Energy storage salt cavern creation system and method

Abstract

The present invention relates to the technical field of salt cavern formation, and specifically to a system and method for forming a salt cavern formation for energy storage. The system comprises: a production casing, the outlet end of which is connected to an inclined well section and a vertical well section, the vertical well section extending coaxially with the production casing, the inclined well section being perpendicular to the production casing, and the inclined well section being connected to the production casing via a curved transition section; and a surface casing, which is sleeved outside the production casing. By simultaneously arranging the vertical well section and the inclined well section under the production casing, in conjunction with the inclined well formation system, the salt layer can be dissolved simultaneously at different positions of the upper and lower layers during construction, and then the dissolution cavities of the upper and lower layers are connected, ultimately forming a salt cavern gas storage reservoir with a large cavity in a multi-layered salt mine, greatly simplifying the construction process of formation in the layered salt layer of continental salt lakes, shortening the construction period, and reducing construction costs.

Description

Technical Field

[0001] The present invention relates to the technical field of salt cavern construction, and in particular to an energy storage salt cavern construction system and method. Background Art

[0002] Compressed air energy storage systems offer significant advantages, including large-scale energy storage, high efficiency, long lifespan, easy dispatch, complete pollution-free operation, and minimal water consumption. Typically, the gas storage devices in compressed air energy storage systems utilize underground salt caverns mined through water-soluble mining. Because salt rock has extremely low permeability and excellent creep and damage recovery properties, salt caverns offer a high level of safety as underground energy storage.

[0003] Prior art techniques for caving salt deposits with insoluble interlayers have been to prevent the insoluble interlayers from interfering with the cavitation by fully soaking them, softening them, and then allowing them to collapse naturally. However, my country's salt deposits are primarily continental salt lake layered salt deposits, characterized by multiple interlayers and thick individual interlayers. This makes softening the insoluble interlayers difficult, rendering the salt layer below the interlayer unusable. Summary of the Invention

[0004] Therefore, the technical problem to be solved by the present invention is to overcome the defect of the salt cavern construction method in the prior art that it is difficult to construct when constructing terrestrial salt lake layered salt layers with multiple interlayers or single interlayer thickness, thereby providing an energy storage salt cavern construction system and method.

[0005] In order to solve the above technical problems, the present invention provides an energy storage salt cavern formation system, comprising:

[0006] A production casing, the outlet end of which is connected to a deflection well section and a vertical well section, the vertical well section extending coaxially with the production casing, the deflection well section being perpendicular to the production casing, and the deflection well section being connected to the end of the production casing through a curved transition section;

[0007] The surface casing is sleeved outside the production casing.

[0008] Optionally, a pipe hanger is installed at the inlet end of the production casing.

[0009] Optionally, a central pipe is fixedly mounted on the pipe hanger, and the central pipe extends along the inner cavity of the production casing into the inner cavity of the deflection well section.

[0010] The present invention also provides a method for creating an energy storage salt cavern, which uses the energy storage salt cavern creation system of the present invention, comprising the following steps:

[0011] Installing a first production casing and a second production casing at a predetermined position in the salt cavern, ensuring that the first production casing and the second production casing are parallel to each other;

[0012] A vertical well section and a first deflection well section are excavated at the bottom of the first production casing in the salt cavern, and a second deflection well section is excavated at the bottom of the second production casing, so that the first deflection well section is connected to the bottom of the second production casing, and the second deflection well section is connected to the bottom of the vertical well section;

[0013] The dissolving liquid is introduced into the first inclined well section through the first production casing, and the dissolving liquid is introduced into the second inclined well section through the second production casing, so that the first inclined well section forms an upper dissolving cavity and the second inclined well section forms a lower dissolving cavity; the introduction of the dissolving liquid is maintained until the sediment between the upper dissolving cavity and the lower dissolving cavity falls under the action of gravity, so that the upper dissolving cavity and the lower dissolving cavity are completely connected to form an empty dissolving cavity.

[0014] Optionally, the steps of introducing the dissolving liquid into the first inclination well section through the first production casing and simultaneously introducing the dissolving liquid into the second inclination well section through the second production casing include: extending the first central pipe from the first production casing to the end of the first inclination well section, extending the second central pipe from the second production casing to the end of the second inclination well section, and using the first central pipe and the second central pipe to introduce the dissolving liquid into the first inclination well section and the second inclination well section respectively.

[0015] Optionally, the step of forming the upper dissolution cavity includes pulling out the first central tube so that the outlet end of the first central tube gradually moves away from the second production casing, and the upper dissolution cavity is offset away from the second production casing to form a cavity; the step of forming the upper dissolution cavity includes pulling out the first central tube so that the outlet end of the first central tube gradually moves away from the second production casing, and the upper dissolution cavity is offset away from the second production casing to form a cavity.

[0016] Optionally, the steps of forming an upper dissolution cavity in the first inclined well section and forming a lower dissolution cavity in the second inclined well section include: dissolving the salt cavern with a dissolving liquid to form brine, discharging the brine in the lower dissolution cavity with a first production casing, and discharging the brine in the upper dissolution cavity with a second production casing.

[0017] Optionally, the steps of discharging the brine in the lower dissolution cavity using the first production casing and discharging the brine in the upper dissolution cavity using the second production casing include: regularly injecting cleaning liquid into the first production casing and the second production casing to ensure the cleanliness of the inner walls of the first production casing and the second production casing.

[0018] Optionally, after the step of completely connecting the upper dissolution cavity and the lower dissolution cavity to form an empty dissolution cavity, the method further includes: lowering the first central pipe to the bottom of the empty dissolution cavity to serve as a brine drainage wellhead.

[0019] Optionally, high-pressure gas is injected into the empty dissolution cavity through the second production casing, so that the brine remaining in the empty dissolution cavity is discharged out of the empty dissolution cavity through the first central tube.

[0020] The technical solution of the present invention has the following advantages:

[0021] 1. The energy storage salt cavern system provided by the present invention includes: a production casing, the outlet end of which is connected to a deflection well section and a vertical well section, the vertical well section extends coaxially with the production casing, the deflection well section is perpendicular to the production casing, and the deflection well section is connected to the production casing through a curved transition section; a surface casing, which is sleeved outside the production casing.

[0022] The energy storage salt cavern construction system is designed to work in conjunction with existing auxiliary inclined wells to construct dual-well caverns in continental salt lake layered salt formations with multiple insoluble interlayers or thick single insoluble interlayers. Production casing is installed in the continental salt lake layered salt formations, and a vertical well section and a horizontal inclined well section are excavated beneath the production casing. During construction, the end of the coordinated inclined well is connected to the bottom of the vertical well section, and the end of the inclined well section is connected to the end of the production casing above the coordinated inclined well. Dissolving fluid is introduced into the coordinated inclined well and the inclined well section, respectively, dissolving salt layers at different heights. The dissolved brine is then pumped out of the production casings on both sides, forming two dissolving cavities in the salt formation, one above the other. As the upper and lower cavities continue to expand, the salt layer between them collapses under the action of gravity, connecting the upper and lower cavities to form a single empty cavity for storing compressed air. By setting up a vertical well section and an inclined well section under the production casing at the same time, the salt layer can be dissolved at different positions of the upper and lower layers at the same time during construction, and then the dissolution cavities of the upper and lower layers can be connected, and finally a salt cavern gas storage with a large cavity is formed in the multi-layered salt mine, which greatly simplifies the construction process of cavern construction in the layered salt layers of continental salt lakes, can shorten the construction period and reduce construction costs.

[0023] 2. The energy storage salt cavern formation system provided by the present invention features a central tube fixedly mounted on the pipe hanger. The central tube extends along the inner lumen of the production casing into the inner lumen of the formation well section. By inserting the central tube into the formation well section and using the central tube to introduce dissolving liquid into the formation well section, the position of the dissolving liquid in the formation well section can be controlled, thereby facilitating the control of the formation location of the dissolving cavity.

[0024] 3. The energy storage salt cavern formation method provided by the present invention includes the following steps: installing a first production casing and a second production casing at a predetermined position in the salt cavern to ensure that the first production casing and the second production casing are parallel to each other; digging a straight well section and a first inclined well section at the bottom of the first production casing in the salt cavern, and digging a second inclined well section at the bottom of the second production casing, so that the first inclined well section is connected to the bottom of the second production casing, and the second inclined well section is connected to the bottom of the straight well section; introducing a dissolving liquid into the first inclined well section through the first production casing, and at the same time introducing a dissolving liquid into the second inclined well section through the second production casing, so that the first inclined well section forms an upper dissolving cavity and the second inclined well section forms a lower dissolving cavity; maintaining the introduction of the dissolving liquid until the sediment between the upper dissolving cavity and the lower dissolving cavity falls under the action of gravity, so that the upper dissolving cavity and the lower dissolving cavity are completely connected to form an empty dissolving cavity. By setting up a vertical well section and an inclined well section under the production casing at the same time, the salt layer can be dissolved at different positions of the upper and lower layers at the same time during construction, and then the dissolution cavities of the upper and lower layers can be connected, and finally a salt cavern gas storage with a large cavity is formed in the multi-layered salt mine, which greatly simplifies the construction process of cavern construction in the layered salt layers of continental salt lakes, can shorten the construction period and reduce construction costs.

[0025] 4. The energy storage salt cavern formation method provided by the present invention comprises the step of forming an upper dissolution cavity, comprising: pulling out the first central tube so that the outlet end of the first central tube gradually moves away from the second production casing, thereby offsetting the upper dissolution cavity away from the second production casing; the step of forming an upper dissolution cavity comprises: pulling out the first central tube so that the outlet end of the first central tube gradually moves away from the second production casing, thereby offsetting the upper dissolution cavity away from the second production casing. By offsetting the cavity formation, both the upper and lower dissolution cavities can be extended between the first and second production casings, thereby increasing the horizontal lengths of the upper and lower dissolution cavities and improving the overall volume of the ultimately formed empty dissolution cavity. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0027] Figure 1 It is a schematic structural diagram of the cooperation between the surface casing and the production casing provided in an embodiment of the present invention.

[0028] Figure 2 This is a schematic structural diagram of the energy storage salt cavern creation system provided in an embodiment of the present invention.

[0029] Figure 3This is a schematic diagram of the layout of the energy storage salt cavern cavity making system and the inclined shaft cavity making system in a salt mine provided in an embodiment of the present invention.

[0030] Figure 4 Schematic diagram of the formation process of the upper dissolution cavity and the lower dissolution cavity provided in an embodiment of the present invention.

[0031] Figure 5 Schematic diagram of an empty cavity provided in an embodiment of the present invention.

[0032] Figure 6 Schematic diagram of the upper dissolution chamber and the lower dissolution chamber provided in an embodiment of the present invention.

[0033] Explanation of reference numerals: 1, surface casing; 2, production casing; 3, central pipe; 4, pipe hanger; 5, vertical well section; 6, deflection well section;

[0034] 7. First production casing; 8. Second production casing; 9. First central pipe; 10. Second central pipe; 11. First inclination well section; 12. Second inclination well section; 13. Lower dissolution cavity; 14. Upper dissolution cavity; 15. Empty dissolution cavity; 16. Sediment dissolution cavity; 17. Sediment body.

[0035] HA202208744 DETAILED DESCRIPTION

[0036] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0037] In the description of the present invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely to facilitate and simplify the description of the present invention. They are not intended to indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation, and therefore should not be construed as limitations on the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0038] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0039] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0040] Example 1

[0041] like Figure 1 and Figure 2 The figure shows an energy storage salt cavern formation system provided in this embodiment, which includes a production casing 2 and a surface casing 1.

[0042] The outlet of the production casing 2 is connected to a deflection section 6 and a vertical section 5. The vertical section 5 extends coaxially with the production casing 2, while the deflection section 6 is perpendicular to the production casing 2. The deflection section 6 connects to the end of the production casing 2 via a curved transition section. A surface casing 1 is sleeved over the production casing 2, with cement filling the gap between the surface casing 1 and the production casing 2 to secure them. A pipe hanger 4 is installed at the inlet of the production casing 2. A central pipe 3 is fixed to the pipe hanger 4 and extends along the inner cavity of the production casing 2 into the deflection section 6.

[0043] A casing shoe is installed at the bottom of the surface casing 1. During construction, a drilling rig is first used to drill a hole in the salt mine area, lowering the surface casing 1 into the formation. The rig then continues drilling with the drill bit to the location of the casing shoe and lowers the production casing 2 into the borehole, cementing the well. The rig then continues drilling, carrying the drill bit and using the positioning source to complete the drilling of the curved transition section and the inclination section 6. The rig then withdraws from the inclination section 6 and continues drilling in a straight vertical direction to the designated formation location, completing the construction of the vertical well section 5. Finally, after the combined well is constructed, a spool structure and pipe hanger 4 are installed at the inlet end of the surface casing 1. The central pipe 3 is lowered into the combined well along the inclination section 6. The spool is connected to the production casing 2, and the central pipe 3 is secured by the pipe hanger 4 and separated from the production casing 2. The central pipe 3 is used to introduce the solution into the ground, while the production casing 2 is used to discharge the brine formed by the solution dissolving the salt in the solution cavity.

[0044] During construction, the end of the coordinated inclined well is connected to the bottom of the vertical well section 5, and the end of the inclined well section 6 is connected to the end of the production casing 2 on the coordinated inclined well. Dissolving liquid is introduced into the coordinated inclined well and the inclined well section 6 respectively to dissolve the salt layers at different heights, and the brine after dissolving the salt layers is extracted from the production casing 2 on both sides, so that two dissolution cavities are formed in the upper and lower layers of the salt layer. As the upper and lower dissolution cavities continue to expand, the salt layer between the upper and lower dissolution cavities collapses under the action of gravity, so that the upper and lower dissolution cavities are connected to form an overall empty dissolution cavity for storing compressed air. By setting the vertical well section 5 and the inclined well section 6 at the same time under the production casing 2, the salt layer can be dissolved at different positions of the upper and lower layers at the same time during construction, and then the dissolution cavities of the upper and lower layers are connected, finally forming a salt cavern gas storage with a large cavity in the multi-layer salt mine, which greatly simplifies the construction process of cavern construction in the layered salt layer of continental salt lakes, can shorten the construction period, and reduce construction costs.

[0045] Example 2

[0046] like Figures 3 to 6 The figure shows an energy storage salt cavern making method provided by this embodiment, which applies the energy storage salt cavern making system described in Example 1 and the inclined shaft making system in the prior art to carry out cavern making construction in the salt layer of the continental salt lake layered salt mine. The continental salt lake layered salt mine area is generally composed of the earth, the salt mine roof, the salt mine area and the salt layer bottom plate from top to bottom, and the salt layer roof and the salt layer bottom plate support the salt mine area in the middle. In this embodiment, the first production casing 7 is the production casing in the energy storage salt cavern making system, the first inclined shaft section 11 is the inclined shaft section in the energy storage salt cavern making system, and the first central pipe 9 is the central pipe in the energy storage salt cavern making system; the inclined shaft making system includes a second production casing 8 and a second inclined shaft section 12 connected to the outlet end of the second production casing 8. The energy storage salt cavern making method includes the following steps:

[0047] First, a first production casing 7 and a second production casing 8 are installed at predetermined positions in the salt cavern, ensuring that the first production casing 7 and the second production casing 8 are parallel to each other.

[0048] Then, a vertical well section and a first inclined well section 11 are excavated at the bottom of the first production casing 7 in the salt cavern, and a second inclined well section 12 is excavated at the bottom of the second production casing 8, so that the first inclined well section 11 is connected to the bottom of the second production casing 8, and the second inclined well section 12 is connected to the bottom of the vertical well section.

[0049] Subsequently, a dissolving liquid is introduced into the first inclination well section 11 through the first production casing 7, and a dissolving liquid is introduced into the second inclination well section 12 through the second production casing 8. In this embodiment, clean water is used as the dissolving liquid. In other embodiments, the dissolving liquid can also be other solutions that can dissolve the salt layer. Specifically, a first central pipe 9 is extended from the first production casing 7 to the end of the first inclination well section 11, and a second central pipe 10 is extended from the second production casing 8 to the end of the second inclination well section 12. The first central pipe 9 and the second central pipe 10 are used to introduce a dissolving liquid into the first inclination well section 11 and the second inclination well section 12 respectively. The first inclination well section 11 forms an upper dissolving cavity 14, and the second inclination well section 12 forms a lower dissolving cavity 13. Specifically, the first central pipe 9 is pulled out of the chamber, gradually moving the outlet end away from the second production casing 8, and shifting the upper dissolution cavity 14 away from the second production casing 8 to create a cavity. During the formation of the upper and lower dissolution cavities 14 and 13, the dissolving liquid dissolves the salt cavern to form brine. The brine in the lower dissolution cavity 13 is drained through the first production casing 7, and the brine in the upper dissolution cavity 14 is drained through the second production casing 8. During the process of draining the brine from the lower dissolution cavity 13 through the first production casing 7 and from the upper dissolution cavity 14 through the second production casing 8, cleaning fluid is regularly injected into the first and second production casings 7 and 8 to ensure the cleanliness of the inner walls of the first and second production casings 7 and 8.

[0050] The flow of dissolving liquid and the drainage of brine are maintained until the sediment between the upper and lower dissolving cavities 14, 13 falls due to gravity, completely connecting the upper and lower dissolving cavities 14, 13 to form an empty dissolving cavity 15. After the upper and lower dissolving cavities 14, 13 are completely connected to form an empty dissolving cavity 15, the first central pipe 9 is lowered to the bottom of the empty dissolving cavity 15 to serve as the brine drainage wellhead. High-pressure gas is injected into the empty dissolving cavity 15 through the second production casing 8, causing the remaining brine in the empty dissolving cavity 15 to be discharged through the first central pipe 9 and out of the empty dissolving cavity 15.

[0051] Using the energy storage salt cavern formation system and the inclined well formation system, salt cavern formation can be achieved in a staggered, inclined well. The first inclined well section 11 is positioned relative to the cementing position of the second production casing 8, while the second inclined well section 12 is positioned relative to the vertical well section. The first and second central pipes 9 and 10 are lowered from the first and second production casings 7 and 8 into the first and second inclined well sections 11 and 12, respectively. First, clean water is injected into the first central pipe 9. The second production casing 8 is used to observe for brine discharge. If brine is discharged from the second production casing 8, this indicates that the first inclined well section 11 is connected to the bottom formation position of the second production casing 8. Once brine is discharged from the second production casing 8, the injection of clean water into the first central pipe 9 is stopped. Clean water is then introduced into the second central pipe 10, and the first production casing 7 is observed for significant brine outflow. If significant brine is generated in the first production casing 7, clean water is also injected into the first central pipe 9, and cavern formation begins. During the process of draining brine, clean water is regularly injected into the first production casing 7 and the second production casing 8 to clean the inner wall of the first production casing 7 and the second production casing 8. Finally, by injecting clean water into the first central pipe 9 and the second central pipe 10, the upper and lower staggered dissolution cavities are initially formed, such as Figure 3 According to the amount of brine produced, the first central tube 9 and the second central tube 10 are respectively pulled out so that the position of each dissolution cavity is offset to the position of its own vertical well (along the Figure 4 The specific cavity structure is as follows: Figure 5 As shown. At this time, the upper cavity 14 has not yet been connected to the lower cavity 13, and large pieces of mudstone and gypsum form waste residue and are deposited at the bottom of the two cavities. As the two sets of central tubes continue to move, the upper and lower cavities 13 are finally connected. At this time, the large sediment in the upper cavity 14 will fall into the lower cavity 13 due to gravity, and compact some of the expanded sediment in the lower cavity 13, eventually forming a three-layer structure of empty cavity 15, sediment cavity 16, and sediment body 17, as shown. Figure 6 As shown, the sediment dissolution cavity 16 can serve as a cushion gas storage space. Finally, the first central pipe 9 is lowered to the bottom to form a brine drainage wellhead. The second central pipe 10 is removed to form a gas injection well. High-pressure gas is pumped in through the second production casing 8 to achieve smooth gas injection and brine drainage.

[0052] The salt cavern cavitation method proposed in this embodiment realizes the regular deposition of larger-sized mudstone, sandstone and gypsum in the salt cavern through the cavitation method of staggered inclined wells, and can form a salt cavern gas storage with a large cavity in a multi-interlayer salt mine. The salt cavern cavitation method proposed in this embodiment can shorten the construction period of cavitation construction in a multi-interlayer salt mine, reduce the construction cost of the gas storage reservoir, and reduce the flow loss of high-pressure air in the cavity during the energy release process of the compressed air energy storage system, thereby improving the thermodynamic performance of the energy storage system. The energy storage salt cavern cavitation system and the conventional inclined well cavitation system are used to form a well brine extraction, realize the staggered cavitation inside the salt cavern, and cooperate with the lifting pipe of the central pipe to realize the convergence and connection of the staggered dissolution cavities.

[0053] Obviously, the above embodiments are merely examples for clarity of explanation and are not intended to limit the implementation methods. Those skilled in the art will readily appreciate that other variations or modifications based on the above descriptions are possible. It is not necessary and impossible to enumerate all implementation methods here. Obvious variations or modifications arising therefrom remain within the scope of protection of the present invention.

Claims

1. A method for creating a salt cavern for energy storage, characterized in that: An energy storage salt cavern formation system is used, and the energy storage salt cavern formation system includes: A production casing, the outlet end of which is connected to a deflection well section and a vertical well section, the vertical well section extending coaxially with the production casing, the deflection well section being perpendicular to the production casing, and the deflection well section being connected to the end of the production casing through a curved transition section; A surface casing, which is sleeved outside the production casing; The energy storage salt cavern creation method comprises the following steps: Installing a first production casing and a second production casing at a predetermined position in the salt cavern, ensuring that the first production casing and the second production casing are parallel to each other; A vertical well section and a first deflection well section are excavated at the bottom of the first production casing in the salt cavern, and a second deflection well section is excavated at the bottom of the second production casing, so that the first deflection well section is connected to the bottom of the second production casing, and the second deflection well section is connected to the bottom of the vertical well section; A dissolving liquid is introduced into the first inclination well section through the first production casing, and simultaneously a dissolving liquid is introduced into the second inclination well section through the second production casing, so that the first inclination well section forms an upper dissolving cavity and the second inclination well section forms a lower dissolving cavity; the dissolving liquid is continuously introduced until the sediment between the upper dissolving cavity and the lower dissolving cavity falls under the action of gravity, so that the upper dissolving cavity and the lower dissolving cavity are completely connected to form an empty dissolving cavity; The steps of introducing the dissolving liquid into the first inclination well section through the first production casing and simultaneously introducing the dissolving liquid into the second inclination well section through the second production casing include: extending a first central pipe from the first production casing to the end of the first inclination well section, extending a second central pipe from the second production casing to the end of the second inclination well section, and introducing the dissolving liquid into the first inclination well section and the second inclination well section using the first central pipe and the second central pipe respectively; The step of forming the upper dissolution cavity includes pulling out the first central tube so that the outlet end of the first central tube gradually moves away from the second production casing, thereby offsetting the position of the upper dissolution cavity away from the second production casing to form the cavity; The steps of forming an upper dissolution cavity in the first deflection well section and forming a lower dissolution cavity in the second deflection well section include: dissolving the salt cavern with a dissolving liquid to form brine, discharging the brine in the lower dissolution cavity using a first production casing, and discharging the brine in the upper dissolution cavity using a second production casing; After the upper dissolution cavity and the lower dissolution cavity are completely connected to form an empty dissolution cavity, the method further includes: lowering the first central pipe to the bottom of the empty dissolution cavity to serve as a brine drainage wellhead.

2. The energy storage salt cavern construction method according to claim 1, characterized in that: A pipe hanger (4) is installed at the inlet end of the production casing (2).

3. The energy storage salt cavern construction method according to claim 2, characterized in that: A central pipe (3) is fixedly mounted on the pipe hanger (4), and the central pipe (3) extends along the inner cavity of the production casing (2) into the inner cavity of the deflection well section (6).

4. The energy storage salt cavern construction method according to claim 1, characterized in that: The steps of discharging the brine in the lower dissolution cavity (13) by using the first production casing (7) and discharging the brine in the upper dissolution cavity (14) by using the second production casing (8) include: regularly injecting cleaning liquid into the first production casing (7) and the second production casing (8) to ensure the cleanliness of the inner walls of the first production casing (7) and the second production casing (8).

5. The energy storage salt cavern construction method according to claim 1, characterized in that: High-pressure gas is injected into the empty dissolution cavity (15) through the second production casing (8), so that the brine remaining in the empty dissolution cavity (15) is discharged outside the empty dissolution cavity (15) through the first central tube (9).

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