Underground storage cavern sealing maintenance system and detection and maintenance method

Abstract

The invention relates to the technical field of clean energy underground reservoirs, in particular to an underground reservoir sealing maintenance system and a detection and maintenance method, and aims to solve the technical problems that in the prior art, the position of a leakage point cannot be determined, and remedial measures are lacked when a test is unqualified. The underground storage cavern sealing maintenance system comprises a basic sealing suite, a graded sealing test suite and a sealing repair suite. According to the underground storage cavern sealing overhauling system, the sealing performance of a storage cavern shaft structure is enhanced through the basic sealing suite, then step-by-step sealing detection is sequentially conducted on the interior of a shaft, an open hole well section and a cavity through the grading sealing testing suite, the position of a leakage point is determined when detection is unqualified, and finally abnormal leakage is repaired through the sealing repairing suite. And sealing measures corresponding to different leakage points are adopted to meet the requirement for the sealing performance in the construction process of the underground storage cavern. The technical problems that according to an existing shaft sealing testing method, the position of a leakage point cannot be determined, and remedial measures are lacked when testing is not qualified are solved.

Description

Technical Field

[0001] This invention relates to the field of clean energy underground storage technology, and in particular to an underground storage sealing inspection and maintenance system and inspection and maintenance method. Background Technology

[0002] Underground reservoirs typically use the cemented casing as the production string without additional sealing measures. However, in compressed air storage systems, the production string is subjected to air intake and exhaust stress, which can easily lead to cracks in the cement sheath and casing bond, resulting in a complete loss of the reservoir's seal. Simultaneously, the cemented casing uses ordinary threaded connections without gas-tight sealing capabilities, making it susceptible to corrosion in the brine of salt cavern reservoirs, further compromising the overall seal. Existing brine and gas injection booster wellbore testing methods cover the production string, casing shoe, and open hole section, but cannot perform precise sealing performance testing. If the test fails, the leak location cannot be determined, resulting in weak targeting of seal inspections and a lack of remedial measures when tests fail.

[0003] Existing wellbore sealing testing methods have technical problems such as being unable to determine the location of leaks and lacking remedial measures when tests fail. Summary of the Invention

[0004] The purpose of this invention is to provide an underground storage tank sealing inspection and maintenance system and inspection and maintenance method to solve the technical problems in related technologies where the location of leaks cannot be determined and there are no remedial measures when tests fail.

[0005] To solve the above-mentioned technical problems, the technical solution provided by the present invention is as follows:

[0006] In a first aspect, the underground storage sealing and maintenance system provided by the present invention includes:

[0007] The system comprises a basic sealing kit, a staged sealing test kit, and a sealing repair kit. The basic sealing kit is installed on the reservoir wellbore structure and serves as the production tubing. The staged sealing test kit is used to sequentially test the sealing of the wellbore, open hole section, and cavity. The sealing repair kit is used to repair any areas where the staged sealing test kit indicates a failure to meet sealing standards.

[0008] Specifically, the basic sealing kit includes a dedicated injection-production string and a first packer installed on the dedicated injection-production string. The dedicated injection-production string is set inside the casing by the first packer as a production string, and the annular space between the dedicated injection-production string and the casing is filled with annular protection fluid.

[0009] Specifically, the graded sealing test kit includes a measurement tubing assembly, a brine / gas injection assembly, and a pressure detection assembly. The measurement tubing assembly is installed on the reservoir wellbore structure, dividing it into a first test zone and a second test zone. The brine / gas injection assembly includes a liquid injection unit and a gas injection unit, used to inject brine or nitrogen into the first and second test zones. The pressure detection assembly is installed on the measurement tubing assembly and includes a detection pressure gauge, a detection module, and a storage pressure gauge. The detection pressure gauge is electrically connected to the detection module, which is located on the ground, via a cable. The storage pressure gauge is installed at the end of the measurement tubing assembly furthest from the ground. Both the detection pressure gauge and the storage pressure gauge are immersed in the brine and serve as data verification objects for each other.

[0010] Specifically, the measurement string assembly includes a test string and a cavity testing unit, used for sealing tests of the dedicated injection / production string, open hole section, and cavity, respectively. A storage pressure gauge is installed at the end of the test string or cavity testing unit furthest from the ground. The cavity testing unit includes a bridging plug string, a bridging plug, and a reagent package. The bridging plug is detachably connected to the furthest end of the bridging plug string and seated in the open hole neck, used to isolate the cavity from the reservoir wellbore structure. The storage pressure gauge is detachably connected to the lower part of the bridging plug. The reagent package is designed as a capsule structure, with an outer shell made of a brine-degradable material, and contains a reagent that reacts with brine to generate gas.

[0011] Specifically, the sealing repair kit includes an open-hole sealing string, a second packer, and a basic sealing kit. Both the basic sealing kit and the open-hole sealing string achieve sealing repair by replacing spare parts. The second packer can be installed on the open-hole sealing string and, through its mating with the open-hole sealing string, achieves sealing repair of the casing shoe and open-hole section.

[0012] Secondly, the present invention provides a method for the inspection and maintenance of underground storage facilities, including the aforementioned underground storage facility sealing and maintenance system, characterized by the following steps:

[0013] The wellbore system is divided into four phases: overall water tightness testing, in-wellbore gas tightness testing, open-hole gas tightness testing, and cavity gas tightness testing. The overall water tightness testing phase is used to test and repair the overall water tightness of the reservoir wellbore structure. The in-wellbore gas tightness testing phase is used to test and repair the gas tightness of the dedicated injection / production tubing, the first packer, the casing shoe, the open-hole sealing tubing, and the second packer. The open-hole gas tightness testing phase is used to test and repair the gas tightness of the open-hole section. The cavity gas tightness testing phase is used to test and repair the gas tightness of the cavity.

[0014] Specifically, the overall water seal testing phase includes water seal testing and water seal leakage detection and repair.

[0015] Water seal test: Brine is injected into the wellbore structure and pressurized. A pressure gauge is lowered into the well and the pressure is increased to the safe test pressure. After waiting for 10 minutes and the pressure stabilizes, the pressure data from the pressure gauge is received in real time within 24 hours, and then the pressure gauge is raised. The safe test pressure is 0.9 times the maximum withstand pressure of the cavity.

[0016] Water seal leakage assessment and repair: The standard for judging whether the seal is qualified is that the pressure drop is no more than 0.1 MPa within 24 hours. When the pressure gauge data indicates that the seal is unqualified, the brine in the reservoir well structure is pumped out, and then gel twice the volume of the reservoir well structure is injected into the well structure and the pressure is stabilized for 5 days. After 5 days, the excess gel is pumped out, and the water seal test procedure is returned to normal.

[0017] Specifically, the wellbore gas seal testing phase includes gas seal testing of the dedicated injection and production tubing, leak detection and repair of the injection and production tubing, gas seal testing of the first packer, leak detection and repair of the first packer, gas seal testing of the casing shoe, leak detection and repair of the casing shoe, gas seal testing of the open hole sealing tubing, leak detection and repair of the open hole sealing tubing, gas seal testing of the second packer and leak detection and repair of the second packer.

[0018] Gas-tightness test of dedicated injection-production tubing: Lower the dedicated injection-production tubing and the first packer, setting the first packer within the casing and within 5m above the casing shoe. Lower the test tubing into the dedicated injection-production tubing, and insert a pressure gauge into the annulus between the dedicated injection-production tubing and the test tubing. Increase the annulus pressure to the safe test pressure and adjust the gas-liquid interface height above the first packer, with a distance ≤1m. Wait 10 minutes until the pressure stabilizes, and then receive the pressure data from the pressure gauge in real time for 1 hour.

[0019] The current gas-liquid interface height in the annulus is calculated based on a preset formula. The preset formula for calculating the gas-liquid interface height is as follows:

[0020]

[0021] in,

[0022] h represents the height of the gas-liquid interface within the annulus.

[0023] H represents the total depth to which the pressure gauge is inserted.

[0024] △h represents the depth of the pressure gauge below the gas-liquid interface during the sealing test.

[0025] P w The pressure value was read after the pressure gauge was lowered into the brine depth H in the annulus and remained still for 10 minutes.

[0026] P1 is the pressure value read after the pressure gauge has been in place for 10 minutes at a depth h0 within the inert gas column in the annulus.

[0027] h0 is the height to which the pressure gauge is lifted into the inert gas column within the annulus.

[0028] P2 is the pressure value read after the pressure gauge is raised 25m from a depth h0 inside the inert gas column in the annulus and left to stand for 10 minutes.

[0029] Leakage Assessment and Repair of Injection-Production Tubing: Compare and analyze the data from the storage pressure gauge and the detection pressure gauge. The standard for a satisfactory seal is a pressure drop of no more than 0.1 MPa within 1 hour. If the data from the storage and detection pressure gauges are inconsistent, replace both gauges and return to the dedicated injection-production tubing gas tightness test procedure. If both gauges show a non-compliant result, the dedicated injection-production tubing is deemed to be unsatisfactory; replace the dedicated injection-production tubing and return to the dedicated injection-production tubing gas tightness test procedure.

[0030] First packer gas tightness test: Run the test string and storage pressure gauge, and run the test pressure gauge in the annulus between the dedicated injection / production string and the test string. Increase the annulus pressure to the safe test pressure and adjust the gas-liquid interface height between the first packer and the casing shoe. Wait 10 minutes until the pressure stabilizes, and then receive the pressure data from the test pressure gauge in real time for 1 hour.

[0031] First Packer Leakage Assessment and Repair: Compare and analyze the data from the storage pressure gauge and the detection pressure gauge. If the data from the storage pressure gauge and the detection pressure gauge are inconsistent, replace both the storage pressure gauge and the detection pressure gauge, and return to the first packer airtightness test procedure. If both the storage pressure gauge and the detection pressure gauge show unqualified data, the first packer is deemed to be unqualified for sealing. Replace the first packer and return to the first packer airtightness test procedure.

[0032] Casing shoe gas seal test: Re-insert the test string and storage pressure gauge, and insert the test pressure gauge into the annulus between the dedicated injection / production string and the test string. Increase the annulus pressure to the safe test pressure and adjust the gas-liquid interface height to below the casing shoe, with a distance ≤1m. Wait 10 minutes until the pressure stabilizes, and then receive the pressure data from the test pressure gauge in real time for 1 hour.

[0033] Sleeve Leak Assessment and Repair: Compare and analyze the data from the storage pressure gauge and the detection pressure gauge. If the results from the storage and detection pressure gauges are inconsistent, replace both gauges and return to the sleeve shoe gas tightness test procedure. If both gauges show unqualified results, the sleeve shoe seal is deemed unqualified. In this case, lower the open-hole sealing string and the second packer, and set the second packer below the sleeve shoe to seal it.

[0034] Open-eye sealed tubing gas tightness test: Insert a test tubing and a storage pressure gauge into the open-eye sealed tubing, and insert the test pressure gauge into the annulus between the open-eye sealed tubing and the test tubing. Increase the annulus pressure to the safe test pressure and adjust the gas-liquid interface height to above the second packer, with a distance ≤1m. Wait 10 minutes until the pressure stabilizes, and then receive the pressure data from the test pressure gauge in real time for 1 hour.

[0035] Leakage Assessment and Repair of Open-Glass Sealing Strings: Compare and analyze the data from the storage pressure gauge and the detection pressure gauge. If the data from the storage and detection pressure gauges are inconsistent, replace both the storage and detection pressure gauges and return to the open-glass sealing string gas tightness test procedure. If both the storage and detection pressure gauges show unqualified data, the open-glass sealing string is deemed unqualified. Replace the open-glass sealing string and return to the open-glass sealing string gas tightness test procedure.

[0036] Second packer gas tightness test: A test column and a storage pressure gauge are inserted into the open-hole sealing column, and a test pressure gauge is inserted into the annulus between the open-hole sealing column and the test column. The annulus pressure is increased to the safe test pressure, and the gas-liquid interface height is adjusted to be below the second packer, with a distance ≤1m. After waiting 10 minutes for the pressure to stabilize, the pressure data from the test pressure gauge is received in real time for 1 hour.

[0037] Second Packer Leakage Assessment and Repair: Compare and analyze the data from the storage pressure gauge and the detection pressure gauge. If the data from the storage pressure gauge and the detection pressure gauge are inconsistent, replace both the storage pressure gauge and the detection pressure gauge, and return to the second packer airtightness test procedure. If both the storage pressure gauge and the detection pressure gauge show unqualified data, the second packer is deemed to be unqualified for sealing. Replace the second packer and return to the second packer airtightness test procedure.

[0038] Specifically, the open hole gas seal testing phase includes open hole gas seal testing, open hole leakage assessment and repair, open hole sealing string gas seal retesting, open hole sealing string retesting leakage assessment and repair, second packer gas seal retesting, and second packer retesting leakage assessment and repair.

[0039] Open-hole gas seal test: If the casing shoe seal fails, run a test string and a storage pressure gauge into the open-hole sealing string, and run a test pressure gauge into the annulus between the open-hole sealing string and the test string. If the casing shoe seal is successful, run a test string and a storage pressure gauge into the dedicated injection-production string, and run a test pressure gauge into the annulus between the dedicated injection-production string and the test string. Increase the annulus pressure to the safe test pressure and adjust the gas-liquid interface height to above the open-hole neck, with a distance ≤1m. Wait 10 minutes until the pressure stabilizes, and then start receiving pressure data from the test pressure gauge in real time for 1 hour.

[0040] Open-hole leakage assessment and repair: Compare and analyze the data from the storage pressure gauge and the detection pressure gauge. If the data from the storage pressure gauge and the detection pressure gauge are inconsistent, replace both the storage pressure gauge and the detection pressure gauge, and return to the open-hole gas seal test procedure. If the casing shoe seal is qualified but both the storage pressure gauge and the detection pressure gauge show unqualified data, the open-hole section is judged to be unqualified. At this time, run the open-hole sealing string and the second packer, and set the second packer above the open-hole neck at a distance ≤1m to seal the casing shoe and the open-hole section. If the casing shoe seal is unqualified and both the storage pressure gauge and the detection pressure gauge show unqualified data, the open-hole section is judged to be unqualified. At this time, unseal the second packer and move it down, then reseat the second packer above the open-hole neck at a distance ≤1m to form a new open-hole sealing string to seal the casing shoe and the open-hole section.

[0041] Retesting the gas tightness of the open-eye sealed tubing: Insert a test tubing and a storage pressure gauge into the open-eye sealed tubing, and insert the test pressure gauge into the annulus between the open-eye sealed tubing and the test tubing. Increase the annulus pressure to the safe test pressure and adjust the gas-liquid interface height to above the second packer, with a distance ≤1m. Wait 10 minutes until the pressure stabilizes, and then receive the pressure data from the test pressure gauge in real time for 1 hour.

[0042] Leakage assessment and repair for open-eye sealed tubing: Compare and analyze the data from the storage pressure gauge and the detection pressure gauge. If the results from the storage and detection pressure gauges are inconsistent, replace both the storage and detection gauges and return to the open-eye sealed tubing gas tightness retesting procedure. If both the storage and detection pressure gauges show unqualified results, the open-eye sealed tubing is deemed to be unqualified. Replace the open-eye sealed tubing and return to the open-eye sealed tubing gas tightness retesting procedure.

[0043] Second packer gas seal retest: Insert a test column and a storage pressure gauge into the open-hole sealing column, and insert a test pressure gauge into the annulus between the open-hole sealing column and the test column. Increase the annulus pressure to the safe test pressure and adjust the gas-liquid interface height to below the second packer, with a distance ≤1m. Wait 10 minutes until the pressure stabilizes, and then receive the pressure data from the test pressure gauge in real time for 1 hour.

[0044] Second Packer Leakage Retesting and Repair: Compare and analyze the data from the storage pressure gauge and the detection pressure gauge. If the results from the storage and detection pressure gauges are inconsistent, replace both the storage and detection pressure gauges and return to the second packer gas tightness retesting procedure. If both the storage and detection pressure gauges show unqualified data, the second packer is deemed to be unqualified. Replace the second packer and return to the second packer gas tightness retesting procedure.

[0045] Specifically, the cavity gas tightness test stage includes calculating drug dosage, drug package delivery, bridge plug sealing test, bridge plug leakage judgment and repair, cavity gas tightness test, and cavity leakage judgment.

[0046] Dosage Calculation: The required dosage of the medicine packet is calculated based on a preset dosage calculation formula. The preset dosage calculation formula is as follows:

[0047]

[0048] in,

[0049] P g This refers to the pressure inside the cavity.

[0050] P0 is the initial pressure inside the cavity, and is the formation pressure.

[0051] m represents the required drug dosage.

[0052] n0 is the amount of substance that produces gas.

[0053] R is the gas constant.

[0054] T represents temperature.

[0055] K is the bulk modulus of the brine.

[0056] m0 represents the unit mass of the drug.

[0057] V w The volume of the brine inside the cavity is the same as the volume of the cavity itself.

[0058] Drug pack placement: Fill the storage well structure with brine and then place the drug pack into the cavity.

[0059] Bridge plug sealing test: Run the bridge plug insertion string and the bridge plug, with a storage pressure gauge connected to the bottom of the bridge plug. Set the bridge plug in the open hole neck. Separate the bridge plug insertion string and the bridge plug, and remove the insertion string. Then continue injecting brine into the dedicated injection-production string to raise the pressure to the safe detection pressure, stabilize the pressure for 1 hour, and receive the pressure data in real time for 1 hour through the pressure gauge at the wellhead.

[0060] Bridge plug leakage assessment and repair: 1 hour later, if the pressure gauge at the wellhead indicates that the bridge plug seal is unqualified, run the bridge plug retrieval string to unseal and retrieve the bridge plug. After replacing the bridge plug, return to the bridge plug seal testing procedure.

[0061] Cavity gas seal test: Wait for the outer shell of the reagent package to degrade in the brine and react with the brine to generate gas, so that the cavity is gradually pressurized. The pressure data in the cavity is stored and recorded by a storage pressure gauge installed on the bridge plug and located in the cavity.

[0062] Leakage Assessment: After 24 hours, lower the salvage bridge plug string to release the bridge plug and depressurize the cavity. Remove the salvage bridge plug string and bridge plug, and read the pressure data from the storage pressure gauge. If the pressure reaches the safety test pressure and remains stable for 1 hour or more before depressurization, the cavity is considered sealed. If the pressure reaches the safety test pressure but the pressure remains stable for less than 1 hour before depressurization, return to the reagent delivery step and extend the observation time. If the pressure reaches the safety test pressure but does not remain stable before depressurization (i.e., the reagent reaction is complete and the cavity pressure reaches its maximum before a pressure drop occurs), the cavity is considered unsealed. Fill the cavity with brine, stabilize the pressure, and let it stand for 20-30 days. Return to the reagent delivery step and repeat 3-5 times. If the seal test still fails, the cavity has natural cracks and is unsuitable for use as an underground storage facility. If the pressure value fails to reach the safe detection pressure, it is determined that the amount of medicine added to the medicine pack is insufficient, and the medicine dosage needs to be readjusted, returning to the medicine pack dispensing step.

[0063] In summary, the technical effects achieved by this invention are as follows:

[0064] The underground storage tank sealing maintenance system includes a basic sealing kit, a graded sealing test kit, and a sealing repair kit. The basic sealing kit is installed on the storage tank wellbore structure and serves as the production tubing. The graded sealing test kit is used to sequentially perform sealing tests on the wellbore interior, open hole section, and cavity. The sealing repair kit is used to repair the sealing of areas where the graded sealing test kit indicates a failure to meet sealing standards.

[0065] As can be seen, compared with existing technologies, this underground storage sealing and maintenance system enhances the sealing performance of the storage well structure by adding a basic sealing kit. Then, it uses a tiered sealing test kit to perform step-by-step sealing tests on the well casing, open hole section, and cavity. If a test fails, the leak location is identified. Finally, a sealing repair kit repairs any abnormal leaks. By implementing corresponding sealing measures for different leak points, this system meets the sealing performance requirements during the construction of underground storage facilities. It overcomes the technical problems of existing well casing sealing test methods, which cannot determine the leak location and lack remedial measures when tests fail. Attached Figure Description

[0066] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0067] Figure 1 This is a schematic diagram of the wellbore when the basic sealing kit of the present invention is installed in the wellbore structure during normal sealing.

[0068] Figure 2 A schematic diagram for sealing testing of a dedicated injection and production tubing string;

[0069] Figure 3 This is a schematic diagram of the sealing test of the first packer.

[0070] Figure 4 A schematic diagram for sealing testing of sleeve shoes;

[0071] Figure 5 A schematic diagram of sealing measures in case of abnormal leakage during casing shoe seal detection;

[0072] Figure 6 This is a schematic diagram of the sealing test of the second packer.

[0073] Figure 7 A schematic diagram illustrating sealing measures in case of abnormal leakage during open-hole well sealing detection;

[0074] Figure 8 A diagram illustrating the placement of a bridge plug in the neck area for the naked eye;

[0075] Figure 9 This is a schematic diagram of the cavity sealing test.

[0076] Figure 10 A flowchart illustrating the sealing measures and step-by-step sealing inspection process for the underground storage facility's inspection and maintenance.

[0077] Figure 11This is a flowchart of the sealing test and sealing measures in case of abnormal leakage for this dedicated injection and production tubing.

[0078] Figure 12 This is a flowchart of the sealing test for the cavity and the sealing measures in case of abnormal leakage.

[0079] Figure 13 This is a schematic diagram for calculating the gas-liquid interface in the annulus.

[0080] icon:

[0081] 001. Storage wellbore structure; 002. Casing; 003. Open hole section; 004. Cavity; 005. Annular protective fluid; 006. Brine; 007. Nitrogen; 008. Casing shoe; 009. Open hole neck; 010. Cementing sheath;

[0082] 100. Basic sealing kit; 110. Dedicated injection / production tubing; 120. First packer;

[0083] 200. Graded sealing test kit; 210. Measurement string assembly; 211. Test string; 212. Cavity test unit; 2121. Bridged plug string; 2122. Bridged plug; 220. Brine and gas injection assembly; 221. Liquid injection unit; 222. Gas injection unit; 230. Pressure detection assembly; 231. Detection pressure gauge; 232. Detection module; 233. Storage pressure gauge;

[0084] 300, Sealing Repair Kit; 310, Open-Glass Sealing String; 320, Second Packer. Detailed Implementation

[0085] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0086] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0087] The following detailed description of some embodiments of the present invention is provided in conjunction with the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0088] Existing wellbore sealing testing methods have technical problems such as being unable to determine the location of leaks and lacking remedial measures when tests fail.

[0089] In view of this, the present invention provides an underground storage sealing and maintenance system, comprising:

[0090] The system comprises a basic sealing kit 100, a graded sealing test kit 200, and a sealing repair kit 300. The basic sealing kit 100 is installed on the reservoir wellbore structure 001 and serves as the production tubing. The graded sealing test kit 200 is used to sequentially perform sealing tests on the wellbore interior, open hole section 003, and cavity 004. The sealing repair kit 300 is used to repair the sealing defects found by the graded sealing test kit 200.

[0091] This underground storage tank sealing and maintenance system enhances the sealing performance of the storage wellbore structure 001 by adding a basic sealing kit 100. Then, a graded sealing test kit 200 sequentially performs sealing tests on the wellbore interior, the open hole section 003, and the cavity 004. If a test fails, the leak location is identified. Finally, a sealing repair kit 300 repairs any abnormal leaks. By implementing corresponding sealing measures for different leak points, this system meets the sealing performance requirements during the construction of underground storage tanks. It overcomes the technical problems of existing wellbore sealing test methods, which cannot pinpoint leak locations and lack remedial measures when tests fail.

[0092] The following combination Figures 1 to 13 The structure and shape of the underground storage sealing and maintenance system provided in this embodiment are described in detail:

[0093] Regarding the structural composition of the storage wellbore structure 001, specifically:

[0094] Storage wellbore structure 001, well wall, casing 002, open hole section 003, cavity 004, casing shoe 008, open hole neck 009, cementing sheath 010;

[0095] The reservoir wellbore structure 001 includes the wellbore, casing 002, cavity 004, casing shoe 008, and cementing sheath 010. The wellbore serves as the outer boundary of the wellbore, directly contacting the surrounding soil and rock layers. Inside the wellbore, the casing 002 is installed; its diameter varies depending on geological conditions and pressure requirements. The casing shoe 008 is located at the lower end of the casing 002. The cementing sheath 010, formed by injecting cement, is located between the casing 002 and the wellbore; it not only secures the casing 002 but also provides a seal to prevent gas and fluid leakage. The cavity 004 is a cavity formed at the bottom of the well by the dissolution of the salt layer, used for gas storage. The open-hole section 003 is the portion of the wellbore between the casing 002 and the cavity 004 without the protection of the casing 002, directly contacting the gas reservoir and serving as the channel for gas injection and extraction. The open-hole neck 009 is located at the junction of the cavity 004 and the open-hole section 003.

[0096] In this embodiment, the basic sealing kit 100 includes a dedicated injection-production string 110 and a first packer 120 installed on the dedicated injection-production string 110. The dedicated injection-production string 110 is seated inside the casing 002 by the first packer 120 as a production string, and the annular space between the dedicated injection-production string 110 and the casing 002 is provided with annular protection fluid 005.

[0097] In this embodiment, the graded sealing test kit 200 includes a measuring tubing assembly 210, a brine and gas injection assembly 220, and a pressure detection assembly 230. The measuring tubing assembly 210 is installed on the reservoir wellbore structure 001, dividing the wellbore structure 001 into a first test area and a second test area. The brine and gas injection assembly 220 includes a liquid injection unit 221 and a gas injection unit 222, used to inject brine 006 or nitrogen 007 into the first and second test areas. The pressure detection assembly 230 is installed on the measuring tubing assembly 210 and includes a pressure gauge 231, a detection module 232, and a storage pressure gauge 233. The pressure gauge 231 is electrically connected to the detection module 232, which is located on the ground, via a cable. The storage pressure gauge 233 is installed at the end of the measuring tubing assembly 210 away from the ground. Both the pressure gauge 231 and the storage pressure gauge 233 are immersed in the brine 006 and serve as data verification objects for each other. The first and second test zones are physically isolated by a measuring tube assembly 210. The sealing condition of the gas storage space can be assessed by periodically monitoring the internal nitrogen or brine pressure and the depth of the gas-liquid interface. Any pressure anomalies or changes in the gas-liquid interface depth may indicate the presence of a leak.

[0098] In this embodiment, the measurement string assembly 210 includes a detection string 211 and a cavity testing unit 212, used for sealing detection of the dedicated injection-production string 110, the open hole section 003, and the cavity 004, respectively. A storage pressure gauge 233 is installed at the end of the detection string 211 or the cavity testing unit 212 away from the ground. The cavity testing unit 212 includes a bridging plug string 2121, a bridging plug 2122, and a reagent package. The bridging plug 2122 is detachably connected to the end of the bridging plug string 2121 away from the ground and is seated on the open hole neck 009, used to separate the cavity 004 from the reservoir wellbore structure 001. The storage pressure gauge 233 is detachably connected to the lower part of the bridging plug 2122. The reagent package is configured as a capsule structure, with the outer shell made of a material biodegradable by brine 006, and the interior containing a reagent that reacts with brine 006 to generate gas. The gas generated by the reaction of the reagent with brine 006 replaces the gas injection unit 222 to pressurize the inside of cavity 004.

[0099] In this embodiment, the sealing repair kit 300 includes an open-hole sealing string 310, a second packer 320, and a basic sealing kit 100. Both the basic sealing kit 100 and the open-hole sealing string 310 achieve sealing repair by replacing spare parts. The second packer 320 can be installed on the open-hole sealing string 310 and, through its cooperation with the open-hole sealing string 310, achieves sealing repair of the casing shoe 008 and the open-hole section 003. Because the second packer 320 needs to simultaneously pass through the dedicated injection-production string 110 and be seated in the open-hole section 003, the expansion ratio of the second packer 320 is much greater than that of the first packer 120.

[0100] In this embodiment, both the detection string 211 and the open-hole sealing string 310 are equipped with a flared end. The flared end is located at the end of the string furthest from the ground, serving as a marker for the very end of the string. If the string is retrieved from the well and reaches the flared end, it indicates that the string has been completely retrieved. If no flared end is seen and the string is no longer in the well, it indicates that part of the string has fallen into the well and a retrieval operation is required.

[0101] In this embodiment, the threads at each connection are machined into air-tight threads, and air-tight thread oil is applied to the male threads.

[0102] The present invention also provides a method for the inspection and maintenance of underground storage facilities, which uses the above-mentioned underground storage facility sealing inspection and maintenance system and includes the following steps:

[0103] The wellbore system is divided into four stages: overall water tightness testing, in-wellbore gas tightness testing, open-hole section gas tightness testing, and cavity gas tightness testing. The overall water tightness testing stage is used to test and repair the overall water tightness of the wellbore structure 001. The in-wellbore gas tightness testing stage is used to test and repair the gas tightness of the dedicated injection-production tubing string 110, the first packer 120, the casing shoe 008, the open-hole sealing tubing string 310, and the second packer 320. The open-hole section gas tightness testing stage is used to test and repair the gas tightness of the open-hole section 003. The cavity gas tightness testing stage is used to test the gas tightness of cavity 004. This refined, step-by-step sealing test allows for rapid identification of leak locations and the implementation of corresponding sealing measures to meet the sealing performance requirements during the construction of underground reservoirs.

[0104] In this embodiment, the overall water seal test stage includes water seal testing and water seal leakage detection and repair.

[0105] Water seal test: Brine 006 is injected into the wellbore structure 001 of the reservoir and pressurized. Pressure gauge 231 is lowered into the well and the pressure is increased to the safe test pressure. After waiting for 10 minutes and the pressure stabilizes, the pressure data of pressure gauge 231 is received in real time within 24 hours, and then pressure gauge 231 is raised. The safe test pressure is 0.9 times the maximum withstand pressure of cavity 004.

[0106] Water seal leakage assessment and repair: The standard for judging whether the seal is qualified is that the pressure drop is no more than 0.1 MPa within 24 hours. When the data from pressure gauge 231 indicates that the seal is unqualified, the brine 006 in the reservoir well structure 001 is extracted, and then gel with twice the volume of the reservoir well structure 001 is injected into the reservoir well structure 001 and pressurized for 5 days. The pressurized gel fills the cracks to repair the water tightness of the reservoir well structure 001. After 5 days, the excess gel is extracted, and the water seal test procedure is returned.

[0107] In this embodiment, the wellbore gas seal testing stage includes gas seal testing of a dedicated injection-production tubing string, leakage judgment and repair of the injection-production tubing string, gas seal testing of the first packer, leakage judgment and repair of the first packer, gas seal testing of the casing shoe, leakage judgment and repair of the casing shoe, gas seal testing of the open hole sealing tubing string, leakage judgment and repair of the open hole sealing tubing string, gas seal testing of the second packer and leakage judgment and repair of the second packer.

[0108] Gas-tightness test of dedicated injection-production tubing: Dedicated injection-production tubing 110 and the first packer 120 are lowered into the casing 002, positioned within 5m above the casing shoe 008. A detection tubing 211 is lowered into the dedicated injection-production tubing 110, and a pressure gauge 231 is lowered into the annulus between the dedicated injection-production tubing 110 and the detection tubing 211. The annulus pressure is increased to the safe detection pressure, and the gas-liquid interface height is adjusted to be above the first packer 120, with a distance ≤1m. After waiting 10 minutes for the pressure to stabilize, pressure data from the pressure gauge 231 is received in real-time for 1 hour.

[0109] The current gas-liquid interface height in the annulus is calculated based on a preset formula. The preset formula for calculating the gas-liquid interface height is as follows:

[0110]

[0111] in,

[0112] h represents the height of the gas-liquid interface within the annulus.

[0113] H represents the total depth to which the pressure gauge 231 is inserted.

[0114] △h represents the depth of the pressure gauge 231 below the gas-liquid interface during the sealing test.

[0115] P w The pressure value was read after the pressure gauge 231 was inserted into the brine depth H in the annulus and remained still for 10 minutes.

[0116] P1 is the pressure value read after the pressure gauge 231 has been stationary for 10 minutes at a depth h0 within the inert gas column in the annulus.

[0117] h0 is the height at which the pressure gauge 231 is lifted into the inert gas column within the annulus.

[0118] P2 is the pressure value read after the pressure gauge 231 is raised 25m from a depth h0 inside the inert gas column in the annulus and left to stand for 10 minutes.

[0119] Leakage Assessment and Repair of Injection-Production Tubing: Compare and analyze the data from the storage pressure gauge 233 with the data from the detection pressure gauge 231. The standard for judging whether the seal is qualified is that the pressure drop is not greater than 0.1 MPa within 1 hour. When the data from the storage pressure gauge 233 and the detection pressure gauge 231 are inconsistent, replace both the storage pressure gauge 233 and the detection pressure gauge 231, and return to the dedicated injection-production tubing gas tightness test procedure. When both the storage pressure gauge 233 and the detection pressure gauge 231 show a non-qualified data assessment result, it is determined that the dedicated injection-production tubing 110 is unqualified for sealing. Replace the dedicated injection-production tubing 110, and return to the dedicated injection-production tubing gas tightness test procedure.

[0120] First packer gas tightness test: Insert the test string 211 and storage pressure gauge 233, and insert the test pressure gauge 231 into the annulus between the dedicated injection / production string 110 and the test string 211. Increase the annulus pressure to the safe test pressure and adjust the gas-liquid interface height between the first packer 120 and the casing shoe 008. Wait 10 minutes until the pressure stabilizes, then begin real-time reception of the pressure data from the test pressure gauge 231 for 1 hour.

[0121] First Packer Leakage Assessment and Repair: Compare and analyze the data from the storage pressure gauge 233 with the data from the detection pressure gauge 231. If the data from the storage pressure gauge 233 and the detection pressure gauge 231 are inconsistent, replace both the storage pressure gauge 233 and the detection pressure gauge 231, and return to the first packer airtightness test procedure. If both the storage pressure gauge 233 and the detection pressure gauge 231 show unqualified data, the first packer 120 is deemed to be unqualified for sealing. Replace the first packer 120, and return to the first packer airtightness test procedure.

[0122] Gas seal test of casing shoe: Re-insert the test string 211 and the storage pressure gauge 233, and insert the test pressure gauge 231 into the annulus between the dedicated injection / production string 110 and the test string 211. Increase the annulus pressure to the safe test pressure and adjust the gas-liquid interface height to below the casing shoe 008, with a distance ≤1m. Wait 10 minutes until the pressure stabilizes, and then start receiving the pressure data of the test pressure gauge 231 in real time for 1 hour.

[0123] Leakage detection and repair of the casing shoe: Compare and analyze the data from the storage pressure gauge 233 with the data from the detection pressure gauge 231. If the data from the storage pressure gauge 233 and the detection pressure gauge 231 are inconsistent, replace both the storage pressure gauge 233 and the detection pressure gauge 231, and return to the casing shoe airtightness test procedure. If both the storage pressure gauge 233 and the detection pressure gauge 231 show unqualified data, the casing shoe 008 is judged to be unqualified for sealing. At this time, lower the open-hole sealing tube 310 and the second packer 320, and set the second packer 320 below the casing shoe 008 to seal the casing shoe 008.

[0124] Open-eye sealed tubing gas tightness test: Insert the test tubing 211 and storage pressure gauge 233 into the open-eye sealed tubing 310, and insert the test pressure gauge 231 into the annulus between the open-eye sealed tubing 310 and the test tubing 211. Increase the annulus pressure to the safe test pressure and adjust the gas-liquid interface height above the second packer 320, with a distance ≤1m. Wait 10 minutes until the pressure stabilizes, then begin real-time reception of pressure data from the test pressure gauge 231 for 1 hour.

[0125] Leakage assessment and repair of the open-eye sealed tubing: Compare and analyze the data from the storage pressure gauge 233 with the data from the detection pressure gauge 231. If the data from the storage pressure gauge 233 and the detection pressure gauge 231 are inconsistent, replace both the storage pressure gauge 233 and the detection pressure gauge 231, and return to the open-eye sealed tubing gas tightness test procedure. If both the storage pressure gauge 233 and the detection pressure gauge 231 show unqualified data, the open-eye sealed tubing 310 is deemed to be unqualified for sealing. Replace the open-eye sealed tubing 310, and return to the open-eye sealed tubing gas tightness test procedure.

[0126] Second packer gas tightness test: A test column 211 and a storage pressure gauge 233 are inserted into the open-hole sealing column 310, and the test pressure gauge 231 is inserted into the annulus between the open-hole sealing column 310 and the test column 211. The annulus pressure is increased to the safe test pressure, and the gas-liquid interface height is adjusted to be below the second packer 320, with a distance ≤1m. After waiting 10 minutes for the pressure to stabilize, pressure data from the test pressure gauge 231 is received in real time for 1 hour.

[0127] Second Packer Leakage Assessment and Repair: Compare and analyze the data from the storage pressure gauge 233 with the data from the detection pressure gauge 231. If the data from the storage pressure gauge 233 and the detection pressure gauge 231 are inconsistent, replace both the storage pressure gauge 233 and the detection pressure gauge 231, and then return to the second packer gas tightness test procedure. If both the storage pressure gauge 233 and the detection pressure gauge 231 show unqualified data, the second packer 320 is deemed to be unqualified for sealing. Replace the second packer 320, and then return to the second packer gas tightness test procedure.

[0128] In this embodiment, the open hole gas seal test stage includes open hole gas seal test, open hole leakage judgment and repair, open hole sealing string gas seal retest, open hole sealing string retest leakage judgment and repair, second packer gas seal retest and second packer retest leakage judgment and repair.

[0129] Open-hole gas seal test: If the casing shoe 008 seal fails, run a test string 211 and a storage pressure gauge 233 into the open-hole sealing string 310, and run the test pressure gauge 231 into the annulus between the open-hole sealing string 310 and the test string 211. If the casing shoe 008 seal passes, run a test string 211 and a storage pressure gauge 233 into the dedicated injection-production string 110, and run the test pressure gauge 231 into the annulus between the dedicated injection-production string 110 and the test string 211. Increase the annulus pressure to the safe test pressure and adjust the gas-liquid interface height above the open-hole neck 009, with a distance ≤1m. Wait 10 minutes until the pressure stabilizes, and then start receiving the pressure data from the test pressure gauge 231 in real time for 1 hour.

[0130] Leakage judgment and repair of open-hole section: Compare and analyze the data of the memory pressure gauge 233 with the data of the detection pressure gauge 231. When the judgment results of the data of the memory pressure gauge 233 and the detection pressure gauge 231 are inconsistent, after replacing the memory pressure gauge 233 and the detection pressure gauge 231, return to the gas tightness test step of the open-hole section. When the casing shoe 008 is sealed qualified and both the memory pressure gauge 233 and the detection pressure gauge 231 show that the judgment result of the data is unqualified, it is judged that the open-hole section 003 is sealed unqualified. At this time, lower the open-hole seal string 310 and the second packer 320, set the second packer 320 above the open-hole neck 009, and the distance ≤ 1m, so as to isolate the casing shoe 008 and the open-hole section 003. When the casing shoe 008 is sealed unqualified and both the memory pressure gauge 233 and the detection pressure gauge 231 show that the judgment result of the data is unqualified, it is judged that the open-hole section 003 is sealed unqualified. At this time, release the second packer 320 and move it down, reset the second packer 320 above the open-hole neck 009, and the distance ≤ 1m, to form a new open-hole seal string 310, so as to isolate the casing shoe 008 and the open-hole section 003.

[0131] Gas tightness retest of open-hole seal string: Lower the detection string 211 and the memory pressure gauge 233 into the open-hole seal string 310, and lower the detection pressure gauge 231 into the annulus between the open-hole seal string 310 and the detection string 211. Raise the annulus pressure to the safe detection pressure and adjust the gas-liquid interface height to above the second packer 320, and the distance ≤ 1m. Wait for 10 min. After the pressure is stable, start receiving the pressure data of the detection pressure gauge 231 in real time for 1 h.

[0132] Leakage judgment and repair of open-hole seal string retest: Compare and analyze the data of the memory pressure gauge 233 with the data of the detection pressure gauge 231. When the judgment results of the data of the memory pressure gauge 233 and the detection pressure gauge 231 are inconsistent, after replacing the memory pressure gauge 233 and the detection pressure gauge 231, return to the gas tightness retest step of the open-hole seal string. When both the memory pressure gauge 233 and the detection pressure gauge 231 show that the judgment result of the data is unqualified, it is judged that the open-hole seal string 310 is sealed unqualified. After replacing the open-hole seal string 310, return to the gas tightness retest step of the open-hole seal string.

[0133] Gas tightness retest of the second packer: Lower the detection string 211 and the memory pressure gauge 233 into the open-hole seal string 310, and lower the detection pressure gauge 231 into the annulus between the open-hole seal string 310 and the detection string 211. Raise the annulus pressure to the safe detection pressure and adjust the gas-liquid interface height to below the second packer 320, and the distance ≤ 1m. Wait for 10 min. After the pressure is stable, start receiving the pressure data of the detection pressure gauge 231 in real time for 1 h.

[0134] Second Packer Leakage Retesting and Repair: Compare and analyze the data from the storage pressure gauge 233 with the data from the detection pressure gauge 231. If the data from the storage pressure gauge 233 and the detection pressure gauge 231 are inconsistent, replace both the storage pressure gauge 233 and the detection pressure gauge 231, and return to the second packer gas tightness retesting step. If both the storage pressure gauge 233 and the detection pressure gauge 231 show unqualified data, the second packer 320 is judged to be unqualified for sealing. Replace the second packer 320, and return to the second packer gas tightness retesting step.

[0135] In this embodiment, the cavity airtightness test stage includes calculating drug dosage, drug package delivery, bridge plug sealing test, bridge plug leakage judgment and repair, cavity airtightness test, and cavity leakage judgment.

[0136] Dosage Calculation: The required dosage of the medicine packet is calculated based on a preset dosage calculation formula. The preset dosage calculation formula is as follows:

[0137]

[0138] in,

[0139] P g The pressure value read by the storage pressure gauge 233 inside cavity 004.

[0140] P0 is the initial pressure inside cavity 004, and is the formation pressure.

[0141] m represents the required drug dosage.

[0142] n0 is the amount of substance that produces gas.

[0143] R is the gas constant.

[0144] T represents temperature.

[0145] K is the bulk modulus of brine 006.

[0146] m0 represents the unit mass of the drug.

[0147] V w The volume of brine 006 inside cavity 004 is the same as the volume of cavity 004.

[0148] Drug pack placement: Fill the storage well structure 001 with brine 006 and put the drug pack into the cavity 004.

[0149] Bridge plug sealing test: Run bridge plug string 2121 and bridge plug 2122, and set bridge plug 2122 in the open hole neck 009. Separate bridge plug string 2121 and bridge plug 2122 and remove bridge plug string 2121. Then continue to inject brine 006 into the dedicated injection and production string 110 to raise the pressure to the safe detection pressure, stabilize the pressure for 1 hour, and receive the pressure data of the detection pressure gauge 231 in real time through the pressure gauge at the wellhead for 1 hour.

[0150] Bridge plug leakage assessment and repair: 1 hour later, when the pressure gauge at the wellhead indicates that bridge plug 2122 is not properly sealed, the bridge plug retrieval string is lowered to unseal and retrieve bridge plug 2122. After replacing bridge plug 2122, return to the bridge plug seal testing procedure.

[0151] Cavity gas seal test: Wait for the outer shell of the reagent package to degrade in brine 006 and react with brine 006 to generate gas, so that the pressure in cavity 004 is gradually increased. The pressure data in the cavity is stored and recorded by the storage pressure gauge 233 installed on the bridge plug 2122 and located in cavity 004.

[0152] Cavity Leakage Assessment: After 24 hours, the retrieval bridge plug string is lowered to unseal bridge plug 2122, completing the depressurization of cavity 004. The retrieval bridge plug string and bridge plug 2122 are then removed, and the pressure data from the storage pressure gauge 233 is read. If the pressure value reaches the safety detection pressure, and the pressure remains stable for 1 hour or more before depressurization, cavity 004 is considered to be properly sealed. If, at this point, the pressure value reaches the safety detection pressure, but the pressure remains stable for less than 1 hour before depressurization, the procedure returns to the reagent pack dispensing step, and the observation time is extended. If the pressure reaches the safe testing pressure, but there is no time for pressure stabilization before depressurization, indicating that the reagent reaction is complete and the pressure drops before reaching its maximum in cavity 004, it is determined that the seal of cavity 004 is unqualified. Fill cavity 004 with brine 006, stabilize the pressure, and let it stand for 20-30 days. Return to the reagent pack addition procedure and repeat 3-5 times. If the seal test still fails, it is determined that cavity 004 has natural cracks and is unsuitable for use as an underground storage facility. If the pressure fails to reach the safe testing pressure, it is determined that the amount of reagent added to the reagent pack is insufficient, and the dosage needs to be readjusted. Return to the reagent pack addition procedure.

[0153] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A sealed maintenance system for underground storage facilities, characterized in that... ,include: The package includes a basic sealing kit (100), a graded sealing test kit (200), and a sealing repair kit (300). The basic sealing kit (100) is installed on the reservoir wellbore structure (001) and is used as a production tubing. The graded sealing test kit (200) is used to sequentially perform sealing tests on the wellbore, the open hole section (003), and the cavity (004). The sealing repair kit (300) is used to repair the sealing performance of areas where the graded sealing test kit (200) indicates that the sealing is substandard.

2. The underground storage sealing and maintenance system according to claim 1, characterized in that... : The basic sealing kit (100) includes a dedicated injection and production line (110) and a first packer (120) installed on the dedicated injection and production line (110); the dedicated injection and production line (110) is set inside the casing (002) by the first packer (120) as a production line, and the annular space between the dedicated injection and production line (110) and the casing (002) is provided with annular protective fluid (005).

3. The underground storage sealing and maintenance system according to claim 1, characterized in that... : The graded sealing test kit (200) includes a measurement string assembly (210), a brine and gas injection assembly (220), and a pressure detection assembly (230); the measurement string assembly (210) is installed on the reservoir wellbore structure (001) and divides the reservoir wellbore structure (001) into a first test area and a second test area; the brine and gas injection assembly (220) includes a liquid injection unit (221) and a gas injection unit (222) for injecting brine (006) or nitrogen (007) into the first test area and the second test area; the pressure detection assembly (230) 30) Installed on the measuring column assembly (210), the pressure detection assembly (230) includes a detection pressure gauge (231), a detection module (232), and a storage pressure gauge (233); the detection pressure gauge (231) is electrically connected to the detection module (232) set on the ground via a cable, and the storage pressure gauge (233) is installed at the end of the measuring column assembly (210) away from the ground; the detection pressure gauge (231) and the storage pressure gauge (233) are both immersed in the brine (006) and serve as data verification objects for each other.

4. The underground storage sealing and maintenance system according to claim 3, characterized in that... : The measurement string assembly (210) includes a detection string (211) and a cavity testing unit (212), used for sealing detection of the dedicated injection-production string (110), the open hole section (003), and the cavity (004), respectively; the storage pressure gauge (233) is installed at the end of the detection string (211) or the cavity testing unit (212) away from the ground; the cavity testing unit (212) includes a bridging plug string (2121), a bridging plug (2122), and a reagent package; The bridge plug (2122) is detachably connected to the end of the bridge plug string (2121) away from the ground and seated on the open hole neck (009) to separate the cavity (004) from the reservoir wellbore structure (001); the storage pressure gauge (233) is detachably connected to the bridge plug (2122); the reagent package is configured as a capsule structure, the outer shell is made of a material that can be degraded by the brine (006), and the inside contains a reagent that can react with the brine (006) to generate gas.

5. The underground storage sealing and maintenance system according to claim 4, characterized in that... : The sealing repair kit (300) includes an open-hole sealing string (310), a second packer (320), and the base sealing kit (100); both the base sealing kit (100) and the open-hole sealing string (310) achieve sealing repair by replacing spare parts; the second packer (320) can be installed on the open-hole sealing string (310) and achieves sealing repair of the casing shoe (008) and the open-hole section (003) by cooperating with the open-hole sealing string (310).

6. A method for inspecting and maintaining an underground storage facility, used in the underground storage facility sealing inspection system as described in any one of claims 1 to 5, characterized by the following steps: The test includes an overall water seal test stage, a wellbore gas seal test stage, an open hole section gas seal test stage, and a cavity gas seal test stage. The overall water seal test stage is used to test and repair the overall water tightness of the reservoir wellbore structure (001). The wellbore gas seal test stage is used to test and repair the gas tightness of the dedicated injection and production tubing string (110), the first packer (120), the casing shoe (008), the open hole sealing tubing string (310), and the second packer (320). The open hole section gas seal test stage is used to test and repair the gas tightness of the open hole section (003). The cavity gas seal test stage is used to test the gas tightness of the cavity (004).

7. The method for inspecting and maintaining underground storage facilities according to claim 6, characterized in that... : The overall water seal testing phase includes water seal testing and water seal leakage detection and repair. Water seal test: The brine (006) is injected into the well structure (001) of the reservoir and pressurized. The pressure gauge (231) is lowered and the pressure is increased to the safe test pressure. After waiting for 10 minutes and the pressure stabilizes, the pressure data of the pressure gauge (231) is received in real time within 24 hours. The pressure gauge (231) is then lifted. The safe test pressure is 0.9 times the maximum pressure that the cavity (004) can withstand. Water seal leakage judgment and repair: The standard for judging the sealing performance is that the pressure data drops by no more than 0.1 MPa within 24 hours; when the data judgment result of the pressure gauge (231) is unqualified, the brine (006) in the reservoir well structure (001) is extracted, and then gel with twice the volume of the reservoir well structure (001) is injected into the reservoir well structure (001) and stabilized for 5 days; after 5 days, the excess gel is extracted and the water seal test procedure is returned.

8. The method for inspecting and maintaining underground storage facilities according to claim 7, characterized in that... : The wellbore gas seal testing phase includes gas seal testing of the dedicated injection and production tubing, leakage detection and repair of the injection and production tubing, gas seal testing of the first packer, leakage detection and repair of the first packer, gas seal testing of the casing shoe, leakage detection and repair of the casing shoe, gas seal testing of the open hole sealing tubing, leakage detection and repair of the open hole sealing tubing, gas seal testing of the second packer and leakage detection and repair of the second packer; Gas-tightness test of dedicated injection and production tubing: The dedicated injection and production tubing (110) and the first packer (120) are lowered into the casing (002), and the first packer (120) is set in the casing (002) and located within 5m above the casing shoe (008); The detection tubing (211) is lowered into the dedicated injection and production tubing (110), and the detection pressure gauge (231) is lowered into the annulus between the dedicated injection and production tubing (110) and the detection tubing (211); The annulus pressure is raised to the safe detection pressure and the gas-liquid interface height is adjusted to be above the first packer (120) and the distance is ≤1m. Wait for 10 minutes. After the pressure stabilizes, the pressure data of the detection pressure gauge (231) is received in real time for 1 hour. The current gas-liquid interface height in the annulus is calculated using a preset formula. The preset formula for calculating the gas-liquid interface height is as follows: in, h is the height of the gas-liquid interface in the annulus; H is the total depth to which the pressure gauge (231) is inserted; △h is the depth of the detection pressure gauge (231) below the gas-liquid interface during the sealing test; P w The pressure value is read after the pressure gauge (231) is lowered into the brine in the annulus to a depth H and remains still for 10 minutes. P1 is the pressure value read after the pressure gauge (231) has been stationary for 10 minutes at a depth h0 in the inert gas column in the annulus. h0 is the lifting height of the detection pressure gauge (231) into the inert gas column in the annulus; P2 is the pressure value read after the pressure gauge (231) is raised 25m from a depth h0 inside the inert gas column in the annulus and left to stand for 10 minutes. Leakage Judgment and Repair of Injection and Production Tubing: Compare and analyze the data from the storage pressure gauge (233) and the detection pressure gauge (231); the standard for judging whether the sealing is qualified is that the pressure data drops by no more than 0.1 MPa within 1 hour; when the judgment results of the data from the storage pressure gauge (233) and the detection pressure gauge (231) are inconsistent, replace the storage pressure gauge (233) and the detection pressure gauge (231) and return to the dedicated injection and production tubing gas seal test step; when both the storage pressure gauge (233) and the detection pressure gauge (231) show that the data judgment result is unqualified, it is judged that the dedicated injection and production tubing (110) is unqualified for sealing, replace the dedicated injection and production tubing (110) and return to the dedicated injection and production tubing gas seal test step; First packer gas tightness test: The detection string (211) and the storage pressure gauge (233) are lowered in, and the detection pressure gauge (231) is lowered in the annulus between the dedicated injection and production string (110) and the detection string (211); the annulus pressure is raised to the safe detection pressure and the gas-liquid interface height is adjusted between the first packer (120) and the casing shoe (008). After waiting for 10 minutes and the pressure stabilizes, the pressure data of the detection pressure gauge (231) is received in real time for 1 hour. First packer leakage judgment and repair: Compare and analyze the data of the storage pressure gauge (233) with the data of the detection pressure gauge (231); when the judgment results of the data of the storage pressure gauge (233) and the detection pressure gauge (231) are inconsistent, replace the storage pressure gauge (233) and the detection pressure gauge (231) and return to the first packer gas tightness test step; when both the storage pressure gauge (233) and the detection pressure gauge (231) show that the data judgment result is unqualified, it is judged that the first packer (120) is unqualified for sealing, replace the first packer (120) and return to the first packer gas tightness test step; Gas seal test of the casing shoe: Re-insert the detection string (211) and the storage pressure gauge (233), and insert the detection pressure gauge (231) into the annulus between the dedicated injection and production string (110) and the detection string (211); raise the annulus pressure to the safe detection pressure and adjust the gas-liquid interface height to below the casing shoe (008) with a distance ≤1m, wait for 10min, and after the pressure stabilizes, receive the pressure data of the detection pressure gauge (231) in real time for 1 hour; Leakage detection and repair of the sleeve shoe: The data of the storage pressure gauge (233) and the data of the detection pressure gauge (231) are compared and analyzed; when the data judgment results of the storage pressure gauge (233) and the detection pressure gauge (231) are inconsistent, the storage pressure gauge (233) and the detection pressure gauge (231) are replaced, and the sleeve shoe air tightness test step is returned; when the data judgment results of the storage pressure gauge (233) and the detection pressure gauge (231) are both unqualified, it is determined that the sleeve shoe (008) is unqualified; the bare hole sealing tube column (310) and the second packer (320) are lowered, and the second packer (320) is set below the sleeve shoe (008) to seal the sleeve shoe (008); Airtightness test of the open-eye sealed column: The detection column (211) and the storage pressure gauge (233) are inserted into the open-eye sealed column (310), and the detection pressure gauge (231) is inserted into the annulus between the open-eye sealed column (310) and the detection column (211); the annulus pressure is increased to the safe detection pressure and the gas-liquid interface height is adjusted to be above the second packer (320) and the distance is ≤1m. Wait for 10 minutes. After the pressure stabilizes, the pressure data of the detection pressure gauge (231) is received in real time for 1 hour. Leakage detection and repair of the naked-eye sealed tubing: Compare and analyze the data from the storage pressure gauge (233) with the data from the detection pressure gauge (231); when the data judgment results of the storage pressure gauge (233) and the detection pressure gauge (231) are inconsistent, replace the storage pressure gauge (233) and the detection pressure gauge (231) and return to the naked-eye sealed tubing gas tightness test step; when both the storage pressure gauge (233) and the detection pressure gauge (231) show that the data judgment result is unqualified, it is determined that the naked-eye sealed tubing (310) is unqualified for sealing, replace the naked-eye sealed tubing (310) and return to the naked-eye sealed tubing gas tightness test step; Second packer gas tightness test: The detection column (211) and the storage pressure gauge (233) are lowered into the open-hole sealing column (310), and the detection pressure gauge (231) is lowered into the annulus between the open-hole sealing column (310) and the detection column (211); the annulus pressure is raised to the safe detection pressure and the gas-liquid interface height is adjusted to be below the second packer (320) and the distance is ≤1m. Wait for 10 minutes. After the pressure stabilizes, the pressure data of the detection pressure gauge (231) is received in real time for 1 hour. Second packer leakage judgment and repair: Compare and analyze the data of the storage pressure gauge (233) with the data of the detection pressure gauge (231); when the judgment results of the data of the storage pressure gauge (233) and the detection pressure gauge (231) are inconsistent, replace the storage pressure gauge (233) and the detection pressure gauge (231) and return to the second packer gas tightness test step; when both the storage pressure gauge (233) and the detection pressure gauge (231) show that the data judgment result is unqualified, it is judged that the second packer (320) is unqualified for sealing, replace the second packer (320) and return to the second packer gas tightness test step.

9. The method for inspecting and maintaining underground storage facilities according to claim 8, characterized in that... : The open hole gas seal test phase includes open hole gas seal test, open hole leakage judgment and repair, open hole sealing string gas seal retest, open hole sealing string retest leakage judgment and repair, second packer gas seal retest and second packer retest leakage judgment and repair. Gas seal test of open hole section: If the casing shoe (008) seal is unqualified, the detection string (211) and the storage pressure gauge (233) are installed in the open hole sealing string (310), and the detection pressure gauge (231) is installed in the annulus between the open hole sealing string (3100) and the detection string (211); If the casing shoe (008) seal is qualified, the detection string (211) and the storage pressure gauge (233) are installed in the dedicated injection and production string (110), and the detection pressure gauge (231) is installed in the annulus between the dedicated injection and production string (110) and the detection string (211); The annulus pressure is raised to the safe detection pressure and the gas-liquid interface height is adjusted to above the open hole neck (009) with a distance ≤1m. Wait for 10 minutes. After the pressure stabilizes, the pressure data of the detection pressure gauge (231) is received in real time for 1 hour. Leakage Judgment and Repair in Open Hole Section: Compare and analyze the data from the storage pressure gauge (233) with the data from the detection pressure gauge (231); when the data judgment results of the storage pressure gauge (233) and the detection pressure gauge (231) are inconsistent, replace the storage pressure gauge (233) and the detection pressure gauge (231), and return to the open hole section gas seal test step; when the casing shoe (008) is sealed and both the storage pressure gauge (233) and the detection pressure gauge (231) show data judgment results of being unqualified, it is judged that the open hole section (003) is unqualified; run the open hole sealing string (310) and the second packer (32) into the well. 0), the second packer (320) is set above the open hole neck (009) at a distance ≤1m to seal the casing shoe (008) and the open hole section (003); when the casing shoe (008) is not sealed properly and both the storage pressure gauge (233) and the detection pressure gauge (231) show unqualified data, it is determined that the open hole section (003) is not sealed properly; the second packer (320) is unsealed and moved down, and the second packer (320) is re-set above the open hole neck (009) at a distance ≤1m to seal the casing shoe (008) and the open hole section (003); Airtightness retest of the open-eye sealed column: The detection column (211) and the storage pressure gauge (233) are lowered into the open-eye sealed column (310), and the detection pressure gauge (231) is lowered into the annulus between the open-eye sealed column (310) and the detection column (211); the annulus pressure is raised to the safe detection pressure and the gas-liquid interface height is adjusted to be above the second packer (320) and the distance is ≤1m. Wait for 10 minutes. After the pressure stabilizes, the pressure data of the detection pressure gauge (231) is received in real time for 1 hour. Leakage detection and repair of the naked-eye sealed tubing: Compare and analyze the data from the storage pressure gauge (233) with the data from the detection pressure gauge (231); when the data judgment results of the storage pressure gauge (233) and the detection pressure gauge (231) are inconsistent, replace the storage pressure gauge (233) and the detection pressure gauge (231) and return to the naked-eye sealed tubing gas seal retesting step; when both the storage pressure gauge (233) and the detection pressure gauge (231) show that the data judgment result is unqualified, it is determined that the naked-eye sealed tubing (310) is unqualified, replace the naked-eye sealed tubing (310) and return to the naked-eye sealed tubing gas seal retesting step; Second packer gas seal retest: The detection column (211) and the storage pressure gauge (233) are lowered into the open-hole sealing column (310), and the detection pressure gauge (231) is lowered into the annulus between the open-hole sealing column (310) and the detection column (211); the annulus pressure is raised to the safe detection pressure and the gas-liquid interface height is adjusted to be below the second packer (320) and the distance is ≤1m. Wait for 10 minutes. After the pressure stabilizes, the pressure data of the detection pressure gauge (231) is received in real time for 1 hour. Second packer retest leakage judgment and repair: Compare and analyze the data of the storage pressure gauge (233) with the data of the detection pressure gauge (231); when the judgment results of the data of the storage pressure gauge (233) and the detection pressure gauge (231) are inconsistent, replace the storage pressure gauge (233) and the detection pressure gauge (231) and return to the second packer gas seal retest step; when both the storage pressure gauge (233) and the detection pressure gauge (231) show that the data judgment result is unqualified, it is judged that the second packer (320) is unqualified, replace the second packer (320) and return to the second packer gas seal retest step.

10. The method for inspecting and maintaining underground storage facilities according to claim 9, characterized in that... : The cavity airtightness test stage includes calculating drug dosage, drug package delivery, bridge plug sealing test, bridge plug leakage judgment and repair, cavity airtightness test, and cavity leakage judgment. Dosage calculation: The required dosage of the medicine package is calculated based on a preset dosage calculation formula. The preset dosage calculation formula is as follows: in, P g The pressure inside the cavity (004); P0 is the initial pressure inside the cavity (004), which is the formation pressure; m represents the required drug dosage; n0 is the amount of substance that produces gas; R is the gas constant; T represents temperature; K is the bulk modulus of the brine (006); m0 is the unit mass of the drug; V w The volume of the brine (006) inside the cavity (004) is the same as the volume of the cavity (004); Drug pack delivery: Fill the storage well structure (001) with the brine (006) and put the drug pack into the cavity (004); Bridge plug sealing test: The bridge plug string (2121) and the bridge plug (2122) are lowered into the well. The bottom of the bridge plug (2122) is connected to the storage pressure gauge (233). The bridge plug (2122) is seated on the open hole neck (009). The bridge plug string (2121) and the bridge plug (2122) are separated and the bridge plug string (2121) is removed. The brine (006) is then injected into the dedicated injection and production string (110) to raise the pressure to the safe detection pressure. The pressure is stabilized for 1 hour. The pressure data of the detection pressure gauge (231) is received in real time for 1 hour through the pressure gauge at the wellhead. Bridge plug leakage judgment and repair: 1 hour later, when the data displayed by the pressure gauge at the wellhead indicates that the bridge plug (2122) is not sealed properly, the bridge plug retrieval string is lowered to unseal the bridge plug (2122) and remove it; after replacing the bridge plug (2122), return to the bridge plug sealing test procedure; Cavity gas seal test: Wait for the outer shell of the drug pack to degrade in the brine (006) and react with the brine (006) to generate gas, so that the cavity (004) is gradually pressurized. The pressure data in the cavity is stored and recorded by the storage pressure gauge (233) installed on the bridge plug (2122) and located in the cavity (004). Cavity Leakage Judgment: After 24 hours, the salvage bridge plug string is lowered to unseal the bridge plug (2122) and complete the depressurization of the cavity (004); the salvage bridge plug string and the bridge plug (2122) are removed, and the pressure data of the storage pressure gauge (233) is read; when the pressure value reaches the safety detection pressure, and the pressure remains stable for 1 hour or more before depressurization, the cavity (004) is judged to be sealed properly; when the pressure value reaches the safety detection pressure, but the pressure stability time before depressurization is less than 1 hour, the process returns to the drug delivery step and the observation time is extended; when the pressure value reaches the safety detection pressure... If, during the pressure test, the pressure does not stabilize before the pressure is released, meaning the drug reaction is complete and the pressure in the cavity (004) reaches its maximum, and a pressure drop occurs, it is determined that the cavity (004) is not properly sealed. The cavity (004) is then filled with brine (006), and the pressure is stabilized for 20-30 days. The process is repeated 3-5 times, returning to the drug pack dispensing step. If the sealing test still fails, it is determined that the cavity (004) has natural cracks and is not suitable for use as an underground storage facility. If the pressure value fails to reach the safety test pressure, it is determined that the amount of drug added to the drug pack is insufficient, and the dosage needs to be readjusted. The process is then returned to the drug pack dispensing step.

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