve stem with a sealing surface that matches the central air hole of the air nozzle. The large plunger valve stem has the same structure as the small plunger valve stem, but the diameter of its lower plunger is larger than that of the lower plunger of the small plunger valve stem. An airbag protective cylinder is installed at the lower part of the main body. The middle part of the airbag protective cylinder is a section that has been expanded into a smooth tube, and four symmetrical gas-liquid through holes are drilled on the upper part of the smooth tube. The inner diameter of the airbag protective cylinder forms an airbag expansion chamber. An inflatable airbag is installed in the airbag expansion chamber. The inflatable airbag is an oil-resistant cylindrical capsule with an inflation airtight valve at the bottom.

[0007] Furthermore, the lower end of the airbag protective cylinder is connected to the flow guide shield, and the upper part of the outer diameter of the flow guide shield is a uniform diameter light tube and the lower part is an inverted cone.

[0008] Furthermore, a small plunger sealing ring and a large plunger sealing ring are respectively provided on the lower plunger of the small plunger valve stem and the large plunger valve stem.

[0009] Furthermore, the inner diameter of both ends of the oil pipe coupling is Φ48.3mm, which is a flat oil pipe female thread, and the outer diameter of the oil pipe coupling is Φ56mm, which is a bare pipe.

[0010] Furthermore, the upper end of the outer diameter of the air nozzle is a section of light tube with a wrench-shaped surface milled symmetrically on the light tube, and the lower end of the air nozzle is provided with a male thread section that connects to the central hole of the main body.

[0011] Furthermore, the outer diameter of the main body is provided with male threads of Φ48.3mm flat oil pipes that connect to the Φ48.3mm drain oil pipe column at the top and bottom, and an air passage leading to the central axis at the top and bottom is provided in the middle. The upper part of the air passage on the inner diameter of the main body is provided with a female thread section that connects to the lower part of the air nozzle, and the lower part is provided with a male thread that connects to the airbag protection cylinder.

[0012] Furthermore, the upper outer diameter of the airbag protective cylinder is provided with male threads that connect to the lower part of the main body's central axis, and the lower end is provided with male threads that connect to the flow guide cover.

[0013] The advantages and beneficial effects of this invention are as follows: 1. This invention enables the liquid column in the upper small tube of the concentric double-tube gas jet pump to be automatically and smoothly discharged in segments at low injection pressure, so as to quickly enable the gas jet pump to enter the jetting, atomizing, suction and expansion working process, allowing the gas to smoothly push the liquid in the oil pipe and wellbore to be continuously and completely discharged to the surface for external transportation, thereby reducing the bottom hole back pressure, maintaining the simultaneous discharge of gas and liquid, avoiding water accumulation in the well, and achieving the goal of continuous high and stable production of self-flowing oil and gas wells.

[0014] 2. This invention significantly reduces the initial small annulus injection gas pressure in the concentric dual-tube gas jet pump drainage and gas production process. It enables the automatic segmented and smooth discharge of the liquid column in the upper small tube of the concentric dual-tube gas jet pump. This allows the gas jet pump to smoothly jet, atomize, suck, and expand the water accumulated in the small tube, continuously and smoothly discharging the liquid to the surface for external transport. This achieves the goal of quickly discharging the water in the gas (oil) well and simultaneously discharging the gas and liquid, avoiding water accumulation in the well, and achieving the goal of maintaining high and stable production in the gas (oil) well. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the half-section structure of the present invention.

[0016] Explanation of reference numerals in the attached figures 1-Oil pipe coupling, 2-Air nozzle, 3-Main body, 4-Small plunger valve stem, 5-Large plunger valve stem, 6-Airbag protection cylinder, 7-Inflatable airbag, 8-Flow guide shield, 9-Large plunger sealing ring, 10-Small plunger sealing ring. Detailed Implementation

[0017] The present invention will be further described in detail below through specific embodiments. The following embodiments are merely descriptive and not limiting, and should not be used to limit the scope of protection of the present invention.

[0018] This invention relates to a concentric double-tube gas jet pump with an internal air lift valve in the small tube of the concentric double-tube pipe. Its innovation is that it consists of: (1) a Φ48.3 oil pipe coupling, (2) an air nozzle, (3) a main body, (4) a small plunger valve stem, (5) a large plunger valve stem, (6) an airbag protection cylinder, (7) an inflatable airbag, (8) a flow guide shield, (9) a large plunger sealing ring, and (10) a small plunger sealing ring.

[0019] (1) The Φ48.3 oil pipe coupling is designed to connect the upper Φ48.3 drain oil pipe column to the lower (3) main body. The inner diameter of both the upper and lower ends is a standard Φ48.3mm flat oil pipe female thread, and the entire outer diameter is a Φ56mm bare pipe; (2) The air nozzle is designed according to the Laval principle. Its inner diameter is a Laval principle curve air nozzle, the upper end of the outer diameter is a section of bare pipe and a wrench-shaped plane is milled at the symmetrical part of the bare pipe, and the lower end is provided with a male thread section that connects to the center hole of the (3) main body; (3) The main body is a series of Φ48.3 drain oil pipes connected vertically. The upper part of the inner diameter center is equipped with (2) air nozzle, the lower part is equipped with (6) high pressure airbag protection cylinder, the middle part is equipped with air inlet channel and (4) small plunger valve rod and (5) large plunger valve rod. The axial upper and lower liquid-gas channels are designed for the outer ring. The outer diameter is equipped with Φ48.3mm flat oil pipe male thread for connecting with Φ48.3 drain oil pipes, and the middle part is equipped with an axial upper and lower air passage leading to the center. The upper part of the upper and lower air passages of its inner diameter is equipped with a female thread section for connecting with the lower part of (2) air nozzle, and the lower part is equipped with a male thread for connecting with (6) high pressure airbag protection cylinder. The axial upper and lower liquid-gas channels are provided near the outer diameter; (4) The small plunger valve stem is designed to switch the air intake channel. One end of it is a plunger with a groove for installing the (10) small plunger sealing ring. The lower end of the plunger has a female thread for connecting to the (5) large plunger valve stem at the central shaft. The other end is a long valve stem that matches the sealing surface of the (2) air nozzle central air hole. (5) The large plunger valve stem has the same function as the (4) small plunger valve stem and is designed to switch the air intake channel. Its structure is similar to that of the (4) small plunger valve stem, except that the diameter of the plunger at the lower end is larger and there is no connecting thread at the central shaft at the lower end. (6) The outer body of the high-pressure airbag protective cylinder is designed for the pressure transmission of the liquid column inside the Φ48.3 drain oil pipe column at the central axis of the main body of (3) and for the installation of the protective (7) inflatable airbag. Its upper outer diameter is provided with a male thread that connects to the lower part of the central axis of the main body of (3). Downward is a section of the tube that is expanded to a smooth tube and has 4 symmetrical gas-liquid through holes drilled on the upper part of the smooth tube. The lower end is provided with a male thread that connects to the (8) flow guide cover. The upper part of the inner diameter is connected to the expansion chamber for installing the (7) inflatable airbag. (7) The inflatable airbag is designed to store nitrogen at a certain pressure. It is an oil-resistant cylindrical capsule with an inflation valve at the bottom. (8) The flow guide shield is designed to guide the liquid and gas flow from below, reduce flow resistance, and protect and fix the (7) inflatable airbag. Its outer diameter is a uniform diameter tube at the top and a tapered pile body at the bottom. (9) The large plunger sealing ring and (10) the small plunger sealing ring are designed to cooperate with the matching cylinder wall to play a sealing role. See the schematic diagram for details: The working principle of this invention is as follows: In actual use, the number and spacing depth of the gas lift valves configured on the drainage string are calculated based on the formation depth of the oil and gas well, the gas-liquid ratio produced, the liquid level in the wellbore before production, and the production capacity. After the gas lift valve is connected to the drainage string and lowered into the well along with the entire drainage string, the concentric double-pipe drainage and gas production wellhead is installed in preparation for production. Once the surface gas injection and external transmission processes are connected, the gas output from the existing gas compression equipment at the well site is injected into the small annulus of the concentric double-pipe. At this time, the liquid level in the small annulus is pushed downwards under the pressure of the injected gas. Because the concentric double-pipe internal drainage lifting tubes are connected in series, the pressure of the liquid column in the tube is pressed on the large plunger at the bottom of the large plunger valve rod by the four symmetrical through holes at the top of the high-pressure airbag protective cylinder (6) through the expansion diameter. The large plunger at the bottom of the large plunger valve rod (5) is compressed by the liquid column, and the pressurizable airbag (7) shrinks (volume). The pressurizable airbag (7) shrinks (volume). The large plunger valve rod (5) drives the small plunger valve rod (4) to move down. At this time, the valve rod at the top of the small plunger valve rod (4) leaves the central air inlet hole of the (2) air nozzle. That is, the air inlet hole in the middle of the (3) main body is connected to the central air inlet hole of the (2) air nozzle. The liquid surface of the small annulus smoothly enters the tube and is lifted to the wellhead under the action of the gas injection pressure. When the liquid surface above the air inlet in the middle of the small annulus (3) is fully pressed in, the high-pressure gas begins to enter. At this time, the high-pressure gas continuously passes through the Laval curve of the (2) nozzle to atomize and lift the liquid in the drainage gas extraction lifting tube. When the liquid above the gas nozzle in the drainage and gas lifting pipe (2) is basically lifted and carried out of the wellhead by gas, due to the decrease in the pressure of the large plunger at the bottom of the large plunger valve stem (5), the pressurized air bag is restored to its original state and pushed up (5) the large plunger valve stem and (4) the small plunger valve stem. At this time, the valve stem head at the top of the small plunger valve stem (4) blocks the central air inlet hole of the gas nozzle (2) and stops the gas intake of this valve section. The liquid surface of the small annulus is then pressed into the next valve section under the action of the injected gas pressure, and the next drainage and gas lifting pipe is carried out for atomization and lifting. This process continues until all the liquid in the small annulus and the pipe is discharged, so that the lowest gas jet pump can quickly form a jet, atomize, expand, lift and discharge the accumulated liquid in the well, and the oil and gas well can restore its production capacity.

[0020] This invention determines the number, spacing, and control (liquid column) pressure of each valve based on the ratio of formation gas production to liquid production in the well, the depth of the gas jet pump, and the initial liquid level. To achieve automatic, segmented, and smooth discharge of the liquid column in the upper small tube of the concentric dual-tube gas jet pump using low injection pressure, and to quickly enable the gas jet pump to enter the jetting, atomizing, suction, and expansion process, allowing the gas to smoothly propel the liquid in the tubing and wellbore to the surface for continuous and complete external transport, this invention aims to reduce bottom hole back pressure, maintain simultaneous gas and liquid discharge, prevent water accumulation in the well, and achieve continuous high and stable production in self-flowing oil and gas wells.

[0021] Oil and gas wells that experienced reduced or halted production due to water accumulation before this invention: 1) The formation production pressure, production capacity during normal production, and liquid-to-gas ratio of the well should be summarized and analyzed to design the depth of the gas jet pump. Then, based on the liquid level height when production is stopped, the number and spacing of the gas lift valves should be configured. 2) Well cleaning should be performed on the oil and gas wells. The outer diameter of the well cleaning gauge should be selected according to the inner diameter of the casing to clean the well to the depth where the pump is installed. 3) Well completion is carried out according to the concentric double-tube automatic segmented gas lift jet design.

[0022] Once the surface gas injection and external transmission processes are connected, the gas output from the existing gas compression equipment at the well site is injected into the small annulus of the concentric double pipe. At this time, the liquid surface of the small annulus is pressed downward under the pressure of the injected gas, and the liquid is lifted and discharged from top to bottom in stages. When the gas jet pump at the bottom starts to jet, atomize, expand, lift and discharge, the self-flowing oil and gas well resumes normal production.

[0023] Although embodiments and drawings of the present invention have been disclosed for illustrative purposes, those skilled in the art will understand that various substitutions, variations and modifications are possible without departing from the spirit and scope of the present invention and the appended claims. Therefore, the scope of the present invention is not limited to the contents disclosed in the embodiments and drawings.

Claims

1. A concentric double tube gas lift valve for use in a concentric double tube gas jet pump, characterized by: The utility model provides a kind of oil pipe coupling (1), air cock (2), main body (3), small plunger valve rod (4), big plunger valve rod (5), air bag protection cylinder (6), inflatable air bag (7) and flow guide shield (8), the upper end of the oil pipe coupling (1) is connected with drainage oil pipe column, the lower end of the oil pipe coupling (1) is connected with the main body (3), the central hole of the main body (3) is connected with the air cock (2), the middle part of the main body (3) is provided with air inlet channel, the outer circle of the main body (3) is provided with upper and lower liquid gas channel, the main body (3) is provided with small plunger valve rod (4) and big plunger valve rod (5) in the inside, the small plunger valve rod (4) is one end for plunger, plunger lower end central shaft is equipped with female thread with big plunger valve rod (5) connection, the other end of the small plunger valve rod (4) is long valve rod with air cock (2) center hole matching sealing surface;The big plunger valve rod (5) is same with the small plunger valve rod (4) in structure, and the diameter of plunger in lower end is greater than the small plunger valve rod (4) lower end plunger;The lower part of the main body (3) is installed air bag protection cylinder (6), the middle part of the air bag protection cylinder (6) is a section of light pipe with diameter expansion, and four symmetrical gas-liquid through holes are drilled on the upper part of light pipe, the inner diameter of the air bag protection cylinder (6) forms air bag diameter expansion chamber, the inflatable air bag (7) is installed in the air bag diameter expansion chamber, the inflatable air bag (7) is oil-resistant cylindrical capsule with inflation air-tight valve in lower part.

2. The concentric double tube gas lift valve for use in the small tube of the concentric double tube gas jet pump according to claim 1, characterized in that: The lower end of the air bag protection cylinder (6) is connected with the flow guide shield (8), the outer diameter of the flow guide shield (8) is light pipe with equal diameter in upper part and inverted truncated cone in lower part.

3. The concentric double tube gas lift valve for use in the small tube of the concentric double tube gas jet pump according to claim 1, characterized in that: Small plunger sealing ring (10) and big plunger sealing ring (9) are respectively arranged on the lower end plunger of the small plunger valve rod (4) and the big plunger valve rod (5).

4. The concentric double tube gas lift valve for use in the small tube of the concentric double tube gas jet pump according to claim 1, characterized in that: The inner diameter of the upper and lower ends of the oil pipe coupling (1) is Φ48.3mm flat oil pipe female thread, and the outer diameter of the oil pipe coupling (1) is Φ56mm light pipe.

5. The concentric double tube gas lift valve for use in the small tube of the concentric double tube gas jet pump according to claim 1, characterized in that: The outer diameter of the upper end of the air cock (2) is a section of light pipe, and the plane for wrenching is milled on the symmetrical part of light pipe, and the lower end of the air cock (2) is provided with male thread section connected with the central hole of the main body (3).

6. The concentric double tube gas lift valve for use in the small tube of the concentric double tube gas jet pump according to claim 1, characterized in that: The outer diameter of the upper and lower ends of the main body (3) is provided with Φ48.3mm flat oil pipe male thread connected with Φ48.3 drainage oil pipe column, and the middle part is provided with gas passage to central axis upward and downward, the inner diameter of the main body (3) is provided with female thread section connected with the lower part of the air cock (2) on the upper part of gas passage upward and downward, and is provided with male thread connected with the air bag protection cylinder (6) on the lower part.

7. The concentric double tube gas lift valve for use in the small tube of the concentric double tube gas jet pump according to claim 1, characterized in that: The outer diameter of the upper part of the air bag protection cylinder (6) is provided with male thread connected with the lower part of the central axis of the main body (3), and the lower end is provided with male thread connected with the flow guide shield (8).

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