Brine discharge well water hammer pulse plug removal method in sediment type salt cavern low-position brine discharge process

Abstract

The invention discloses a brine discharge well water hammer pulse plug removal method in the sediment type salt cavern low-position brine discharge process. The method comprises the following steps that the clogging degree of sediment at the bottom of a brine discharge well is judged according to changes of brine discharge flow and gas injection pressure; opening and closing parameters of the variable-frequency valve are set according to the clogging degree; opening and closing of brine in the central pipe are controlled through the variable-frequency valve, and then the brine flow speed of the brine discharging wellhead is adjusted; sediment particles accumulated at the bottom of the brine discharging well are impacted by vibration generated by the water hammer effect, large particles in sediments are impacted into a salt cavity, fine particles are brought out of the ground by flowing brine, and sediment particle clogging at the bottom of the brine discharging well is dredged. The phenomenon that sediment particles are often blocked at the bottom of the brine discharging well in the low-position brine discharging process can be effectively solved, the brine discharging efficiency is improved, and the brine discharging time is shortened.

Description

Technical Field

[0001] This invention belongs to the field of salt cavern energy storage technology, and relates to the fields of salt mine water-soluble mining and high-impurity salt mine sediment pore gas storage expansion technology, and particularly relates to a method for unblocking water hammer pulses in the low-level brine discharge process of sediment-type salt caverns. Background Technology

[0002] Deep salt mines are excellent geological formations for underground energy reserves. All existing salt cavern gas storage facilities, both domestically and internationally, are built in high-grade salt mines. However, most salt mines in China are generally high-impurity salt mines with high impurity content, numerous interlayers, and low grades. In high-impurity salt mines, the traditional water-soluble cavity-building technology for salt cavern gas storage leaves a large amount of sediment at the bottom of the cavity after construction. After gas injection and brine removal, only small-scale gas storage facilities can be formed, resulting in low cavity formation rates and poor economic efficiency in construction.

[0003] Compared to foreign salt cavern gas storage facilities, which are mostly built in thick salt domes of marine sediments, Chinese salt mines are mostly lacustrine sedimentary layered salt rock structures. These strata are characterized by thin salt layers, many interlayers, and high impurity content. After water dissolution and cavity creation, the cavity is buried by a large amount of insoluble sediment, resulting in a small effective storage volume.

[0004] With the development of salt cavern gas storage construction technology, the technology of utilizing sediment voids for gas storage is expected to solve this problem. Most salt mines in my country have high impurity content, resulting in the solution cavity space being largely buried by impurity sediment. In salt cavities formed in high-impurity, multi-layered salt mines, the mining space is relatively large, but sonar measurements show that the upper net brine space is significantly smaller than the mining space. This indicates that a large amount of mining space is buried by sediment, which occupies a large amount of usable gas storage space, reducing the space available for gas storage in the cavity.

[0005] Utilizing the voids in sediment for gas storage can solve the problems of small effective gas storage volume and poor economic efficiency in constructing gas storage facilities in high-impurity salt mines, significantly increasing the effective storage capacity of salt cavern gas storage facilities. While low-level brine discharge can effectively remove brine from the voids in sediment, sediment particles often clog the bottom of the discharge well during this process, leading to increased gas injection pressure or reduced discharge flow, severely impacting discharge efficiency and progress.

[0006] To address the aforementioned issues, there is an urgent need to propose a method for unblocking brine wells by water hammer pulses during the low-level brine discharge process of sediment-type salt caverns. Summary of the Invention

[0007] To address the aforementioned technical problems, this invention provides a method for unblocking brine discharge wells using pulsed water hammer during low-level brine discharge from sediment-type salt caverns. This method involves suddenly closing the valve at the discharge wellhead under different discharge flow rates, causing a water hammer effect in the central pipe of the discharge well. The vibration of the central pipe continuously impacts the sediment particles, pushing large particles into the salt cavity while fine particles are carried to the surface by the flowing brine. This clears the blockage caused by sediment particles at the bottom of the discharge well, thereby achieving the purpose of unblocking the sediment at the bottom of the discharge well using pulsed water hammer.

[0008] This invention proposes a method for unblocking water hammer pulses in brine discharge wells during low-level brine discharge from sediment-type salt caverns, comprising the following steps:

[0009] The degree of sludge blockage at the bottom of the brine discharge well is determined by the changes in brine discharge flow rate and gas injection pressure.

[0010] Set the opening and closing parameters of the variable frequency valve according to the degree of sludge;

[0011] The opening and closing of the brine discharge wellhead is controlled by a frequency converter valve, which causes a water hammer effect in the central pipe of the brine discharge well.

[0012] The vibration generated by the water hammer effect impacts the sediment particles accumulated at the bottom of the brine discharge well, pushing the large particles into the salt cavity, while the fine particles are carried to the surface by the flowing brine, thus clearing the blockage of sediment particles at the bottom of the brine discharge well.

[0013] Optionally, the process of setting the opening and closing parameters of the variable frequency valve according to the degree of clogging includes:

[0014] If the rate of increase in gas injection pressure or decrease in brine discharge flow exceeds the preset threshold, the degree of sludge blockage is determined to be severe, and the frequency converter frequency is increased accordingly to the specified value; if the rate of increase in gas injection pressure or decrease in brine discharge flow is less than the preset threshold, the degree of sludge blockage is determined to be mild, and the frequency converter frequency remains unchanged accordingly.

[0015] Optionally, the process of controlling the opening and closing of the brine in the central pipe by using a frequency converter valve, thereby adjusting the brine flow rate at the brine discharge wellhead and causing a water hammer effect in the central pipe of the brine discharge well, includes:

[0016] Based on the basic principle of water hammer by Kutta Joukowsky, by suddenly closing the brine discharge valve at the brine discharge well, the brine in the pipeline is subjected to instantaneous pressure, which forces the central pipeline to vibrate, thereby agitating the sediment particles accumulated at the bottom of the brine discharge well.

[0017] Optionally, the instantaneous pressure generated by the brine in the pipeline is:

[0018] P = cρu,

[0019] In the formula, c is the longitudinal wave velocity of the liquid, ρ is the liquid density, and u is the liquid flow velocity;

[0020] The longitudinal wave velocity of the liquid is:

[0021]

[0022] In the formula, K is the Young's modulus of the liquid, E is the elastic modulus of the central tube, e is the wall thickness of the central tube, and D is the diameter of the central tube.

[0023] Optionally, depending on the needs of gas injection and brine discharge, a compressor, a brine discharge pump, and a brine discharge pipeline can be installed on the ground, and pressure gauges and flow meters can be installed at the gas injection well and the brine discharge wellhead, while a variable frequency valve can be installed at the brine discharge wellhead.

[0024] Optionally, the opening and closing parameters of the variable frequency valve can be adjusted according to the changes in the amount of sediment returned to the ground and the flow rate of brine after water hammer pulsation unblocking, so as to evaluate the unblocking effect; and the variable frequency parameters can be reset according to the quality of the unblocking effect.

[0025] Optionally, the process of setting the opening and closing parameters of the variable frequency valve according to the degree of clogging also includes:

[0026] After 36-72 hours of continuous brine discharge operations, the degree of sediment blockage at the bottom of the brine discharge well is determined, and then water hammer pulsation is used to unblock it.

[0027] This invention also proposes a water hammer pulse unblocking system for brine discharge wells during the low-level brine discharge process of sediment-type salt caverns, used to implement the method, comprising:

[0028] The blockage detection module is used to determine the degree of blockage of sediment at the bottom of the brine discharge well based on changes in brine discharge flow rate and gas injection pressure.

[0029] The parameter setting module is used to set the opening and closing parameters of the variable frequency valve according to the degree of clogging;

[0030] The variable frequency control module is used to control the opening and closing of the brine discharge wellhead through the variable frequency valve, so that the central pipe of the brine discharge well will generate a water hammer effect.

[0031] The water hammer unblocking module is used to utilize the vibration generated by the water hammer effect to impact the sediment particles accumulated at the bottom of the brine discharge well. Larger particles in the sediment are impacted into the brine cavity, while finer particles are carried to the surface by the flowing brine, thus clearing the sediment particles clogging the bottom of the brine discharge well.

[0032] Optionally, the parameter setting module includes: a frequency amplification unit and a frequency holding unit;

[0033] The frequency increase unit is used to determine the degree of sludge blockage when the rate of increase in gas injection pressure or decrease in brine discharge flow exceeds a preset threshold, and accordingly increase the frequency of the variable frequency to the specified value.

[0034] The frequency holding unit is used to determine that the degree of sediment blockage is mild when the rate of increase in gas injection pressure or decrease in brine discharge flow is less than a preset threshold, and the corresponding frequency remains unchanged.

[0035] Optionally, it also includes a deblocking evaluation module, which is used to adjust the opening and closing parameters of the frequency converter valve according to the changes in the amount of sediment returned to the ground and the flow rate of brine after water hammer pulsation deblocking, to evaluate the deblocking effect, and to reset the frequency converter parameters according to the deblocking effect.

[0036] Compared with the prior art, the present invention has the following advantages and technical effects:

[0037] This invention employs a method of suddenly opening and closing the brine discharge pipe, causing vibration in the central discharge pipe and generating a water hammer effect in the flowing brine, thereby clearing blockages caused by sediment particles at the bottom of the discharge port. The opening and closing of the discharge valve can be achieved simply by installing a frequency converter valve on the ground. By designing the opening and closing time of the frequency converter valve, different instantaneous pressures generated by the water hammer can be obtained, clearing blockages of varying degrees. This method is convenient and simple to operate, requiring no excessive equipment at the bottom of the discharge port. Furthermore, this method can be completed in a short time, and the water hammer effect can be reflected by the return flow of sediment or the discharge brine flow rate, allowing for adjustments to ground parameters in real time.

[0038] This invention can effectively solve the problem of sediment particles clogging the bottom of the brine discharge well during the low-level brine discharge process, thereby improving the brine discharge efficiency and reducing the brine discharge time. Attached Figure Description

[0039] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings:

[0040] Figure 1 This is a schematic diagram of low-level brine discharge at the bottom of the sediment according to an embodiment of the present invention;

[0041] Figure 2 A flowchart illustrating the on-site implementation steps for unclogging brine discharge wells using pulsed water hammer according to an embodiment of the present invention;

[0042] Figure 3 This is a schematic diagram of water hammer backflushing sediment formed by closing the brine discharge well at a low-level discharge point in an embodiment of the present invention.

[0043] Figure 4 This is a schematic diagram of water hammer carrying sediment formed by opening the brine discharge well for low-level brine discharge in an embodiment of the present invention. Detailed Implementation

[0044] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0045] It should be noted that the steps shown in the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions, and although a logical order is shown in the flowchart, in some cases the steps shown or described may be executed in a different order than that shown here.

[0046] Example 1

[0047] This embodiment provides a method for unblocking water hammer pulses in brine discharge wells during low-level brine discharge from sediment-type salt caverns, including the following steps:

[0048] The degree of sludge blockage at the bottom of the brine discharge well is determined by the changes in brine discharge flow rate and gas injection pressure.

[0049] Set the opening and closing parameters of the variable frequency valve according to the degree of sludge;

[0050] The opening and closing of the brine discharge wellhead is controlled by a frequency converter valve, which causes a water hammer effect in the central pipe of the brine discharge well.

[0051] The vibration generated by the water hammer effect impacts the sediment particles accumulated at the bottom of the brine discharge well, pushing the large particles into the salt cavity, while the fine particles are carried to the surface by the flowing brine, thus clearing the blockage of sediment particles at the bottom of the brine discharge well.

[0052] Feasible, Figure 1 The diagram illustrates the low-level brine discharge from the bottom of the sediment. Taking a high-impurity salt mine at a depth of 1000m as an example, a large amount of insoluble sediment particles accumulate at the bottom of the salt cavity. During the aeration and brine discharge process, the brine flows through the gaps in the sediment to the open section at the bottom of the discharge well and is then discharged through the well. In this embodiment, the aeration pressure is 12.5-13.5MPa, and the brine discharge flow rate is 50-300m³ / h. 3 The system operates at a flow rate of / h, using a central pipe with a diameter of 114.3mm (4-1 / 2) and a wall thickness of 6.88mm for brine discharge. Due to the continuous increase in discharge flow rate, sediment particles accumulate at the bottom of the discharge well under the influence of the flowing brine carrying sand, reducing the cross-sectional area of ​​the discharge port and consequently decreasing the discharge flow rate. This leads to a corresponding increase in gas injection pressure and higher energy consumption.

[0053] This embodiment primarily utilizes a sudden closure of the brine discharge well opening to create a water hammer effect on the central pipe, forcing it to vibrate. This vibration, in turn, stirs up the sediment particles accumulated at the bottom of the discharge well, thus clearing the blockage caused by the sediment particles. The brine used has a density of 1.2 × 10⁻⁶. 3 kg / m 3 The brine bulk modulus is 2.2 × 10⁻⁶.9 Pa, the elastic modulus of the steel in the central oil pipe is 200 GPa.

[0054] According to the basic principle of water hammer by Kutta Joukowsky, the instantaneous pressure generated in the brine in the pipeline due to the sudden closure of the brine discharge valve at the brine discharge well is:

[0055] P=cρu (1)

[0056] In the formula, c is the longitudinal wave velocity of the liquid, ρ is the liquid density, and u is the liquid flow velocity. The longitudinal wave velocity generated in the liquid is:

[0057]

[0058] In the formula, K is the bulk modulus of the liquid, E is the elastic modulus of the central tube, e is the wall thickness of the central tube, and D is the diameter of the central tube. Generally, the longitudinal wave velocity generated in pure water is 1200-1500 m / s.

[0059] As can be seen from equation (1), the greater the flow velocity of the liquid in the tube column, the greater the instantaneous pressure generated by the brine in the central tube, the greater the driving force of the brine on the sediment particles at the bottom of the brine outlet, the greater the agitation of the silted sediment, and the better the dredging of the accumulated sediment.

[0060] Taking the derivative of both sides of equation (1) with respect to time, we get:

[0061]

[0062] It can be observed that when the brine outlet valve is switched on and off rapidly, due to the incompressibility of the brine, the instantaneous pressure generated in the central pipe by the brine is usually dozens of times higher than the normal pressure, which is sufficient to disturb the sediment at the bottom of the brine outlet and prevent blockage.

[0063] In this embodiment, the longitudinal wave velocity generated in the brine is 1.25 × 10⁻⁶. 3 The speed is m / s, and the instantaneous pressure generated by the brine in the pipeline is calculated to be approximately 7.5 MPa.

[0064] As an optional implementation method, Figure 2 The following are the on-site implementation steps for unclogging brine wells using pulsed water hammer:

[0065] First, install the necessary equipment on the ground, including compressors, pumps, and pipelines for gas injection and brine discharge. Install pressure gauges and flow meters at the injection and discharge wells, and install variable frequency valves at the discharge wells. If abnormal situations occur, such as a decrease in discharge flow or an increase in injection pressure, or if, after 36-72 hours of continuous brine discharge operations, it is determined that sediment has blocked the bottom of the discharge well, water hammer pulsation can be used to unblock it.

[0066] Then, based on the changes in gas injection pressure and brine discharge flow rate, the degree of sediment blockage is comprehensively judged, and the opening and closing parameters of the variable frequency valve are set. Figure 3 The diagram shown is a schematic of water hammer backflushing of sediment formed by closing the brine discharge well at a low level.

[0067] If the injection pressure suddenly increases sharply or the discharge flow rate suddenly decreases sharply, and the injection pressure is greater than 13.5 MPa or higher, and the rate of increase in injection pressure is greater than 0.1 MPa / s, then the injection pressure is considered to have suddenly increased sharply. The normal discharge flow rate is 200 m³ / s. 3 / h, if the injection pressure remains constant and the brine discharge flow rate decreases by 20% within 1 hour, it is considered that the brine discharge flow rate has suddenly and drastically decreased. It is considered that the sludge blockage is severe, and the corresponding frequency of the variable frequency is increased. The frequency is the reciprocal of the period. Generally, the switching period is set in the range of 0.1-10s, and the frequency of the variable frequency f is 0.1-10. If the period dt is 1s, the velocity change du is 5.5m / s. According to formula (3), the instantaneous pressure generated in the central tube is 8.22MPa. When the frequency of the variable frequency is 0.1-10, the instantaneous pressure generated in the central tube is in the range of 0.822-82.2MPa.

[0068] If increased impact force on silt and sediment is needed, the frequency converter can be increased to 10 to enhance the unblocking effect. If the injection pressure increases slowly or the brine discharge flow rate decreases slowly, but does not exceed the specified value (an injection pressure greater than 13.5 MPa and an increase rate greater than 0.1 MPa / s is considered a sudden and sharp increase in injection pressure; the normal brine discharge flow rate is 200 m³ / s). 3 If the brine discharge flow rate decreases by 20% within 1 hour while the gas injection pressure remains unchanged, it is considered that the brine discharge flow rate has suddenly and drastically decreased. This indicates that the sludge blockage is relatively clear. The corresponding frequency f is kept unchanged or reduced to 0.1, and the impact force on the blockage sludge remains unchanged or is reduced, which is sufficient to clear the blockage sludge normally.

[0069] Finally, observe the changes in the amount of sediment returned to the surface and the brine discharge flow rate. The sediment discharge amount is determined by observing the mass of sediment discharged from the wellhead per unit time. If it is within the range of 5-10 kg / h, the sediment return amount is considered normal. The brine discharge flow rate is considered normal if the change within 1 hour is within 20%. Adjust the opening and closing parameters of the variable frequency valve to evaluate the unblocking effect after water hammer pulsation. If the unblocking effect is poor, increase the variable frequency of the wellhead switch to increase the impact force on the sediment, thereby increasing the unblocking effect. If the unblocking effect is good, the accumulated sediment can be unblocked. Once the brine discharge flow rate and gas injection pressure are normal, the variable frequency f of the wellhead switch can be adjusted to a lower state (f = 0.1). Figure 4 The diagram shown is a schematic of water hammer backflushing of sediment formed by opening the brine discharge well at a low position for sludge discharge.

[0070] Based on the same general inventive concept, this invention also provides a water hammer pulse unblocking system for brine wells during low-level brine discharge from sediment-type salt caverns. The system provided by this invention is described below. The water hammer pulse unblocking system for brine wells during low-level brine discharge from sediment-type salt caverns described below can be referred to in correspondence with the water hammer pulse unblocking method for brine wells during low-level brine discharge from sediment-type salt caverns described above. The system includes:

[0071] The blockage detection module is used to determine the degree of blockage of sediment at the bottom of the brine discharge well based on changes in brine discharge flow rate and gas injection pressure.

[0072] The parameter setting module is used to set the opening and closing parameters of the variable frequency valve according to the degree of clogging;

[0073] The variable frequency control module is used to control the opening and closing of the brine discharge wellhead through the variable frequency valve, so that the central pipe of the brine discharge well will generate a water hammer effect.

[0074] The water hammer unblocking module is used to utilize the vibration generated by the water hammer effect to impact the sediment particles accumulated at the bottom of the brine discharge well. Larger particles in the sediment are impacted into the brine cavity, while finer particles are carried to the surface by the flowing brine, thus clearing the sediment particles clogging the bottom of the brine discharge well.

[0075] Optionally, the parameter setting module includes: a frequency amplification unit and a frequency holding unit;

[0076] The frequency increase unit is used to determine the degree of sludge blockage when the rate of increase in gas injection pressure or decrease in brine discharge flow exceeds a preset threshold, and accordingly increase the frequency of the variable frequency to the specified value.

[0077] The frequency holding unit is used to determine that the degree of sediment blockage is mild when the rate of increase in gas injection pressure or decrease in brine discharge flow is less than a preset threshold, and the corresponding frequency remains unchanged.

[0078] Optionally, it also includes a deblocking evaluation module, which is used to adjust the opening and closing parameters of the frequency converter valve according to the changes in the amount of sediment returned to the ground and the flow rate of brine after water hammer pulsation deblocking, to evaluate the deblocking effect, and to reset the frequency converter parameters according to the deblocking effect.

[0079] The above are merely preferred embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for unblocking water hammer pulses in brine discharge wells during low-level brine discharge from sediment-type salt caverns, characterized in that, Includes the following steps: The degree of sludge blockage at the bottom of the brine discharge well is determined by the changes in brine discharge flow rate and gas injection pressure. Set the opening and closing parameters of the variable frequency valve according to the degree of sludge; The opening and closing of the brine in the central pipe is controlled by a frequency converter valve, thereby adjusting the brine flow rate at the brine discharge wellhead and causing a water hammer effect in the central pipe of the brine discharge well. The vibration generated by the water hammer effect impacts the sediment particles accumulated at the bottom of the brine discharge well, pushing the large particles into the salt cavity, while the fine particles are carried to the surface by the flowing brine, thus clearing the blockage of sediment particles at the bottom of the brine discharge well.

2. The method according to claim 1, characterized in that, The process of setting the opening and closing parameters of the variable frequency valve according to the degree of clogging includes: If the rate of increase in gas injection pressure or decrease in brine discharge flow exceeds the preset threshold, the degree of sludge blockage is determined to be severe, and the frequency converter frequency is increased accordingly to the specified value; if the rate of increase in gas injection pressure or decrease in brine discharge flow is less than the preset threshold, the degree of sludge blockage is determined to be mild, and the frequency converter frequency remains unchanged accordingly.

3. The method according to claim 1, characterized in that, The process of controlling the opening and closing of the brine discharge wellhead using a frequency converter valve to induce a water hammer effect in the central pipe of the brine discharge well includes: Based on the basic principle of water hammer by Kuttajoukowsky, by suddenly closing the brine discharge valve at the brine discharge well, the brine in the pipeline is subjected to instantaneous pressure, which forces the central pipeline to vibrate, thereby agitating the sediment particles accumulated at the bottom of the brine discharge well.

4. The method according to claim 3, characterized in that, The instantaneous pressure generated by the brine in the pipe is: P = cρu, In the formula, c is the longitudinal wave velocity of the liquid, ρ is the liquid density, and u is the liquid flow velocity; The longitudinal wave velocity of the liquid is: In the formula, K is the bulk modulus of the liquid, E is the elastic modulus of the central tube, e is the wall thickness of the central tube, and D is the diameter of the central tube.

5. The method according to claim 1, characterized in that, According to the requirements of gas injection and brine discharge, compressors, brine discharge pumps and brine discharge pipelines are installed on the ground, and pressure gauges and flow meters are installed at the gas injection well and brine discharge wellhead, while variable frequency valves are installed at the brine discharge wellhead.

6. The method according to claim 1, characterized in that, Based on the changes in the amount of sediment returned to the ground and the flow rate of brine discharge after water hammer pulsation unblocking, the opening and closing parameters of the frequency converter valve are adjusted to evaluate the unblocking effect; based on the quality of the unblocking effect, the frequency converter parameters are reset.

7. The method according to claim 2, characterized in that, The process of setting the opening and closing parameters of the variable frequency valve according to the degree of clogging also includes: After 36-72 hours of continuous brine discharge operations, the degree of sediment blockage at the bottom of the brine discharge well is determined, and then water hammer pulsation is used to unblock it.

8. A water hammer pulse unblocking system for brine discharge wells during low-level brine discharge from sediment-type salt caverns, characterized in that, For implementing the method according to any one of claims 1-7, comprising: The blockage detection module is used to determine the degree of blockage of sediment at the bottom of the brine discharge well based on changes in brine discharge flow rate and gas injection pressure. The parameter setting module is used to set the opening and closing parameters of the variable frequency valve according to the degree of clogging; The variable frequency control module is used to control the opening and closing of the brine discharge wellhead through the variable frequency valve, so that the central pipe of the brine discharge well will generate a water hammer effect. The water hammer unblocking module is used to utilize the vibration generated by the water hammer effect to impact the sediment particles accumulated at the bottom of the brine discharge well. Larger particles in the sediment are impacted into the brine cavity, while finer particles are carried to the surface by the flowing brine, thus clearing the sediment particles clogging the bottom of the brine discharge well.

9. The system according to claim 8, characterized in that, The parameter setting module includes: a frequency amplification unit and a frequency holding unit; The frequency amplification unit is used to determine the degree of sludge blockage when the rate of increase in gas injection pressure or decrease in brine discharge flow exceeds a preset threshold, and accordingly increase the frequency of the variable frequency to the specified value. The frequency holding unit is used to determine that the degree of sediment blockage is mild when the rate of increase in gas injection pressure or decrease in brine discharge flow is less than a preset threshold, and the corresponding frequency remains unchanged.

10. The system according to claim 8, characterized in that, It also includes a deblocking evaluation module, which is used to adjust the opening and closing parameters of the variable frequency valve based on the changes in the amount of sediment returned to the ground and the flow rate of brine discharge after water hammer pulsation deblocking, to evaluate the deblocking effect, and to reset the variable frequency parameters according to the deblocking effect.

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