A salt cavern group sequential displacement mining method based on dynamic production unit

Abstract

The application relates to a salt cavern group sequential displacement mining method based on dynamic production units. A plurality of salt cavities in a mining area are divided into a plurality of dynamic production units, and one brine discharge salt cavity and at least two solution mining salt cavities are arranged in each unit. The solution mining salt cavity and the brine discharge salt cavity in the first unit are connected through a bottom solution mining channel and an upper pressure channel, a solvent is injected into the solution mining salt cavity for solution mining, and brine is discharged from the brine discharge salt cavity. After the solution mining salt cavity reaches a designed mining volume, the solution mining salt cavity is converted into a filling cavity, the solution mining channel is blocked and filled, a positive pressure environment is maintained, and the unsolution-mined salt cavities are connected to realize continuous operation. The solution mining, filling and continuous operation in the unit are repeated, the next unit solution mining salt cavity is connected to realize overlapping and continuous operation, the filling in the current unit is completed, the next unit brine discharge salt cavity is switched, and the operation is repeated until the mining area is mined. The application realizes continuous and unitized sequential displacement mining of the salt cavern group, improves mining efficiency and resource utilization rate, and guarantees operation safety and stratum stability.

Description

Technical Field

[0001] This invention relates to the field of salt cavern mining technology, and in particular to a method for sequential replacement mining of salt cavern clusters based on dynamic production units. Background Technology

[0002] Salt rock, as a mineral resource with dual value in both resource extraction and underground space utilization, presents a core technical challenge in the field of mining engineering: its leaching and goaf treatment. The widely distributed layered salt rock deposits in my country generally exhibit geological characteristics such as thin salt layers, well-developed interlayers, and poor integrity. This makes it difficult to form large, regularly shaped, and highly stable solution cavities, thus lacking the economic viability and safety for constructing salt cavern gas storage facilities. The primary objective of mining these types of salt deposits is to obtain brine resources.

[0003] Currently, traditional salt rock mining generally adopts a decentralized well layout and independent mining mode, with large spacing between salt cavities and low well network density. In order to prevent cavity penetration, surrounding rock instability and surface subsidence, a large number of natural salt rock pillars must be reserved between cavities for isolation and support. These pillars cannot be mined and utilized, forming a large number of ineffective rock pillars, resulting in low salt rock resource recovery rate, large drilling workload, limited control range of single wells, and low overall production efficiency.

[0004] In terms of goaf treatment, traditional processes often employ a delayed "mining first, then backfilling" operation mode. The mining and backfilling processes are disconnected and separated in time and space, making parallel operations impossible. This not only further reduces overall mining efficiency but also leads to untimely backfilling, resulting in stress release in the strata and passive control of goaf subsidence, making it difficult to actively regulate surrounding rock deformation and surface subsidence. Furthermore, traditional processes lack a unitized collaborative operation mechanism, making it difficult to continuously connect processes such as leaching, brine removal, and backfilling, thus failing to meet the needs of efficient, green, and safe integrated development of layered salt rock deposits. Summary of the Invention

[0005] To address the aforementioned technical problems, this application provides a method for sequential replacement mining of salt cavern clusters based on dynamic production units.

[0006] The technical solution adopted by this application to solve its technical problem is: a method for sequential replacement mining of salt caverns based on dynamic production units, comprising the following steps: S1. Provide a mining area, and set up multiple salt chambers in the mining area according to a predetermined layout. Divide the multiple salt chambers into several dynamic production units according to a predetermined plan. In each dynamic production unit, designate one salt chamber as a brine discharge salt chamber and the remaining salt chambers as dissolution salt chambers. There are at least two dissolution salt chambers. S2. Connect at least two of the salt extraction chambers and the brine discharge chambers in the first dynamic production unit. The connection between the salt extraction chambers and the brine discharge chambers includes the connection of the salt extraction channel between the bottom of the salt chambers and the connection of the pressure channel at the top of the salt chambers. In the current dynamic production unit, solvent is injected into the salt extraction chamber connected to the brine discharge chamber for salt extraction. The brine produced is discharged through the brine discharge chamber of the current dynamic production unit. S3. In the salt slurry chambers where slurry extraction is being carried out, when at least one of the salt slurry chambers reaches the designed extraction volume, it is converted into a filling chamber, the slurry extraction channel of the filling chamber is blocked, and the filling chamber is filled. The filling chamber is kept in a positive pressure environment through a pressure channel. At the same time, at least one of the salt slurry chambers that has not been slurry extracted is connected to the brine discharge chamber of the current dynamic production unit to achieve continuous operation. S4. Within the current dynamic production unit, as the salt cavities successively reach the designed mining volume and are converted into filling cavities, the above-mentioned salt extraction, filling and follow-up operations are repeated until all salt cavities within the current dynamic production unit have been mined; then, at least one salt cavity in the next dynamic production unit is connected to the current brine discharge cavity for salt extraction, so as to realize the overlapping and follow-up mining operations between adjacent dynamic production units; S5. After all filling cavities in the current dynamic production unit are filled, the dissolution channels between all dissolution cavities in the next dynamic production unit and the current brine discharge cavity are blocked, and the channels are connected to the brine discharge cavity in the next dynamic production unit. The mining of the next dynamic production unit is started, and the mining operations within the dynamic production unit and between adjacent dynamic production units are repeated until all dynamic production units in the mining area are mined.

[0007] More specifically, by implementing differentiated solvent injection flow rates and / or injection concentrations for different salt cavities, the dissolution rate of different salt cavities is adjusted so that each salt cavity reaches the designed mining volume in a preset order.

[0008] More specifically, during the filling operation, by adjusting the brine discharge rate of the brine discharge chamber, a positive pressure environment is maintained inside the filling chamber. The pressure of the positive pressure environment is higher than the formation hydrostatic pressure and lower than the formation fracturing pressure.

[0009] More specifically, the pressure P of the positive pressure environment satisfies: P 静水 <P≤0.8P 破裂 , Among them, P 静水 P is the formation hydrostatic pressure. 破裂 This refers to the formation fracturing pressure.

[0010] More specifically, the filling operation uses an alkali slag-based slurry for filling. The alkali slag-based slurry is composed of alkali slag material and water, and the weight ratio of the alkali slag material to water is 1:0.8-1:1.2.

[0011] More specifically, the alkali slag material includes alkali slag, fly ash, and cement, with a weight ratio of alkali slag: fly ash: cement of 7:2:1.

[0012] More specifically, the predetermined layout is a quincunx pattern, and the brine discharge chamber is located at the center of multiple dissolving and mining chambers; the spacing between the wells above each of the chambers is not less than 150m.

[0013] More specifically, the multiple dynamic production units are arranged along the direction of minimum principal stress or the direction of main fracture development in the mining area's geostress field.

[0014] More specifically, the continuous operation and overlapping continuous operation include, while the salt slurry cavity reaches the designed mining volume and is converted into a filling cavity to start the filling operation, using directional drilling technology to realize the connection of the salt slurry cavity and the brine discharge cavity through the slurry channel and the pressure channel.

[0015] The beneficial effects of this application are: adopting unitized dense well layout and sequential operation to significantly reduce ineffective rock columns and improve the recovery rate of salt rock resources; forming a continuous production process through parallel operation of leaching and backfilling, significantly improving mining efficiency and reducing the overall cost of drilling and operation; at the same time, relying on the regulation of brine discharge rate to achieve positive pressure control of the backfilling cavity, transforming the traditional passive delayed backfilling into active synchronous backfilling, which can actively stabilize the surrounding rock, control formation subsidence and surface deformation, and realize the resource utilization of solid waste in conjunction with alkali slag-based backfilling slurry, ultimately achieving safe, efficient and green integrated development of salt rock resources. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the process of the sequential replacement mining method for salt caverns based on dynamic production units according to the present invention; Figure 2 This is a schematic diagram of the plum blossom-shaped layout of the salt chamber within the dynamic production unit of this invention; Figure 3 This is a schematic diagram of the connection structure between the salt extraction chamber and the brine discharge chamber of the present invention; Figure 4 This is a schematic diagram of the three dynamic production units of the present invention: melting and extraction, filling, continuous operation, and overlapping continuous operation.

[0017] In the diagram: 100, Dynamic Production Unit; 10, Salt Dissolution Chamber; 20, Brine Discharge Chamber; 30, Salt Dissolution Channel; 40, Pressure Channel. Detailed Implementation

[0018] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. The direction of movement is also relative and is not limited to an absolute direction of movement. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0020] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances. Furthermore, the technical features involved in the different embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0021] like Figure 1-4 The present invention proposes a sequential replacement mining method for salt caverns based on dynamic production units. By dividing multiple salt caverns into dynamic production units (100), dynamically converting the functions of the caverns, conducting parallel operations of leaching and filling, actively regulating the positive pressure of the filling cavity, and conducting overlapping and continuous operations between units, it achieves efficient leaching and extraction of salt rock resources, continuous brine production, timely filling of goaf areas, and coordinated control of long-term formation stability. It is particularly suitable for layered salt rock deposits with thin salt layers, widespread interlayer development, weak integrity of the salt rock mass, and difficulty in constructing large-scale salt cavern gas storage facilities, where brine resource extraction is the main development objective. It can overcome the technical defects of traditional salt mining methods, such as low resource recovery rate, large drilling investment, low production efficiency, serious disconnect between mining and filling processes, passive control of formation subsidence and surrounding rock deformation, and difficulty in ensuring the long-term stability of goaf areas.

[0022] Before formally implementing the mining method described in this application, a comprehensive and detailed geological exploration and engineering condition analysis of the target mining area is required. This will provide reliable data support and theoretical basis for subsequent mining area division, well network layout, construction of dynamic production units 100, design of injection and production parameters, and selection of filling technology. Geological exploration should comprehensively employ various technical means such as geological mapping, borehole exploration, geophysical logging, core sampling tests, in-situ stress testing, and formation pressure monitoring to systematically obtain the spatial occurrence characteristics of salt layers, rock physical and mechanical parameters, formation fluid conditions, and distribution patterns of the stress field within the mining area. Suitable mining areas should be identified, overall mining boundaries delineated, and key technical parameters such as the salt cavity design volume, salt cavity spacing, drilling layout, scale of dynamic production units 100, and mining advance direction determined to ensure operational safety and formation stability throughout the entire mining cycle.

[0023] Based on the completion of geological exploration and parameter analysis, a unified mining area plan, well network layout, and dynamic production unit division were carried out for the entire mining area. First, the mining area was divided into multiple continuously operating mining areas, with a sufficiently wide isolation zone reserved between the mining areas. Permanent isolation pillars were set at the boundaries of each mining area. The purpose of the isolation pillars is to block the transmission of internal stress from the mining area to the outside, prevent mutual disturbance between mining operations in adjacent mining areas, prevent the goaf from expanding beyond the boundary, and protect surface buildings and the ecological environment from the impact of mining.

[0024] Within each mining area, the salt cavities can be laid out in various predetermined patterns, such as... Figure 2 As shown in this application, a dense, quincunx-shaped layout is used for drilling. This quincunx layout allows for more uniform stress distribution and smoother stress transmission between cavities. Compared to traditional rectangular or dispersed layouts, it significantly reduces the number of ineffective rock columns between salt cavities and improves the overall recovery rate of salt resources. Based on the quincunx-shaped well network, and with a structure of one brine discharge cavity 20 and multiple dissolution and production cavities 10, all salt cavities in the mining area are divided into several independently operating and sequentially connected dynamic production units 100. Within each dynamic production unit 100, one salt cavity is designated as the brine discharge cavity 20, and the remaining cavities are designated as dissolution and production cavities 10. The brine discharge cavity 20 is located at the geometric center of the dissolution and production cavities 10 within the corresponding dynamic production unit 100, ensuring that the distance from the brine discharge cavity 20 to each dissolution and production cavity 10 is basically uniform, facilitating brine collection and pressure transmission.

[0025] The spacing between surface wells above each salt cavity is no less than 150m. This spacing ensures that the cavities do not break through prematurely during the leaching and expansion process, while also minimizing the distance between cavities and reducing the number of unminable salt rock pillars left between them. Multiple dynamic production units 100 are sequentially arranged along the direction of the minimum principal stress in the geostress field within the mining area. This ensures that the leaching and expansion direction and the direction of filling stress in the salt cavities are consistent with the direction of formation stress, reducing the risk of tensile failure, shear failure, and creep deformation of the surrounding rock, and improving the overall stability and long-term safety of the salt cavern group.

[0026] After completing the mining area planning and dividing the dynamic production unit 100, the process enters the construction and initial leaching and mining stage of the first dynamic production unit 100. This stage marks the starting point of the entire sequential replacement mining process. The brine discharge chamber 20 and each leaching and mining chamber 10 are connected underground via directional drilling technology, such as... Figure 3 The connection operation shown is divided into two parts. The first part is the connection of the dissolution and extraction channel 30 at the bottom of the salt cavity. The dissolution and extraction channel 30 is located at the bottom of the salt cavity and is used for the collection and flow of brine after the salt rock is dissolved. The second part is the connection of the pressure channel 40 at the top of the salt cavity. It is mainly used to realize the pressure transmission between the brine discharge salt cavity 20 and the corresponding dissolution and extraction salt cavity 10, and to provide a stable pressure transmission path for the positive pressure control in the subsequent filling stage, so that the pressure inside the filling cavity can be indirectly adjusted by the brine discharge rate.

[0027] After completing the underground passage connection and the installation of the surface injection and extraction system, the initial leaching and extraction operation is officially launched. First, at least two leaching and extraction salt chambers 10 within the first dynamic production unit 100 are selected as the first batch of leaching and extraction salt chambers 10. Solvent is continuously injected into the first batch of leaching and extraction salt chambers 10 through the surface injection pump station and injection well. After entering the leaching and extraction salt chambers 10, the solvent flows downward under the action of gravity and injection pressure difference and makes full contact with the salt rock surface. The salt rock gradually dissolves under the action of the solvent and forms high-concentration brine, which accumulates at the bottom of the leaching and extraction salt chambers 10 and flows through the bottom leaching and extraction channel 30 to the brine discharge salt chamber 20 in the center. Finally, under the action of pump suction, it is lifted by the well of the brine discharge salt chamber 20 to the surface brine collection and treatment system, realizing continuous water injection leaching and extraction and centralized brine discharge, forming a multi-injection and one-discharge production structure. The solvent mentioned in this application can be fresh water or brine with a certain concentration and unsaturation.

[0028] In actual operation, a higher injection flow rate is used for the corresponding salt extraction chamber 10 to reduce the real-time salt concentration in the salt extraction chamber 10, expand the concentration difference, and increase the dissolution mass flux, so that it can quickly reach the designed mining volume; a lower injection flow rate is used for subsequent salt extraction chambers 10 to increase the real-time salt concentration in the salt extraction chamber 10, narrow the concentration difference, reduce the dissolution mass flux, and delay the reaching of the designed mining volume, thereby controlling the leaching progress of each salt extraction chamber 10 and realizing the sequential conversion and orderly succession of salt chamber functions.

[0029] Once the corresponding salt-mining chamber 10 within the first dynamic production unit 100 reaches the designed mining volume, the salt chamber function conversion and the new salt chamber connection operation will be executed immediately.

[0030] The salt extraction chamber 10, which has completed its extraction task, is converted into a filling chamber. Its extraction function is stopped, and its filling function is started. At the same time, the pressure pipeline between the filling chamber and the brine discharge chamber 20 is kept connected. The specific implementation process is as follows: First, the injection valve of the salt extraction chamber 10 is closed to stop the solvent injection operation. Then, the bottom extraction channel 30 between the salt extraction chamber 10 and the brine discharge chamber 20 is sealed using downhole sealing technology to block the brine flow path. The pressure channel 40 at the top of the salt extraction chamber 10 is retained to maintain the pressure transmission relationship between the salt extraction chamber 10 and the brine discharge chamber 20. After sealing is completed, the salt cavity is converted from the dissolution and extraction cavity 10 into a filling cavity, entering the filling preparation stage. Simultaneously, at least one new dissolution and extraction cavity 10 is started, using directional drilling technology for rapid drilling to connect the brine discharge cavity 20 with the next dissolution and extraction cavity 10 to be mined within the dynamic production unit 100. A bottom dissolution and extraction channel 30 and an upper pressure channel 40 are established respectively. Once the connection is completed, the dissolution and extraction operation of the new dissolution and extraction cavity 10 is immediately started, ensuring that at least two of the aforementioned dissolution and extraction cavities 10 are always in a synchronous dissolution and extraction state within the entire dynamic production unit 100, ensuring continuous and uninterrupted brine production. After the new dissolution and extraction cavity 10 is completed, a parallel operation pattern of filling, dissolution and extraction, and centralized brine discharge is formed within the dynamic production unit 100. The dissolution and extraction process and the filling process proceed synchronously, without interference, and in coordination.

[0031] After the filling cavity enters the formal filling operation, it is filled with an alkali-slag-based filling slurry for compaction. The alkali-slag-based filling slurry is composed of alkali slag material and water, with a weight ratio of 1:0.8-1:1.2. The alkali slag material includes alkali slag, fly ash, and cement, with a weight ratio of alkali slag:fly ash:cement of 7:2:1. At the surface slurry preparation station, alkali slag, fly ash, and cement are weighed in sequence according to the design ratio. They are first dry-mixed to ensure uniform mixing, and then a fixed amount of clean water is added according to the set ratio. The mixture is continuously stirred by a high-speed slurry mixer to ensure that the slurry is free of lumps and segregation, has uniform density, and meets the fluidity standards. After the slurry preparation is completed, the slurry is pressurized and transported to the underground filling cavity through a filling pump to ensure that the slurry enters the filling cavity smoothly and diffuses evenly without leaving voids or gaps. After the filling grout gradually solidifies and hardens within the cavity, it forms a solid support, providing continuous, reliable, and long-term support for the surrounding rock, reducing the amount of ineffective rock pillars left behind, and improving the recovery rate of salt rock resources.

[0032] Throughout the filling operation, this application indirectly controls the internal pressure of the filling chamber by adjusting the brine discharge rate of the brine discharge chamber 20 in the wellbore, ensuring that the filling chamber maintains a stable, safe, and controllable positive pressure environment. This application maintains a slightly positive pressure environment to control both formation stability and filling effectiveness. The pressure value P of the positive pressure environment satisfies the following constraints: P 静水 <P≤0.8P 破裂 , Among them, P 静水 P is the formation hydrostatic pressure. 破裂 This refers to the formation fracturing pressure.

[0033] Controlling the pressure in the filling cavity to no more than 0.8 times the formation fracture pressure can prevent safety risks such as tension failure between the salt rock and the surrounding rock, fracture expansion, brine leakage, and formation cross-contamination caused by excessive pressure inside the filling cavity.

[0034] In actual control, the pressure inside the filling cavity is monitored in real time by downhole pressure sensors. The monitoring data is transmitted to the ground control terminal in real time. Based on the preset pressure threshold, the opening of the brine discharge valve in the brine discharge chamber 20 is automatically adjusted, thereby changing the brine discharge rate and realizing closed-loop pressure control. When the monitored pressure is lower than the set lower limit, the brine discharge valve is automatically closed to reduce the brine discharge rate, allowing the pressure in the filling cavity to gradually rise. When the monitored pressure is higher than the set upper limit, the brine discharge valve is automatically opened to increase the brine discharge rate, allowing the pressure in the filling cavity to gradually decrease. When the pressure is within the target range, the brine discharge rate is kept stable to maintain the pressure at a constant level. Through the above regulation, the filling slurry can be filled more densely and tightly connected to the roof under the action of micro-positive pressure. The contact between the filling slurry and the surrounding rock is more sufficient, and the support effect is more significant.

[0035] Within the current dynamic production unit 100, the process proceeds in a complete sequence: leaching, reaching the designed volume, functional conversion, compaction filling, new cavity connection, and continued leaching, thereby achieving the sequential replacement of all salt cavities within the current dynamic production unit 100. During this process, the leaching salt cavity 10 that completes leaching first is prioritized for conversion into a filling cavity, and is prioritized for filling and forming support; ensuring that there are no fewer than two leaching salt cavities 10 simultaneously in operation, ensuring continuous brine production and uninterrupted production flow.

[0036] After the last salt extraction chamber 10 in the current dynamic production unit 100 reaches its designed extraction volume, to avoid production interruptions during the switching process of the dynamic production unit 100, this application adopts an overlapping and continuous operation mode between adjacent dynamic production units 100, achieving seamless connection and continuous progress between adjacent dynamic production units 100. In the overlapping and continuous operation, at least one of the salt extraction chambers 10 in the next dynamic production unit 100 is designated as a transition salt chamber, which is preferably located between two adjacent dynamic production units 100. When the current dynamic production unit 100 enters the final filling stage and production operations are nearing completion, the transitional salt extraction chamber 10 is connected to the brine discharge chamber 20 of the current dynamic production unit 100 in advance using directional drilling technology. It is also connected to the brine discharge chamber 20 of the next dynamic production unit 100 (this connection is then sealed to prevent brine from entering the next brine discharge chamber 20). The salt extraction operation of this chamber 10 is then initiated, allowing the mining operations of the next dynamic production unit 100 to commence ahead of schedule, running concurrently with the final filling operation of the current dynamic production unit 100. After the current dynamic production unit 100 is fully filled, the salt extraction channel 30 between the transitional salt extraction chamber 10 and the current brine discharge chamber 20 is sealed. Then, the salt extraction channel 30 between the transitional salt extraction chamber 10 and the brine discharge chamber 20 of the next dynamic production unit 100 is opened, completing the switchover of the production system and officially starting the mining process of the next dynamic production unit 100.

[0037] Through the overlapping and sequential operation mode, there is a period of parallel operation between adjacent dynamic production units 100, eliminating the time loss caused by unit switching. According to the above-mentioned sequential operation within dynamic production units 100 and overlapping and sequential operation between adjacent dynamic production units 100, the mining operation of all dynamic production units 100 in the mining area is completed in sequence until all salt cavities in the mining area are completely leached and filled.

[0038] Throughout the entire process of mining, filling, and overlapping operations, a real-time monitoring and intelligent control system is established both on the surface and underground. This system continuously monitors key parameters, equipment status, formation deformation, and production indicators to ensure operational safety and stable production. The monitoring system mainly includes surface subsidence monitoring, surrounding rock deformation monitoring, internal pressure monitoring of salt cavities, brine flow and concentration monitoring, filling slurry parameter monitoring, and injection and production equipment operating status monitoring.

[0039] Based on the above process, and for easier description, the following example illustrates the progress of this application in detail.

[0040] like Figure 4 Taking three dynamic production units 100 as an example, namely the first dynamic production unit A, the second dynamic production unit B, and the third dynamic production unit C.

[0041] The first dynamic production unit A includes a brine discharge chamber Q1 and salt extraction chambers A1, A2, A3, and A4; The second dynamic production unit B includes the brine discharge chamber Q2 and the salt extraction chambers B1, B2, B3, and B4; The third dynamic production unit C includes the brine discharge chamber Q3 and the salt extraction chambers C1, C2, C3, and C4.

[0042] First, the connection, extraction, and filling operations of the first dynamic production unit A are carried out. The brine discharge chamber Q1 is connected to the extraction chambers A1 and A2. Water is injected into A1 and A2 for extraction, and the produced brine is discharged uniformly through Q1. Once A1 reaches its designed extraction volume, the extraction channel between A1 and Q1 is blocked, A1 is converted into a filling chamber, and filling begins. Simultaneously, Q1 is connected to A3, and extraction of A3 is initiated, ensuring synchronous extraction of A2 and A3. Once A2 reaches its designed extraction volume, the extraction channel between A2 and Q1 is blocked, A2 is converted into a filling chamber, and filling begins. Simultaneously, Q1 is connected to A4, and extraction of A4 is initiated, ensuring synchronous extraction of A3 and A4. Once A3 reaches its designed mining volume, the leaching channel between A3 and Q1 is blocked, and A3 is converted into a filling cavity for filling. At the same time, B1 and Q1 are connected and leaching of B1 is started, so that A4 and B1 are leached synchronously. Once A4 reaches its designed mining volume, the leaching channel between A4 and Q1 is blocked, and A4 is converted into a filling cavity for filling. The first dynamic production unit A enters the final filling stage.

[0043] Simultaneously, the dissolution channels between B1 and Q1 are blocked, B1 is connected to the brine discharge chamber Q2, and Q2 is connected to B2, initiating dissolution of both B1 and B2. The produced brine is discharged uniformly through Q2. Once B1 reaches its designed extraction volume, the dissolution channel between B1 and Q2 is blocked, converting B1 into a filling chamber and initiating filling. Simultaneously, Q2 is connected to B3, initiating dissolution of B3, ensuring synchronous dissolution of B2 and B3. Once B2 reaches its designed extraction volume, the connection between B2 and Q2 is blocked, converting B2 into a filling chamber and initiating filling. Simultaneously, Q2 is connected to B4, initiating dissolution of B4, ensuring synchronous dissolution of B3 and B4. Once B3 reaches its designed mining volume, the leaching channel between B3 and Q2 is blocked, and B3 is converted into a filling cavity for filling. At the same time, C1 is connected to Q2 and leaching of C1 is started, so that B4 and C1 are leached synchronously. Once B4 reaches its designed mining volume, the leaching channel between B4 and Q2 is blocked, and B4 is converted into a filling cavity for filling. The second dynamic production unit B enters the final filling stage.

[0044] Simultaneously, the dissolution channels between C1 and Q2 are blocked, C1 is connected to the brine discharge chamber Q3, and Q3 is connected to C2, initiating dissolution of C1 and C2. The produced brine is discharged uniformly through Q3. Once C1 reaches its designed extraction volume, the dissolution channel between C1 and Q3 is blocked, C1 is converted into a filling chamber and filling begins. Simultaneously, Q3 is connected to C3 and dissolution of C3 is initiated, ensuring synchronous dissolution of C2 and C3. Once C2 reaches its designed extraction volume, the dissolution channel between C2 and Q3 is blocked, C2 is converted into a filling chamber and filling begins. Simultaneously, Q3 is connected to C4 and dissolution of C4 is initiated, ensuring synchronous dissolution of C3 and C4. Once C3 reaches its designed mining volume, the karst channel between C3 and Q3 is blocked, and C3 is converted into a filling cavity for filling. Once C4 reaches its designed mining volume, the karst channel between C4 and Q3 is blocked, and C4 is converted into a filling cavity for filling, thus completing all operations of the third dynamic production unit C. At this point, the three dynamic production units have completed all processes in sequence.

[0045] The above embodiment is two injections per row and one filler. Multiple injections per row and multiple fillers can also be considered as needed, such as three injections per row and one filler, four injections per row and two fillers, etc.

[0046] It should be emphasized that the above are merely preferred embodiments of the present invention and are not intended to limit the present invention in any way. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. A method for sequential replacement mining of salt cavern clusters based on dynamic production units, characterized in that, Includes the following steps: S1. Provide a mining area, and set up multiple salt chambers in the mining area according to a predetermined layout. Divide the multiple salt chambers into several dynamic production units according to a predetermined plan. In each dynamic production unit, designate one salt chamber as a brine discharge salt chamber and the remaining salt chambers as dissolution salt chambers. There are at least two dissolution salt chambers. S2. Connect at least two of the salt extraction chambers and the brine discharge chambers in the first dynamic production unit. The connection between the salt extraction chambers and the brine discharge chambers includes the connection of the salt extraction channel between the bottom of the salt chambers and the connection of the pressure channel at the top of the salt chambers. In the current dynamic production unit, solvent is injected into the salt extraction chamber connected to the brine discharge chamber for salt extraction. The brine produced is discharged through the brine discharge chamber of the current dynamic production unit. S3. In the salt slurry chambers where slurry extraction is being carried out, when at least one of the salt slurry chambers reaches the designed extraction volume, it is converted into a filling chamber, the slurry extraction channel of the filling chamber is blocked, and the filling chamber is filled. The filling chamber is kept in a positive pressure environment through a pressure channel. At the same time, at least one of the salt slurry chambers that has not been slurry extracted is connected to the brine discharge chamber of the current dynamic production unit to achieve continuous operation. S4. Within the current dynamic production unit, as the salt cavities successively reach the designed mining volume and are converted into filling cavities, the above-mentioned salt extraction, filling and follow-up operations are repeated until all salt cavities within the current dynamic production unit have been mined; then, at least one salt cavity in the next dynamic production unit is connected to the current brine discharge cavity for salt extraction, so as to realize the overlapping and follow-up mining operations between adjacent dynamic production units; S5. After all filling cavities in the current dynamic production unit are filled, the dissolution channels between all dissolution cavities in the next dynamic production unit and the current brine discharge cavity are blocked, and the channels are connected to the brine discharge cavity in the next dynamic production unit. The mining of the next dynamic production unit is started, and the mining operations within the dynamic production unit and between adjacent dynamic production units are repeated until all dynamic production units in the mining area are mined.

2. The method for sequential replacement mining of salt caverns based on dynamic production units according to claim 1, characterized in that, By implementing differentiated solvent injection flow rates and / or injection concentrations for different salt cavities, the dissolution rate of different salt cavities is adjusted so that each salt cavity reaches the designed mining volume in a preset order.

3. The method for sequential replacement mining of salt caverns based on dynamic production units according to claim 1, characterized in that, During the filling operation, the brine discharge rate of the brine discharge chamber is adjusted to maintain a positive pressure environment inside the filling chamber. The pressure of the positive pressure environment is higher than the formation hydrostatic pressure and lower than the formation fracture pressure.

4. The method for sequential replacement mining of salt caverns based on dynamic production units according to claim 3, characterized in that, The pressure P of the positive pressure environment satisfies: P 静水 <P≤0.8P 破裂 , Among them, P 静水 P is the formation hydrostatic pressure. 破裂 This refers to the formation fracturing pressure.

5. The method for sequential replacement mining of salt caverns based on dynamic production units according to claim 1, characterized in that, The filling operation uses an alkali slag-based slurry, which is made by mixing alkali slag material with water in a weight ratio of 1:0.8 to 1:1.

2.

6. The method for sequential replacement mining of salt caverns based on dynamic production units according to claim 5, characterized in that, The alkaline residue material includes alkaline residue, fly ash, and cement, with a weight ratio of alkaline residue: fly ash: cement of 7:2:

1.

7. The method for sequential replacement mining of salt caverns based on dynamic production units according to claim 1, characterized in that, The predetermined layout is a quincunx pattern, with the brine drainage chamber located at the center of multiple salt extraction chambers; the spacing between wells above each salt chamber is not less than 150m.

8. The method for sequential replacement mining of salt caverns based on dynamic production units according to claim 1, characterized in that, Multiple dynamic production units are arranged to advance along the direction of minimum principal stress or the direction of main fracture development in the mining area's geostress field.

9. The method for sequential replacement mining of salt caverns based on dynamic production units according to claim 1, characterized in that, The continuous operation and overlapping continuous operation include, at the same time as the salt slurry cavity reaches the designed mining volume and is converted into a filling cavity to start the filling operation, using directional drilling technology to realize the connection of the salt slurry cavity and the brine discharge cavity through the slurry channel and the pressure channel.

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