Gas injection and brine discharge system of complex salt cavern cavity
By designing a multi-injection and production well and halogen drainage well system for complex salt cavity cavity, the problem that the existing technology cannot efficiently inject gas and halogen drainage complex salt cavity cavity is solved, and efficient gas and halogen drainage is achieved, which improves the utilization rate and economic benefits of the system.
Patent Information
- Application Number
- CN202422204211.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-09
- Publication Date
- 2025-06-06
- Estimated Expiration
- 2034-09-09
AI Technical Summary
The existing gas injection and halogen exhaust technology cannot effectively perform gas injection and halogen exhaust for complex salt cavity cavity, resulting in a low gas injection and halogen exhaust rate, poor effect, longer cycles and higher cost.
A gas injection and halogen exhaust system with complex salt cavity cavity is designed, including multiple injection and mining wells and one halogen exhaust well. The outlet end of the injection and mining pipe is located in the brine filling area between different interlayers, and the inlet end of the halogen exhaust pipe is located at the junction of the comprehensive filling area and the interlayer slump block. Pressurized air is injected simultaneously through multiple injection and mining wells. The halogen exhaust pipe is quickly discharged from brine under the joint action of multiple groups of pressurized air.
It effectively improves the gas injection and halogen exhaust rate and effect of complex salt cavity cavity, shortens the gas injection and halogen exhaust cycle, reduces costs, and avoids the waste of underground resources.
Smart Images
Figure CN222949837U_ABST
Abstract
Description
Technical Field
[0001] The present specification relates to the field of compressed air energy storage technology, and in particular to an air injection and brine removal system for a complex salt cavern cavity. Background Art
[0002] Salt mining produces a large number of complex salt caverns. Effectively utilizing complex salt caverns for compressed air energy storage can avoid the waste of underground resources. The gas injection and brine removal technology can inject high-pressure natural gas or air into the salt caverns to discharge the brine in the salt caverns, thereby realizing the storage of compressed air in the salt caverns.
[0003] Existing gas injection and brine removal technologies mainly include single-well single-cavity gas injection and brine removal mode, single-cavity low-position gas injection and brine removal mode, double-cavity low-position gas injection and brine removal mode, and double-well double-cavity U-shaped gas injection and brine removal mode. However, these gas injection and brine removal methods are only applicable to regular cavities, and cannot meet the requirements of gas injection and brine removal in complex salt cavern cavities (salt cavern gas storages) with the characteristics of many interlayers, thick interlayers, much sediment, and irregular cavity shapes. This leads to problems such as low gas injection and brine removal rate, poor effect, long cycle, and high cost in complex salt cavern cavities.
[0004] To address the above problems, no effective solution has been proposed yet. Utility Model Content
[0005] This specification provides a gas injection and brine removal system for a complex salt cavern cavity to solve the problem that the prior art is unable to perform gas injection and brine removal for complex salt cavern cavities, resulting in a low gas injection and brine removal rate, poor effect, long cycle and high cost for the complex salt cavern cavity.
[0006] In order to solve the above technical problems, the embodiment of this specification provides a gas injection and brine removal system for a complex salt cavern cavity, comprising at least: a complex salt cavern cavity, a plurality of injection and production wells connected to the top of the complex salt cavern cavity, and a brine removal well connected to a target position at the bottom of the complex salt cavern cavity;
[0007] The complex salt cavern cavity includes a plurality of interlayers, between each of the plurality of interlayers is a brine filling area, below the bottom interlayer of the plurality of interlayers is a comprehensive filling area, below the comprehensive filling area is an interlayer collapse block;
[0008] Each of the multiple injection and production wells is equipped with an injection and production pipe, and the brine discharge well is equipped with a brine discharge pipe. The outlet end of the injection and production pipe is located in the brine filling area between different interlayers, and the inlet end of the brine discharge pipe is located in the junction of the integrated filling area and the interlayer collapsed block. The injection and production pipe is used to be injected with pressurized air and to discharge the pressurized air from the outlet end at the same time, and the brine discharge pipe is used to discharge the brine in the integrated filling area under the joint action of multiple groups of pressurized air.
[0009] In some embodiments, the complex salt cavern cavity includes but is not limited to a salt cavern cavity with a small salt layer thickness, a large interlayer thickness, a high interlayer ratio, an irregular cavity shape, a large aspect ratio, a large amount of sediment, and large sediment gaps. The salt cavern cavity is spindle-shaped and has a long strip-shaped structure in plane.
[0010] In some embodiments, the multiple injection and production wells include 8 injection and production wells, and the 8 injection and production wells are arranged in 2 rows and 4 lines. The row spacing of the injection and production wells is 30m, and the row spacing of the injection and production wells is 50m.
[0011] In some embodiments, the outlet end of the injection and production pipe is located in the brine filling area between different interlayers, including:
[0012] The injection and production pipe outlet ends of the second injection and production wells in the second row and the injection and production pipe outlet ends of the third injection and production wells in the third row are located in the brine filling area between the top of the complex salt cavern cavity and the first interlayer, and the first interlayer is the first interlayer among the multiple interlayers;
[0013] The injection and production pipe outlet ends of the first injection and production well in the first row and the injection and production pipe outlet ends of the fourth injection and production well in the fourth row are located in the brine filling area between the first interlayer and the second interlayer, and the second interlayer is the second interlayer among the multiple interlayers.
[0014] In some embodiments, a first integrated sensor is installed in the wall of the injection and production well, and a second integrated sensor is installed in the wall of the brine drainage well. The first integrated sensor is used to monitor the stability of the first wellbore structure of the injection and production well, and the second integrated sensor is used to monitor the stability of the second wellbore structure of the brine drainage well.
[0015] In some embodiments, an injection-production well valve is provided on the inlet end of each of the multiple injection-production wells, and an injection-production well master valve is provided on the injection-production well valve, and the injection-production well master valve is used to control the injection-production well valve.
[0016] In some embodiments, after the injection-production well valve is opened, pressurized air is simultaneously injected into the inlet end of the injection-production pipe.
[0017] In some embodiments, the target position is the farthest end of the plane of the complex salt cavern cavity and is 10 m upward from the bottom of the complex salt cavern cavity.
[0018] In some embodiments, the coating material of the inner wall of the injection and production tube is nickel-alloy, and the thickness of the coating material is 0.4 mm to 0.5 mm.
[0019] In some embodiments, the outlet end of the injection and production pipe is located 10m from the brine filling area, the inlet end of the brine discharge pipe is located 0.5m from the junction of the integrated filling area and the collapsed block, and the diameter of the injection and production pipe is 339.7mm.
[0020] The embodiment of the present specification provides a gas injection and brine removal system for a complex salt cavern cavity, comprising at least: a complex salt cavern cavity, a plurality of injection and production wells connected to the top of the complex salt cavern cavity, and a brine removal well connected to a target position at the bottom of the complex salt cavern cavity; wherein the complex salt cavern cavity comprises a plurality of interlayers, brine filling areas are located between two of the plurality of interlayers, a comprehensive filling area is located below the bottom interlayer of the plurality of interlayers, and an interlayer collapse block is located below the comprehensive filling area; each of the plurality of injection and production wells is provided with an injection and production pipe, and the brine removal well is provided with a brine removal pipe, the outlet end of the injection and production pipe is located in the brine filling area between different interlayers, and the inlet end of the brine removal pipe is located at the junction of the comprehensive filling area and the interlayer collapse block, the injection and production pipe is used to be injected with pressurized air at the same time and to discharge the pressurized air from the outlet end, and the brine removal pipe is used to discharge the brine in the comprehensive filling area under the joint action of multiple groups of pressurized air. In the embodiments of this specification, by connecting multiple injection and production wells at the top of the complex salt cavern cavity and connecting the brine drainage well at the target position at the bottom of the complex salt cavern cavity, the purpose of injecting gas from multiple injection and production wells and draining brine from one brine drainage well can be achieved for the complex salt cavern cavity, and the gas injection and brine drainage rate of the complex salt cavern cavity can be effectively improved. By setting the outlet end of the injection and production pipe in the brine filling area between different interlayers, the problem of brine being hindered by the interlayer and causing the flow rate to decrease can be avoided. At the same time, the brine filling area between different interlayers can also accelerate the collapse of the interlayer under the pressure of pressurized air (high-pressure air). The collapse of the collapsed block increases the useful volume of the complex salt cavern cavity due to dissolution in the brine, thereby increasing the utilization rate of the complex salt cavern cavity. By setting the inlet end of the brine discharge pipe at the junction of the comprehensive filling area and the interlayer collapsed block, the problem of slow brine flow rate caused by the obstruction of brine flow due to the collapsed block or collapsed body, a lot of sediment debris, and a small internal porosity can be avoided, the brine discharge rate can be accelerated, the brine discharge effect can be improved, and the time cost of gas injection and brine discharge can be saved. By setting up multiple injection and production wells, the built-in injection and production pipes can be injected with pressurized air at the same time, so that the gas injection volume can be increased, and the brine discharge pipe can be quickly discharged from the comprehensive filling area under the joint action of multiple groups of pressurized air, so that compressed air can be stored in the complex salt cavern cavity, shortening the time cost of power generation and production, and avoiding the waste of underground resources. BRIEF DESCRIPTION OF THE DRAWINGS
[0021] In order to more clearly illustrate the technical solutions in the embodiments of this specification or the prior art, the following briefly introduces the drawings required for use in the embodiments or the prior art description. Obviously, the drawings described below are only some embodiments recorded in this specification. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. In the drawings:
[0022] Figure 1 It is a structural schematic diagram of a gas injection and brine removal system for a complex salt cavern cavity provided in an embodiment of this specification;
[0023] Figure 2 It is a schematic diagram of the plan layout of multiple injection and production wells provided in the embodiments of this specification;
[0024] Figure 3 It is a schematic diagram of the wellbore structure of the injection-production well provided in the embodiment of this specification;
[0025] Figure 4 It is a schematic diagram of the well body structure of the brine drainage well provided in the embodiment of this specification.
[0026] [Description of Reference Numerals]
[0027] 0. Complex salt cavern cavity; 1. Injection and production well valve; 2. Inlet end of injection and production pipe; 3. Injection and production pipe; 4. First integrated sensor; 5. Packer; 6. Casing shoe; 7. Outlet end of injection and production pipe; 8. Injection and production well main valve; 9. Injection and production well row spacing; 10. Brine drainage well valve; 11. Brine drainage pipe; 12. Second integrated sensor; 13. Inlet end of brine drainage pipe; 14. Target position; 15. Outlet end of brine drainage pipe. DETAILED DESCRIPTION
[0028] In order to enable those skilled in the art to better understand the technical solutions in this specification, the technical solutions in the embodiments of this specification will be clearly and completely described below in conjunction with the drawings in the embodiments of this specification. Obviously, the described embodiments are only part of the embodiments of this specification, not all of the embodiments. Based on the embodiments in this specification, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of this specification.
[0029] Salt mining produces a large number of irregular salt caverns. Effectively utilizing irregular salt caverns for compressed air energy storage can avoid the waste of underground resources. The gas injection and brine removal technology can inject high-pressure natural gas or air into the salt caverns to discharge the brine in the salt caverns, thereby realizing the storage of compressed air in the salt caverns.
[0030] Compressed air energy storage is to store abandoned wind and photovoltaic power and off-peak electricity in the form of high-pressure air, and use turbine expansion to do work during peak electricity consumption hours to drive generators to generate electricity. Salt cavern gas storage is often used as a pressure vessel for storing compressed air because of its large available volume, good sealing, and low investment cost. Compressed air energy storage in salt cavern gas storage refers to the use of excess unused electricity during the off-peak period of the power grid load to compress air and store it in underground salt caverns, and the release of compressed air in the underground salt cavity during the peak period of the power grid load to drive air turbines to generate electricity.
[0031] Existing gas injection and brine removal technologies mainly include single-well single-cavity gas injection and brine removal mode, single-cavity low-position gas injection and brine removal mode, double-cavity low-position gas injection and brine removal mode, and double-well double-cavity U-shaped gas injection and brine removal mode. However, these gas injection and brine removal methods are only applicable to regular cavities, and cannot meet the requirements of gas injection and brine removal in complex salt cavern cavities (salt cavern gas storages) with the characteristics of small salt layer thickness, large interlayer thickness, large interlayer proportion, irregular cavity shape, large aspect ratio, much sediment, and large sediment gaps. As a result, the gas injection and brine removal rate of complex salt cavern cavities is low, the effect is poor, the cycle is long, the cost is high, and it does not meet the project schedule and production needs.
[0032] For example, for cavities with large interlayer thickness and large interlayer proportion, when using the current gas injection brine extraction technology, the presence of multiple interlayers will greatly reduce the gas pressure, flow rate and fluidity, thereby reducing the brine discharge rate;
[0033] For cavities with a large aspect ratio, the volume of the collapsed blocks in the interlayer (length greater than 250 meters, width greater than 100 meters, thickness ranging from 0.5 meters to 10.3 meters) is larger than that in regular cavities, with more sediment and larger sediment gaps. When the current gas injection and brine removal technology is used, the disordered accumulation of a large number of collapsed blocks with unequal volumes and poor grading will greatly reduce the fluidity of the brine.
[0034] In view of the above-mentioned problems existing in the existing methods and the specific reasons for the above-mentioned problems, the present application considers introducing a gas injection and brine removal system for complex salt cavern cavities, which can meet the requirements of gas injection and brine removal for complex salt cavern cavities with the characteristics of small salt layer thickness, large interlayer thickness, high interlayer proportion, irregular cavity shape, large aspect ratio, much sediment, and large sediment gaps, improve the gas injection and brine removal rate and effect of the complex salt cavern cavities, and reduce the gas injection and brine removal cycle and cost.
[0035] See also Figure 1 As shown, the gas injection and brine removal system of the complex salt cavern cavity may at least include: a complex salt cavern cavity 0, a plurality of injection and production wells (including: a first injection and production well, a second injection and production well, a third injection and production well, and a fourth injection and production well) connected to the top of the complex salt cavern cavity 0, and a brine removal well connected to the target position 14 at the bottom of the complex salt cavern cavity 0;
[0036] The complex salt cavern cavity 0 may include a plurality of interlayers, wherein the space between any two interlayers in the plurality of interlayers is a brine filling area, and below the bottom interlayer in the plurality of interlayers is a comprehensive filling area, and below the comprehensive filling area is an interlayer collapse block;
[0037] Each of the multiple injection and production wells is equipped with an injection and production pipe 3, and the brine discharge well is equipped with a brine discharge pipe 11. The outlet end 7 of the injection and production pipe 3 is located in the brine filling area between different interlayers, and the inlet end 13 of the brine discharge pipe is located at the junction of the integrated filling area and the interlayer collapsed block. The injection and production pipe 3 can be used to simultaneously inject pressurized air and discharge the pressurized air from the outlet end 7, and the brine discharge pipe 11 can be used to discharge the brine in the integrated filling area under the joint action of multiple groups of pressurized air.
[0038] In some embodiments, the complex salt cavern cavity 0 may include, but is not limited to, a salt cavern cavity with a small salt layer thickness, a large interlayer thickness, a high interlayer ratio, an irregular cavity shape, a large aspect ratio, a large amount of sediment, and large sediment gaps. The salt cavern cavity may be spindle-shaped and have a long strip-shaped structure in plane.
[0039] Specifically, the length of the complex salt cavern cavity 0 can be greater than 300m (meters), the width can be greater than 115m, the height can be greater than 110m, the length can be greater than the height, the aspect ratio can be greater than 1.2, the aspect ratio can be greater than 0.55, and the spatial shape of the cavity is irregular, and is a spindle-shaped structure with a long strip in plane. The complex salt cavern cavity 0 has many interlayers (the number of interlayers can be greater than 20 layers), a large single-layer thickness (the maximum single-layer thickness can be greater than 10m), a total interlayer ratio of more than 50%, and the interlayer collapse is not serious. The total thickness of the interlayer accounts for more than 60% of the cavity volume. The bottom of the complex salt cavern cavity 0 is an interlayer collapse block, the interior of the block can be filled with sediment debris, the porosity is small, and brine will not flow in this area. The comprehensive filling area on the interlayer collapsed block in the complex salt cavern cavity 0 is the filling area of brine, collapsed block (or collapsed block or collapsed block) and sediment. The sediment debris in this area is not densely accumulated, and the flow rate of brine in this area is relatively large.
[0040] After the salt mine is mined, the underground (i.e. Figure 1 The existing gas injection and brine removal technology is not suitable for complex salt cavern cavities, resulting in low gas injection and brine removal rate, poor effect, long cycle and high cost. Based on this, the present application provides a gas injection and brine removal system for complex salt cavern cavities, which can effectively improve the gas injection and brine removal rate and effect of complex salt cavern cavities, and reduce the gas injection and brine removal cycle and cost.
[0041] In some embodiments, see Figure 2As shown, the multiple injection and production wells may include 8 injection and production wells, and the 8 injection and production wells may be arranged in 2 rows and 4 lines, with a line spacing of 30m and a row spacing of 50m.
[0042] Specifically, the injection and production wells in the first row can be called the first injection and production wells, the injection and production wells in the second row can be called the second injection and production wells, the injection and production wells in the third row can be called the third injection and production wells, and the injection and production wells in the fourth row can be called the fourth injection and production wells.
[0043] By arranging 8 injection and production wells in 2 rows and 4 lines on the top of a complex salt cavern, the gas injection volume can be effectively increased, thereby improving the subsequent brine drainage rate. The injection and production wells are spaced 30 meters apart and 50 meters apart. This arrangement not only ensures safe and effective wellhead spacing, but also greatly shortens the time for drilling equipment relocation and site leveling, thereby achieving both time and economic benefits.
[0044] In some embodiments, the outlet end 7 of the injection and production pipe is located in the brine filling area between different interlayers, and may include:
[0045] The injection and production pipe outlet end 7 of the second injection and production well in the second row and the injection and production pipe outlet end 7 of the third injection and production well in the third row may be located in the brine filling area between the top of the complex salt cavern cavity and the first interlayer, wherein the first interlayer is the first interlayer among the multiple interlayers;
[0046] The injection and production pipe outlet end 7 of the first injection and production well in the first row and the injection and production pipe outlet end 7 of the fourth injection and production well in the fourth row can be located in the brine filling area between the first interlayer and the second interlayer, and the second interlayer is the second interlayer among the multiple interlayers.
[0047] For details, see Figure 1 As shown, counting from the top of the cavity to the bottom of the cavity, the first interlayer in the complex salt cavern cavity 0 can be called the first interlayer, the second interlayer can be called the second interlayer, and the last interlayer can be called the bottom interlayer. The injection and production pipe outlet end 7 of the second injection and production well and the injection and production pipe outlet end 7 of the third injection and production well can be located in the brine filling area between the top of the complex salt cavern cavity and the first interlayer, and the injection and production pipe outlet end 7 of the first injection and production well and the injection and production pipe outlet end 7 of the fourth injection and production well can be located in the brine filling area between the first interlayer and the second interlayer. Among them, the brine filling area between the top of the complex salt cavern cavity and the first interlayer and the brine filling area between the first interlayer and the second interlayer are brine filling areas between two different interlayers.
[0048] By arranging the outlet end 7 of the injection and production pipe to be located in the brine filling area between different interlayers, the problem of brine flow velocity being reduced due to the obstruction of the interlayer can be avoided. At the same time, the brine filling area between different interlayers can also accelerate the collapse of the interlayer under the pressure of pressurized air (high-pressure air). The collapse of the collapsed block increases the useful volume of the complex salt cavern cavity 0 due to dissolution in the brine, thereby increasing the utilization rate of the complex salt cavern cavity 0.
[0049] In some embodiments, a first integrated sensor 4 can be installed in the well wall of the above-mentioned injection and production wells (which may include: a first injection and production well, a second injection and production well, a third injection and production well, and a fourth injection and production well), and a second integrated sensor 12 can be installed in the well wall of the above-mentioned brine drainage well. The first integrated sensor 4 can be used to monitor the first wellbore structural stability of the injection and production well, and the second integrated sensor 12 can be used to monitor the second wellbore structural stability of the brine drainage well.
[0050] Specifically, the first integrated sensor 4 can be an integrated sensor for injection and production well pressure and pipe wall deformation. The injection and production well pressure data can be obtained through the first integrated sensor 4 to adjust the surface gas injection pressure (e.g., pressurized air (i.e., high-pressure air) can be continuously injected to increase the gas injection pressure). The pipe wall deformation data can also be obtained to determine the current corrosion of the injection and production pipe, and then the stability of the first wellbore structure of the injection and production pipe can be determined. For example, when the pipe wall deformation data is greater than the set value, it is determined that the injection and production pipe is severely corroded, and then the current first wellbore structure stability is determined to be poor. At this time, the injection and production well master valve 8 can be closed, and when the first wellbore structure of the injection and production well is stable, the injection and production well master valve 8 can be opened again.
[0051] The second integrated sensor 12 can be an integrated sensor for the flow rate, flow velocity and pressure of the brine drainage well. The second integrated sensor 12 can obtain the brine flow rate and flow velocity data, and the brine drainage well pressure data. The air tightness of the cavity can be judged by the pressure data, and then the stability of the second wellbore structure can be judged. If the pressure data is too small, it can be judged that the air tightness of the cavity is poor and the stability of the second wellbore structure is poor. At this time, the main valve 8 of the injection and production well can be opened, and when the second wellbore structure of the brine drainage well is stable, the main valve 8 of the injection and production well can be closed. The flow rate and flow velocity data can also determine the brine discharge rate. If the flow rate and flow velocity data are too small, the main valve 8 of the injection and production well can be opened to continue injecting high-pressure air.
[0052] The data monitored by the first integrated sensor 4 and the second integrated sensor 12 can be used as the basis for opening and closing the main valve 8 of the injection and production well. The main valve 8 of the injection and production well can control and prevent sudden situations such as pressure and structural instability in the cavity, thereby shortening the gas injection and brine removal cycle of the complex salt cavern cavity and increasing the gas injection and brine removal rate.
[0053] In some embodiments, an injection and production well valve 1 may be provided on the inlet end 2 of each of the multiple injection and production wells mentioned above, and an injection and production well master valve 8 may be provided on the injection and production well valve 1, and the injection and production well master valve 8 may be used to control the injection and production well valve 1.
[0054] In some embodiments, after the injection-production well valve 1 is opened, pressurized air is simultaneously injected into the inlet end 2 of the injection-production pipe.
[0055] Specifically, the main valve 8 of the injection and production well can be opened first, and then the injection and production well valve 1 on the inlet end 2 of each injection and production well can be opened in turn, and the pressure can be gradually increased to the maximum pressure. That is, after the first injection and production well reaches the rated gas injection pressure (maximum pressure), the injection and production well valve 1 on the second injection and production inlet end 2 is opened. When the second injection and production well reaches the rated gas injection pressure, the injection and production well valve 1 on the inlet end 2 of the third injection and production well is opened, and the injection and production well valves 1 of the 8 injection and production wells are opened successively to the rated pressure. Then, 2 rows and 4 lines of 8 injection and production wells are injected with pressurized air (high-pressure air) at the same time, and the pressurized air enters the brine filling area between different interlayers in the complex salt cavern cavity 0. Through pressure conduction, the brine in the comprehensive filling area is finally quickly discharged through the outlet end 15 of the brine discharge pipe 11 in the brine discharge well.
[0056] By injecting pressurized air into eight injection and production wells at the same time, the gas injection volume can be increased, so that the brine discharge pipe 11 can quickly discharge the brine in the comprehensive filling area from the outlet end 15 of the brine discharge well under the joint action of multiple groups of pressurized air, thereby realizing a gas injection and brine discharge technology suitable for multiple injection and production wells in complex salt cavern cavities to inject gas together and one brine discharge well to discharge brine.
[0057] In some embodiments, see Figure 1 As shown, the target position 14 may be the farthest end of the plane of the complex salt cavern cavity 0 and a position 10 m upward from the bottom of the complex salt cavern cavity 0 .
[0058] Specifically, the brine drainage well can be a directional well, and the target position (target position) 14 can be located 10m above the bottom of the cavity and at the farthest end of the cavity plane. This method avoids the risk of the inlet end 13 of the brine drainage pipe being blocked by interlayer collapse blocks and sediment debris, and at the same time avoids the sediment and interlayer collapse blocks reducing the flow rate of brine and reducing the brine drainage speed.
[0059] In some embodiments, the coating material of the inner wall of the injection and production pipe may be nickel-alloy, and the thickness of the coating material is 0.4 mm to 0.5 mm.
[0060] Since the inner wall of the injection and production pipe is subjected to long-term gas injection and brine discharge, the chloride ions and oxygen ions of the brine will corrode the pipe wall in the high temperature and high pressure environment in the cavity. Laser cladding welding technology can be used to avoid the risk of corrosion damage and structural instability of the injection and production pipe due to pipeline corrosion, thereby increasing the service life of the injection and production pipe string.
[0061] Specifically, the inner wall of the injection and production pipe can be welded by laser cladding technology, and the coating material can be inconel 625 nickel-bonded alloy with a thickness of 0.4mm (millimeter) to 0.5mm. With the support of laser cladding welding technology, the corrosion efficiency of the inner wall of the injection and production pipe is less than 0.01mm / a, which can ensure the sealing and stability of the injection and production pipe column within the designed working life.
[0062] In some embodiments, the outlet end 7 of the injection and production pipe 3 is located 10m from the brine filling area, the inlet end 13 of the brine discharge pipe 11 is located 0.5m from the junction of the integrated filling area and the collapsed block, and the diameter of the injection and production pipe 3 is 339.7mm.
[0063] In order to increase the injection pressure and unit air flow, and improve the pressure of the pressurized air on the brine in the complex salt cavern cavity 0, in addition to arranging 2 rows and 4 lines of 8 injection and production wells, the diameter of the injection and production pipe 3 can also be increased. For example, the diameter of the existing injection and production pipe 3 is usually 277mm, and the diameter of the injection and production pipe 3 of this application is set to 339.7mm. The brine discharge pipe 11 can adopt a 177.8mm oil casing. The above settings can effectively improve the brine discharge rate while ensuring the feasibility of the construction technology and the stability of the wellbore structure.
[0064] The outlet end 7 of the injection and production pipe 3 is located 10m away from the brine filling area, which can avoid fatigue damage caused by the injection of pressurized air and frequent disturbance of the wellhead by high-pressure and high-speed air under gas production conditions. Fatigue damage may lead to collapse of the wellhead block and ultimately cause instability of the well wall structure.
[0065] The inlet end 13 of the brine discharge pipe 11 is located 0.5m from the junction of the comprehensive filling area and the collapsed block, and the brine discharge well is located 10m upward from the bottom of the cavity, which can eliminate the problem of slow flow rate of brine in the sediment gaps and pores, and effectively avoid the obstruction of brine discharge by interlayers, large collapsed blocks and sediment salt debris, thereby improving the brine discharge efficiency and rate, discharging brine to the maximum extent, increasing the usable volume of the cavity, and achieving the maximum utilization rate in a certain time and space.
[0066] In some embodiments, see Figure 3As shown, the wellbore structure of the injection-production well is designed as a three-opening structure, which is from the outside to the inside: guide tube (762mm, can enter 50m underground), first opening: surface casing (609.6mm, the designed well depth can be 500m), second opening: production casing (476.32mm, the depth to the top of the cavity can be 30m), annulus protection fluid, packer (can separate oil, gas, water layers, protect casing), casing shoe (acts together with the packer to separate the production layer section to prevent interlayer fluid and pressure from communicating and interfering), third opening: injection-production pipe (339.7mm, from the wellhead to 10 in the cavity, the injection-production pipe is the maximum injection-production pipe diameter, which can increase the injection pressure and injection flow), pressure, well wall deformation, thickness sensors (first comprehensive sensors) can also be set on the injection-production pipe, and the injection-production pipe extends 10m into the cavity.
[0067] In some embodiments, see Figure 4 As shown, the well body structure of the brine drainage well is as follows from the outside to the inside: one opening: wellbore 346.1mm, two openings: wellbore 241.3mm, three openings: wellbore 152.4mm. Flow velocity, flow rate, and pressure sensors (second integrated sensors) can also be set on the brine drainage pipe, and the brine drainage pipe extends into the cavity by 0.5m.
[0068] The gas injection and brine removal system of the embodiment of this specification can realize the gas injection and brine removal technology of injecting gas together with one brine removal well for the complex salt cavern cavity 0 and removing brine with one brine removal well by connecting multiple injection and production wells at the top of the complex salt cavern cavity 0 (having the characteristics of small salt layer thickness, large interlayer thickness, high interlayer proportion, irregular cavity shape, large aspect ratio, large sediment, large sediment gap, etc.) to inject pressurized air together, and connecting one brine removal well at the target position at the bottom of the complex salt cavern cavity 0 (the farthest end of the plane of the complex salt cavern cavity 0 and the position 10m upward from the bottom of the complex salt cavern cavity 0). There are multiple injection and production wells, and the maximum injection and production pipe diameter is used, which can increase the gas injection pressure and gas injection flow rate and improve the brine removal rate. Since the interlayer blocks at the bottom of the cavity are filled with sediment, in order to eliminate the effect of the reduced flow rate of brine in the sediment voids and pores, the brine drainage well is not set at the bottom, but at the bottom target position (i.e., at the farthest end of the complex salt cavern cavity plane and 10m upward from the bottom). The inlet end of the brine drainage pipe is located 0.5m from the junction of the comprehensive filling area and the collapsed block, which can eliminate the problem of slow flow rate of brine in the sediment voids and pores, effectively avoid the obstruction of brine discharge by interlayers, large collapsed blocks and sediment salt debris, improve the brine drainage efficiency and rate, and at the same time, can discharge brine to the maximum extent, increase the usable volume of the cavity, and achieve the maximum utilization rate in a certain time and space. The outlet end of the injection and production pipe is located in the brine filling area between different interlayers, specifically 10m away from the brine filling area, which can avoid the problem of brine flow velocity reduction caused by the obstruction of the interlayer. At the same time, the brine filling area between different interlayers can also accelerate the collapse of the interlayer under the pressure of pressurized air (high-pressure air). The collapse of the collapsed block increases the useful volume of the complex salt cavern cavity due to dissolution in the brine, thereby increasing the utilization rate of the complex salt cavern cavity.
[0069] Each embodiment in this specification is described in a progressive manner, and the same and similar parts between the embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the system embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment. In the description of this specification, the description of the reference terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the embodiment of this specification. In this specification, the schematic representation of the above terms does not necessarily target the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, in the absence of contradiction, a person skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.
[0070] The above is only an example of the embodiment of the present specification and is not intended to limit the embodiment of the present specification. For those skilled in the art, the embodiment of the present specification may have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the embodiment of the present specification shall be included in the scope of the claims of the embodiment of the present specification.
Claims
1. A gas injection and brine removal system for a complex salt cavern cavity, characterized in that: At least comprising: a complex salt cavern cavity, a plurality of injection and production wells connected to the top of the complex salt cavern cavity, and a brine drainage well connected to a target position at the bottom of the complex salt cavern cavity; The complex salt cavern cavity includes a plurality of interlayers, between each of the plurality of interlayers is a brine filling area, below the bottom interlayer of the plurality of interlayers is a comprehensive filling area, below the comprehensive filling area is an interlayer collapse block; Each of the multiple injection and production wells is equipped with an injection and production pipe, and the brine discharge well is equipped with a brine discharge pipe. The outlet end of the injection and production pipe is located in the brine filling area between different interlayers, and the inlet end of the brine discharge pipe is located in the junction of the integrated filling area and the interlayer collapsed block. The injection and production pipe is used to be injected with pressurized air and to discharge the pressurized air from the outlet end at the same time, and the brine discharge pipe is used to discharge the brine in the integrated filling area under the joint action of multiple groups of pressurized air.
2. The gas injection and brine removal system according to claim 1, characterized in that: The complex salt cavern cavity includes but is not limited to salt cavern cavities with small salt layer thickness, large interlayer thickness, high interlayer ratio, irregular cavity shape, large aspect ratio, much sediment, and large sediment gaps. The salt cavern cavity is spindle-shaped and has a long strip structure in plane.
3. The gas injection and brine removal system according to claim 1, characterized in that: The multiple injection and production wells include 8 injection and production wells, and the 8 injection and production wells are arranged in 2 rows and 4 lines. The row spacing of the injection and production wells is 30m, and the row spacing of the injection and production wells is 50m.
4. The gas injection and brine removal system according to claim 1, characterized in that: The outlet end of the injection and production pipe is located in the brine filling area between different interlayers, including: The injection and production pipe outlet ends of the second injection and production wells in the second row and the injection and production pipe outlet ends of the third injection and production wells in the third row are located in the brine filling area between the top of the complex salt cavern cavity and the first interlayer, and the first interlayer is the first interlayer among the multiple interlayers; The injection and production pipe outlet ends of the first injection and production well in the first row and the injection and production pipe outlet ends of the fourth injection and production well in the fourth row are located in the brine filling area between the first interlayer and the second interlayer, and the second interlayer is the second interlayer among the multiple interlayers.
5. The gas injection and brine removal system according to claim 1, characterized in that: A first integrated sensor is installed in the wall of the injection and production well, and a second integrated sensor is installed in the wall of the brine drainage well. The first integrated sensor is used to monitor the stability of the first wellbore structure of the injection and production well, and the second integrated sensor is used to monitor the stability of the second wellbore structure of the brine drainage well.
6. The gas injection and brine removal system according to claim 1, characterized in that: An injection-production well valve is arranged on the inlet end of each of the plurality of injection-production wells, and an injection-production well master valve is arranged on the injection-production well valve, and the injection-production well master valve is used to control the injection-production well valve.
7. The gas injection and brine removal system according to claim 6, characterized in that: After the injection-production well valve is opened, pressurized air is simultaneously injected into the inlet end of the injection-production pipe.
8. The gas injection and brine removal system according to claim 1, characterized in that: The target position is the farthest end of the complex salt cavern cavity plane and is a position 10 m upward from the bottom of the complex salt cavern cavity.
9. The gas injection and brine removal system according to claim 1, characterized in that: The coating material of the inner wall of the injection and production pipe is nickel-bonded alloy, and the thickness of the coating material is 0.4 mm to 0.5 mm.
10. The gas injection and brine removal system according to claim 1, characterized in that: The outlet end of the injection and production pipe is located 10m from the brine filling area, the inlet end of the brine discharge pipe is located 0.5m from the junction of the comprehensive filling area and the collapsed block, and the diameter of the injection and production pipe is 339.7mm.