Test method for testing performance of sealing coating of underground gas storage

Abstract

The invention discloses a test method for testing the performance of a sealing coating of an underground gas storage, and relates to the technical field of new materials of underground gas storage. The test method comprises a test for verifying the characteristics of a to-be-tested material, the test for verifying the characteristics of the to-be-tested material is carried out by adopting a seamless sample, and the seamless sample is a sample with a smooth, flat and crack-free substrate surface; the method further comprises a test for verifying the characteristics of the to-be-tested material under the limiting working condition, the test for verifying the characteristics of the to-be-tested material under the limiting working condition is carried out by adopting a seamed sample, and the seamed sample refers to a sample with cracks on the surface of the base material. The invention provides the test method for selecting the material of the sealing coating of the underground gas storage of the compressed air energy storage system.

Description

Technical Field

[0001] This invention relates to the field of new materials technology for underground gas storage facilities, and in particular to a test method for evaluating the performance of sealing coatings in underground gas storage facilities. Background Technology

[0002] Underground gas storage facilities are used for compressed air energy storage. Compressed air energy storage technology is a type of energy storage technology that can be applied to power generation. During off-peak hours, excess electricity is used to compress air and store it in the gas storage system. During peak hours, the stored high-pressure air is released to generate electricity, thus achieving "peak shaving and valley filling" for unstable energy supplies.

[0003] Underground gas storage facilities involve excavating underground spaces within relatively hard rock strata with good integrity. The inner surface of these spaces contains sealing structures to seal high-pressure compressed air. The high cost of underground gas storage facilities leads to high initial investment for compressed air energy storage systems. Analysis of the cost structure of underground gas storage facilities reveals that the high-strength steel plates used for the innermost sealing structure are expensive, and the underground welding required for these plates increases the difficulty and speed of construction, further raising the construction cost. To reduce the cost of underground gas storage facilities, those skilled in the art have considered using a sealing coating structure for the sealing structure. Currently, sealing coatings are still in the research and development stage, and a testing method for evaluating the performance of the sealing coating is needed during this process. Summary of the Invention

[0004] The purpose of this invention is to provide a test method for testing the performance of sealing coatings used in underground gas storage tanks in compressed air energy storage systems.

[0005] To achieve this objective, on the one hand, a test method for testing the performance of sealing coatings in underground gas storage facilities is provided, including a test to verify the properties of the material itself, wherein the test to verify the properties of the material itself is conducted using a seamless specimen, wherein the seamless specimen is a specimen with a smooth and flat substrate surface without cracks; and on the other hand, a test to verify the properties of the material under extreme operating conditions is conducted using a seamed specimen, wherein the seamed specimen is a specimen with cracks on the substrate surface.

[0006] Furthermore, the substrate of the seamless sample is steel, and the seamless sample with steel substrate is divided into reinforced sample and unreinforced sample, or into repaired sample and unrepaired sample, or into sample with flat spraying, vertical spraying, and overhead spraying.

[0007] Further, the seamless sample substrate is concrete, and the seamless sample of the concrete substrate has two types of no reinforcement and no repair and no reinforcement and repair, and the coating to be tested of each type of sample is made by using three coating methods of flat spraying, vertical spraying and upward spraying.

[0008] Further, the test for verifying the properties of the material to be tested itself includes a water boiling test, which is used to simulate the sample in an extreme hot and humid environment in the underground gas storage; the water boiling test is to put the sample into high-pressure water for a period of time, and then test the adhesion and permeability of the sealing coating after taking out.

[0009] Further, the test for verifying the properties of the material to be tested itself includes a bending test, which tests the bendability of the material under pressure working condition; after the bending test, it is observed and recorded whether the coating of the sample is damaged, and if the coating of the sample is not damaged, the bending test is passed.

[0010] Further, the substrate of the sample with a seam is steel material, and the sample with a seam has an elongated hole, which is used to simulate the working condition of cracks on the substrate of the sealing coating of the underground gas storage; the sample with a seam of the steel substrate has four types of no reinforcement and no repair, reinforcement and no repair, no reinforcement and repair, and reinforcement and repair, and the coating to be tested of each type of sample is made by using three coating methods of flat spraying, vertical spraying and upward spraying.

[0011] Further, the test for verifying the properties of the material to be tested itself includes a test for obtaining the adhesion change of the material at different temperatures, the lower limit of the temperature is the minimum design temperature of the underground gas storage, the upper limit of the temperature is the maximum design temperature of the underground gas storage, and the gradient is 1-10℃.

[0012] Further, the test for verifying the properties of the material to be tested under extreme working conditions includes a substrate crack water pressure test, which is carried out by using a water pressure testing machine, the set temperature of the water pressure test is determined according to the design temperature of the underground gas storage, the pressing pressure of the water pressure test is at least 1.3 times of the design pressure of the underground gas storage, and the pressure maintaining time is at least 1h.

[0013] Further, the test for verifying the properties of the material to be tested under extreme working conditions includes a substrate crack pressure fatigue test; the substrate crack pressure fatigue test is carried out by using a water pressure testing machine, the test temperature is at least 10℃ higher than the set temperature of the underground gas storage, the lower limit of the cyclic pressure is the minimum operating pressure of the underground gas storage, and the upper limit of the pressure is 1.1 times of the design pressure of the underground gas storage.

[0014] Further, the test for verifying the characteristics of the material under test under extreme working conditions comprises a base material crack temperature fatigue test, wherein the set pressure is 1.1 times or more than the design temperature of the underground gas storage, the lower limit of the cycle temperature is the minimum design temperature of the underground gas storage, and the upper limit of the temperature is 10 degrees higher than the design temperature of the underground gas storage.

[0015] One of the above technical solutions has the following advantages or beneficial effects: the present solution aims to provide a test method, which can test whether a material can be used for the sealing coating of the underground gas storage. The test sample used in the test simulates the structural design of the sealing coating in the underground gas storage, and the test method is designed around the working conditions of the underground gas storage. The present solution includes a test for verifying the characteristics of the material under test and a test for verifying the characteristics of the material under test under extreme working conditions. The test for verifying the characteristics of the material under test is performed using a seamless sample, which is a sample with a smooth and flat surface without cracks. The test for verifying the characteristics of the material under test under extreme working conditions is performed using a sample with cracks, which is a sample with cracks on the surface of the base material. Through the above test method, it can be evaluated whether a material can be used for the sealing coating of the underground gas storage. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 is a schematic diagram of a seamless sample;

[0017] Figure 2 is a schematic diagram of a sample with cracks.

[0018] In the figure: 1-coating area; 2-repair area; 3-overlapping area; 4-sponge strip; 5-elongated hole. DETAILED DESCRIPTION

[0019] In order to make the technical problems solved by the present application, the technical solutions adopted and the technical effects achieved more clear, the technical solutions of the embodiments of the present application will be further described in detail below in conjunction with the drawings. Obviously, the described embodiments are only a part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application. It should be noted that the following embodiments and features in the embodiments can be combined with each other without conflict.

[0020] The sealing structure of the underground gas storage is generally high-strength steel plate at present, which is fixed and supported by concrete in the underground gas storage. In order to reduce the cost of the underground gas storage and compressed air energy storage system, the sealing coating is used to replace the high-strength steel plate by the technical route of using flexible concrete and reinforcing steel. The sealing coating is coated on the innermost side of the gas storage chamber, and the cavity surrounded by the sealing coating is the gas storage area. The test method of the embodiment is used to test whether a material can be used for the sealing coating of the underground gas storage. The test sample simulates the structural design of the sealing coating in the underground gas storage, and the test method is designed around the working condition of the underground gas storage.

[0021] The test method of the embodiment includes seamless samples and samples with cracks. The seamless sample refers to a sample with a smooth and flat surface without cracks. The sample with cracks refers to a sample with cracks on the surface of the substrate. The test method for testing whether a material can test the performance of the sealing coating of the underground gas storage includes testing the properties of the material itself and testing the properties of the material under extreme conditions. The seamless sample is used to test the properties of the material itself, and the sample with cracks is used to test the properties of the material under extreme conditions. The above tests are carried out independently.

[0022] Further, the sealing coating of the underground gas storage can adopt a reinforced structure. In order to test the effect of the reinforced structure on the sealing coating, the samples are divided into reinforced samples and non-reinforced samples according to the coating structure. Reinforced means that there is a reinforcing structure in the coating to be tested, and the reinforcing structure adopts glass fiber or glass cloth. Non-reinforced means that there is no reinforcing structure in the coating to be tested.

[0023] Further, during the construction of the underground gas storage, the sealing coating material may have leakage points or areas with insufficient thickness after normal coating, which need to be repaired after coating. The repair operation refers to grinding the coating to be tested first, and then coating the coating to be tested in the grinding area. In order to test the effect of the repair operation, the samples are divided into repaired samples and non-repaired samples according to whether the repair operation is performed.

[0024] Further, the coating method of the sealing coating material on the substrate of the underground gas storage also affects the performance of the sealing coating after coating. In order to test the effect of different coating methods on the coating to be tested, the samples are divided into flat spraying, vertical spraying and upward spraying according to the coating method.

[0025] In summary, both seamless and jointed samples can be classified according to different coating structures, into samples with and without reinforcing structure; can also be classified according to whether repaired, into samples with and without repair; can also be classified according to different coating methods, into samples using flat spray, vertical spray, and upward spray. Therefore, there are 12 kinds of seamless and jointed samples through the above combinations. In order to facilitate testing, the above 12 kinds of samples are divided into four categories, which are no reinforcement and no repair, with reinforcement and no repair, no reinforcement and with repair, and with reinforcement and with repair, each category is made according to three coating methods, a total of 12 kinds. That is, both seamless and jointed samples have four categories and 12 kinds of samples.

[0026] Further, the base material of the seamless sample has two kinds, which are steel base material and concrete base material. The seamless sample of steel base material simulates the sealing coating of underground gas storage coated on ordinary steel plate. The seamless sample of concrete plate base material simulates the sealing coating of underground gas storage coated on concrete layer.

[0027] As shown in Figure 1 , the manufacturing method of the 12 kinds of seamless samples of steel base material is described in detail below.

[0028] The base material of the seamless sample of steel base material is sheet steel, one side has a coating area 1, the coating area 1 is the area coated with the coating material to be tested, and the base material outside the coating area 1 is used for clamping the sample by the test equipment. The coating to be tested in the coating area 1 is attached to the base material by an adhesive, preferably, the adhesive uses an existing primer for increasing adhesion.

[0029] Before manufacturing the seamless sample of steel base material, the shielding cloth is cut according to the size of the coating area 1, and a hole matching the size and shape of the coating area 1 is cut in the center area of the shielding cloth. When manufacturing the seamless sample, first cover the shielding cloth on the side to be coated of the seamless sample, expose the coating area 1, then paste the strip-shaped sponge around the coating area 1 for partitioning. The area shielded by the shielding cloth and the part outside the sponge strip 4 are clean steel plates, which are used for clamping the sample during testing.

[0030] The first kind of seamless sample of steel base material without reinforcement and repair is used to simulate the underground gas storage containing no reinforcing structure of the sealing coating, and there is no leakage point when the sealing coating is coated. The manufacturing method is as follows: S101: shielding cloth and sponge strip 4 are covered on one side of the sample coating area 1, the coating area 1 is exposed, and primer is coated in the coating area 1 first; S102: the coating to be tested is coated on the primer, and after the coating to be tested is cured, the shielding cloth and the sponge strip 4 are removed, and the experiment is carried out.

[0031] The second type of steel seamless sample without reinforcement and without repair is used to simulate the underground gas storage structure with reinforcement structure and without leakage point during coating construction. The manufacturing method is as follows: S201: cover the sample coating area 1 with a cloth and a sponge strip 4, expose the coating area 1, and first coat the primer in the coating area 1; S202: coat the first layer of the coating to be tested on the primer; S203: lay the reinforcement structure on the first layer of the coating to be tested, and the reinforcement structure can be either glass fiber cloth or glass silk cloth; S204: spray the second layer of the coating to be tested on the reinforcement structure, remove the cloth and the sponge strip 4 after the coating to be tested is cured, and then perform the experiment.

[0032] The third type of steel seamless sample without reinforcement and with repair is used to simulate the underground gas storage structure without reinforcement structure and with leakage point during coating construction. The manufacturing method is as follows: S301: cover the sample coating area 1 with a cloth and a sponge strip 4, expose the coating area 1, and first coat the primer in the coating area 1; S302: coat the coating to be tested on the primer; S303: draw the repair area 2 and the lap area 3 in the coating area 1, the lap area 3 is located outside the repair area 2 and is arranged around the repair area 2. Scrape off all the primer and the coating to be tested in the repair area 2 to expose the steel substrate, the edge of the repair area 2 forms the lap area 3, the outside of the lap area 3 is the coating area 1, the lap area 3 is used to smoothly transition between the repair area 2 and the coating area 1, and part of the coating to be tested is scraped off in the lap area 3. The repair area 2 and the lap area 3 are used to simulate the underground gas storage repair operation. During the underground gas storage repair operation, first find the leakage point, then scrape off the primer and the sealing coating around the leakage point, and then scrape off part of the coating to smoothly transition the leakage point and the surrounding sealing coating. The lap area 3 ensures the adhesion between the sealing coating to be repaired in the repair area 2 and the surrounding sealing coating that is not repaired. S304: surround the second sponge strip 4 on the outer edge of the lap area 3, paste the blocking tape on the coating area 1 outside the second sponge strip 4, and spray the primer in the area surrounded by the second sponge strip 4. S305: coat the coating to be tested on the primer in the area surrounded by the second sponge strip 4. S306: remove the blocking tape, all the sponge strips 4, and the blocking tape, and then perform the experiment after the coating to be tested is cured.

[0033] The fourth type of reinforced and repaired seamless steel substrate sample is used to simulate the sealing coating structure of the gas storage after the reinforcement structure is contained during the construction of the gas storage sealing coating and the leakage repair operation is performed during the coating of the sealing coating. The manufacturing method is as follows: S401: the shielding cloth and the sponge strip 4 are applied, the coating area 1 is exposed, and the primer is coated in the coating area 1; S402: the coating to be tested is coated on the primer. S403: the repair area 2 and the lap area 3 are drawn in the coating area 1; all the primer and the coating to be tested in the repair area 2 are scraped off to expose the steel substrate, the edge of the repair area 2 forms the lap area 3, the outer side of the lap area 3 is the coating area 1, the lap area 3 is used to smoothly transition between the repair area 2 and the coating area 1, and part of the coating to be tested in the lap area 3 is scraped off. S404: a second sponge strip 4 is surrounded on the outer edge of the lap area 3, the coating area 1 outside the second sponge strip 4 is pasted with the shielding cloth, and the primer is sprayed in the area surrounded by the second sponge strip 4. S405: the first layer of the coating to be tested is coated on the primer in the area surrounded by the second sponge strip 4. S406: the glass fiber is added on the first layer of the coating to be tested; S407: the second layer of the coating to be tested is coated on the glass fiber; S408: the shielding cloth, all the sponge strips 4 and the shielding cloth are removed, and the experiment is performed after the coating to be tested is cured.

[0034] The seamless samples with concrete substrates have two types: no reinforcement and no repair and no reinforcement and repair. The coating to be tested of each type of seamless sample has three coating methods: flat spraying, vertical spraying and upward spraying, a total of six types.

[0035] The seamless sample with concrete substrate can use a concrete plate to coat the primer and the coating to be tested on the concrete plate. The manufacturing method of the sample with the concrete plate as the substrate without reinforcement and repair is the same as that of the seamless sample with the steel substrate without reinforcement and repair. The manufacturing method of the sample with the concrete plate as the substrate without reinforcement and repair is the same as that of the seamless sample with the steel substrate without reinforcement and repair.

[0036] The seamless sample with concrete substrate can also be made by a free film. The free film sample has two types: no reinforcement and no repair and no reinforcement and repair. The coating to be tested of each type of seamless sample has three coating methods: flat spraying, vertical spraying and upward spraying, a total of six types. The free film sample is used in occasions where the sample needs to be bent.

[0037] The manufacturing method of the free film sample of the seamless sample with the concrete substrate without reinforcement and repair is as follows: S111: the concrete substrate surface is first coated with oil to isolate the free film and the concrete; S112: the free film is laid on the oil-coated concrete substrate, and the coating area is divided on the free film; S113: the coating to be tested is coated on the free film, and the free film is removed for testing after the coating is fixed.

[0038] The method for preparing the free film sample of the seamless sample of the reinforced concrete substrate with repair is as follows: S121: the surface of the concrete substrate is first coated with oil; S122: the free film is laid on the concrete substrate coated with oil; S123: the free film is divided into a coating area and a repair area in the coating area, a first shielding cloth is covered on the free film in the coating area, a first sponge strip is pasted around the inner edge of the first shielding cloth, a second shielding cloth is covered in and outside the repair area, a second sponge strip is pasted around the outer edge of the second shielding cloth, the area outside the repair area and inside the coating area is exposed, the free film in the area outside the repair area and inside the coating area is coated with the coating to be tested, after the coating is fixed, the second shielding cloth is removed, the first shielding cloth is retained, and the free film of the repair area is exposed; S124: a third shielding cloth is covered outside the repair area, a third sponge strip is pasted around the inner edge of the third shielding cloth, the third shielding cloth is pressed on the first shielding cloth to expose the repair area, the coating to be tested is coated in the repair area, after the coating is fixed, all the shielding cloths and sponge strips are removed, and the free film of the reinforced concrete substrate with repair is taken off.

[0039] The seamless sample is used to perform a test for verifying the properties of the material to be tested, and the test methods of the seamless samples of the two substrates are the same. In the embodiment, the test for verifying the properties of the material to be tested includes a bending test for verifying the bending performance of the material, a boiling test for verifying the aging resistance of the material, and a test for obtaining the adhesion change of the material at different temperatures, and the above tests are independently performed.

[0040] The bending test is a test for measuring the mechanical properties of the material when the material bears a bending load. In the test process, the sample is placed on two support points, and a force is applied to the coating area 1 to make the sample bend to a fixed angle. Optionally, the fixed angle is 3° / PD-6° / PD, and preferably, the fixed angle is 5° / PD.

[0041] The bending test is performed on the seamless samples of various steel substrates and the free film of various concrete substrates respectively, and 3 samples are taken for each type of seamless sample. The concrete substrate seamless sample subjected to the bending test adopts the free film sample. It is observed and recorded whether the coating of the sample is damaged. If the coating of the sample is not damaged, the sample passes the bending test.

[0042] If 3 samples of a type of sample are all undamaged, the type of sample passes the bending test. If the samples of 3 spraying modes corresponding to each type of seamless sample are all qualified, it is considered that the type of sample is qualified, which indicates that the material can be used as a sealing coating in the corresponding simulated working conditions in the underground gas storage. If all types of samples are qualified, it indicates that the material can be used in the underground gas storage. Otherwise, the use scenarios and conditions of the material for the sealing coating of the underground gas storage are further analyzed.

[0043] Boiling test A test method for evaluating the heat resistance of a material, simulating the heat resistance of a sample in an extreme hot and humid environment in an underground gas storage. In the test, the sample is placed in high pressure water for a period of time, and after being taken out, the adhesion and permeability of the sealing coating are tested.

[0044] The boiling test of the present embodiment is performed on each of various steel seamless samples and free films of various concrete substrates, and three samples are taken for each seamless sample. The test pressure is 10-15 MPa, and the boiling is performed in air with 100℃ water for N days, during which the seamless sample is taken out M times, and the adhesion and electrical impedance of the sample are measured. Optionally, N is greater than 7, i.e., the boiling time is not less than 7 days. Preferably, the boiling time is 14 days. Optionally, M is greater than or equal to 4. Optionally, the time interval for each time the sample is taken out is different. Optionally, the time interval for each time the sample is taken out is gradually increased. Preferably, the boiling time is 14 days, and the sample is taken out six times. The time for measuring the adhesion and electrical impedance of the sample taken out for the first time is 12 hours after boiling, the time for measuring the adhesion and electrical impedance of the sample taken out for the second time is 1 day after boiling, the time for measuring the adhesion and electrical impedance of the sample taken out for the third time is 2 days after boiling, the time for measuring the adhesion and electrical impedance of the sample taken out for the fourth time is 4 days after boiling, the time for measuring the adhesion and electrical impedance of the sample taken out for the fifth time is 7 days after boiling, and the time for measuring the adhesion and electrical impedance of the sample taken out for the sixth time is 14 days after boiling.

[0045] The adhesion is measured by a pull-out method, using a mushroom head and a test column, and the adhesive is applied between the test column and the mushroom head, and between the mushroom head and the coated area of the seamless sample, and the test column, the mushroom head, and the coated area of the seamless sample are bonded together. The test column is pulled at a specified speed by hydraulic or mechanical method, a vertical and uniform pulling force is applied on the bonding surface of the seamless sample, and the stress of the coating to be measured in the vertical direction is measured, and the adhesion of the coating is expressed by the size of the pulling force per unit area, expressed by N / cm 2 .

[0046] The electrical impedance of the coating to be measured of the sample can represent the permeability of the coating to be measured, and the higher the electrical impedance value, the lower the permeability of the coating to be measured, and the better the sealing performance of the coating to be measured. The method for measuring the electrical impedance of the sample can use existing experimental methods, for example, by electrochemical impedance spectroscopy (EIS) technology.

[0047] The same samples as those subjected to boiling are taken, and the adhesion and electrical impedance of each sample are measured as a comparison group. If the difference between the results of the three samples is within 5%, the average value is recorded as the initial value of the sample. If the difference between the results of the three samples is greater than 5%, the sample is taken again for measurement until the difference between the results of the three samples is within 5%.

[0048] For the samples subjected to boiling test, if the adhesion decreases by more than 20% compared with the initial value or the adhesion is less than 5 MPa, and the electrical impedance is less than 109 If yes, the sample fails the boiling water test. Otherwise, the sample passes the boiling water test.

[0049] The test for obtaining the adhesion change of the material at different temperatures is respectively conducted on the seamless sample of each steel base material and the free film of each concrete base material. The temperature gradient of the test can be: the lower limit of the temperature is the minimum design temperature of the gas storage, and the upper limit of the temperature is the maximum design temperature of the gas storage, and the gradient is 1℃-10℃. After the test is completed, the curve of the adhesion of the sample changing with the temperature is drawn, and the curve of the adhesion of the material changing with the temperature is further drawn by mathematical method. The curve can reflect the attenuation degree of the adhesion of the material when used in the sealing coating of the underground gas storage with the increase of the temperature, and can not only be used as the attribute of the material, but also provide a reference for selecting the test temperature during the test.

[0050] As shown in Figure 2 , the following will describe in detail the manufacturing method of 12 kinds of jointed samples.

[0051] The base material of the jointed sample is steel material, and the jointed sample has an elongated hole 5. The elongated hole 5 is used to simulate the working condition of the cracks on the base material of the sealing coating of the underground gas storage. The elongated hole 5 is a through hole. One side of the jointed sample has a coating area 1, and the elongated hole 5 is located in the coating area 1 of the jointed sample. The coating structure in the coating area 1 of the jointed sample is the same as that of the seamless sample, that is, there are 12 kinds of samples, which are divided into four categories according to the coating method of the coating to be tested. Each category of jointed sample is manufactured by using three coating methods of flat spraying, vertical spraying and upward coating. The four categories of jointed samples can be divided into: jointed sample without reinforcement and repair, jointed sample with reinforcement and repair, jointed sample without reinforcement and repair, jointed sample with reinforcement and repair.

[0052] During the manufacturing of the jointed sample, a plug matching the shape of the elongated hole 5 is arranged at the elongated hole 5. During the manufacturing of the coating area 1, the plug is inserted into the elongated hole 5. The coating area 1 of the jointed sample with the plug installed is a plane. After the coating area 1 is manufactured, the plug is pulled out from the side of the sample away from the coating area 1. Further, the surface of the plug needs to be oiled or covered with a cloth for easy removal.

[0053] Before manufacturing the coating area 1, a shielding cloth is manufactured, and a hole matching the size and shape of the coating area 1 is cut in the central area of the shielding cloth. During the manufacturing of the jointed sample, the shielding cloth is first covered on the side of the jointed sample to be coated, and the coating area 1 is exposed, and then a strip-shaped sponge is pasted around the coating area 1 for partitioning. The area shielded by the shielding cloth and the part outside the strip-shaped sponge 4 are clean steel plates, which are used to clamp the sample during the test.

[0054] The specific manufacturing method of the four categories of jointed samples is as follows:

[0055] The first type of un-reinforced and un-repaired sample with cracks is used to simulate the construction of the underground gas storage when the sealing coating does not contain reinforcing structure, the base material coated with the sealing coating has cracks, and the underground gas storage has no leakage point when the sealing coating is coated. The manufacturing method comprises the following steps: S501: after installing the plug on the elongated hole 5, covering the cloth and the sponge strip 4 on one side of the sample coating area 1, exposing the coating area 1, and coating the primer in the coating area 1; S502: coating the to-be-tested coating on the primer, removing the covering cloth and the sponge strip 4 after the to-be-tested coating is cured, and extracting the plug from the back, and then performing the experiment.

[0056] The second type of reinforced and un-repaired sample with cracks is used to simulate the construction of the underground gas storage when the sealing coating contains reinforcing structure, the base material coated with the sealing coating has cracks, and the underground gas storage has no leakage point when the sealing coating is coated. The manufacturing method comprises the following steps: S601: after installing the plug on the elongated hole 5, covering the cloth and the sponge strip 4 on one side of the sample coating area 1, exposing the coating area 1, and coating the primer in the coating area 1; S602: coating the first layer of to-be-tested coating on the primer; S603: laying the reinforcing structure on the first layer of to-be-tested coating, and the reinforcing structure can be any one of glass fiber or glass silk cloth; S604: spraying the second layer of to-be-tested coating on the reinforcing structure, removing the covering cloth and the sponge strip 4 after the to-be-tested coating is cured, extracting the plug from the back, and then performing the experiment.

[0057] The third type of un-reinforced and repaired sample with cracks is used to simulate the construction of the underground gas storage when the sealing coating does not contain reinforcing structure, the base material coated with the sealing coating has cracks, and the underground gas storage has leakage points after the repair operation when the sealing coating is coated. The manufacturing method comprises the following steps: S701: after installing the plug on the elongated hole 5, covering the cloth and the sponge strip 4 on one side of the sample coating area 1, exposing the coating area 1, and coating the primer in the coating area 1; S702: coating the to-be-tested coating on the primer; S703: drawing the repair area 2 and the lap area 3 in the coating area 1, the lap area 3 is located outside the repair area 2, and is arranged around the repair area 2. The to-be-tested coating in the lap area 3 is scraped off. S704: surrounding the second sponge strip 4 on the outer edge of the lap area 3, pasting the covering adhesive tape on the coating area 1 outside the second sponge strip 4, and spraying the primer in the area surrounded by the second sponge strip 4. S705: coating the to-be-tested coating on the primer in the area surrounded by the second sponge strip 4. S706: removing the covering cloth, all the sponge strips 4, and the covering adhesive tape, extracting the plug from the back, and then performing the experiment after the to-be-tested coating is cured.

[0058] The fourth type is a reinforced and repaired and slotted sample for simulating the construction of a gas storage reservoir. The sealing coating contains a reinforcing structure, the base material of the sealing coating has cracks, and the underground gas storage reservoir is repaired after the coating process with leakage points. The manufacturing method comprises the following steps: S801: after installing the plug on the elongated hole 5, covering the cloth and sponge strip 4 on one side of the sample coating area 1, exposing the coating area 1, and coating the primer in the coating area 1; S802: coating the to-be-tested coating on the primer; S803: drawing a repair area 2 and an overlapping area 3 in the coating area 1; scraping off all the primer and the to-be-tested coating in the repair area 2 to expose the steel base material and the elongated hole 5, forming the overlapping area 3 at the edge of the repair area 2, and the outer side of the overlapping area 3 being the coating area 1, the overlapping area 3 being used for smoothly transitioning between the repair area 2 and the coating area 1, and scraping off part of the to-be-tested coating in the overlapping area 3; S804: surrounding the second sponge strip 4 on the outer edge of the overlapping area 3, pasting the blocking adhesive tape on the coating area 1 outside the second sponge strip 4, and spraying the primer in the area surrounded by the second sponge strip 4; S805: coating the first layer of to-be-tested coating on the primer in the area surrounded by the second sponge strip 4; S806: adding glass fiber on the first layer of to-be-tested coating; S807: coating the second layer of to-be-tested structure on the glass fiber; S808: removing the blocking cloth, all the sponge strips 4, and the blocking adhesive tape, and pulling out the plug from the back, and performing the experiment after the to-be-tested coating is cured.

[0059] In this embodiment, the tests for verifying the properties of the to-be-tested material under extreme conditions include a base material crack hydrostatic test, a base material crack pressure fatigue test, and a base material crack temperature fatigue test. The above tests are independently performed, that is, 12 slotted samples, each of which selects at least 3 samples to perform the above tests, and each test is independently performed.

[0060] The base material crack hydrostatic test is used to simulate the coating of the sealing coating of the underground gas storage reservoir, the base material of the sealing coating has cracks, and the gas storage reservoir is in a full load pressure-bearing condition, to test the changes of the sealing property and the adhesion of the sealing coating on the cracked base material. The base material crack hydrostatic test is performed by using a hydrostatic testing machine. The hydrostatic testing machine comprises a flange short section and a flange blind plate, and the slotted sample is fixed between the flange short section and the flange blind plate by bolts. The middle part of the flange short section has a water inlet pipe, and the water inlet pipe has a pressure adjusting device for adjusting the pressure. During the test, the slotted sample is installed at one end of the flange short section, the flange blind plate is installed, the flange sealing surface is effectively guaranteed, then the water of a set temperature is filled to exhaust the gas, and then the pressure is pressed to the required pressure and kept for a certain time. The set temperature of the hydrostatic test is determined according to the design temperature of the underground gas storage reservoir. Alternatively, the set temperature of the hydrostatic test is 5℃ or more higher than the design temperature of the underground gas storage reservoir. Preferably, the set temperature of the hydrostatic test is 10℃ higher than the design temperature of the underground gas storage reservoir, the pressure of the hydrostatic test is at least 1.3 times higher than the design pressure of the underground gas storage reservoir, and the pressure is kept for at least 1h. Preferably, the required pressure of the hydrostatic test is 1.5 times the design pressure of the underground gas storage reservoir, and the pressure is kept for 1h.

[0061] Another sample of the same kind as the sample for the substrate crack hydrostatic test is taken, and the adhesion and the electrical impedance of each sample are measured as a comparison group. If the results of the three samples differ by less than 5%, the average value is recorded as the initial value of the cover test sample. If the results of the three samples differ by more than 5%, the sample measurement is repeated with new samples until the results of the three samples differ by less than 5%.

[0062] After the hydrostatic test, the samples are removed, and the selection of qualified samples is carried out. The selection conditions include whether there is water seepage and light leakage. Whether there is water seepage is observed by naked eye, observing whether there is water seepage on the back of the sample (i.e. the side of the sample with no coating area 1), if there is water seepage, the sample is discarded; if there is no water seepage, then the light leakage test is carried out. The light leakage test uses a spotlight to irradiate the sample, and observes whether there is light transmission, if there is light transmission, the sample is discarded.

[0063] After the water seepage and light leakage selection, the electrical impedance of the samples that are not discarded is measured, and if the electrical impedance is greater than 10 9 and the electrical impedance decreases by no more than 10% compared with the initial value measured by the comparison group, it is considered that the permeability of the coating to be tested of the sample is not affected. At the same time, the sample with affected permeability is discarded.

[0064] Then, the adhesion of the sample with unaffected permeability is tested, and if the adhesion is greater than 5MPa or the adhesion decreases by no more than 10% compared with the initial value, it is considered that the adhesion of the coating to be tested is not affected, and the sample passes the substrate crack hydrostatic test. At the same time, the sample that does not pass the substrate crack hydrostatic test is discarded.

[0065] If three samples of a kind of slit test sample all pass the hydrostatic test, it is considered that the kind of slit test sample is qualified. If two samples pass and one sample does not pass, two new samples of the kind of slit test sample need to be added to retest the hydrostatic test. If the two new samples all pass the test, it is considered that the kind of test sample is qualified. If one or more of the two new samples do not pass, it is considered that the kind of test sample is unqualified. If only one of the three samples is qualified, or all three samples are unqualified, it is considered that the kind of test sample is unqualified.

[0066] The base material crack pressure fatigue test is used to simulate the condition that the base material of the sealing coating of the underground gas storage has cracks when the sealing coating is applied, and the gas storage is in the condition of frequent gas charging and discharging. The base material crack pressure fatigue test is used to test the changes of the sealing property and the adhesion of the sealing coating on the cracked base material. The equipment of the base material crack pressure fatigue test is the same as that of the base material crack water pressure test, and a water pressure testing machine is used. During the pressure fatigue test, after the sample is fixed, the water pressure testing machine is filled with water at the set temperature to exhaust the air, and the pressure is cycled to be increased and decreased. The cycle is repeated for N times, and each time the pressure is maintained for more than half an hour. The lower limit of the pressure in the cycle is the minimum operating pressure of the gas storage, and the upper limit of the pressure is 1 to 1.5 times of the design pressure of the gas storage. The set temperature of the pressure fatigue test is at least 10 degrees higher than the design temperature of the underground gas storage. In each cycle of N times of the sample, the sample is taken out at an average interval of 2 to 4 times to measure the adhesion and the electrical impedance value of the sample.

[0067] Alternatively, the test conditions of the base material crack pressure fatigue test are as follows: the set temperature is 10 degrees higher than the design temperature of the underground gas storage. The lower limit of the cycle pressure is the minimum operating pressure of the gas storage, and the upper limit of the pressure is 1.1 times of the design pressure of the gas storage. The cycle number N is 300, and each time the pressure is maintained for 1 hour. The sample is taken out every 50 cycles to test the adhesion and the electrical impedance value of the sample.

[0068] Another sample is taken from the same sample as the base material crack pressure fatigue test, and the adhesion and the electrical impedance of each sample are measured as a comparison group. If the difference between the results of the three samples is within 5%, the average value is recorded as the initial value of the cover sample. If the difference between the results of the three samples is greater than 5%, the sample is taken again to measure until the difference between the results of the three samples is within 5%.

[0069] After the pressure fatigue test is completed, the sample is taken out, and the selection of qualified samples is performed. If the adhesion of the sample is less than 5 MPa, or the adhesion of the sample is decreased by more than 20% compared with the initial value, or the electrical impedance is less than 10 9 , the sample fails the base material crack pressure fatigue test.

[0070] If three samples of a kind of cracked sample pass the pressure fatigue test, the kind of cracked sample is considered to be qualified. If two samples pass and one sample fails, two new samples of the kind of cracked sample need to be added to perform the water pressure test again. If the two new samples both pass the test, the kind of sample is considered to be qualified. If one or more of the two new samples fails, the kind of sample is considered to be unqualified. If only one sample of the three samples is qualified, or all the three samples are unqualified, the kind of sample is considered to be unqualified.

[0071] During the charging and discharging of underground gas storage, not only the pressure borne by the sealing coating changes, but also the temperature borne by the sealing coating changes. The base material crack temperature fatigue test is used to test the changes in the sealing property and adhesion of the sealing coating on the cracked base material when the base material of the underground gas storage has cracks and the temperature changes. The base material crack temperature fatigue test equipment is the same as the base material crack water pressure test and the base material crack pressure fatigue test, and a water pressure testing machine is used. In the base material crack temperature fatigue test, the water temperature in the water pressure testing machine is controlled by electric heating. In the base material crack temperature fatigue test, the lower limit of the temperature is the minimum design temperature of the underground gas storage, and the upper limit of the temperature is at least 8 degrees higher than the design temperature of the underground gas storage. The rise and fall of the water temperature is controlled by electric heating. The water pressure is fixed at the set pressure. Alternatively, the set pressure is 1.1 times or more than the design temperature of the underground gas storage. Cycle N times, and each time the pressure is maintained for more than half an hour.

[0072] Alternatively, the test conditions of the temperature fatigue test are: the set pressure is 1.5 times the design temperature of the underground gas storage, the lower limit of the cycle temperature is the minimum design temperature of the underground gas storage, and the upper limit of the temperature is 10 degrees higher than the design temperature of the underground gas storage. The cycle number N = 300, and each time the temperature is maintained for 2 hours. Every 50 cycles, a sample is taken out for testing of the adhesion and electrical impedance value.

[0073] Another sample is taken from the same sample as the base material crack temperature fatigue test, and the adhesion and electrical impedance of each sample are measured as a comparison group. If the results of the three samples differ by less than 5%, the average value is recorded as the initial value of the sample. If the difference between the results of the three samples is greater than 5%, the sample is measured again until the difference between the results of the three samples is less than 5%.

[0074] After the temperature fatigue test is completed, the sample is removed, and the selection of qualified samples is performed. If the adhesion of the sample is less than 5 MPa, or the adhesion of the sample decreases by more than 20% compared with the initial value, or the electrical impedance is less than 109, the sample fails the base material crack pressure fatigue test.

[0075] If three samples of a kind of cracked sample pass the temperature fatigue test, the kind of cracked sample is considered to be qualified. If two samples pass and one sample fails, two new samples of the kind of cracked sample need to be added for water pressure testing. If both of the two new samples pass the test, the kind of sample is considered to be qualified. If one or more of the two new samples fails, the kind of sample is considered to be unqualified. If only one of the three samples is qualified, or all three samples are unqualified, the kind of sample is considered to be unqualified.

[0076] If the three samples of each type of seamless sample corresponding to the three spraying modes are all qualified, it is considered that the type of sample is qualified, indicating that the material can be used as a sealing coating in the corresponding simulated working condition in the underground gas storage. If all types of samples are qualified, it indicates that the material can be used in the underground gas storage. In addition to the above, the above tests can determine the application scenario of a material in the sealing coating of the underground gas storage, including the coating structure, the spraying mode of the coating, and the construction method of the sealing coating according to the test results after the coating is repaired.

[0077] Therefore, the test method for testing the performance of the sealing coating of the underground gas storage in the embodiment includes the test for verifying the characteristics of the material itself and the test for verifying the characteristics of the material under extreme working conditions, and the two tests are independently performed.

[0078] The test for verifying the characteristics of the material itself uses seamless samples, and the test includes a bending test, a water boiling test, and a test for obtaining the adhesion change of the material at different temperatures, and the above tests are independently performed. The bending test can measure the bendability of the material when used as a sealing coating under pressure working condition. The water boiling test can measure the heat resistance of the material when used as a sealing coating in the extreme hot and humid environment of the underground gas storage. The adhesion change curve of the material at different temperatures reflects the attenuation degree of the adhesion with the increase of the temperature.

[0079] The test for verifying the characteristics of the material under extreme working conditions uses samples with cracks, and the test includes a substrate crack water pressure test, a substrate crack pressure fatigue test, and a substrate crack temperature fatigue test, and the above tests are independently performed. The substrate crack water pressure test is used to simulate the case that the substrate of the sealing coating has a crack when the sealing coating is coated on the underground gas storage, and the underground gas storage is in full load pressure working condition, to test the change of the sealing property and adhesion of the sealing coating on the cracked substrate. The substrate crack pressure fatigue test is used to simulate the case that the substrate of the sealing coating has a crack when the sealing coating is coated on the underground gas storage, and the underground gas storage is in frequent gas charging and discharging working condition, to test the change of the sealing property and adhesion of the sealing coating on the cracked substrate. The substrate crack temperature fatigue test is used to test the change of the sealing property and adhesion of the sealing coating on the cracked substrate when the temperature of the underground gas storage changes.

[0080] The material that passes all the above tests is the preferred material for the sealing coating of the underground gas storage. If part of it passes, the use conditions of the material for the underground gas storage can be determined according to the test conditions and results. Of course, if all of them do not pass, the material cannot be used for the sealing coating of the underground gas storage. Therefore, the test method for testing the performance of the sealing coating of the underground gas storage in the embodiment can verify whether a material can be used for the sealing coating of the underground gas storage.

[0081] In the description of the application, unless otherwise clearly specified and limited, the terms "connected", "connected", "fixed" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0082] In the present application, unless otherwise clearly specified and limited, "on" or "under" of the first feature to the second feature can include that the first and second features are in direct contact, or that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, the first feature "on", "above" and "above" the second feature includes that the first feature is directly above and obliquely above the second feature, or only indicates that the horizontal height of the first feature is higher than that of the second feature. The first feature "below", "below" and "below" the second feature includes that the first feature is directly below and obliquely below the second feature, or only indicates that the horizontal height of the first feature is less than that of the second feature.

[0083] Obviously, the above embodiments of the present application are only examples for the purpose of clear illustration, and are not the limitation of the embodiments of the present application. Based on the above description, other different forms of changes or variations can also be made by those skilled in the art. Here, it is not necessary and impossible to enumerate all the embodiments. Any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the claims of the present application.

Claims

1. A test method for testing the performance of a seal coating for a subsurface gas storage reservoir, characterized by, The test includes verifying the properties of the material itself, which is carried out by using a seamless sample, i.e. a sample with a smooth and even surface without cracks. The test also includes verifying the properties of the material under extreme conditions, which is carried out by using a sample with cracks, i.e. a sample with cracks on the surface of the base material.

2. The test method for testing the performance of a seal coat of a subsurface gas storage reservoir according to claim 1, wherein, The base material of the seamless sample is steel, and the seamless sample of the steel base material is divided into a sample with reinforcement and a sample without reinforcement, or a sample with repair and a sample without repair, or a sample with flat spraying, vertical spraying and upward spraying of the coating.

3. The test method for testing the performance of a seal coat of a subsurface gas storage reservoir of claim 1, wherein, The base material of the seamless sample is concrete, and the seamless sample of the concrete base material is divided into two types, i.e. a sample without reinforcement and repair and a sample without reinforcement but with repair, and each type of sample is prepared by using flat spraying, vertical spraying and upward spraying of the coating.

4. The test method for testing the performance of a seal coat of a subsurface gas storage reservoir of claim 1, wherein, The test for verifying the properties of the material itself includes a water boiling test, which is used to simulate the sample in an extreme hot and humid environment in the underground gas storage.

5. The test method for testing the performance of a seal coat of a subsurface gas reservoir according to claim 1, wherein, The test for verifying the properties of the material itself includes a bending test, which is used to test the bendability of the material under pressure conditions.

6. The test method for testing the performance of a seal coat of a subsurface gas reservoir according to claim 1, wherein, The base material of the sample with cracks is steel material, and the sample with cracks has an elongated hole, which is used to simulate the condition of cracks on the base material of the sealing coating of the underground gas storage. The sample with cracks of the steel base material has four types, i.e. a sample without reinforcement and repair, a sample with reinforcement and repair, a sample without reinforcement but with repair, and a sample with reinforcement and repair, and each type of sample is prepared by using flat spraying, vertical spraying and upward spraying of the coating.

7. The test method for testing the performance of a seal coat of a subsurface gas reservoir according to claim 1, wherein, The test for verifying the properties of the material itself includes a test for obtaining the change of the adhesion of the material at different temperatures, and the lower limit of the temperature is the minimum design temperature of the underground gas storage, the upper limit of the temperature is the maximum design temperature of the underground gas storage, and the gradient is 1-10℃.

8. The test method for testing the performance of a seal coat of a subsurface gas reservoir according to claim 1, wherein, The test for verifying the properties of the material under extreme conditions includes a base material crack water pressure test, which is carried out by using a water pressure testing machine, the set temperature of the water pressure test is determined according to the design temperature of the underground gas storage, the pressure of the water pressure test is at least 1.3 times the design pressure of the underground gas storage, and the pressure holding time is at least 1h.

9. The test method for testing the performance of a seal coat of a subsurface gas reservoir according to claim 1, wherein, The test for verifying the properties of the material under extreme conditions includes a base material crack pressure fatigue test. The base material crack pressure fatigue test is carried out by using a water pressure testing machine, the test temperature is at least 10℃ higher than the set temperature of the underground gas storage, the lower limit of the cyclic pressure is the minimum operating pressure of the underground gas storage, and the upper limit of the pressure is 1.1 times the design pressure of the underground gas storage.

10. The test method for testing the performance of a seal coat of a subsurface gas reservoir according to claim 1, wherein, The test for verifying the properties of the material under extreme conditions includes a base material crack temperature fatigue test. The set pressure of the substrate crack temperature fatigue test is 1.1 times or more of the design temperature of the underground gas storage; the lower limit of the cycle temperature is the minimum design temperature of the underground gas storage, and the upper limit of the temperature is 10 degrees higher than the design temperature of the underground gas storage.

Images