Twin-well brine mining device capable of increasing salt mine brine ore content and multi-well series connection method of twin-well brine mining device

Abstract

The invention relates to the technical field of well mine salt mining, in particular to a twin-well brine mining device capable of increasing salt mine brine content and a multi-well series connection method thereof, the device comprises a newly-built well unit, a single-well convection brine mining process is set, and the newly-built well unit comprises a water injection well and a brine mining well; the old well unit adopts a twin-well convection brine extraction process and comprises a water injection well and a brine extraction well; the pipeline connecting system is used for communicating the brine extraction well of the newly-built well unit with the water injection well of the old well unit; the flow adjusting device is arranged on the pipeline connecting system and used for adjusting the flow in the pipeline; the central control system is used for monitoring and adjusting operation parameters of each well group; by establishing a series system between the newly-built well and the old well, graded utilization and circulation optimization of brine resources are achieved, a traditional independently-operated well group is converted into an organic whole for cooperative production, low-concentration brine generated during the groove building period of the newly-built well can be secondarily utilized by the old well, and therefore the utilization rate of the resources is remarkably increased.

Description

Technical Field

[0001] The present invention relates to the technical field of well salt mining, in particular to a double-well brine mining device capable of increasing the brine content of salt mines and a multi-well series connection method thereof. Background Art

[0002] The drilling water solution mining method is a mining method in which solvents and water are injected into the dissolution chamber of the mined ore layer through drilling when mining salt deposits, and dissolution is carried out on site to generate brine rich in the mined mineral components, and then the brine is extracted from the drilled well.

[0003] In traditional salt mine brine mining systems, old wells and newly built wells usually operate independently and lack a collaborative optimization mechanism, resulting in the ineffective utilization of a large amount of low-concentration brine produced during the construction of new wells and trenches, causing waste of resources. In addition, conventional constant-pressure water injection methods are difficult to adapt to the heterogeneous characteristics of salt layers, which can easily lead to uneven development of dissolution cavities, thus affecting mining efficiency.

[0004] Therefore, in order to address the above-mentioned problems of low multi-well coordination efficiency and inaccurate dissolution cavity control, the present invention proposes a dual-well brine extraction device and a multi-well series connection method that can increase the brine content of salt mines. By establishing a dynamic connection mechanism between new wells and old wells, the hierarchical utilization of brine resources is achieved, and gradient boosting water injection technology is used to ensure uniform development of dissolution cavities. Summary of the Invention

[0005] In order to overcome the problems of low multi-well coordination efficiency and inaccurate cavity control in traditional salt mine brine mining systems, the present invention proposes a dual-well brine mining device and a multi-well series connection method thereof that can improve the brine content of salt mines.

[0006] The technical solution of the present invention is: a dual-well brine extraction device capable of increasing the brine content of salt mines, comprising:

[0007] New well units are built, with a single-well convection brine extraction process, including water injection wells and brine extraction wells;

[0008] The old well unit is set up with a double-well convection brine extraction process, including a water injection well and a brine extraction well;

[0009] Pipeline connection system, used to connect the brine production wells of the new well unit with the water injection wells of the old well unit;

[0010] A flow regulating device is provided on the pipeline connection system and is used to regulate the flow in the pipeline;

[0011] The central control system is used to monitor and adjust the operating parameters of each well group.

[0012] Preferably, the newly built well unit is configured as a single-well convection structure, including a central water injection pipe and an annular brine outlet channel, wherein the central water injection pipe is made of a high-strength alloy steel pipe, and a porous injection head is provided at its lower end to promote uniform distribution of water flow. The annular brine outlet channel is composed of an annular space between the wellbore and the central pipe, the inner wall of the channel is lined with corrosion-resistant composite materials, and the upper part is connected to a rotary gas-liquid separator to remove free gas in the brine. The water injection pipe is connected to the ground fresh water source through a high-pressure hose, and a quick-disassembly flange is provided at the connection. An anti-backflow device is installed at the interface between the brine outlet channel and the pipeline connection system. The single-well convection structure can form a uniformly expanded dissolution cavity space through the circulation mode of central water injection and annular brine outlet.

[0013] Preferably, the old well unit is configured as a double-well convection structure, including an injection well and a brine production well that are interconnected, wherein the injection well is equipped with an adjustable-speed submersible pump, the pump body is made of duplex stainless steel, and the pumping pressure can be steplessly adjusted according to the condition of the dissolution cavity; a multi-stage filtration device is installed in the brine production well, the filter screen is configured as a trapezoidal cross-section, and the filtration accuracy can be adjusted online; the connecting channel between the two wells is an artificially constructed horizontal well section, and the brine production well is connected to the water injection system of the newly built well unit through a pipeline connection system, and a three-way switching valve group is provided at the connection point. The entire system is equipped with vibration monitoring and corrosion detection devices.

[0014] Preferably, the pipeline connection system includes a high-pressure corrosion-resistant main pipeline, a branch connection pipeline and a quick-connect flange, wherein the main pipeline is configured as a composite pipe wall structure, the inner layer is an ultra-high molecular weight polyethylene wear-resistant lining, the middle is a glass fiber reinforced layer, and the outer layer is an anti-UV PVC protective cover, the branch connection pipeline is configured as a flexible metal hose structure, and is equipped with a universal adjustment joint, the quick-connect flange is provided with a hydraulically driven clamp for connection, equipped with a self-tightening sealing ring and a status indicator, the anti-crystallization coating on the inner wall of the main pipeline is composed of a specially formulated fluoropolymer, which is used to prevent salt crystallization and deposition in the brine, the temperature compensator equipped with the branch pipeline is configured as a bellows structure, which is used to eliminate pipeline stress caused by temperature changes, the entire pipeline system is arranged with multiple sampling ports and cleaning ports along the way, and is configured as a modular design, and the system is also integrated with a pressure fluctuation absorption device to suppress the water hammer effect.

[0015] Preferably, the flow regulating device includes an electric regulating valve group, a flow sensor, a pressure buffer and an emergency manual operating mechanism, wherein the electric regulating valve group is a multi-valves arranged in parallel, the main regulating valve is an intelligent electric ball valve equipped with a high-precision stepper motor drive, the spare valve is a pneumatic diaphragm regulating valve, the flow sensor uses the contact ultrasonic measurement principle, there is no flow-blocking component in the measuring tube, the pressure buffer is an accumulator structure, the effective volume is 10% of the instantaneous flow of the pipeline, and the internal pressure is filled with an adjustable pressure nitrogen cushion, the multi-stage throttling design of the electric regulating valve includes a front fixed throttling orifice and a rear adjustable V-type throttling port, the emergency manual operating mechanism adopts a worm gear drive, which is used to adjust the flow through a handwheel in the event of a power outage, the entire device is equipped with an explosion-proof casing and an anti-corrosion coating, and the control system adopts a PID+fuzzy control algorithm.

[0016] Preferably, the multi-well series connection method of the dual-well brine extraction device includes the following steps:

[0017] S1, connect the brine extraction outlet of the newly built well unit to the water injection inlet of the old well unit through a pipeline system;

[0018] S2, start the water injection system of the newly built well unit to carry out cavity construction;

[0019] S3, adjusts the flow in the connecting pipeline to maintain stable production of the old well unit;

[0020] S4, monitoring the brine concentration of the newly built well unit and connecting it to the production system after reaching the predetermined value;

[0021] S5, continuously optimize the operating parameters of each well group to achieve system synergy and efficiency.

[0022] Preferably, the cavity construction stage of the newly built well unit is set to a gradient boosted water injection method, which divides the entire trench construction process into three stages: the initial stage uses a low-pressure, low-flow water injection mode, the injection pressure is controlled at a low level, and the flow rate is maintained at a small value, which is used to form an initial dissolution channel in the salt layer and establish a basic hydraulic connection; the intermediate stage uses medium pressure and flow for water injection, at which time the cavity begins to gradually expand, and the injection parameters increase linearly with the increase in the cavity volume; the final stage uses the designed working pressure and maximum flow for water injection, so that the cavity quickly reaches the target size, and the cavity development is monitored in real time during this process. The three-dimensional morphological data of the cavity is obtained through the downhole camera system and the acoustic ranging device, and the water injection parameters are dynamically adjusted accordingly. The conversion timing of each stage is comprehensively judged based on the real-time monitoring of the brine concentration change rate and the injection pressure fluctuation.

[0023] Preferably, the brine concentration at each node is monitored in real time during system operation, and the flow distribution ratio between the newly built well unit and the old well unit is dynamically adjusted according to the concentration change; the device is equipped with an online density meter and a conductivity meter at the key node of the pipeline connection system, and the brine concentration data is collected once a minute. The data is transmitted to the central control system through the industrial bus. The system has a built-in intelligent distribution algorithm. When the brine concentration of the newly built well unit is lower than the set threshold, the system automatically increases the proportion of brine flowing to the old well unit, and uses the residual dissolution capacity of the old well to further increase the brine concentration. When the brine concentration of the old well unit decreases, its distribution flow is reduced accordingly to extend the residence time of the brine in the dissolution cavity. The flow distribution ratio is adjusted by adjusting the electric regulating valves on each branch. The adjustment range is calculated according to the preset algorithm based on the concentration deviation value. At the same time, the system will record historical operation data and optimize the distribution strategy through machine learning algorithms to keep the brine production and concentration of the entire system at the optimal balance point.

[0024] Preferably, the residence time of the brine in the dissolution cavity is controlled by adjusting the flow in the connecting pipe to optimize the dissolution efficiency; based on the dissolution kinetics of the salt mine, a mathematical model of the residence time and dissolution efficiency is established to determine the optimal residence time range; during operation, the brine flow rate is adjusted to the design value by precisely controlling the flow regulating valve in the pipeline system, so that the actual residence time of the brine in the dissolution cavity is controlled within the optimal range; the system is equipped with a high-precision timing device and a flow meter for calculating the time it takes for the brine to pass through the dissolution cavity in real time; when it is detected that the residence time deviates from the set value, the system adjusts the opening of the relevant valve for correction; for different ore layer sections, differentiated residence time parameters are set according to the purity and structural characteristics of the salt rock; when encountering a high-purity salt layer, a pulse flow regulation method can be temporarily adopted to enhance the dissolution effect by periodically changing the flow rate.

[0025] Preferably, the system is provided with an emergency operation mode. When any well group is detected to be abnormal, the system automatically switches to an independent operation state. The system is provided with a parameter safety monitoring network, including a wellbore pressure sensor, a flow mutation detector and a brine leakage alarm, which is used to collect the operation status data of each well group in real time. The central control system has a built-in intelligent diagnosis module. When any parameter is detected to exceed the safety threshold, the emergency response program is immediately started. The emergency switching process is divided into three stages: first, quickly adjust the relevant valves to cut off the connection between the abnormal well group and other well groups, then adjust the operating parameters of the remaining well groups, and finally start the backup equipment to maintain basic production. The entire switching process can be completed within 2 minutes, and the water hammer effect is avoided by the pressure buffer device and the flow gradient control during the switching process. During the emergency mode operation, the system will continue to diagnose the cause of the fault and provide treatment suggestions. After the fault is eliminated, the original operation mode can be restored with one click.

[0026] Beneficial effects of the present invention:

[0027] 1. By establishing a series system between new wells and old wells, the hierarchical utilization and circulation optimization of brine resources are realized, and the traditional independently operated well groups are transformed into an organic whole with coordinated production. The low-concentration brine produced during the construction of new wells can be reused by old wells, thereby significantly improving the utilization rate of resources and effectively solving the serious resource waste problem in traditional mining methods.

[0028] 2. Gradient pressure injection technology ensures the uniform development and stable expansion of the solution cavity by precisely controlling the injection parameters in stages, shortens the time of solution cavity formation, and makes the solution cavity morphology more regular and complete. It not only improves the production capacity of single wells, but also greatly reduces the risk of solution cavity collapse, extends the service life of the well group, and lays a good foundation for subsequent efficient mining. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 What is shown is a schematic diagram of the workflow of the present invention;

[0030] Figure 2 Shown is a schematic diagram of the emergency treatment process of the present invention. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative work are within the scope of protection of the present invention.

[0032] The present invention provides an embodiment: a dual-well brine extraction device capable of increasing the brine content of salt mines, comprising:

[0033] New well units are built, with a single-well convection brine extraction process, including water injection wells and brine extraction wells;

[0034] The old well unit is set up with a double-well convection brine extraction process, including a water injection well and a brine extraction well;

[0035] Pipeline connection system, used to connect the brine production wells of the new well unit with the water injection wells of the old well unit;

[0036] A flow regulating device is provided on the pipeline connection system and is used to regulate the flow in the pipeline;

[0037] The central control system is used to monitor and adjust the operating parameters of each well group.

[0038] Furthermore, the newly built well unit is configured as a single-well convection structure, including a central water injection pipe and an annular brine outlet channel, wherein the central water injection pipe is made of a high-strength alloy steel pipe, and a porous injection head is provided at its lower end to promote uniform distribution of water flow. The annular brine outlet channel is composed of an annular space between the wellbore and the central pipe, the inner wall of the channel is lined with corrosion-resistant composite materials, and the upper part is connected to a rotary gas-liquid separator to remove free gas in the brine. The water injection pipe is connected to the ground fresh water source through a high-pressure hose, and a quick-disassembly flange is provided at the connection. An anti-backflow device is installed at the interface between the brine outlet channel and the pipeline connection system. The single-well convection structure can form a uniformly expanded dissolution cavity space through the circulation mode of central water injection and annular brine outlet.

[0039] Furthermore, the old well unit is set up as a double-well convection structure, including interconnected water injection wells and brine production wells. The water injection well is equipped with an adjustable-speed submersible pump. The pump body is made of duplex stainless steel, and the pumping pressure can be adjusted steplessly according to the condition of the dissolution cavity. A multi-stage filtration device is installed in the brine production well. The filter screen is set to a trapezoidal cross-section, and the filtration accuracy can be adjusted online. The connecting channel between the two wells is an artificially constructed horizontal well section. The brine production well is connected to the water injection system of the newly built well unit through a pipeline connection system. A three-way switching valve group is provided at the connection. The entire system is equipped with vibration monitoring and corrosion detection devices.

[0040] Furthermore, the pipeline connection system includes a high-pressure corrosion-resistant main pipeline, a branch connection pipeline and a quick-connect flange, wherein the main pipeline is configured as a composite pipe wall structure, the inner layer is an ultra-high molecular weight polyethylene wear-resistant lining, the middle is a glass fiber reinforced layer, and the outer layer is an anti-UV PVC protective cover, the branch connection pipeline is configured as a flexible metal hose structure, and is equipped with a universal adjustment joint, the quick-connect flange is provided with a hydraulically driven clamp for connection, equipped with a self-tightening sealing ring and a status indicator, the anti-crystallization coating on the inner wall of the main pipeline is composed of a specially formulated fluoropolymer, which is used to prevent salt crystallization and deposition in the brine, the temperature compensator equipped with the branch pipeline is configured as a bellows structure, which is used to eliminate pipeline stress caused by temperature changes, the entire pipeline system is arranged with multiple sampling ports and cleaning ports along the way, and is configured as a modular design, and the system is also integrated with a pressure fluctuation absorption device to suppress the water hammer effect.

[0041] Furthermore, the flow regulating device includes an electric regulating valve group, a flow sensor, a pressure buffer and an emergency manual operating mechanism, wherein the electric regulating valve group is a multi-valves parallel arrangement, the main regulating valve is an intelligent electric ball valve equipped with a high-precision stepper motor drive, the backup valve is a pneumatic diaphragm regulating valve, the flow sensor uses the contact ultrasonic measurement principle, there is no flow-blocking component in the measuring tube, the pressure buffer is an accumulator structure with an effective volume of 10% of the instantaneous flow of the pipeline, and is filled with an adjustable pressure nitrogen cushion. The multi-stage throttling design of the electric regulating valve includes a front fixed throttling orifice and a rear adjustable V-type throttling port, and the emergency manual operating mechanism adopts a worm gear drive, which is used to adjust the flow through a handwheel in the event of a power outage. The entire device is equipped with an explosion-proof casing and an anti-corrosion coating, and the control system adopts PID+fuzzy control algorithm, which can achieve precise flow distribution and pressure balance between each well group to ensure stable operation of the system.

[0042] Furthermore, the present invention provides a multi-well series connection method for a dual-well brine extraction device, comprising the following steps:

[0043] S1, connect the brine extraction outlet of the newly built well unit to the water injection inlet of the old well unit through a pipeline system;

[0044] S2, start the water injection system of the newly built well unit to carry out cavity construction;

[0045] S3, adjusts the flow in the connecting pipeline to maintain stable production of the old well unit;

[0046] S4, monitoring the brine concentration of the newly built well unit and connecting it to the production system after reaching the predetermined value;

[0047] S5, continuously optimize the operating parameters of each well group to achieve system synergy and efficiency.

[0048] Furthermore, the cavity construction stage of the newly built well unit is set to a gradient boosted water injection method, which divides the entire trench construction process into three stages: the initial stage uses a low-pressure and low-flow water injection mode, the injection pressure is controlled at a low level, and the flow rate is maintained at a small value, which is used to form an initial dissolution channel in the salt layer and establish basic hydraulic connections; the intermediate stage uses medium pressure and flow for water injection, at which time the cavity begins to gradually expand, and the injection parameters increase linearly with the increase in the cavity volume; the final stage uses the designed working pressure and maximum flow for water injection, so that the cavity quickly reaches the target size. During this process, the cavity development is monitored in real time, and the three-dimensional morphological data of the cavity is obtained through the downhole camera system and the acoustic ranging device, and the water injection parameters are dynamically adjusted accordingly. The conversion timing of each stage is comprehensively judged based on the real-time monitored brine concentration change rate and injection pressure fluctuations to ensure the uniformity and stability of the cavity development.

[0049] This gradient pressurization method effectively avoids the problems of premature collapse of the cavity top and uneven dissolution that are easily caused by traditional constant-pressure water injection methods, shortens the cavity formation time of newly built wells, and the formed cavity morphology is more regular, creating good conditions for subsequent series operation.

[0050] Furthermore, the system monitors the brine concentration at each node in real time during operation, and dynamically adjusts the flow distribution ratio between the newly built well unit and the old well unit according to the concentration change; the device is equipped with an online density meter and conductivity meter at the key nodes of the pipeline connection system, and collects brine concentration data once a minute. The data is transmitted to the central control system through the industrial bus. The system has a built-in intelligent distribution algorithm. When the brine concentration of the newly built well unit is lower than the set threshold, the system automatically increases the proportion of brine flowing to the old well unit, and uses the residual dissolution capacity of the old well to further increase the brine concentration. When the brine concentration of the old well unit decreases, its distribution flow is reduced accordingly to extend the residence time of the brine in the dissolution cavity. The flow distribution ratio is adjusted by adjusting the electric regulating valves on each branch. The adjustment range is calculated according to the preset algorithm based on the concentration deviation value. At the same time, the system will record historical operation data and optimize the distribution strategy through machine learning algorithms to keep the brine production and concentration of the entire system at the optimal balance point.

[0051] This method effectively solves the problem that the traditional fixed flow distribution method cannot adapt to changes in the ore layer.

[0052] Furthermore, by adjusting the flow in the connecting pipe, the residence time of the brine in the dissolution cavity is controlled to optimize the dissolution efficiency; according to the dissolution kinetics of the salt mine, a mathematical model of residence time and dissolution efficiency is established to determine the optimal residence time range. During operation, the brine flow rate is adjusted to the design value by precisely controlling the flow regulating valve in the pipeline system, so that the actual residence time of the brine in the dissolution cavity is controlled within the optimal range. The system is equipped with a high-precision timing device and a flow meter for real-time calculation of the time it takes for the brine to pass through the dissolution cavity. When it is detected that the residence time deviates from the set value, the system adjusts the opening of the relevant valve for correction. For different ore layers, differentiated residence time parameters are set according to the purity and structural characteristics of the salt rock. When encountering high-purity salt layers, a pulse flow adjustment method can be temporarily adopted to enhance the dissolution effect by periodically changing the flow rate.

[0053] This method breaks through the limitations of the traditional fixed-flow mining mode, improves the dissolution efficiency of salt mines, and avoids the risk of collapse of the cavity top due to too long residence time, significantly improving mining safety. The system will also automatically record the actual dissolution effect data under different residence times and continuously optimize the control parameters.

[0054] Furthermore, the system is equipped with an emergency operation mode. When any well group is detected to be abnormal, the system automatically switches to an independent operation state. The system is equipped with a parameter safety monitoring network, including a wellbore pressure sensor, a flow mutation detector and a brine leakage alarm, which are used to collect the operation status data of each well group in real time. The central control system has a built-in intelligent diagnosis module. When any parameter is detected to exceed the safety threshold, the emergency response program is immediately started. The emergency switching process is divided into three stages: first, quickly adjust the relevant valves to cut off the connection between the abnormal well group and other well groups, then adjust the operating parameters of the remaining well groups, and finally start the backup equipment to maintain basic production. The entire switching process can be completed within 2 minutes, and the water hammer effect is avoided through the pressure buffer device and flow gradient control during the switching process. During the emergency mode operation, the system will continue to diagnose the cause of the fault and provide treatment suggestions. After the fault is eliminated, the original operation mode can be restored with one click.

[0055] This emergency mechanism is specially designed with an anti-false triggering function. Through multi-parameter composite judgment, it ensures that it will only be activated when a real abnormality occurs. This method effectively solves the problem of "one well failure, the entire system shuts down" in traditional series systems, and greatly improves production reliability and safety.

[0056] See also Figure 1 and Figure 2 , further, the specific workflow of the present invention is described:

[0057] The central control system starts a self-test program to calibrate monitoring equipment such as pressure sensors, flow meters, and concentration detectors for each well group. At the same time, it initializes actuators such as electric control valves and water injection pumps, establishes communication connections with all downhole equipment, and ensures that each subsystem is in a ready state. This process is usually completed automatically within 30 seconds after the system is powered on, laying the foundation for subsequent operations.

[0058] The newly built well unit starts gradient boost water injection and trench construction. In the initial stage, a low-pressure and low-flow mode is adopted, and water is slowly injected into the salt layer through the central injection pipe. At this time, low-concentration brine is discharged from the annular brine outlet channel. As the cavity is initially formed, the system automatically switches to the medium-parameter water injection stage, and the pressure and flow are gradually increased to 60% of the rated value. When the brine concentration reaches the preset threshold, it switches to the high-pressure and high-flow water injection mode to quickly expand the cavity to the designed size. The entire process is monitored in real time by the downhole camera system.

[0059] The pipeline connection system was put into operation, connecting the brine outlet of the newly built well unit with the water injection inlet of the old well unit through a high-pressure corrosion-resistant pipeline. During the connection process, the quick docking flange automatically completed the sealing detection and pressure test to ensure the reliability of the connection. At the same time, the flow regulating device initialized the valve opening according to the preset parameters, established a preliminary flow balance, and prepared for series operation.

[0060] The system enters the series production mode, and the medium-concentration brine produced by the new well unit is introduced into the old well unit through the connecting pipe to continue dissolving the salt layer. During this process, the central control system monitors the changes in brine concentration and flow at each node in real time, and dynamically adjusts the opening of the electric regulating valve through the intelligent algorithm to optimize the brine distribution ratio between the new and old well groups to ensure that the dissolution efficiency of the entire system is maximized.

[0061] Based on the real-time collected operating data, the system automatically adjusts the injection parameters and pipeline flow of each well group to control the residence time of the brine in the dissolution cavity. When the brine concentration of the newly built well unit reaches the production standard, the system automatically switches its brine output to the production system while maintaining a series relationship with the old well unit to achieve hierarchical utilization of resources.

[0062] When the monitoring system detects that any parameter exceeds the safe range, the emergency procedure is immediately activated, and the connection between the faulty well group and other well groups is cut off. The operating parameters of the remaining well groups are adjusted, and the backup equipment is switched to maintain production. At the same time, the system records the fault data and issues an alarm to guide maintenance personnel to quickly locate and handle the problem, ensuring production safety and continuity.

Claims

1. A dual-well brine extraction device capable of increasing the brine content of salt mines, characterized in that: Includes: New well units are built, with a single-well convection brine extraction process, including water injection wells and brine extraction wells; The old well unit is set up with a double-well convection brine extraction process, including a water injection well and a brine extraction well; Pipeline connection system, used to connect the brine production wells of the new well unit with the water injection wells of the old well unit; A flow regulating device is provided on the pipeline connection system and is used to regulate the flow in the pipeline; The central control system is used to monitor and adjust the operating parameters of each well group.

2. The dual-well brine extraction device capable of increasing the brine content in salt mines according to claim 1, characterized in that: The newly built well unit is configured as a single-well convection structure, including a central water injection pipe and an annular brine outlet channel, wherein the central water injection pipe is made of a high-strength alloy steel pipe, and a porous injection head is provided at its lower end to promote uniform distribution of water flow. The annular brine outlet channel is composed of an annular space between the wellbore and the central pipe, and the inner wall of the channel is lined with corrosion-resistant composite materials. The upper part is connected to a rotary gas-liquid separator to remove free gas in the brine. The water injection pipe is connected to the ground fresh water source through a high-pressure hose, and a quick-disassembly flange is provided at the connection. An anti-backflow device is installed at the interface between the brine outlet channel and the pipeline connection system. The single-well convection structure can form a uniformly expanded dissolution cavity space through the circulation mode of central water injection and annular brine outlet.

3. The dual-well brine extraction device capable of increasing the brine content in salt mines according to claim 1, characterized in that: The old well unit is configured as a double-well convection structure, comprising an injection well and a brine production well that are interconnected. The injection well is equipped with a submersible pump with an adjustable speed. The pump body is made of duplex stainless steel, and the pumping pressure can be adjusted steplessly according to the condition of the dissolution cavity. A multi-stage filtration device is installed in the brine production well, and the filter screen is configured as a trapezoidal cross-section. The filtration accuracy can be adjusted online. The connecting channel between the two wells is an artificially constructed horizontal well section. The brine production well is connected to the water injection system of the newly built well unit through a pipeline connection system. A three-way switching valve group is provided at the connection point. The entire system is equipped with vibration monitoring and corrosion detection devices.

4. The dual-well brine extraction device capable of increasing the brine content in salt mines according to claim 1, characterized in that: The pipeline connection system includes a high-pressure corrosion-resistant main pipeline, a branch connection pipeline and a quick-connect flange, wherein the main pipeline is configured as a composite pipe wall structure, the inner layer is an ultra-high molecular weight polyethylene wear-resistant lining, the middle is a glass fiber reinforced layer, and the outer layer is an anti-UV PVC protective cover, the branch connection pipeline is configured as a flexible metal hose structure, and is equipped with a universal adjustment joint, the quick-connect flange is provided with a hydraulically driven clamp for connection, equipped with a self-tightening sealing ring and a status indicator, the anti-crystallization coating on the inner wall of the main pipeline is composed of a specially formulated fluoropolymer to prevent salt crystallization and deposition in the brine, the temperature compensator equipped with the branch pipeline is configured as a bellows structure to eliminate pipeline stress caused by temperature changes, the entire pipeline system is arranged with multiple sampling ports and cleaning ports along the way, and is configured as a modular design, and the system is also integrated with a pressure fluctuation absorption device to suppress the water hammer effect.

5. The dual-well brine extraction device capable of increasing the brine content in salt mines according to claim 1, characterized in that: The flow regulating device includes an electric regulating valve group, a flow sensor, a pressure buffer and an emergency manual operating mechanism, wherein the electric regulating valve group is a multi-valves arranged in parallel, the main regulating valve is an intelligent electric ball valve equipped with a high-precision stepper motor drive, the spare valve is a pneumatic diaphragm regulating valve, the flow sensor uses the contact ultrasonic measurement principle, there is no flow-blocking component in the measuring tube, the pressure buffer is an accumulator structure with an effective volume of 10% of the instantaneous flow of the pipeline, and is filled with an adjustable pressure nitrogen cushion. The multi-stage throttling design of the electric regulating valve includes a front fixed throttling orifice and a rear adjustable V-type throttling port, the emergency manual operating mechanism adopts a worm gear drive, which is used to adjust the flow through a handwheel in the event of a power outage, the entire device is equipped with an explosion-proof casing and an anti-corrosion coating, and the control system adopts a PID+fuzzy control algorithm.

6. A multi-well series connection method for a dual-well brine extraction device, using the dual-well brine extraction device capable of increasing the brine content of salt mines according to claims 1-5, characterized in that: The following steps are included: S1, connect the brine extraction outlet of the newly built well unit to the water injection inlet of the old well unit through a pipeline system; S2, start the water injection system of the newly built well unit to carry out cavity construction; S3, adjusts the flow in the connecting pipeline to maintain stable production of the old well unit; S4, monitoring the brine concentration of the newly built well unit and connecting it to the production system after reaching the predetermined value; S5, continuously optimize the operating parameters of each well group to achieve system synergy and efficiency.

7. The multi-well series connection method of the dual-well brine extraction device according to claim 6, characterized in that: The cavity construction stage of the new well unit is set as a gradient booster water injection method, which divides the entire trench construction process into three stages: the initial stage uses a low-pressure and low-flow water injection mode, the injection pressure is controlled at a low level, and the flow rate is maintained at a small value, which is used to form an initial dissolution channel in the salt layer and establish a basic hydraulic connection; the intermediate stage uses medium pressure and flow for water injection, at which time the cavity begins to gradually expand, and the injection parameters increase linearly with the increase in the cavity volume; the final stage uses the designed working pressure and maximum flow for water injection, so that the cavity quickly reaches the target size. During this process, the cavity development is monitored in real time, and the three-dimensional morphological data of the cavity is obtained through the downhole camera system and the acoustic ranging device, and the water injection parameters are dynamically adjusted accordingly. The conversion timing of each stage is comprehensively judged based on the real-time monitoring of the brine concentration change rate and the injection pressure fluctuation.

8. The multi-well series connection method of the dual-well brine extraction device according to claim 6, characterized in that: During the operation of the system, the brine concentration of each node is monitored in real time, and the flow distribution ratio between the newly built well unit and the old well unit is dynamically adjusted according to the concentration change; the device is equipped with an online density meter and conductivity meter at the key node of the pipeline connection system, and the brine concentration data is collected once a minute. The data is transmitted to the central control system through the industrial bus. The system has a built-in intelligent distribution algorithm. When the brine concentration of the newly built well unit is lower than the set threshold, the system automatically increases the proportion of brine flowing to the old well unit, and uses the residual dissolution capacity of the old well to further increase the brine concentration. When the brine concentration of the old well unit decreases, its distribution flow is reduced accordingly to extend the residence time of the brine in the dissolution cavity. The flow distribution ratio is adjusted by adjusting the electric regulating valves on each branch. The adjustment range is calculated according to the preset algorithm based on the concentration deviation value. At the same time, the system will record historical operation data and optimize the distribution strategy through machine learning algorithms to keep the brine production and concentration of the entire system at the optimal balance point.

9. The multi-well series connection method of the dual-well brine extraction device according to claim 6, characterized in that: By adjusting the flow in the connecting pipe, the residence time of the brine in the dissolution cavity is controlled and the dissolution efficiency is optimized; according to the dissolution kinetics of the salt mine, a mathematical model of residence time and dissolution efficiency is established to determine the optimal residence time range. During operation, the brine flow rate is adjusted to the design value by precisely controlling the flow regulating valve in the pipeline system, so that the actual residence time of the brine in the dissolution cavity is controlled within the optimal range. The system is equipped with a high-precision timing device and a flow meter for real-time calculation of the time it takes for the brine to pass through the dissolution cavity. When it is detected that the residence time deviates from the set value, the system adjusts the opening of the relevant valve for correction. For different ore layers, differentiated residence time parameters are set according to the purity and structural characteristics of the salt rock. When encountering high-purity salt layers, a pulse flow adjustment method can be temporarily adopted to enhance the dissolution effect by periodically changing the flow rate.

10. The multi-well series connection method of the dual-well brine extraction device according to claim 6, characterized in that: The system is equipped with an emergency operation mode. When any well group is detected to be abnormal, the system automatically switches to an independent operation state. The system is equipped with a parameter safety monitoring network, including a wellbore pressure sensor, a flow mutation detector and a brine leakage alarm, which are used to collect the operation status data of each well group in real time. The central control system has a built-in intelligent diagnosis module. When any parameter is detected to exceed the safety threshold, the emergency response program is immediately started. The emergency switching process is divided into three stages: first, quickly adjust the relevant valves to cut off the connection between the abnormal well group and other well groups, then adjust the operating parameters of the remaining well groups, and finally start the backup equipment to maintain basic production. The entire switching process can be completed within 2 minutes, and the water hammer effect is avoided by the pressure buffer device and flow gradient control during the switching process. During the emergency mode operation, the system will continue to diagnose the cause of the fault and provide treatment suggestions. After the fault is eliminated, the original operation mode can be restored with one click.

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