Artificial Salt Cavern Gas Storage Facility and Its Construction Method

Abstract

This application provides an artificial salt cavern gas storage facility and its construction method. The artificial salt cavern gas storage facility includes multiple salt cavities and new wells connected to the multiple salt cavities. The new wells include horizontal wells or multi-branch wells. Each new well is equipped with a brine discharge string, and the brine discharge string of the new well is connected to the bottom of the sediment in the multiple salt cavities. This application utilizes a single new well to connect to the sediment at the bottom of multiple salt cavities for brine discharge, allowing the brine within the pore space of the sediment to be discharged for gas storage. This improves the utilization rate of the salt cavern gas storage facility and allows operation on multiple similar or different types of salt cavities, reducing the number of brine discharge wells and improving the cost-effectiveness of brine discharge.

Description

Technical Field

[0001] This application relates to the field of salt cavern gas storage, and more particularly to an artificial salt cavern gas storage and its construction method. Background Technology

[0002] Salt cavern gas storage facilities utilize a water-soluble mining method to create the cavities. Fresh water is injected from the surface into the underground salt layer, dissolving solid sodium chloride minerals to form brine containing sodium and chloride ions. This brine is then brought to the surface, ultimately forming salt caverns within the underground salt layer. Due to the impurity of the salt layer, it contains water-insoluble minerals such as clay and gypsum. These minerals absorb water and expand after being released from the salt layer, loosely accumulating at the bottom of the salt cavern to form sediment. This portion of the space is unusable, severely reducing the utilization rate and economic efficiency of the salt cavern gas storage facility. For example, the Jintan gas storage facility has an average insoluble content of 17%, and after expansion, the sediment volume accounts for approximately 30% of the total cavity volume, with sediment pore volume accounting for approximately 15%. Other gas storage facilities have even higher insoluble content; the Pingdingshan gas storage facility has an insoluble interlayer thickness of 30-40%.

[0003] Utilizing the pore space of sediment for gas storage can significantly improve the economics of salt cavern gas storage facilities. Currently, traditional gas injection and brine removal methods involve lowering a brine removal tubing from the top of the salt cavity. This tubing cannot be lowered into the sediment, preventing the brine from draining from the pores. Existing methods for utilizing sediment pore space often employ a system of one new brine removal well per salt cavity. This well is drilled vertically from the top of the salt cavity to the bottom, or into the side, creating a new cavity that is then connected to the bottom of the existing one. This method requires a new well for each salt cavity, resulting in high costs and poor economic efficiency, especially for smaller salt cavities.

[0004] In summary, the traditional aeration and brine drainage method fails to effectively utilize the brine within the sedimentation space, as the brine cannot be drained. Furthermore, existing new aeration and brine drainage methods that utilize the sedimentation space require one well per chamber, resulting in high costs, poor economic efficiency, and limited adaptability. Summary of the Invention

[0005] To address the aforementioned technical problems, this application provides an artificial salt cavern gas storage facility, comprising multiple salt chambers and a new well connected to the multiple salt chambers, wherein the new well is equipped with a brine discharge string, and the brine discharge string of the new well is connected to the bottom of the salt chamber sediment of the multiple salt chambers.

[0006] According to one embodiment of the present invention, the new well includes a horizontal well or a multi-branch well.

[0007] According to one embodiment of the present invention, the horizontal wells or multi-branch wells with multiple salt cavities connected together include sequential connection or distributed connection.

[0008] According to one embodiment of the present invention, a sieve hole is provided at the connection point between the brine discharge column and the bottom of the brine sediment in the multiple brine chambers.

[0009] According to one embodiment of the present invention, a packer is provided between the brine discharge columns connected to the bottom of the brine sediment of the plurality of brine chambers.

[0010] According to one embodiment of the present invention, the packer includes a temporary sealing method, which can be unsealed as needed.

[0011] According to one embodiment of the present invention, the number of salt chambers is greater than or equal to 4, and the total volume of a single salt chamber is between 100,000 and 1,000,000 cubic meters, the free space is 100,000 cubic meters, the sludge volume is 150,000 cubic meters, the sludge void space is 66,000 cubic meters, the top depth of the chamber is 995 meters, the sludge surface depth is 1,115 meters, and the lowest point 16 at the bottom of the sludge in the salt chamber is 1,170 meters deep.

[0012] According to one embodiment of the present invention, the salt chambers may be of the same or different types; according to another embodiment of the present invention, the salt chambers may be located on the same straight line or not on the same straight line.

[0013] According to one embodiment of the present invention, the new well is constructed using casing cementing technology.

[0014] According to another embodiment of the present invention, the diameter of the technical sleeve includes 20 inches and 9 5 / 8 inches, and the technical sleeve is lowered into the salt layer at a distance of more than 15 meters from the top boundary of the salt layer.

[0015] According to one embodiment of the present invention, the top of the salt chamber further includes an old well, the old well including a brine discharge pipe; preferably, the diameter of the brine discharge pipe of the old well is 4.5 inches or 7 inches, and the depth of the brine discharge pipe is 1 to 2 meters above the sediment surface of the salt chamber.

[0016] Another aspect of the present invention is to provide a method for constructing the above-mentioned artificial salt cavern gas storage facility, comprising the following steps:

[0017] S1. A new well is set up to connect with multiple salt chambers, wherein the new well is equipped with a brine discharge string and the brine discharge string is connected to the bottom of the salt chamber sediment of the multiple salt chambers;

[0018] S2. Each salt chamber is equipped with a brine discharge pipe column extending to the top of the residue for gas injection and brine discharge until the upper free space of the salt chamber is filled with stored gas, and then the brine discharge pipe column is removed.

[0019] S3. Each salt cavity is drained from the bottom of the sediment using a new well, while gas is injected into the old well, until the brine in the sediment pore space is emptied and filled with stored gas, forming an artificial salt cavern gas storage tank.

[0020] According to one embodiment of the present invention, the new well drilling in the method includes a horizontal well or a multi-branch well.

[0021] According to one embodiment of the present invention, in the method, the salt cavities are located on the same straight line, and horizontal wells are selected to connect the salt cavities sequentially; and / or the salt cavities are not located on the same straight line, and multi-branch wells are selected to connect the salt cavities individually.

[0022] According to one embodiment of the present invention, the salt chambers in the method are located on the same straight line. When the salt chambers are of the same type, multiple salt chambers in a horizontal well are selected for simultaneous gas injection and brine discharge.

[0023] According to one embodiment of the present invention, the method of simultaneously injecting gas and draining brine from multiple brine chambers in a horizontal well further includes the following steps:

[0024] A brine discharge string is lowered into the horizontal well, and stored gas is simultaneously injected through multiple old salt wells. The gas displaces the brine in the free space and the brine in the sediment pore space from top to bottom, and is discharged to the surface through the brine discharge string of the horizontal well.

[0025] According to one embodiment of the present invention, the salt cavities in the method are located on the same straight line. When the salt cavity types are different, gas injection and brine removal are performed one by one for individual salt cavities in a horizontal well. According to another embodiment of the present invention, the method of gas injection and brine removal for individual salt cavities in a horizontal well further includes the following steps: a packer is provided on the brine removal string between the first salt cavity and the second salt cavity to seal the annulus between the brine removal string and the open hole; stored gas is injected from the old well at the top of the first salt cavity, and brine is discharged from the brine removal string in the horizontal well until the brine in the sediment of the salt cavity is emptied; the brine removal string is pulled out, and cement is injected to seal the open hole section communicating with the first salt cavity, with the cement surface set between the first and second salt cavities; and so on, gas injection and brine removal are performed for the second salt cavity and subsequent salt cavities.

[0026] According to one embodiment of the present invention, the salt chambers in the method are not located on the same straight line. When the salt chambers are of the same type, multiple salt chambers in a multi-branch well are used to simultaneously perform gas injection and brine discharge.

[0027] According to another embodiment of the present invention, when the method uses multiple branch wells and multiple salt chambers to simultaneously perform gas injection and brine discharge, it includes the following steps: a brine discharge pipe string is installed in each branch well, and stored gas is simultaneously injected through multiple old salt chamber wells. The gas displaces the brine in the free space and the brine in the sediment pore space from top to bottom and is discharged to the surface through the brine discharge pipe string of the multiple branch wells.

[0028] According to another embodiment of the present invention, the salt chambers in the method are not located on the same straight line. When the types of salt chambers are different, gas injection and brine discharge are carried out one by one in a multi-branch well.

[0029] According to another embodiment of the present invention, the method of gas injection and brine removal in a single salt cavity of a multi-branch well includes the following steps: a brine removal string is installed in a branch well of the salt cavity to be gas injected and brine removed, and a packer is provided outside the brine removal string; stored gas is injected from the old well at the top of the salt cavity, and brine is discharged from the brine removal string until the brine in the sediment voids is emptied; cement is injected into the branch well to seal the branch channel; and so on, gas injection and brine removal are carried out in the second salt cavity and subsequent salt cavities.

[0030] Compared with the prior art, this application has at least the following technical effects:

[0031] 1. By using a horizontal well or multiple branch wells to connect the sediment at the bottom of multiple salt caverns for brine discharge, the brine in the pore space of the sediment can be discharged for gas storage, improving the utilization rate of salt cavern gas storage. This is especially true for gas storage facilities with high insoluble content, where the brine in the pore space of the salt cavern can be fully emptied.

[0032] 2. This application can be used for multiple salt chambers of the same or different types. For example, for salt chambers of the same type, air can be injected and brine can be discharged at the same time, while for salt chambers of different types, air can be injected and brine can be discharged one by one. The operation of salt chambers in production and those not in production is more flexible.

[0033] 3. By setting up a new well, multiple brine chambers can be filled with gas and drained, reducing the number of brine draining wells, reducing costs, and offering high cost-effectiveness. Attached Figure Description

[0034] Figure 1 This is a flowchart of a method for draining brine from bottom sediment by connecting multiple salt chambers using horizontal wells or multi-branch wells, provided in one embodiment of the present invention.

[0035] Figure 2 This is a schematic diagram of the initial state after step S1 is completed when multiple salt chambers in a horizontal well are simultaneously injected with gas and drained of brine according to an embodiment of the present invention.

[0036] Figure 3 This is a schematic diagram showing the state after step S2 is completed when multiple salt chambers in a horizontal well are simultaneously injected with gas and drained of brine according to an embodiment of the present invention.

[0037] Figure 4 This is a schematic diagram of the final state of a horizontal well after completing step S3, where multiple salt chambers are simultaneously injected with gas and drained of brine, according to an embodiment of the present invention.

[0038] Figure 5 This is a schematic diagram of the initial state after step S1 is completed, provided by an embodiment of the present invention, in which gas injection and brine removal are performed one by one in a horizontal well single brine chamber.

[0039] Figure 6This is a schematic diagram showing the state after the first salt chamber in step S3 has been injected with gas and drained of brine in a horizontal well, according to an embodiment of the present invention.

[0040] Figure 7 This is a schematic diagram showing the state after the second salt chamber in step S3 has been injected with gas and drained of brine in a horizontal well, according to an embodiment of the present invention.

[0041] Figure 8 A schematic diagram showing the state after the third salt chamber in step S3 has been completed in an embodiment of the present invention, where gas injection and brine removal are performed one by one in a horizontal well single salt chamber;

[0042] Figure 9 This is a schematic diagram of the final state after completing step S3 of injecting gas and draining brine into four salt chambers in a single salt chamber of a horizontal well, according to an embodiment of the present invention.

[0043] Figure 10 This is a schematic diagram of the initial state after step S1 is completed when multiple salt chambers in a multi-branch well are simultaneously injected with gas and drained of brine in an embodiment of the present invention.

[0044] Figure 11 A top view of a multi-branch well with gas injection and brine removal provided in one embodiment of the present invention;

[0045] Figure 12 This is a schematic diagram of the final state after step S3 is completed using multiple salt chambers in a multi-branch well for gas injection and brine removal, as provided in one embodiment of the present invention.

[0046] Figure 13 This is a schematic diagram of the initial state after step S1 is completed, which is provided by an embodiment of the present invention, in which gas injection and brine removal are performed one by one in a single salt cavity of a multi-branch well.

[0047] Figure 14 This is a schematic diagram of the final state after step S3 is completed, provided by an embodiment of the present invention, which involves injecting gas and draining brine one by one in a single salt chamber of a multi-branch well.

[0048] Attached reference numerals: 1-Old well 1, 2-Old well 2, 3-Old well 3, 4-Old well 4, 5-Newly drilled horizontal well, 6-Overlying mudstone caprock, 7-Salt layer, 8-Underlying mudstone base, 9-Old well technical casing, 10-Old well brine discharge string, 11-Brine in the free space of the salt cavity, 12-Brine in the sediment space, 13-Salt cavity, 14-New well technical casing, 15-New well brine discharge string, 16-Lowest point of sediment, 17-Sieve hole, 18-Stored gas in the free space of the salt cavity, 19-Stored gas in the sediment space, 20-Packer, 21-Cement plug, 22-Newly drilled multi-branch well. Detailed Implementation

[0049] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0050] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0051] like Figure 1 As shown, according to a specific embodiment of the present invention, a method for constructing an artificial salt cavern gas storage facility is provided, comprising the following steps:

[0052] S1. A new well is set up to connect with multiple salt chambers, wherein the new well is equipped with a brine discharge string and the brine discharge string is connected to the bottom of the salt chamber sediment of the multiple salt chambers;

[0053] S2. Each salt chamber is equipped with a brine discharge pipe column extending to the top of the residue for gas injection and brine discharge until the upper free space of the salt chamber is filled with stored gas, and then the brine discharge pipe column is removed.

[0054] S3. Each salt cavity is drained from the bottom of the sediment using a new well, while gas is injected into the old well, until the brine in the sediment pore space is emptied and filled with stored gas, forming an artificial salt cavern gas storage tank.

[0055] The technical solution of the present invention is further illustrated below through specific embodiments:

[0056] Example 1

[0057] This embodiment employs a horizontal well multi-salt chamber simultaneous gas injection and brine discharge method, such as... Figure 2 As shown.

[0058] See Figure 2Within the salt mine area, there are four old salt wells that have not yet been put into production: Old Well 1, Old Well 2, Old Well 3, and Old Well 4. The salt wells are filled with saturated brine and are located on a straight line.

[0059] Sonar measurements were taken during and after cavity construction. The total volume of a single cavity is approximately 250,000 cubic meters. The free space brine (11) contains approximately 100,000 cubic meters, the volume of insoluble sediment is approximately 150,000 cubic meters, the sediment void space brine (12) contains approximately 66,000 cubic meters, the cavity top depth is 995 meters, the sediment surface depth is 1115 meters, and the lowest point of the sediment bottom (16) in the salt cavity has a depth of 1170 meters.

[0060] Execute step S1, see Figure 2 The newly drilled horizontal well 5 serves as a brine discharge well. The horizontal well sequentially connects to the salt cavities corresponding to the old wells 4, 3, 2, and 1, with the target point being the lowest point 16 at the bottom of the salt cavities. A technical casing 14, 9 5 / 8 inches in diameter, is installed in the well to a depth of 980 meters, 15 meters above the top of salt layer 7 at 965 meters. A brine discharge string 15, 4 1 / 2 inches in diameter, is also installed in the well, with perforated screens 17 at each connection point between the discharge string and the salt cavities.

[0061] Execute step S2, see [link / reference] Figure 3 In the un-operated old wells 1, 2, 3, and 4 of the salt cavity, brine discharge pipe strings 10 are installed. Natural gas is injected into the annulus between the technical casing 9 and the brine discharge pipe string 10. Brine is extracted from the brine discharge pipe string 10, and gas is injected to discharge brine until the upper free space of the salt cavity is filled with natural gas 18. After completing step S2, the state of the salt cavity is as follows. Figure 3 As shown.

[0062] After the free space gas injection and brine removal are completed, the brine removal tubing string 10 is removed using a non-pressure well operation.

[0063] Execute step S3, see [link / reference] Figure 4 Natural gas is simultaneously injected from the technical casing 9 of four old wells, displacing the brine 12 in the sediment voids from top to bottom and draining it from the brine discharge string 15 in the horizontal well 5 to the surface, until the sediment space is filled with natural gas 19, forming a gas storage tank. After completing step S3, the state of the salt cavity is as follows: Figure 4 As shown.

[0064] Example 2

[0065] This embodiment uses a horizontal well single-chamber gas injection and brine removal method, such as... Figure 5 As shown.

[0066] See Figure 5 Within the salt mine area, there are four old salt wells that have not yet been put into production: Old Well 1, Old Well 2, Old Well 3, and Old Well 4. The salt wells are filled with saturated brine and are located on a straight line.

[0067] Sonar measurements were taken during and after cavity construction. The total volume of a single cavity is approximately 250,000 cubic meters. The free space brine (11) contains approximately 100,000 cubic meters, the volume of insoluble sediment is approximately 150,000 cubic meters, the sediment void space brine (12) contains approximately 66,000 cubic meters, the cavity top depth is 995 meters, the sediment surface depth is 1115 meters, and the lowest point of the sediment bottom (16) in the salt cavity has a depth of 1170 meters.

[0068] Execute step S1, see Figure 5 The newly drilled horizontal well 5 serves as a brine discharge well. The horizontal well sequentially connects to the salt cavities corresponding to the old wells 4, 3, 2, and 1, with the target point being the lowest point 16 at the bottom of the salt cavities. A technical casing 14, 9 5 / 8 inches in diameter, is run into the well to a depth of 980 meters, 15 meters above the top of salt layer 7 at 965 meters. A brine discharge string 15, 4 1 / 2 inches in diameter, is also run into the well, with a screen 17 only at the tail end. A packer is installed on the brine discharge string between old wells 1 and 2 to seal the annulus between the discharge string and the open hole.

[0069] Execute step S2, see [link / reference] Figure 5 In the un-operated salt wells 1, 2, 3 and 4, a brine discharge pipe string 10 is installed. Natural gas is first injected into the annulus between the technical casing 9 of the old well 1 and the brine discharge pipe string 10. Brine is extracted from the brine discharge pipe string 10. At the same time, gas is injected to discharge the brine until the free space in the upper part of the salt cavity is filled with natural gas 18.

[0070] After the free space gas injection and brine removal are completed, the brine removal tubing string 10 is removed using a non-pressure well operation.

[0071] Execute step S3, see [link / reference] Figure 6 Natural gas is injected from the technical casing 9 of the old well 1, and brine is discharged from the brine discharge string 15 inside the horizontal well 5 until the brine in the salt cavity sediment space is emptied and filled with natural gas 19.

[0072] Execute step S3, see [link / reference] Figure 6 The brine drain string 15 in the horizontal well is pulled out, and cement is injected to form a cement plug 21 to seal the salt cavity 13 corresponding to the old well 1, preventing the brine inside from leaking out.

[0073] Repeat steps (4)-(7) to sequentially perform sedimentation space aeration and brine discharge operations on old wells 2, 3, and 4, as follows: Figures 7-9 As shown. Eventually, all the brine in the salt chambers is drained, forming a gas storage reservoir. The final state of the salt chambers is as follows. Figure 9 As shown.

[0074] Example 3

[0075] This embodiment employs a multi-branch well, multi-salt cavity simultaneous gas injection and brine discharge method, such as... Figure 10 and Figure 11 As shown, Figure 11 for Figure 10 Top view.

[0076] See Figure 10 There are four old salt wells (Well 1, Well 2, Well 3, and Well 4) that have not yet been put into production in the salt mine area. The salt wells are filled with saturated brine and are located in a relatively scattered manner.

[0077] Sonar measurements were taken during and after cavity construction. The total volume of a single cavity was approximately 250,000 cubic meters, with approximately 100,000 cubic meters of brine in the free space (11), approximately 150,000 cubic meters of insoluble sediment, and approximately 66,000 cubic meters of brine in the sediment void space (12). The cavity top depth was 995 meters, the sediment surface depth was 1115 meters, and the lowest point (16) at the bottom of the salt cavity sediment was 1170 meters deep.

[0078] Execute step S1, see Figure 10 and Figure 11 The following explanation is provided. The newly drilled multi-branch well 22 serves as a brine discharge well. Its four branches are sequentially drilled to connect to the salt cavities corresponding to the old wells 1, 2, 3, and 4, with the target point being the lowest point 16 at the bottom of the salt cavities. A technical casing 14, 9 5 / 8 inches in diameter, is installed in the well to a depth of 980 meters, 15 meters above the top of salt layer 7 at 965 meters. Each of the four branch wells has a brine discharge string 15, 4 1 / 2 inches in diameter, connected to each salt cavity, with a screen 17 at the connection point.

[0079] Execute step S2, see [link / reference] Figure 10 In the un-operated old wells 1, 2, 3 and 4 of the salt cavity, a brine discharge pipe string 10 is installed. Natural gas is injected into the annulus between the technical casing 9 and the brine discharge pipe string 10. Brine is extracted from the brine discharge pipe string 10. At the same time, gas is injected to discharge brine until the free space in the upper part of the salt cavity is filled with natural gas 18.

[0080] After the free space gas injection and brine removal are completed, the brine removal tubing string 10 is removed using a non-pressure well operation.

[0081] Execute step S3, see [link / reference] Figure 12 Natural gas is simultaneously injected from the technical casing 9 of four old wells, displacing the brine 12 in the sediment voids from top to bottom and draining it from the brine discharge string 15 in the horizontal well 5 to the surface, until the sediment space is filled with natural gas 19, forming a gas storage tank. After completing step S3, the state of the salt cavity is as follows: Figure 12 As shown.

[0082] Example 4

[0083] This embodiment employs a multi-branch well single-salt-cavity gas injection and brine removal method, such as... Figure 13 As shown.

[0084] See Figure 13There are four old salt wells (Well 1, Well 2, Well 3, and Well 4) that have not yet been put into production in the salt mine area. The salt wells are filled with saturated brine and are located in a relatively scattered manner.

[0085] Sonar measurements were taken during and after cavity construction. The total volume of a single cavity was approximately 250,000 cubic meters, with approximately 100,000 cubic meters of brine in the free space (11), approximately 150,000 cubic meters of insoluble sediment, and approximately 66,000 cubic meters of brine in the sediment void space (12). The cavity top depth was 995 meters, the sediment surface depth was 1115 meters, and the lowest point (16) at the bottom of the salt cavity sediment was 1170 meters deep.

[0086] Execute step S1, see Figure 13 The following explanation is provided. The newly drilled multi-branch well 22 serves as a brine drainage well. Its four branches are sequentially drilled to connect to the salt cavities corresponding to the old wells 1, 2, 3, and 4, with the target point being the lowest point 16 at the bottom of the salt cavities. A technical casing 14, 9 5 / 8 inches in diameter, is installed in the well to a depth of 980 meters, 15 meters above the top boundary of salt layer 7 (965 meters). Only in the branch well corresponding to old well 1 is a brine drainage string 15, 4 1 / 2 inches in diameter, installed. This string connects to the salt cavity, with a screen 17 at the connection point. A packer is installed on the brine drainage string in the branch well of old well 1, sealing the annulus between the string and the open hole to prevent brine from other salt cavities from entering the drainage string.

[0087] Execute step S2, see [link / reference] Figure 13 In the un-operated salt wells 1, 2, 3 and 4, a brine discharge pipe string 10 is installed. Natural gas is first injected into the annulus between the technical casing 9 of the old well 1 and the brine discharge pipe string 10. Brine is extracted from the brine discharge pipe string 10. At the same time, gas is injected to discharge the brine until the free space in the upper part of the salt cavity is filled with natural gas 18.

[0088] After the free space gas injection and brine removal are completed, the brine removal tubing string 10 is removed using a non-pressure well operation.

[0089] Execute step S3, see [link / reference] Figure 14 Natural gas is injected from the technical casing 9 of the old well 1, and brine is discharged from the brine discharge string 15 in the corresponding branch of the old well 1 in the multi-branch well until the brine in the salt cavity sediment space is emptied and filled with natural gas 19.

[0090] Execute step S3, see [link / reference] Figure 14 Remove the brine discharge string 15, inject cement into the branch well to form a cement plug 21 to seal the salt cavity 13 corresponding to the old well 1, and prevent the brine inside from leaking out.

[0091] Repeat steps (4)-(7) to sequentially perform aeration and brine discharge operations in the sedimentation space of old wells 2, 3, and 4. Finally, all brine in the salt chambers is completely drained, forming a gas storage tank. The final state of the salt chambers is as follows: Figure 14 As shown.

[0092] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A method of constructing an artificial salt cavern gas storage, characterized in that, The artificial salt cave gas storage comprises a plurality of salt cavities and new drilled wells connected with the plurality of salt cavities, wherein the new drilled wells are provided with a brine discharge pipe column connected with the salt cavity sediment bottoms of the plurality of salt cavities; the new drilled wells comprise horizontal wells or multi-branch wells; the horizontal wells or multi-branch wells connected with the plurality of salt cavities comprise sequentially connected or distributed connection; the number of the salt cavities is greater than or equal to 4, the positions of the salt cavities are on the same straight line, the horizontal wells are selected to sequentially connect the salt cavities; and / or the positions of the salt cavities are not on the same straight line, the multi-branch wells are selected to separately connect the salt cavities; and the method comprises the following steps: S1. providing new drilled wells connected with the plurality of salt cavities, wherein the new drilled wells are provided with a brine discharge pipe column connected with the salt cavity sediment bottoms of the plurality of salt cavities; S2. providing a brine discharge pipe column to the residue top of each salt cavity for gas injection and brine discharge until the upper free space of the salt cavity is filled with storage gas, and the brine discharge pipe column is removed; S3. using the new drilled wells to discharge brine from the sediment bottoms while the old wells inject gas until the brine in the sediment pore space is discharged and filled with storage gas to form an artificial salt cave gas storage. When the positions of the salt cavities are on the same straight line and the types of the salt cavities are the same, the horizontal wells are selected to simultaneously inject gas and discharge brine for the plurality of salt cavities. When the positions of the salt cavities are on the same straight line and the types of the salt cavities are different, the horizontal wells are selected to sequentially inject gas and discharge brine for the single salt cavities. When the positions of the salt cavities are not on the same straight line and the types of the salt cavities are the same, the multi-branch wells are selected to simultaneously inject gas and discharge brine for the plurality of salt cavities. When the positions of the salt cavities are not on the same straight line and the types of the salt cavities are different, the multi-branch wells are selected to sequentially inject gas and discharge brine for the single salt cavities.

2. The construction method of the artificial salt cave gas storage according to claim 1, wherein the selection of the horizontal wells to simultaneously inject gas and discharge brine for the plurality of salt cavities further comprises the following steps: running the brine discharge pipe column into the horizontal well, simultaneously injecting storage gas through the old wells of the plurality of salt cavities, and driving the brine in the free space and the brine in the sediment pore space from top to bottom to be discharged to the ground through the brine discharge pipe column of the horizontal well.

3. The construction method of the artificial salt cave gas storage according to claim 1, wherein the selection of the horizontal wells to sequentially inject gas and discharge brine for the single salt cavities comprises the following steps: providing a packer on the brine discharge pipe column between the first salt cavity and the second salt cavity to seal the annulus between the brine discharge pipe column and the open hole; injecting storage gas from the old well at the top of the first salt cavity and discharging the brine from the brine discharge pipe column in the horizontal well until the brine in the sediment of the salt cavity is discharged; pulling out the brine discharge pipe column, injecting cement to cement the well section of the open hole connected with the first salt cavity, and setting the cement face between the first salt cavity and the second salt cavity; and sequentially injecting gas and discharging brine for the second salt cavity and the subsequent salt cavities.

4. The construction method of the artificial salt cave gas storage according to claim 1, wherein ​ ​ The method for constructing the artificial salt cavern gas storage comprises the following steps: inserting a brine discharge pipe string into each branch well, injecting storage gas into the old wells of the multiple salt cavities, and driving the brine in the free space and the brine in the pore space of the sediment from the top to the bottom to be discharged to the ground through the brine discharge pipe string of the multiple branch wells.

5. The method for constructing the artificial salt cavern gas storage according to claim 1, wherein the total space volume of the single salt cavity is 1-10 million cubic meters, the free space is 100,000 cubic meters, the sediment volume is 150,000 cubic meters, the pore space of the sediment is 66,000 cubic meters, the depth of the top of the salt cavity is 995 meters, the depth of the sediment surface is 1,115 meters, and the depth of the lowest point of the bottom of the sediment of the salt cavity is 1,170 meters. The method for constructing the artificial salt cavern gas storage according to claim 1, wherein the new well is cemented by inserting a technical casing, and / or the diameter of the technical casing is 20 inches or 9 5 / 8 inches, and the technical casing is inserted into the salt layer at a distance of more than 15 meters from the top boundary of the salt layer.

6. The method of constructing an artificial salt cavern gas storage according to claim 1, wherein, The method for constructing the artificial salt cavern gas storage according to claim 1, wherein the top of the salt cavity further comprises an old well, the old well comprises a brine discharge pipe string, the diameter of the brine discharge pipe string of the old well is 4.5 inches or 7 inches, and the insertion depth of the brine discharge pipe string is 1-2 meters higher than the sediment surface of the salt cavity.

7. The method of constructing an artificial salt cavern gas storage according to claim 1, wherein, The method for constructing the artificial salt cavern gas storage according to claim 1, wherein the brine discharge pipe string is connected to the bottom of the sediment of the salt cavity, and a screen hole is arranged at the connection position.

8. The method of constructing an artificial salt cavern gas storage according to claim 1 or 6 or 7, characterized in that, The method for constructing the artificial salt cavern gas storage according to claim 1, wherein a packer is arranged between the brine discharge pipe strings connected to the bottom of the sediment of the salt cavities, and / or the packer comprises a temporary setting mode and can be unsealed according to needs.

9. The method of constructing an artificial salt cavern gas storage according to claim 1 or 6 or 7, characterized in that, The method for constructing the artificial salt cavern gas storage according to claim 1, wherein the total space volume of the single salt cavity is 1-10 million cubic meters, the free space is 100,000 cubic meters, the sediment volume is 150,000 cubic meters, the pore space of the sediment is 66,000 cubic meters, the depth of the top of the salt cavity is 995 meters, the depth of the sediment surface is 1,115 meters, and the depth of the lowest point of the bottom of the sediment of the salt cavity is 1,170 meters. The method for constructing the artificial salt cavern gas storage according to claim 1, wherein the new well is cemented by inserting a technical casing, and / or the diameter of the technical casing is 20 inches or 9 5 / 8 inches, and the technical casing is inserted into the salt layer at a distance of more than 15 meters from the top boundary of the salt layer.

10. The method of constructing an artificial salt cavern gas storage according to claim 1 or 6 or 7, characterized in that, The method for constructing the artificial salt cavern gas storage according to claim 1, wherein the top of the salt cavity further comprises an old well, the old well comprises a brine discharge pipe string, the diameter of the brine discharge pipe string of the old well is 4.5 inches or 7 inches, and the insertion depth of the brine discharge pipe string is 1-2 meters higher than the sediment surface of the salt cavity.

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