A plunger for use in a water drainage gas recovery portable liquid foamer

Abstract

The application discloses a plunger for carrying liquid foaming agent in water drainage gas production, which comprises a plunger outer cavity and a plunger shaft block; a lower cavity is left between the plunger outer cavity and the plunger shaft block, the lower cavity is filled with a foaming agent, and a liquid discharge one-way valve for outputting from inside to outside is arranged on the outer side wall of the lower cavity; the plunger shaft block is internally provided with a cavity, a mass ball and a limiter are arranged above the cavity, the mass ball is used for penetrating the limiter under the action of inertia and moving towards the lower part of the cavity; a spring buffer is arranged below the cavity, the lower end of the spring buffer extends out of the lower end of the plunger shaft block from the cavity, and the mass ball is used for driving the spring buffer to extend towards the inside of the lower cavity. By adopting the scheme, the plunger is used as a carrier of foam falling when the plunger falls, the falling distance of the foam is prolonged, and the foaming effect is improved; when the plunger goes up, the foaming agent carried by the plunger generates a large amount of low-density water-containing foam under the agitation of gas-liquid two-phase flow, and the blowout time is sufficiently prolonged.

Description

Technical Field

[0001] This invention relates to the field of gas reservoir drainage and gas production technology, specifically to a plunger for drainage and gas production that can carry a liquid foaming agent. Background Technology

[0002] During gas well production, liquids are typically produced, which are carried to the surface as droplets by the gas produced from the formation. As gas well development progresses into the mid-to-late stages, production capacity declines. When the gas energy decreases to an insufficient level to continuously carry the produced liquids from the wellhead, the liquids flow in the opposite direction to the gas flow and accumulate at the bottom of the well, resulting in liquid buildup. This accumulation of liquid in the wellbore increases back pressure in the formation, severely limiting production capacity, hindering gas production, and potentially even completely shutting down the well, leading to production stoppage. Therefore, utilizing drainage gas production technology to promptly remove the accumulated liquid at the bottom of the well is crucial for ensuring continuous gas production and improving the well recovery rate.

[0003] Plunger lifting and foam drainage gas extraction are currently the most common drainage gas extraction technologies.

[0004] Plunger lift separates the high-pressure gas used for lifting from the liquid being lifted through the solid sealing interface of the plunger, forming a stable and ideal slug flow of gas-plunger-liquid in the wellbore. This reduces gas cross-flow and liquid backflow, improving lift efficiency. The reciprocating motion of the plunger prevents wax buildup in the wellbore. The equipment has a simple structure and low installation cost; however, when applied to deep gas wells, plunger lift operations are frequent and the blowout production time is short.

[0005] Foam drainage gas production involves injecting surfactants into the bottom of the well. The high-pressure gas in the formation agitates the surfactants, causing them to come into full contact with the bottom-well liquid, generating a large amount of stable, low-density water-bearing foam. This foam is then carried to the surface by the gas flow. This process is simple to implement, uses simple equipment, and is low-cost, making it widely applicable to water-producing gas wells with depths less than 3500m. However, for deep gas wells, it has limitations such as shallow foam injection depth, small drainage volume, and short effective period.

[0006] To address the problems of short effective period, frequent interventions, and small drainage volume in existing single drainage processes for deep shale gas wells, the plunger-foam drainage composite lifting process provided by this invention has significant practical and economic value for improving gas well recovery. Summary of the Invention

[0007] To solve the above problems, the present invention aims to provide a plunger that can carry liquid foaming agent for drainage and gas extraction. With this solution, when the plunger falls, it acts as a carrier for the falling foam, thereby extending the falling distance of the foam and improving the foaming effect.

[0008] This invention is achieved through the following technical solution: A plunger for drainage gas extraction that can carry liquid foaming agent includes an outer plunger cavity and a plunger shaft block arranged sequentially from the outside to the inside. A lower cavity is left between the outer cavity of the plunger and the plunger shaft block. The lower cavity is filled with a foaming agent, and a drain valve with an outward discharge function is provided on the outer wall of the lower cavity. The plunger block has a cavity inside, and a mass ball and a limiter are provided above the cavity. The mass ball is used to pass through the limiter under the action of inertia and move downwards from the cavity. A spring buffer is provided below the cavity, and the lower end of the spring buffer extends from the lower end of the plunger shaft block from the cavity. The mass ball is used to drive the spring buffer to extend into the lower cavity.

[0009] Compared to existing technologies, which suffer from short effective periods, frequent interventions, and small drainage volumes in deep shale gas wells due to single drainage processes, this solution provides a plunger capable of carrying a liquid foaming agent for drainage and gas production. Specifically, the solution includes an outer plunger cavity and a plunger shaft block. The plunger shaft block is located within the outer plunger cavity and is coaxially positioned. A lower cavity exists between the outer plunger cavity and the plunger shaft block, filled with a foaming agent, thus allowing the plunger to act as a carrier for the falling foaming agent. The plunger shaft block... The device has an internal cavity that runs along the length of the plunger shaft. Above the cavity are a mass ball and a limiter. The limiter is used to fix and restrict the mass ball. When the plunger reaches the bottom of the well, it strikes the locking device at the bottom of the well, causing the speed to decrease rapidly. At this time, the mass ball passes through the limiter under the action of inertia and continues to fall. It then strikes the spring buffer below the cavity, causing the spring buffer to extend into the lower cavity, thereby squeezing the foaming agent in the lower cavity and causing the foaming agent to be discharged from the drain valve.

[0010] Further optimization involves providing an annular slider between the plunger outer cavity and the plunger shaft block, with an upper cavity. The upper cavity and lower cavity are separated by the annular slider, which can slide along the length of the plunger shaft block. A flow valve for inlet liquid is provided on the outer wall of the upper cavity, allowing for the input of liquid from the outside to the inside, to balance the internal and external pressures.

[0011] Further optimization includes a base with an opening at the lower end of the plunger shaft block. The base is used to close the lower opening and is threadedly connected to the lower end of the plunger shaft block. The spring buffer passes through the base to achieve a detachable connection.

[0012] Further optimization involves extending the base sidewall outward beyond the outer wall of the plunger shaft block, with the extended section of the base sidewall preventing the annular slider from exceeding the drain check valve; above the annular slider, each outer wall of the plunger shaft block is provided with a limiting block, which prevents the annular slider from exceeding the inlet check valve; and prevents the sliding range of the annular slider from exceeding two check valves.

[0013] Further optimization involves the spring buffer including a movable block that passes through the middle of the base and is movably connected to the base; both the upper and lower ends of the movable block are large-diameter ends, and a spring is sleeved on the movable block, with the upper and lower ends of the spring respectively connected to the upper end of the movable block and the base; this optimizes the spring buffer.

[0014] Further optimization involves making the limiter an annular rubber ring, with the inner diameter of the limiter being smaller than the outer diameter of the mass ball; this facilitates the reuse of the plunger.

[0015] Further optimization involves using an iron ball as the mass ball, with the iron ball wrapped in rubber to achieve flexible contact and facilitate the mass ball's passage through the limiter.

[0016] Further optimization involves a rubber buffer at the upper end of the cavity; this ensures a flexible contact when the iron ball moves upward and impacts the upper end of the cavity. The bottom of the rubber buffer has a hemispherical groove that matches the size of the mass ball.

[0017] Further optimization involves an opening at the upper end of the plunger outer cavity, with the lower end of the plunger shaft block extending into the plunger outer cavity, and a threaded connection between the upper end of the plunger shaft block and the opening at the upper end of the plunger outer cavity; this is for achieving a detachable connection, and the threaded connection must be sealed.

[0018] Further optimization involves providing a turbulent sealing groove on the outer wall of the plunger's outer cavity to prevent liquid from slipping due to turbulence.

[0019] Compared with the prior art, the present invention has the following advantages and beneficial effects: This invention provides a plunger capable of carrying liquid foaming agent for drainage gas production. This design aims to implement a plunger-foam discharge composite lifting process for deep shale gas wells. When the plunger descends, it acts as a carrier for the falling foam, extending the foam's descent distance and improving the foaming effect. As the plunger ascends to lift the wellbore fluid, the foaming agent carried by the descending plunger generates a large amount of low-density water-containing foam under the agitation of the gas-liquid two-phase flow, significantly extending the release time and forming a plunger-foam discharge connected lifting system, thus enhancing the liquid-carrying effect. Attached Figure Description

[0020] To more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of the present invention and should not be considered as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort. In the drawings: Figure 1 This is a schematic diagram of a plunger structure according to an embodiment of the present invention; Figure 2 This is a schematic diagram of a plunger shaft block structure according to an embodiment of the present invention; Figure 3 This is a schematic diagram of the plunger outer cavity structure according to an embodiment of the present invention; Figure 4 This is a schematic diagram of a spring buffer and base structure according to an embodiment of the present invention; Figure 5 This is a schematic diagram of a mass sphere structure according to an embodiment of the present invention.

[0021] The attached diagram shows the markings and corresponding component names: 1-Plunger shaft block, 2-Rubber buffer, 3-Mass ball, 4-Limiter, 5-Inlet check valve, 6-Plunger outer cavity, 7-Annular slider, 8-Turbulent sealing groove, 9-Spring buffer, 10-Base, 11-Drain check valve. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments and accompanying drawings. The illustrative embodiments and descriptions of the present invention are only used to explain the present invention and are not intended to limit the present invention.

[0023] Example: Figures 1 to 5 As shown, this embodiment provides a plunger for drainage gas extraction that can carry liquid foaming agent, including a plunger outer cavity 6 and a plunger shaft block 1 arranged sequentially from the outside to the inside; A lower cavity is left between the plunger outer cavity 6 and the plunger shaft block 1. The lower cavity is filled with a foaming agent. A drain valve 11 that outputs liquid from the inside to the outside is provided on the outer wall of the lower cavity. The plunger block 1 has a cavity inside, and a mass ball 3 and a limiter 4 are provided above the cavity. The mass ball 3 is used to pass through the limiter 4 under the action of inertia and move downwards in the cavity. A spring buffer 9 is provided below the cavity. The lower end of the spring buffer 9 extends from the lower end of the plunger block 1 from the cavity. The mass ball 3 is used to drive the spring buffer 9 to extend into the lower cavity.

[0024] Compared to existing technologies, which suffer from short effective periods, frequent interventions, and small drainage volumes in deep shale gas wells due to single drainage processes, this solution provides a plunger capable of carrying liquid foaming agents for drainage and gas production. Specifically, the solution includes an outer plunger cavity 6 and a plunger shaft block 1. The plunger shaft block 1 is located within the outer plunger cavity 6 and is coaxially arranged. A lower cavity is left between the outer plunger cavity 6 and the plunger shaft block 1, and this lower cavity is filled with a foaming agent, thus using the plunger as a carrier for the falling foaming agent. Within the plunger shaft block 1... The plunger has a cavity along its length. A mass ball 3 and a limiter 4 are located above the cavity. The limiter 4 is used to fix and restrict the mass ball 3. When the plunger reaches the bottom of the well, it hits the locking device at the bottom of the well, which reduces its speed rapidly. At this time, the mass ball passes through the limiter 4 under the action of inertia and continues to fall. It then hits the spring buffer 9 below the cavity, causing the spring buffer 9 to extend into the lower cavity, thereby squeezing the foaming agent in the lower cavity and causing the foaming agent to be discharged from the drain valve 11.

[0025] In a further embodiment, an annular slider 7 is provided between the plunger outer cavity 6 and the plunger shaft block 1, leaving an upper cavity. The upper cavity and the lower cavity are separated by the annular slider 7, which can slide along the length of the plunger shaft block 1. A flow valve 5 for inlet liquid input from the outside to the inside is provided on the outer wall of the upper cavity. To balance the internal and external pressures, in this embodiment, an annular slider 7 is also provided between the plunger outer cavity 6 and the plunger shaft block 1. The annular slider 7 divides the gap between the plunger outer cavity 6 and the plunger shaft block 1 into an upper cavity and a lower cavity. The annular slider 7 and the plunger shaft block 1 are coaxial. The plunger is set up and can slide along the length of the plunger shaft block 1. When the well is opened, the plunger falls along the tubing, and the pressure in the wellbore increases continuously. The fluid in the wellbore enters the upper cavity through the plunger's inlet check valve 5, thereby balancing the pressure inside and outside the plunger. At this time, the annular slider 7 can separate the well fluid and the foaming agent. Then the plunger hits the locking device at the bottom of the well and discharges the foaming agent through the inertia of the mass block. After the well is opened, the plunger moves upward to lift most of the accumulated fluid in the wellbore. When it hits the wellhead, the speed decreases rapidly, causing the internal mass ball 3 to continue to rise under the action of inertia, thereby passing through the limiter 4 and being restricted by the limiter 4 again.

[0026] The above scheme aims to achieve the following: during blowout production, the plunger is used as a carrier for the falling foam, extending the distance of the foam fall and improving the foaming effect. At the same time, when the plunger lifts the wellbore fluid upward, the foaming agent carried by the plunger downward generates a large amount of low-density water-containing foam under the agitation of the gas-liquid two-phase flow, which fully extends the blowout time and forms a plunger-foam outlet connection type lifting, thereby improving the fluid carrying effect.

[0027] Please see Figure 1 and Figure 4As an embodiment of achieving a detachable connection, it is configured as follows: it further includes a base 10, with an opening at the lower end of the plunger shaft block 1, the base 10 is used to close the lower opening and is threadedly connected to the lower end of the plunger shaft block 1; the spring buffer 9 passes through the base 10; In the above scheme, a base 10 is connected to the lower end of the plunger shaft block 1. The outer side of the base 10 and the inner side of the plunger shaft block 1 have matching threads, and the threaded connection needs to be sealed.

[0028] Please see Figure 1 and Figure 2 As an embodiment to prevent the sliding range of the annular slider 7 from exceeding the two check valves, the following configuration is provided: the side wall of the base 10 extends outward and beyond the outer side wall of the plunger shaft block 1, and the extended section of the side wall of the base 10 is used to prevent the annular slider 7 from exceeding the drain check valve 11; above the annular slider 7, each outer side wall of the plunger shaft block 1 is provided with a limiting block, and the limiting block is used to prevent the annular slider 7 from exceeding the inlet check valve 5; In the above scheme, while the base 10 is closing the lower end of the plunger shaft block 1, its side end extends beyond the outer wall of the plunger shaft block 1 and extends outward. At this time, the side end of the base 10 is located above the drain valve 11 in the vertical direction, thereby preventing the annular slider 7 from sliding out. There is a limit block above the plunger shaft block 1, that is, a variable diameter position. The limit block is located below the inlet valve 5 in the vertical direction, thereby preventing the annular slider 7 from sliding beyond the inlet valve 5.

[0029] Please see Figure 4 A further optimization of the spring buffer 9 is achieved by configuring it as follows: the spring buffer 9 includes a movable block that passes through the middle of the base 10 and is movably connected to the base 10; both the upper and lower ends of the movable block are large-diameter ends, and a spring is sleeved on the movable block, with the upper and lower ends of the spring respectively connected to the upper end of the movable block and the base 10. In the above scheme, the spring buffer 9 includes a moving block and a spring. The moving block is preferably I-shaped and moves through the middle of the base 10 and moves up and down along the length of the plunger shaft block 1. The large diameter ends at the upper and lower ends prevent the moving block from sliding out of the base 10, while also increasing the contact area with the mass block through the upper end and providing space for the spring.

[0030] Please see Figure 1As an implementation method that facilitates the reuse of the plunger, the limiter 4 is an annular rubber, and the inner diameter of the limiter 4 is smaller than the outer diameter of the mass ball 3. In this scheme, the limiter 4 is made of an annular rubber, which is coaxially arranged with the plunger shaft block 1 and fixed on the inner side wall of the plunger shaft block 1. In the initial state, the mass ball 3 is located on the annular rubber because its diameter is larger than the inner diameter of the annular rubber. Under the action of inertia, the mass ball 3 squeezes the annular rubber and falls out of the annular rubber. When the mass ball 3 moves upward, it will also squeeze the annular rubber and thus sit on the annular rubber again.

[0031] Please see Figure 1 and Figure 5 The mass ball 3 is an iron ball, and the iron ball is wrapped with rubber to achieve flexible contact and facilitate the passage of the mass ball 3 through the limiter 4.

[0032] As a redundancy solution, the upper end of the cavity is equipped with a rubber buffer 2; when the iron ball moves upward and hits the upper end of the cavity, it makes a flexible contact. The bottom of the rubber buffer 2 has a hemispherical groove that matches the size of the mass ball 3.

[0033] As one embodiment for achieving a detachable connection, the upper end of the plunger outer cavity 6 is open, the lower end of the plunger shaft block 1 extends into the plunger outer cavity 6, and the upper end of the plunger shaft block 1 and the upper end opening of the plunger outer cavity 6 are threadedly connected; the threaded connection needs to be sealed.

[0034] As a redundancy solution, a turbulence sealing groove 8 is provided on the outer wall of the plunger outer cavity 6 to prevent liquid from slipping due to turbulence.

[0035] Working principle: Initially, the mass ball 3 is located on the rubber limiter 4 inside the plunger shaft block 1. Foaming agent is filled in the gap between the plunger shaft block 1 and the outer cavity 6 of the plunger. The annular slider 7 is located above the liquid foaming agent. During well opening, the plunger falls along the tubing, and the pressure in the wellbore continuously increases. Fluid in the wellbore enters the gap through the plunger inlet check valve 5 to balance the pressure inside and outside the plunger. The annular slider 7 separates the well fluid and the foaming agent in the gap. Upon reaching the bottom of the well, the plunger impacts the bottom-end locking device, and its speed rapidly decreases. The mass ball 3 inside the plunger continues to fall through the limiter 4 under inertia, and then impacts the spring buffer 9 inside the plunger shaft block 1. The spring buffer 9 extends along the base 10 into the gap, squeezing the foaming agent in the gap. At this time, the pressure in the gap is higher than the external pressure of the plunger, and the foaming agent is discharged from the plunger outlet check valve 11. After well opening, the plunger rises and lifts most of the fluid in the wellbore. Upon impacting the wellhead, its velocity decreases rapidly. The internal mass ball 3 continues to rise due to inertia, passing through the limiter 4 and impacting the rubber buffer 2, where its velocity decreases rapidly again before finally landing on the limiter 4. During blowout production, the foaming agent generates a large amount of low-density water-containing foam under the agitation of the gas-liquid two-phase flow, significantly extending the gas blowout time and forming a plunger-foaming linkage lifting system.

[0036] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A plunger for drainage and gas extraction that can carry a liquid foaming agent, characterized in that, It includes a plunger outer cavity (6) and a plunger shaft block (1) arranged sequentially from the outside to the inside; A lower cavity is left between the plunger outer cavity (6) and the plunger shaft block (1), the lower cavity is filled with a foaming agent, and a drain valve (11) is provided on the outer wall of the lower cavity to drain from the inside to the outside. The plunger block (1) has a cavity inside, and a mass ball (3) and a limiter (4) are provided above the cavity. The mass ball (3) is used to pass through the limiter (4) under the action of inertia and move downwards in the cavity. A spring buffer (9) is provided below the cavity. The lower end of the spring buffer (9) extends from the lower end of the plunger block (1) from the cavity. The mass ball (3) is used to drive the spring buffer (9) to extend into the lower cavity. An annular slider (7) is provided between the plunger outer cavity (6) and the plunger shaft block (1), and an upper cavity is left. The upper cavity and the lower cavity are separated by the annular slider (7). The annular slider (7) can slide along the length direction of the plunger shaft block (1). A liquid inlet flow valve (5) is provided on the outer wall of the upper cavity for inlet flow from the outside to the inside. The plunger also includes a base (10), the lower end of the plunger shaft block (1) is open, the base (10) is used to close the lower end opening and is threadedly connected to the lower end of the plunger shaft block (1); the spring buffer (9) passes through the base (10). The spring buffer (9) includes a movable block that passes through the middle of the base (10) and is movably connected to the base (10); the upper and lower ends of the movable block are both large-diameter ends, and a spring is sleeved on the movable block, with the upper and lower ends of the spring respectively connected to the upper end of the movable block and the base (10).

2. A plunger for drainage gas extraction capable of carrying liquid foaming agent according to claim 1, characterized in that, The sidewall of the base (10) extends outward and beyond the outer sidewall of the plunger block (1), and the sidewall extension of the base (10) is used to prevent the annular slider (7) from exceeding the drain valve (11). Above the annular slider (7), there are limit blocks on the outer side wall of the plunger shaft block (1). The limit blocks are used to prevent the annular slider (7) from exceeding the liquid inlet flow valve (5).

3. A plunger for drainage gas extraction capable of carrying liquid foaming agent according to claim 1, characterized in that, The limiter (4) is an annular rubber, and the inner diameter of the limiter (4) is smaller than the outer diameter of the mass ball (3).

4. A plunger for drainage gas extraction capable of carrying a liquid foaming agent according to claim 1, characterized in that, The mass ball (3) is an iron ball, and the iron ball is wrapped with rubber.

5. A plunger for drainage gas extraction capable of carrying a liquid foaming agent according to claim 1, characterized in that, The upper end of the cavity is equipped with a rubber buffer (2).

6. A plunger for drainage gas extraction capable of carrying liquid foaming agent according to claim 1, characterized in that, The upper end of the plunger outer cavity (6) is open, and the lower end of the plunger shaft block (1) extends into the plunger outer cavity (6). The upper end of the plunger shaft block (1) and the upper end of the plunger outer cavity (6) are threadedly connected.

7. A plunger for drainage gas extraction capable of carrying a liquid foaming agent according to claim 1, characterized in that, A turbulent sealing groove is provided on the outer wall of the plunger outer cavity (6).

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