A compressed air energy storage well air spring buffer ball seat

Abstract

The present invention belongs to the technical field of new energy downhole operation of compressed air energy storage wells, and specifically relates to an air spring buffer ball seat for compressed air energy storage wells. The invention aims to solve the problem in the prior art that when the ball seat is knocked off, its reverse force and the water hammer effect will cause the overall vertical force on the pipe string to be too large, resulting in the overall upward movement of the pipe string and damage to the wellhead device. The present invention comprises an outer tube, a first plugging core, a first plugging core cone cap and a second plugging core. A main channel is opened in the middle part of the outer tube along the axial direction and the inner wall of the main channel is provided with steps. The first plugging core is arranged in the main channel of the outer tube, and the outer wall of the first plugging core cone cap is provided with steps. The first plugging core cone cap is threadedly connected to the groove of the first plugging core. The second plugging core is fixedly arranged in the main channel of the outer tube at one end away from the first plugging core, thereby avoiding the problem that the overall vertical force on the pipe string is too large, resulting in the overall upward movement of the pipe string and damage to the wellhead device.

Description

Technical Field

[0001] The invention belongs to the technical field of underground operation of new energy compressed air energy storage wells, and specifically relates to an air spring buffer ball seat for a compressed air energy storage well. Background Art

[0002] Compressed air energy storage refers to a storage method that uses electrical energy to compress air during the low load period of the power grid, seals the air at high pressure in energy storage reservoirs such as underground salt caverns, and releases the compressed air to drive steam turbines to generate electricity during the peak load period of the power grid.

[0003] In order to meet the needs of large-volume air injection and production, the current maximum production casing of underground salt cavern energy storage wells is 18 5 / 8 in, and the corresponding injection and production string is 13 3 / 8 in. In the early stage of compressed air energy storage wells, the injection and production string often needs to undergo high-pressure operations such as packer seat sealing and string pressure testing. Therefore, a ball seat is usually used to seal the entire wellbore channel. After the string operation is completed, the inner core of the ball seat is knocked out with high pressure to ensure that the injection and production string is unobstructed.

[0004] However, due to the large size of the injection and production tubing and the shallow structure of the compressed air energy storage well body, during the high-pressure hitting of the ball seat, the moment the ball seat is knocked off, its reverse force and the water hammer effect will cause the entire tubing to be subjected to excessive vertical upward force, causing the entire tubing to move upward and damage the wellhead device. Summary of the invention

[0005] In order to solve the problem in the prior art that when the ball seat is knocked off, its reverse force and water hammer effect will cause the overall vertical force on the pipe string to be too large, resulting in the overall upward movement of the pipe string and damage to the wellhead device, the present invention provides an air spring buffer ball seat for a compressed air energy storage well, comprising:

[0006] The outer cylinder has a main channel opened in the middle along the axial direction and the inner wall of the main channel is provided with steps;

[0007] A first plugging core is arranged in the main channel of the outer tube, one end of the first plugging core is provided with a groove opened along the axial direction, and the inner wall of the groove is provided with a thread;

[0008] A first plugging core cone cap, the outer wall of which is provided with a step, and the first plugging core cone cap is threadedly connected with the groove of the first plugging core;

[0009] A second plugging core is fixedly disposed in the main passage of the outer tube at one end away from the first plugging core.

[0010] According to a compressed air energy storage well air spring buffer ball seat provided in some embodiments of the present application, one end of the first plugging core cone cap is configured in a conical shape, and the outer wall of the other end is provided with a thread adapted to the first plugging core groove.

[0011] According to some embodiments of the present application, a compressed air energy storage well air spring buffer ball seat is provided, which also includes a first plugging core shear ring, and the first plugging core shear ring is sleeved on the step of the first plugging core cone cap.

[0012] According to some embodiments of the present application, a compressed air energy storage well air spring buffer ball seat further includes a second core plugging shear nail, and the outer cylinder is fixedly connected to the second core plugging by the second core plugging shear nail.

[0013] According to a compressed air energy storage well air spring buffer ball seat provided in some embodiments of the present application, a bypass channel is further opened in the outer cylinder along the axial direction, and the bypass channel is distributed outside the main channel.

[0014] According to some embodiments of the present application, a compressed air energy storage well air spring buffer ball seat is provided, which also includes a soluble blocking ball. The soluble blocking ball is arranged at one end of the bypass channel close to the first plugging core, and the soluble blocking ball can block the bypass channel.

[0015] According to a compressed air energy storage well air spring buffer ball seat provided in some embodiments of the present application, a first plugging core and a second plugging core are respectively installed at two ends of a main channel inside the outer tube, and a sealing rubber ring is provided at the connection between the first plugging core and the second plugging core and the outer tube.

[0016] According to some embodiments of the present application, a compressed air energy storage well air spring buffer ball seat is provided, which also includes a guide tube, which is coaxially arranged at one end of the outer tube close to the second plugging core, and the guide tube is threadedly connected to the outer tube.

[0017] Beneficial effects of the present invention:

[0018] Designed for high-pressure construction inside the 13 3 / 8in injection and production string of air energy storage wells, the bottom of the injection and production string can be sealed to ensure effective high-pressure construction. The impact force caused by high pressure can be reduced when the ball seat plug is removed at the end of high-pressure construction, reducing the risk of the string moving upward due to the reverse force when the ball seat plug is separated from the injection and production string.

[0019] The outer tube of the ball seat adopts a main and side channel design. The main channel and the ball seat plugs at both ends form an air sealing system, and the side channel is used to keep the inside and outside of the injection and production string unobstructed during the lowering of the injection and production string.

[0020] The first plugging core on the upper part of the ball seat is knocked off by the pressure inside the injection and production string. The first plugging core descends and compresses the air column in the main channel of the outer tube of the ball seat. The compression of the air column acts as an air spring to slow down the downward speed of the first plugging core. After the air column is compressed and pressurized, the shear nails of the second plugging core at the lower part are sheared off, and the first and second plugging cores descend and separate from the outer tube of the ball seat.

[0021] The square grooves on the side of the guide pipe can divert the high-pressure water jet laterally, reducing the downward impact force of the water jet. The water jet sprays obliquely upward along the square grooves on the side. The high-pressure water jet causes the guide pipe to be subjected to a reverse oblique downward force, offsetting part of the upward force on the injection and production pipe. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Other features, objects and advantages of the present application will become more apparent by reading the detailed description of non-limiting embodiments made with reference to the following drawings:

[0023] Figure 1 It is a schematic diagram of the internal structure of some embodiments of the present application;

[0024] Figure 2 is an external schematic diagram of some embodiments of the present application;

[0025] Figure 3 It is a schematic diagram of the position of the first core plugging cone cap in some embodiments of the present application.

[0026] In the figure: 1. outer cylinder; 2. cone cap of first plugging core; 3. shear ring of first plugging core; 4. soluble plugging ball; 5. first plugging core; 6. shear pins of second plugging core; 7. second plugging core; 8. flow guide tube. DETAILED DESCRIPTION

[0027] The present application will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the relevant invention, rather than to limit the invention. It should also be noted that, for ease of description, only the parts related to the relevant invention are shown in the accompanying drawings.

[0028] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0029] like Figure 1-Figure 3 As shown, the present invention provides an air spring buffer ball seat for a compressed air energy storage well, comprising an outer tube 1, a first plugging core 5, a first plugging core cone cap 2 and a second plugging core 7.

[0030] A main channel is opened in the middle of the outer tube 1 along the axial direction and the inner wall of the main channel is provided with steps. The first plugging core 5 is arranged in the main channel of the outer tube 1. One end of the first plugging core 5 is provided with a groove opened along the axial direction, and the inner wall of the groove is provided with threads. The outer wall of the first plugging core cone cap 2 is provided with steps. The first plugging core cone cap 2 is threadedly connected with the groove of the first plugging core 5. The second plugging core 7 is fixedly arranged in the main channel of the outer tube 1 at one end away from the first plugging core 5.

[0031] During specific implementation, the main channel of the outer tube 1 is opened through along the axial direction, and the inner wall forms a step-like structure. After the first plugging core cone cap 2 and the first plugging core 5 are adapted and installed, they can block the upper part of the main channel of the outer tube 1, and the second plugging core 7 can block the lower part of the main channel. The first plugging core 5 is the upper plugging core, and the second plugging core 7 is the lower plugging core. The two plugging cores are respectively installed at the upper and lower ends of the main channel inside the outer tube 1, and are sealed with rubber rings to form an air cavity inside the outer tube 1. The elastic effect generated by the compression of the air column is used to reduce the impact force generated when the inner core of the ball seat is knocked off, thereby providing safety protection for high-pressure operations and reducing operational risks.

[0032] In some embodiments, one end of the first plugging core cone cap 2 is configured to be conical, and the outer wall of the other end is provided with a thread adapted to the groove of the first plugging core 5 .

[0033] In specific implementation, the first core plugging cone cap 2 is an upper core plugging cone cap, which is installed by a threaded connection method, so that the connection between the first core plugging cone cap 2 and the first core plugging 5 is tighter, and the threaded connection method is easy to install.

[0034] In some embodiments, a first core plugging shear ring 3 is further included, and the first core plugging shear ring 3 is sleeved on the step of the first core plugging cone cap 2 .

[0035] In specific implementation, the first core plugging shear ring 3 is an upper core plugging shear ring, which is inserted from the lower end of the first core plugging cone cap 2 into the step outside the first core plugging cone cap 2, and the lower end of the first core plugging cone cap 2 is threadedly connected to the upper end of the first core plugging 5. When the first core plugging cone cap 2, the first core plugging shear ring 3 and the first core plugging 5 are assembled, the upper end of the ball seat outer tube 1 is inserted into the interior of the ball seat outer tube 1. The first core plugging shear ring 3 is designed according to the construction pressure of the injection and production string, and the high-pressure maximum construction pressure can shear off the first core plugging shear ring 3.

[0036] In some embodiments, second core plugging shear nails 6 are further included, and the outer cylinder 1 is fixedly connected to the second core plugging 7 via the second core plugging shear nails 6 .

[0037] During specific implementation, the second plugging core shear nail 6 is the lower plugging core shear nail. The injection and production string is pressurized to knock off the first plugging core 5 of the ball seat. The first plugging core descends to compress the air column in the same channel of the outer tube 1 of the ball seat. The compression of the air column plays the role of an air spring, slowing down the downward speed of the first plugging core 5. After the air column is compressed and pressurized, it shears off the lower second plugging core shear nail 6.

[0038] In some embodiments, a bypass channel is also opened in the outer tube 1 along the axial direction, and the bypass channel is distributed outside the main channel.

[0039] During specific implementation, there are 6 bypass channels inside the outer tube 1, which are distributed outside the main channel. The ball seat outer tube 1 adopts an inner and outer channel design. The inner main channel and the ball seat plugs at both ends form an air sealing system, and the outer bypass channel is used to ensure smooth flow inside and outside the injection and production string during the lowering of the string.

[0040] In some embodiments, a soluble blocking ball 4 is also included. The soluble blocking ball 4 is arranged at one end of the bypass channel close to the first blocking core 5. The soluble blocking ball 4 can block the bypass channel.

[0041] During specific implementation, after the injection and production string is lowered into place, a corresponding number of soluble plugging balls 4 are put in, and the soluble plugging balls 4 are guided to the ball seat groove of the bypass channel by utilizing the inclined surface outside the first plugging core cone cap 2 to block the bypass channel and provide a bottom seal for the injection and production string.

[0042] In some embodiments, the first plugging core 5 and the second plugging core 7 are respectively installed at two ends of the main channel inside the outer tube 1 , and sealing rubber rings are provided at the connection between the first plugging core 5 and the second plugging core 7 and the outer tube 1 .

[0043] During specific implementation, a sealing rubber ring is provided to improve the sealing effect between the two plugging cores and the inner channel of the outer tube 1 .

[0044] In some embodiments, a flow guide tube 8 is further included. The flow guide tube 8 is coaxially disposed at one end of the outer tube 1 close to the second plugging core 7 , and the flow guide tube 8 is threadedly connected to the outer tube 1 .

[0045] During specific implementation, the high-pressure liquid inside the injection and production string passes downward through the flow guide tube 8 and forms a diversion at the opening on the side of the flow guide tube 8 .

[0046] Furthermore, in the specific implementation, the outer tube 1 of the ball seat adopts an inner and outer two-channel design, and ball seat plugs are installed at the upper and lower ends of the inner channel to form a closed system with the long section of air in the middle part of the inner channel; the outer channel is 6 through holes distributed outside the inner channel, and during the lowering of the injection and production string, the liquid in the well can enter the injection and production string through the outer channel to balance the pressure inside and outside the string; the injection and production string is lowered to the designated position to put in a soluble blocking ball 4, which falls into the top spherical surface of the outer channel under the guidance of the conical surface on the top of the upper ball seat to block the outer channel, so that the entire ball seat blocks the bottom of the injection and production string, and the soluble blocking ball 4 is completely dissolved in the brine environment within 3 days, so that the outer channel is unobstructed.

[0047] After the high-pressure operation is completed inside the injection and production string, the pressure is increased to slightly higher than the operating pressure, the upper plugging core shear ring at the upper end of the inner channel is cut off, and the upper plugging core and the upper plugging core cone cap move downward. After the upper plugging core and the upper plugging core cone cap move downward beyond the sealing surface, a gap is generated between the upper plugging core and the inner channel of the ball seat outer tube, which can balance part of the upper and lower pressure differences of the upper plugging core; the upper plugging core shear ring is cut off by high pressure, and the liquid in the string drives the upper plugging core and the upper plugging core cone cap to move downward rapidly, compressing the air column in the inner channel of the ball seat outer tube. After the air column is compressed, the pressure increases, which plays the role of an air spring and reduces the downward speed of the upper plugging core; the shear force of the shear nail of the lower plugging core is set to 1 / 2 of the shear force of the shear ring of the upper plugging core. When the pressure of the air column increases to the shear force of the shear nail of the lower plugging core, the lower plugging core moves downward and separates from the ball seat outer tube.

[0048] After the upper and lower plugging cores are separated from the outer tube of the ball seat, they fall into the bottom of the well through the guide tube. The high-pressure liquid in the injection and production pipe column is simultaneously sprayed downward through the guide tube. The side of the guide tube 8 is opened at a 45° angle and tilted upward. When the high-pressure liquid passes through the guide tube, part of the liquid is sprayed upward from the square groove. The high-pressure water jet causes the guide tube 8 to be subjected to a reverse downward force, which offsets part of the upward force of the injection and production pipe. The ball seat has a simple structure, and the air spring reduces the impact force at the moment the ball seat is opened, making the ball seat safe and reliable.

[0049] In the description of the present invention, the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and the like indicating directions or positional relationships are based on the directions or positional relationships shown in the drawings, which are only for the convenience of description, and do not indicate or imply that the device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0050] In addition, it should be noted that in the description of the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0051] The term "comprise" or any other similar term is intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus / device that includes a list of elements includes not only those elements but also other elements not expressly listed, or also includes elements inherent to such process, method, article, or apparatus / device.

[0052] So far, the technical solutions of the present invention have been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present invention is obviously not limited to these specific embodiments. Without departing from the principle of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the protection scope of the present invention.

Claims

1. A compressed air energy storage well air spring buffer ball seat, characterized in that: include: The outer cylinder (1) has a main channel opened in the middle along the axial direction and the inner wall of the main channel is provided with steps; A first plugging core (5) is arranged in the main channel of the outer cylinder (1), one end of the first plugging core (5) is provided with a groove opened along the axial direction, and the inner wall of the groove is provided with a thread; A first plugging core cone cap (2), the outer wall of which is provided with a step, and the first plugging core cone cap (2) is threadedly connected to the groove of the first plugging core (5); A second plugging core (7), the second plugging core (7) being fixedly arranged in the main channel of the outer cylinder (1) at one end away from the first plugging core (5); An air cavity is formed inside the outer cylinder (1); One end of the first plugging core cone cap (2) is in a conical shape, and the outer wall of the other end is provided with a thread adapted to the groove of the first plugging core (5); A bypass channel is also provided in the outer cylinder (1) along the axial direction, and the bypass channel is distributed outside the main channel; It also comprises a soluble blocking ball (4), which is arranged at one end of the bypass channel close to the first blocking core (5), and the soluble blocking ball (4) is capable of blocking the bypass channel.

2. The compressed air energy storage well air spring buffer ball seat according to claim 1, characterized in that: It also comprises a first core plugging shear ring (3), wherein the first core plugging shear ring (3) is sleeved on the step of the first core plugging cone cap (2).

3. The compressed air energy storage well air spring buffer ball seat according to claim 1, characterized in that: It also comprises a second core plugging shear pin (6), and the outer cylinder (1) is fixedly connected to the second core plugging (7) via the second core plugging shear pin (6).

4. The compressed air energy storage well air spring buffer ball seat according to claim 1, characterized in that: The first plugging core (5) and the second plugging core (7) are respectively installed at the two ends of the main channel inside the outer cylinder (1), and a sealing rubber ring is provided at the connection between the first plugging core (5) and the second plugging core (7) and the outer cylinder (1).

5. The compressed air energy storage well air spring buffer ball seat according to claim 1, characterized in that: It also comprises a flow guide tube (8), the flow guide tube (8) being coaxially arranged at one end of the outer tube (1) close to the second plugging core (7), the flow guide tube (8) being threadedly connected to the outer tube (1).

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