Compressed air energy storage salt cavern cavity airtight seal monitoring method and system

Abstract

The invention relates to the technical field of compressed air energy storage salt cavern engineering, and provides a compressed air energy storage salt cavern cavity air-tight seal monitoring method and system, and the method comprises the steps: S1, monitoring preparation; s2, sealing and monitoring brine; s3, gas seal monitoring of the injection-production string; s4, open hole section air-tight seal monitoring; when the three kinds of monitoring meet the requirements at the same time, it is judged that the air sealing performance of the compressed air energy storage salt cavern cavity is qualified. The system comprises an injection and production pipe column, a test pipe column, a first pressure gauge, a second pressure gauge, a packer, a salt cavern cavity brine sealing performance monitoring unit, an injection and production pipe column gas sealing performance monitoring unit and a well body open hole section sealing performance monitoring unit. The method is suitable for air-tight seal monitoring of the compressed air energy storage salt cavern gas storage, the mode that a neutron source is used for measuring a gas-liquid interface is not used, the monitoring process is optimized, monitoring indexes are quantified, it is ensured that the salt cavern cavity sealing performance meets the sealing requirement of compressed air energy storage gas storage engineering, and the engineering utilization efficiency is improved.

Description

Technical Field

[0001] The invention relates to the technical field of compressed air energy storage salt cavern engineering, and in particular to a compressed air energy storage salt cavern cavity air seal monitoring method and system. Background Art

[0002] Compressed gas energy storage is a storage technology that uses low-peak electricity to store compressed air and uses peak electricity to release compressed air to generate electricity. Compressed gas energy storage must have a physical body to store high-pressure air. Many engineering projects have proved that salt cavern gas storage has good sealing, stability and rheology, and is suitable for compressed gas energy storage.

[0003] Traditional gas seal monitoring technology relies on neutron source logging methods to measure the position of the gas-liquid interface, reflecting the gas pressure state and sealing. The traditional method has three disadvantages. First, it ignores the impact of tidal changes on the entire gas-liquid pressure system, which may cause data misjudgment; second, it relies too much on neutron source logging methods to measure the position and changes of the gas-liquid interface, which cannot be implemented without neutron source logging; third, the implementation method is complicated and requires continuous manual operation for measurement.

[0004] Based on this, it is necessary to develop and design an innovative system technical method for monitoring the air tightness of the salt cavern cavity with compressed gas energy storage, to measure the air tightness performance of the salt cavern cavity, to provide quantitative standards, to improve monitoring efficiency, and to facilitate operation and execution. Summary of the invention

[0005] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a method and system for monitoring the air tightness of a compressed gas energy storage salt cavern cavity, which is suitable for monitoring the air tightness of compressed gas energy storage salt cavern gas storage reservoirs and improving the utilization efficiency of the project.

[0006] The present invention adopts the following technical solution:

[0007] In one aspect, the present invention provides a method for monitoring the air tightness of a compressed gas energy storage salt cavern cavity, comprising:

[0008] S1. Monitoring preparation: A test string with a diameter smaller than that of the injection and production string is lowered into the middle of the injection and production string, the bottom of the test string is lowered below the entry point of the salt cavern cavity, and the top of the test string is flush with the top of the injection and production string; a first pressure gauge is installed on the top of the test string to measure the hydraulic pressure of the test string, and a second pressure gauge is installed in the first annular area between the test string and the injection and production string to measure the gas or liquid pressure in the first annular area; a packer is provided in the second annular area between the injection and production string and the external casing, and the packer is located above the salt cavern cavity;

[0009] S2. Brine injection pressure boost and brine sealing monitoring: used to monitor the brine sealing of the salt cavern cavity;

[0010] S3, gas injection pressure boost and injection and production string gas sealing monitoring: used to monitor the gas sealing of the injection and production string;

[0011] S4, open hole section air tightness monitoring: used to monitor the air tightness of the open hole section of the well body;

[0012] When the brine sealing monitoring, injection and production string gas sealing monitoring, and open hole section gas sealing monitoring simultaneously meet the set conditions, the gas sealing performance of the compressed gas energy storage salt cavern cavity is judged to be qualified.

[0013] According to any possible implementation described above, an implementation is further provided, in step S1, the test string is lowered to 10 meters below the entry point of the salt cavern cavity.

[0014] Any possible implementation described above further provides an implementation, wherein the specific method of step S2 includes:

[0015] S21. Pre-test conditions: The salt cavern cavity, injection and production string and test string are filled with saturated brine, and the brine pressure at the top of the test string is zero, in a non-pressurized state;

[0016] S22, brine injection and pressure increase: Use the test pipe string to inject saturated brine into the salt cavern cavity, so that the brine pressure P at the top of the test pipe string 井口液压 The brine column pressure P 卤柱液压 The sum of the pressures is raised to the airtight test design pressure P;

[0017] S23, observe the first set time for steady pressure, and record the wellhead brine pressure monitoring data P every second set time 井口液压i , according to P 井口液压i Forming a pressure change curve;

[0018] S24. Determine the brine sealing performance of the salt cavern cavity according to the pressure variation curve.

[0019] Any possible implementation described above further provides an implementation, in step S22, P 卤柱液压 =ρ 卤 ×g×H×10 ―5 , unit: MPa, where H is the total length of the injection and production string.

[0020] According to any possible implementation described above, a further implementation is provided. In step S24, the criterion for whether the brine sealing performance of the salt cavern cavity meets the requirements is:

[0021] Criteria 1: If there is a tidal phenomenon, the pressure change curve has three obvious peaks and valleys, with the peak value being between 2:00 and 5:00 every day and the valley value being between 13:00 and 16:00 every day, and

[0022] P第二个波峰 ―P 第三个波峰 ≤0.01MPa or P 第二个波谷 ―P 第三个波谷 ≤0.01MPa;

[0023] Criterion 2: The rate of pressure drop gradually decreases with time and eventually reaches a stable state;

[0024] When both criterion one and criterion two are met at the same time, it is determined that the brine sealing performance of the salt cavern cavity meets the requirements.

[0025] Any possible implementation described above further provides an implementation, in which the specific method of step S3 includes:

[0026] S31, brine injection and pressure increase: inject saturated brine into the test column and raise the pressure to the airtight test design pressure P;

[0027] S32, nitrogen injection and pressure increase: nitrogen is injected into the first annulus area between the test string and the injection and production string to pressurize the liquid level to above the position of the packer, and the nitrogen pressure is increased to the design pressure;

[0028] S33, observe the pressure stabilization for a first set time, record the monitoring data of the first pressure gauge and the second pressure gauge once every second set time; and form a pressure change curve according to the monitoring data of the first pressure gauge and the second pressure gauge;

[0029] S34, according to the change law of the gas-liquid interface, calculating the position of the gas-liquid interface at any time, and forming a gas-liquid interface change curve;

[0030] S35. According to the pressure change curve of step S33 and the gas-liquid interface change curve of step S34, the airtightness performance of the injection and production string is determined.

[0031] Any possible implementation described above further provides an implementation, in which the specific method of step S4 includes:

[0032] S41, brine injection and pressure increase: inject saturated brine into the test column and raise the pressure to the airtight test design pressure P;

[0033] S42, nitrogen injection and pressure increase: nitrogen is injected into the first annulus area between the test string and the injection and production string to pressurize the liquid level to the open hole section of the well body below the position of the packer, and the nitrogen pressure is increased to the design pressure;

[0034] S43, stabilizing the pressure for a first set time, and recording the monitoring data of the first pressure gauge and the second pressure gauge every second set time; and forming a pressure change curve according to the monitoring data of the first pressure gauge and the second pressure gauge;

[0035] S44, according to the change law of the gas-liquid interface, calculating the position of the gas-liquid interface at any time, and forming a gas-liquid interface change curve;

[0036] S45. According to the pressure change curve of step S43 and the gas-liquid interface change curve of step S44, the airtightness performance of the open hole section of the well body is determined.

[0037] Any possible implementation as described above further provides an implementation, in step S31, step S32, or step S41, S42, by fine-tuning the amount of injected brine and nitrogen, so that the brine pressure P at the wellhead of the test string is 井口液压 The brine column pressure P in the test tube 卤柱液压 The sum is equal to the annular nitrogen pressure P of the test string and the injection and production pipe 井口气压 and annular air column pressure P 气柱压力 and is equal to the airtight test design pressure P.

[0038] According to any of the possible implementations described above, a further implementation is provided, in step S34 or step S44, the gas-liquid interface position is obtained by the following formula:

[0039] The initial gas-liquid interface H1 is:

[0040] The gas-liquid interface Hi at any other time i is:

[0041]

[0042] Where: 气 , 卤 are the densities of gas and brine respectively; P 井口液压1 , P 井口气压1 are the brine pressure data at the test wellhead at the initial moment and the nitrogen pressure data in the first annulus area; P 井口液压i , P 井口气压i are the brine pressure data at the test wellhead at time i and the nitrogen pressure data in the first annulus area; H1, H i , H i―1 They are the gas-liquid interface positions at the initial moment, moment i, and moment i-1, specifically the depth from the wellhead to the gas-liquid interface, in m.

[0043] According to any of the possible implementations described above, a further implementation is provided, in step S35 or step S45, the criterion for whether the air tightness of the injection and production string or the open hole section of the well body meets the requirements is:

[0044] Criterion A: The rate of pressure drop gradually decreases with time and eventually reaches a stable state;

[0045] Criterion B: The gas-liquid interface change curve shows that the depth of the gas-liquid interface changes by less than 1m in the last 24 hours;

[0046] When both criterion A and criterion B are met at the same time, it is determined that the gas tightness of the injection and production string or the open hole section of the well body meets the requirements.

[0047] As any possible implementation described above, a further implementation is provided, in step S23, the first set time is 72 hours, and the second set time is 1 hour.

[0048] On the other hand, the present invention also provides a compressed gas energy storage salt cavern cavity air-tightness monitoring system, the system is used to implement the compressed gas energy storage salt cavern cavity air-tightness monitoring method, the system comprises: an injection and production string, a test string, a first pressure gauge for testing the top pressure of the test string, a second pressure gauge for testing the liquid or gas pressure in the first annular space area between the test string and the injection and production string, a packer, a salt cavern cavity brine sealing monitoring unit, an injection and production string air-tightness monitoring unit, and a well body open hole section sealing monitoring unit;

[0049] A test string with a diameter smaller than that of the injection and production string is lowered into the middle of the injection and production string, the bottom of the test string is lowered below the entry point of the salt cavern cavity, and the top of the test string is flush with the top of the injection and production string; a first pressure gauge is installed on the top of the test string to measure the hydraulic pressure of the test string, and a second pressure gauge is installed in the first annular area between the test string and the injection and production string to measure the gas or liquid pressure in the first annular area; a packer is provided in the second annular area between the injection and production string and the external casing, and the packer is located above the salt cavern cavity;

[0050] The salt cavern cavity brine sealing monitoring unit is used to monitor the brine sealing of the salt cavern cavity; the brine sealing performance of the salt cavern cavity is determined according to the test string wellhead pressure change curve;

[0051] The injection and production string gas tightness monitoring unit is used to monitor the gas tightness of the injection and production string; the gas tightness of the injection and production string is determined according to the test string wellhead pressure change curve and the change law of the gas-liquid interface;

[0052] The well body open hole section air tightness monitoring unit is used to monitor the air tightness of the well body open hole section; the air tightness of the injection and production string is determined according to the test string wellhead pressure change curve and the change law of the gas-liquid interface.

[0053] The beneficial effects of the present invention are:

[0054] It is suitable for gas sealing monitoring of compressed gas energy storage salt cavern gas storage, which can effectively verify the sealing of injection and production pipes, open hole sections and salt cavern cavities. It does not use neutron source to measure the gas-liquid interface, optimizes the monitoring process, quantifies monitoring indicators, ensures that the sealing of the salt cavern cavity meets the sealing requirements of compressed gas energy storage gas storage projects, reduces project investment risks, and improves project utilization efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Figure 1 Shown is a schematic diagram of brine sealing monitoring of a salt cavern cavity in an embodiment.

[0056] Figure 2 The figure shows a curve diagram of the change of the wellhead liquid pressure when monitoring the brine sealing performance of the salt cavern cavity in the embodiment.

[0057] Figure 3 Shown is a schematic diagram of monitoring the gas tightness of the injection and production string in the embodiment.

[0058] Figure 4 Shown is a schematic diagram of air tightness monitoring of an open hole section of a well body in an embodiment. DETAILED DESCRIPTION

[0059] The specific embodiments of the present invention will be described in detail below in conjunction with specific drawings. It should be noted that the technical features or combinations of technical features described in the following embodiments should not be considered isolated, and they can be combined with each other to achieve better technical effects.

[0060] An embodiment of the present invention provides a method for monitoring the air tightness of a compressed gas energy storage salt cavern cavity, characterized in that the method comprises:

[0061] S1. Monitoring preparation: A test string with a diameter smaller than that of the injection and production string is lowered into the middle of the injection and production string, the bottom of the test string is lowered below the entry point of the salt cavern cavity, and the top of the test string is flush with the top of the injection and production string; a first pressure gauge is installed on the top of the test string to measure the hydraulic pressure of the test string, and a second pressure gauge is installed in the first annular area between the test string and the injection and production string to measure the gas or liquid pressure in the first annular area; a packer is provided in the second annular area between the injection and production string and the external casing, and the packer is located above the salt cavern cavity;

[0062] S2. Brine injection pressure boost and brine sealing monitoring: used to monitor the brine sealing of the salt cavern cavity;

[0063] S3, gas injection pressure boost and injection and production string gas sealing monitoring: used to monitor the gas sealing of the injection and production string;

[0064] S4, open hole section air tightness monitoring: used to monitor the air tightness of the open hole section of the well body;

[0065] When the brine sealing monitoring, injection and production string gas sealing monitoring, and open hole section gas sealing monitoring simultaneously meet the set conditions, the gas sealing performance of the compressed gas energy storage salt cavern cavity is judged to be qualified.

[0066] In a specific embodiment, the specific method of step S2 includes:

[0067] S21. Pre-test conditions: The salt cavern cavity, injection and production string and test string are filled with saturated brine, and the brine pressure at the top of the test string is zero, in a non-pressurized state;

[0068] S22, brine injection and pressure increase: Use the test pipe string to inject saturated brine into the salt cavern cavity, so that the brine pressure P at the top of the test pipe string 井口液压 The brine column pressure P 卤柱液压 The sum of the pressures is raised to the airtight test design pressure P;

[0069] S23, observe the first set time for steady pressure, and record the wellhead brine pressure monitoring data P every second set time 井口液压i , according to P 井口液压i Forming a pressure change curve;

[0070] S24. Determine the brine sealing performance of the salt cavern cavity according to the pressure variation curve.

[0071] Brine sealing performance monitoring system for salt caverns Figure 1 shown.

[0072] In a specific embodiment, in step S23, the brine pressure data at the wellhead of the test string is recorded once every hour after standing for 72 hours, and the pressure recorded in the first hour is set as P 井口液压1 , the pressure recorded at the 72nd hour is set as P 井口液压72 .P 井口液压1 To P 井口液压72 The continuous curve should show three obvious peaks and troughs, such as Figure 2 As shown, and the difference between two adjacent peak values ​​or trough values ​​is less than 0.01 (Formula 3), then this stage of detection is passed.

[0073] Formula 1: P 井口液压 +P 卤柱液压 =P (unit: MPa);

[0074] Formula 2: P 卤柱液压 =ρ 卤 ×g×H×10 ―5 (Unit: MPa);

[0075] Formula 3: P2nd peak - P3rd peak ≤ 0.01 (unit: MPa) or

[0076] P the second trough - P the third trough ≤ 0.01 (unit: MPa); H is the total length of the injection and production string.

[0077] In a specific embodiment, in step S24, the criterion for whether the brine sealing performance of the salt cavern cavity meets the requirements is:

[0078] Criterion 1: If there is a tidal phenomenon, the pressure change curve has three obvious peaks and valleys, and

[0079] P 第二个波峰 ―P 第三个波峰 ≤0.01MPa or P 第二个波谷 ―P 第三个波谷 ≤0.01MPa;

[0080] Criterion 2: The rate of pressure drop gradually decreases with time and eventually reaches a stable state;

[0081] When both criterion one and criterion two are met at the same time, it is determined that the brine sealing performance of the salt cavern cavity meets the requirements.

[0082] In a specific embodiment, the specific method of step S3 includes:

[0083] S31, brine injection and pressure increase: inject saturated brine into the test column and raise the pressure to the airtight test design pressure P;

[0084] S32, nitrogen injection and pressure increase: nitrogen is injected into the first annulus area between the test string and the injection and production string to pressurize the liquid level to above the position of the packer, and the nitrogen pressure is increased to the design pressure;

[0085] S33, observe the pressure stabilization for a first set time, record the monitoring data of the first pressure gauge and the second pressure gauge once every second set time; and form a pressure change curve according to the monitoring data of the first pressure gauge and the second pressure gauge;

[0086] S34, according to the change law of the gas-liquid interface, calculating the position of the gas-liquid interface at any time, and forming a gas-liquid interface change curve;

[0087] S35. According to the pressure change curve of step S33 and the gas-liquid interface change curve of step S34, the airtightness performance of the injection and production string is determined.

[0088] Gas sealing monitoring of injection and production strings Figure 3 shown.

[0089] In a specific embodiment, in step S31 and step S32, the amount of brine and nitrogen injected is finely adjusted so that the brine pressure P at the wellhead of the test string is 井口液压 The brine column pressure P in the test tube 卤柱液压 The sum is equal to the annular nitrogen pressure P of the test string and the injection and production pipe井口气压 and annular air column pressure P 气柱压力 and is equal to the airtight test design pressure P.

[0090] In a specific embodiment, in step S34, the brine pressure data at the wellhead of the test pipe is recorded once every hour after standing for 72 hours, and the pressure recorded in the first hour is set as P 井口液压1 , the pressure recorded at the 72nd hour is set as P 井口液压72 ; Record the annular nitrogen pressure data of the test string and the injection and production string once every hour, and the pressure recorded in the first hour is set as P 井口气压1 , the pressure recorded at the 72nd hour is set as P 井口气压72 .

[0091] Formula 5: P 井口液压 +P 卤柱液压 =P 井口气压 +P 气柱气压 =P (unit: MPa)

[0092] Formula 6: P 气柱气压 =ρ 气 ×g×H×10 ―5 (Unit: MPa)

[0093] Known P 井口液压1 , P 井口气压1 The initial gas-liquid interface H1 can be calculated by combining equations 2, 5, and 6, as shown in equation 7.

[0094]

[0095] According to the principle that the total hydraulic pressure change in the test string at the gas-liquid interface at adjacent moments is equal to the total pressure change of the annular space nitrogen in the test string and the injection and production pipe, the gas-liquid interface H at any other time can be calculated. i , formula 8.

[0096] Formula 8:

[0097] The 72-hour gas-liquid interface change monitoring data is calculated according to Formula 8 to form a gas-liquid interface change curve.

[0098] In a specific embodiment, in step S35, the criterion for whether the air tightness of the injection and production string meets the requirements is:

[0099] Criterion A: The rate of pressure drop gradually decreases with time and eventually reaches a stable state;

[0100] Criterion B: The gas-liquid interface change curve shows that the depth of the gas-liquid interface changes by less than 1m in the last 24 hours;

[0101] When both criterion A and criterion B are met, it is determined that the gas tightness of the injection and production string meets the requirements.

[0102] In a specific embodiment, the specific method of step S4 includes:

[0103] S41, brine injection and pressure increase: inject saturated brine into the test column and raise the pressure to the airtight test design pressure P;

[0104] S42, nitrogen injection and pressure increase: nitrogen is injected into the first annulus area between the test string and the injection and production string to pressurize the liquid level to the open hole section of the well body below the position of the packer, and the nitrogen pressure is increased to the design pressure;

[0105] S43, observe the pressure stabilization for a first set time, record the monitoring data of the first pressure gauge and the second pressure gauge once every second set time; and form a pressure change curve according to the monitoring data of the first pressure gauge and the second pressure gauge;

[0106] S44, according to the change law of the gas-liquid interface, calculating the position of the gas-liquid interface at any time, and forming a gas-liquid interface change curve;

[0107] S45. According to the pressure change curve of step S43 and the gas-liquid interface change curve of step S44, the airtightness performance of the open hole section of the well body is determined.

[0108] Monitoring of air tightness of open hole section of wellbore Figure 4 shown.

[0109] In a specific embodiment, or in steps S41 and S42, by fine-tuning the amount of injected brine and nitrogen, the brine pressure P at the wellhead of the test string is 井口液压 The brine column pressure P in the test tube 卤柱液压 The sum is equal to the annular nitrogen pressure P of the test string and the injection and production pipe 井口气压 and annular air column pressure P 气柱压力 and is equal to the airtight test design pressure P.

[0110] In a specific embodiment, in step S44, the gas-liquid interface position is obtained by the following formula:

[0111] The initial gas-liquid interface H1 is:

[0112] The gas-liquid interface Hi at any other time i is:

[0113]

[0114] In a specific embodiment, in step S45, the criterion for whether the air tightness of the open hole section of the well body meets the requirements is:

[0115] Criterion A: The rate of pressure drop gradually decreases with time and eventually reaches a stable state;

[0116] Criterion B: The gas-liquid interface change curve shows that the depth of the gas-liquid interface changes by less than 1m in the last 24 hours;

[0117] When both criterion A and criterion B are met at the same time, it is determined that the gas tightness of the injection and production string or the open hole section of the well body meets the requirements.

[0118] The embodiment of the present invention provides a compressed gas energy storage salt cavern cavity air tightness monitoring system, the system is used to implement the compressed gas energy storage salt cavern cavity air tightness monitoring method, the system comprises: an injection and production string, a test string, a first pressure gauge for testing the top pressure of the test string, a second pressure gauge for testing the liquid or gas pressure in the first annular area between the test string and the injection and production string, a packer, a salt cavern cavity brine tightness monitoring unit, an injection and production string air tightness monitoring unit, and a well body open hole section and its tightness monitoring unit;

[0119] A test string with a diameter smaller than that of the injection and production string is lowered into the middle of the injection and production string, the bottom of the test string is lowered below the entry point of the salt cavern cavity, and the top of the test string is flush with the top of the injection and production string; a first pressure gauge is installed on the top of the test string to measure the hydraulic pressure of the test string, and a second pressure gauge is installed in the first annular area between the test string and the injection and production string to measure the gas or liquid pressure in the first annular area; a packer is provided in the second annular area between the injection and production string and the external casing, and the packer is located above the salt cavern cavity;

[0120] The salt cavern cavity brine sealing monitoring unit is used to monitor the brine sealing of the salt cavern cavity; the brine sealing performance of the salt cavern cavity is determined according to the test string wellhead pressure change curve;

[0121] The injection and production string gas tightness monitoring unit is used to monitor the gas tightness of the injection and production string; the gas tightness of the injection and production string is determined according to the change curve of the wellhead pressure of the test string and the change law of the gas-liquid interface;

[0122] The well body open hole section air tightness monitoring unit is used to monitor the air tightness of the well body open hole section; the air tightness of the injection and production string is determined according to the test string wellhead pressure change curve and the change law of the gas-liquid interface.

[0123] The present invention proposes the law of tidal changes in liquid pressure, and first verifies the liquid tightness of the wellbore and the cavity by using the law, and then proposes a gas-liquid interface calculation method based on pressure data, and directly obtains the position of the gas-liquid interface by numerical calculation. Based on the above pressure data, a systematic technical method for gas-tightness detection of compressed gas energy storage salt cavern cavity based on pressure data is proposed to ensure that the sealing of the salt cavern cavity meets the sealing requirements of the compressed gas energy storage gas storage project, reduce the investment risk of the project, and improve the utilization efficiency of the project.

[0124] Although several embodiments of the present invention have been given herein, those skilled in the art should understand that the embodiments of the present invention may be modified without departing from the spirit of the present invention. The above embodiments are merely exemplary and should not be used as a limitation on the scope of the present invention.

Claims

1. A method for monitoring the air tightness of a compressed gas energy storage salt cavern cavity, characterized in that: The method comprises: S1. Monitoring preparation: A test string with a diameter smaller than that of the injection and production string is lowered into the middle of the injection and production string, the bottom of the test string is lowered below the entry point of the salt cavern cavity, and the top of the test string is flush with the top of the injection and production string; a first pressure gauge is installed on the top of the test string to measure the hydraulic pressure of the test string, and a second pressure gauge is installed in the first annular area between the test string and the injection and production string to measure the gas or liquid pressure in the first annular area; a packer is provided in the second annular area between the injection and production string and the external casing, and the packer is located above the salt cavern cavity; S2. Brine injection pressure boost and brine sealing monitoring: used to monitor the brine sealing of the salt cavern cavity; S3, gas injection pressure boost and injection and production string gas sealing monitoring: used to monitor the gas sealing of the injection and production string; S4, open hole section air tightness monitoring: used to monitor the air tightness of the open hole section of the well body; When the brine sealing monitoring, injection and production string gas sealing monitoring, and open hole section gas sealing monitoring simultaneously meet the set conditions, the gas sealing performance of the compressed gas energy storage salt cavern cavity is judged to be qualified.

2. The compressed gas energy storage salt cavern cavity air tightness monitoring method according to claim 1, characterized in that: The specific method of step S2 includes: S21. Pre-test conditions: The salt cavern cavity, injection and production string and test string are filled with saturated brine, and the brine pressure at the top of the test string is zero, in a non-pressurized state; S22, brine injection and pressure increase: Use the test string to inject saturated brine into the salt cavern cavity, so that the brine pressure P 井口液压 The brine column pressure P 卤柱液压 The sum of the pressures is raised to the airtight test design pressure P; S23, observe the first set time for steady pressure, and record the wellhead brine pressure monitoring data P every second set time 井口液压i , according to P 井口液压i Forming a pressure change curve; S24. Determine the brine sealing performance of the salt cavern cavity according to the pressure variation curve.

3. The compressed gas energy storage salt cavern cavity air tightness monitoring method according to claim 2, characterized in that: In step S24, the criterion for whether the brine sealing performance of the salt cavern cavity meets the requirements is: Criterion 1: If there is a tidal phenomenon, the pressure change curve has three obvious peaks and valleys, and P 第二个波峰 ―P 第三个波峰 ≤0.01MPa or P 第二个波谷 ―P 第三个波谷 ≤0.01MPa; Criterion 2: The rate of pressure drop gradually decreases with time and eventually reaches a stable state; When both criterion one and criterion two are met at the same time, it is determined that the brine sealing performance of the salt cavern cavity meets the requirements.

4. The compressed gas energy storage salt cavern cavity air tightness monitoring method according to claim 1, characterized in that: The specific method of step S3 includes: S31, brine injection and pressure increase: inject saturated brine into the test column and raise the pressure to the airtight test design pressure P; S32, nitrogen injection and pressure increase: nitrogen is injected into the first annulus area between the test string and the injection and production string to pressurize the liquid level to above the position of the packer, and the nitrogen pressure is increased to the design pressure; S33, observe the pressure stabilization for a first set time, record the monitoring data of the first pressure gauge and the second pressure gauge once every second set time; and form a pressure change curve according to the monitoring data of the first pressure gauge and the second pressure gauge; S34, according to the change law of the gas-liquid interface, calculating the position of the gas-liquid interface at any time, and forming a gas-liquid interface change curve; S35. According to the pressure change curve of step S33 and the gas-liquid interface change curve of step S34, the airtightness performance of the injection and production string is determined.

5. The compressed gas energy storage salt cavern cavity air tightness monitoring method according to claim 1, characterized in that: The specific method of step S4 includes: S41, brine injection and pressure increase: inject saturated brine into the test column and raise the pressure to the airtight test design pressure P; S42, nitrogen injection and pressure increase: nitrogen is injected into the first annulus area between the test string and the injection and production string to pressurize the liquid level to the open hole section of the well body below the position of the packer, and the nitrogen pressure is increased to the design pressure; S43, stabilizing the pressure for a first set time, and recording the monitoring data of the first pressure gauge and the second pressure gauge every second set time; and forming a pressure change curve according to the monitoring data of the first pressure gauge and the second pressure gauge; S44, according to the change law of the gas-liquid interface, calculating the position of the gas-liquid interface at any time, and forming a gas-liquid interface change curve; S45. According to the pressure change curve of step S43 and the gas-liquid interface change curve of step S44, the airtightness performance of the open hole section of the well body is determined.

6. The compressed gas energy storage salt cavern cavity air tightness monitoring method according to claim 4 or 5, characterized in that: In step S31, step S32, or step S41, S42, the amount of brine and nitrogen injected is finely adjusted to make the brine pressure P at the wellhead of the test string 井口液压 The brine column pressure P in the test tube 卤柱液压 The sum is equal to the annular nitrogen pressure P of the test string and the injection and production pipe 井口气压 and annular air column pressure P 气柱压力 and is equal to the airtight test design pressure P.

7. The compressed gas energy storage salt cavern cavity air tightness monitoring method according to claim 4 or 5, characterized in that: In step S34 or S44, the gas-liquid interface position is obtained by the following formula: The initial gas-liquid interface H1 is: The gas-liquid interface Hi at any other time i is: Where: 气 , 卤 are the densities of gas and brine respectively; P 井口液压1 , P 井口气压1 are the brine pressure data at the test wellhead at the initial moment and the nitrogen pressure data in the first annulus area; P 井口液压i , P 井口气压i are the brine pressure data at the test wellhead at time i and the nitrogen pressure data in the first annulus area; H1, H i , H i―1 are the gas-liquid interface positions at the initial moment, moment i, and moment i-1, respectively, in m.

8. The compressed gas energy storage salt cavern cavity air tightness monitoring method according to claim 4 or 5, characterized in that: In step S35 or step S45, the criterion for whether the air tightness of the injection and production string or the open hole section of the well body meets the requirements is: Criterion A: The rate of pressure drop gradually decreases with time and eventually reaches a stable state; Criterion B: The gas-liquid interface change curve shows that the depth of the gas-liquid interface changes by less than 1m in the last 24 hours; When both criterion A and criterion B are met at the same time, it is determined that the gas tightness of the injection and production string or the open hole section of the well body meets the requirements.

9. The compressed gas energy storage salt cavern cavity air tightness monitoring method according to any one of claims 2, 4, and 5, characterized in that: In step S23, the first set time is 72 hours, and the second set time is 1 hour.

10. A compressed gas energy storage salt cavern cavity air seal monitoring system, characterized in that: The system is used to implement the compressed gas energy storage salt cavern cavity air tightness monitoring method according to any one of claims 1 to 9, and the system comprises: an injection and production string, a test string, a first pressure gauge for testing the top pressure of the test string, a second pressure gauge for testing the liquid or gas pressure in the first annular area between the test string and the injection and production string, a packer, a salt cavern cavity brine tightness monitoring unit, an injection and production string air tightness monitoring unit, and a well body open hole section and its tightness monitoring unit; A test string with a diameter smaller than that of the injection and production string is lowered into the middle of the injection and production string, the bottom of the test string is lowered below the entry point of the salt cavern cavity, and the top of the test string is flush with the top of the injection and production string; a first pressure gauge is installed on the top of the test string to measure the hydraulic pressure of the test string, and a second pressure gauge is installed in the first annular area between the test string and the injection and production string to measure the gas or liquid pressure in the first annular area; a packer is provided in the second annular area between the injection and production string and the external casing, and the packer is located above the salt cavern cavity; The salt cavern cavity brine sealing monitoring unit is used to monitor the brine sealing of the salt cavern cavity; the brine sealing performance of the salt cavern cavity is determined according to the test string wellhead pressure change curve; The injection and production string gas tightness monitoring unit is used to monitor the gas tightness of the injection and production string; the gas tightness of the injection and production string is determined according to the change curve of the wellhead pressure of the test string and the change law of the gas-liquid interface; The well body open hole section air tightness monitoring unit is used to monitor the air tightness of the well body open hole section; the air tightness of the injection and production string is determined according to the test string wellhead pressure change curve and the change law of the gas-liquid interface.

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