Well structure for injecting suspended-state repairing agent and injection method

Abstract

The invention discloses a well structure and an injection method for injecting a suspended-state repairing agent. The well structure comprises an injection well, a lower-end injection pipeline and an upper-end injection pipeline. Wherein the lower end injection pipeline downwards penetrates into the injection well from the top of the injection well; the upper end injection pipeline is arranged on the side wall of one side of the top of the injection well; and a Y-shaped tee joint is arranged at the bottom of the lower end injection pipeline. By adopting the well structure, the migration and distribution uniformity of the suspended state repairing agent is remarkably improved, the reaction efficiency with pollutants is enhanced, meanwhile, the repairing cost is reduced, the construction period is shortened, and the repairing quality is ensured. And meanwhile, the problem that a suspended-state repairing agent is difficult to inject when the repairing depth exceeds the injection range or the repairing medium is bed rock in a traditional injection method is solved.

Description

Technical Field

[0001] The invention relates to the technical field of soil and groundwater restoration, and more particularly to a well structure and an injection method for injecting a suspended restoration agent. Background Art

[0002] With the rapid development of industrialization and urbanization, soil and groundwater pollution problems have become increasingly serious, posing a major threat to the ecosystem and human health. In the process of exploring pollution control technologies, researchers have found that the use of suspended remediation agents, especially iron powder as a representative, has significant advantages in environmental remediation when using in-situ chemical / biological remediation technology to repair contaminated soil and groundwater.

[0003] At present, the traditional method of injecting suspended remediation agents is the direct push injection method, but it cannot be used when the remediation depth exceeds the injection range (generally around 15m) or when the remediation medium is bedrock.

[0004] In the field of groundwater remediation, the injection well method of injecting suspended liquid into the ground as a remediation agent is a common technical means. However, in actual operation, this method faces multiple challenges. Suspended remediation agents are prone to agglomeration and precipitation due to their physical and chemical properties, which may not only cause the injection well to be quickly blocked, hindering normal operations, but also interrupt the remediation work. Blockage problems or wellhead reconstruction often require additional manpower, material resources and time investment, significantly increasing the cost of remediation and extending the construction period. Although diluting the suspended remediation agent to increase its injection volume can alleviate the injection volume problem to a certain extent, it also brings new problems. The increase in water volume will significantly increase the probability of surface passivation of suspended remediation agents (such as suspensions made of iron powder), reduce the reaction activity of the agent with pollutants, and weaken its ability and efficiency to degrade pollutants. In addition, traditional gravity or pressurized injection methods have shortcomings in terms of agent dispersion, blockage reduction and migration capacity improvement, and it is difficult to meet the needs of efficient remediation.

[0005] At the same time, for the suspended repair agent made of iron powder, the iron powder dilution measures taken to increase the injection volume also reduce its activity due to the passivation of the iron powder surface, further weakening the repair effect.

[0006] The existing invention patent "Anti-blocking method, device and process for injecting powdered repair agents into porous aquifers (patent number: CN116696447A)" proposes to solve the blockage problem during suspension injection through an "injection + extraction" cycle. However, this method has the problem of too low injection concentration (less than 0.3% by mass), resulting in too large a proportion of water. If the suspension is iron powder, its surface passivation will increase. In addition, since the injection method is not pulsed, the suspension is prone to sedimentation in the soil pores after entering the aquifer, affecting its migration capacity.

[0007] In order to solve these technical problems, the present invention proposes an innovative suspended remediation agent injection well structure and method. The purpose of this technical innovation is to solve the problems of well sedimentation, pore blockage, agent migration difficulties, uneven migration, and low injection concentration encountered in the process of injecting suspended remediation agents by the traditional injection well method, so as to effectively save remediation costs, shorten construction period and ensure remediation quality. Summary of the invention

[0008] The invention aims to solve the problems of sedimentation in the well, pore blockage, difficulty in agent migration, uneven migration and low injection concentration during the traditional injection well method of injecting suspended remediation agents. Based on this, a well structure and injection method for injecting suspended remediation agents are provided.

[0009] In order to achieve the above object, the present invention adopts the following technical solution:

[0010] A well structure for injecting a suspended repair agent, comprising: an injection well, a lower injection pipeline and an upper injection pipeline;

[0011] Wherein, the lower injection pipe runs downward from the top of the injection well to the inside of the injection well; the upper injection pipe is arranged on the side wall of one side of the top of the injection well;

[0012] A Y-shaped tee is arranged at the bottom of the lower end injection pipe.

[0013] Preferably, at least two Y-shaped tees are provided and are interconnected.

[0014] The Y-type tees are evenly distributed around the injection pipe at the lower end to increase the cross-sectional area for the upward impact of the reagent;

[0015] Preferably, a pipe plug is provided at the bottom of the bottommost Y-shaped tee.

[0016] The Y-type tee + pipe plugging method is used at the bottom, which can promote the repair agent to flow upward through the Y-type tee, avoiding the problem of suspended repair agent being deposited in the well during the injection process.

[0017] Preferably, the pipe plug is 30-50 cm away from the bottom of the injection well to prevent silt in the well from blocking the injection port of the lower Y-shaped tee.

[0018] Another object of the present invention is to provide a method for injecting a suspended repair agent, using the above-mentioned well structure, specifically comprising: using a pulse pump to simultaneously inject the suspended repair agent into the upper injection pipe and the lower injection pipe;

[0019] Among them, the pulse frequency of the pulse pump is 50-500 times / minute;

[0020] The pressure in the injection well is 0.2Mpa-1.0Mpa;

[0021] The mass ratio of insoluble solutes in the suspended repair agent is ≤30%;

[0022] The injection flow rate is calculated using the following formula:

[0023]

[0024] Q=KAv*n

[0025] In the above formula, Q is the injection flow rate, v is the injection velocity, P is the injection pressure, ρ is the density of the injected suspended remediation agent, K is the permeability coefficient of the soil, A is the surface area of ​​the flower tube, and n is the porosity of the flower tube.

[0026] Preferably, the pulse pump comprises a diaphragm pump, a peristaltic pump, a rotary piston pump, a plunger pump or a vane pump.

[0027] The present invention injects the prepared suspension repair agent synchronously through the injection ports of the injection pipes at the upper and lower ends of the injection well. The upper injection port allows the agent to flow downward, while the special design of the Y-type tee and the pipe plug at the lower end allows the agent to move upward, effectively avoiding the problem of sedimentation at the bottom of the well. Under a certain pressure, the repair agent evenly penetrates into the soil through the flower tube.

[0028] It can be seen from the above technical solution that compared with the prior art, the present invention has the following beneficial effects:

[0029] (1) The present invention provides a novel well structure, which can simultaneously inject reagents at the wellhead and the well bottom, thereby solving the problem of reagent deposition at the well bottom;

[0030] (2) The present invention adopts a Y-shaped tee combined with a pipe plug in the bottom hole injection pipeline (where the lower end of the Y-shaped tee is sealed by the pipe plug). This design further cleverly prevents the suspended repair agent from being deposited in the well;

[0031] (3) The injection method of the present invention adopts the form of pulse injection, which solves the problems of clogging of suspended remediation agents in the soil, difficulty in agent migration and uneven migration;

[0032] (4) By effectively combining the structure of the suspended remediation agent injection well and its use method, the purpose of ensuring the quality of remediation and saving remediation costs and construction period is achieved. Specifically, ① using this method, the suspended remediation agent does not deposit at the bottom of the well, the migration distance is long, and the agent is evenly distributed in the soil, which ensures the quality of remediation; ② using this well structure and use method, multiple injections can be made, which can be used for remediation depths exceeding the injection range of the direct push injection method or when the remediation medium is bedrock;

[0033] (5) The use of the injection well structure and injection method can increase the injection mass ratio (the insoluble agent addition ratio can reach 30%), increase the injection concentration, and reduce the passivation problem of iron powder suspended repair agents, ultimately achieving the purpose of reducing manpower, material and agent costs and shortening the repair period. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0035] Figure 1 This is a schematic diagram of the well structure for injecting a suspended repair agent according to the present invention;

[0036] Figure 2 This is a schematic diagram of the operation of injecting a suspended repair agent according to the present invention;

[0037] Figure 3 This is a schematic diagram of the Y-type tee + pipe plug structure of the present invention;

[0038] Among them, in the figure:

[0039] 1-injection well; 2-lower end injection pipeline; 3-upper end injection pipeline; 41-Y-type tee one; 42-Y-type tee two; 5-pipe plug; 6-flowered pipe. DETAILED DESCRIPTION

[0040] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0041] Example 1

[0042] This embodiment provides a well structure for injecting a suspended repair agent, comprising: an injection well 1, a lower end injection pipeline 2 and an upper end injection pipeline 3;

[0043] The lower injection pipe 2 penetrates downward from the top of the injection well 1 to the inside of the injection well 1; the upper injection pipe 3 is arranged on the side wall of one side of the top of the injection well 1;

[0044] Two connected Y-type tees 1 41 and 2 42 are arranged at the bottom of the lower injection pipe 2 . A pipe plug 5 is arranged at the bottom of the bottommost Y-type tee 2 42 . The pipe plug 5 is 30-50 cm away from the bottom of the injection well 1 .

[0045] Example 2

[0046] In a chemical reduction technology remediation project, the remediation area is 100m 2 For the chlorinated hydrocarbon contaminated site in soil + bedrock fissures at a depth of 25 meters, a reducing agent based on zero-valent iron is used. The agent formula also contains ingredients such as molasses and sodium lactate. Among them, the mass proportion of insoluble zero-valent iron in water reaches 30%.

[0047] Pneumatic diaphragm pump pulse injection is used, the injection pressure is set to 0.3Mpa, and the injection flow rate is 2.9-4.8m 3 / h.

[0048] The injection well 1 adopts the method of synchronous injection at both ends. The bottom of the lower injection pipe 2 is equipped with a Y-type tee 41 and a Y-type tee 42. The bottom of the Y-type tee 42 is provided with a pipe plug 5, which is precisely kept above the bottom of the well at a distance of 40cm, ensuring the uniform distribution of the reagent and avoiding sedimentation. The depth of the injection well 1 is 25.5m, of which 25-25.5m is a sedimentation pipe, and the diameter of the injection well 1 is 60mm.

[0049] In the single well test, about 500 kg of iron powder was injected cumulatively within 2 hours.

[0050] During the injection process, the seven groundwater monitoring wells at different distances around the injection well were monitored in real time through the rapid detection methods of conductivity and magnet adsorption. The contaminated groundwater was extracted through the Beyler tube, and the magnet attracted the iron powder on the side wall of the Beyler tube to verify whether the iron powder had migrated to the groundwater monitoring well. The conductivity of the groundwater was tested using a conductivity detector, and the migration of iron powder was further demonstrated from the perspective of conductivity. The on-site rapid test results showed that the conductivity of the groundwater monitoring well had changed significantly, and iron powder was found in the groundwater monitoring well. The specific data are shown in the table below.

[0051] Table 1 Quick test results of conductivity and magnetic adsorption

[0052]

[0053] It can be seen from the above table that by comparing the groundwater conductivity and iron powder content before and after the injection of suspended remediation agents made of iron powder and other agents, it can be seen that the conductivity of each groundwater monitoring well increased significantly after the injection, and iron powder was found in all of them.

[0054] Later, the well was explored by magnets and the well depth was measured to determine whether the well pipe was blocked. The well depth was measured to be 25.1m and the designed well depth was 25.5m. Considering that the sedimentation in the sedimentation tube was a normal phenomenon, it was judged that the zero-valent iron powder was not deposited in the well. The iron powder in the well was adsorbed by a magnet, but no large amount of iron powder was found on the magnet, which further demonstrated that the iron powder was deposited at the bottom of the well. The conductivity of the groundwater monitoring well 4.5m away from the injection well increased significantly and iron powder was found, proving that the iron powder migrated over a long distance, migrated evenly, and was not blocked in the soil pores. This verifies the efficient operation of the injection system and the wide distribution and penetration of the remediation agent.

[0055] Combined with this embodiment, it can be further illustrated that the patent of the present invention can effectively solve the problems of sedimentation at the bottom of the well, clogging in the soil pores, difficult and uneven migration and low injection concentration during the injection of suspended remediation agents.

[0056] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.

[0057] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A well structure for injecting a suspended repair agent, characterized in that: include: Injection well, lower injection pipeline and upper injection pipeline; Wherein, the lower injection pipe runs downward from the top of the injection well to the inside of the injection well; the upper injection pipe is arranged on the side wall of one side of the top of the injection well; A Y-shaped tee is arranged at the bottom of the lower end injection pipe.

2. A well structure for injecting a suspended repair agent according to claim 1, characterized in that: At least two Y-shaped tees are provided and are connected to each other.

3. A well structure for injecting a suspended repair agent according to claim 2, characterized in that: A pipe plug is provided at the bottom of the bottommost Y-type tee.

4. A well structure for injecting a suspended repair agent according to claim 3, characterized in that: The pipe plug is 30-50 cm away from the bottom of the injection well.

5. A method for injecting a suspended repair agent, characterized in that: The well structure of claim 4 is used, specifically comprising: using two pulse pumps to simultaneously inject the suspended repair agent into the upper injection pipe and the lower injection pipe; Among them, the pulse frequency of the pulse pump is 50-500 times / minute; The pressure in the injection well is 0.2Mpa-1.0Mpa; The mass ratio of insoluble solutes in the suspended repair agent is ≤30%; The injection flow rate is calculated using the following formula: Q=KAv*n In the above formula, Q is the injection flow rate, v is the injection velocity, P is the injection pressure, ρ is the density of the injected suspended remediation agent, K is the permeability coefficient of the soil, A is the surface area of ​​the flower tube, and n is the porosity of the flower tube.

6. A method for injecting a suspended repair agent according to claim 5, characterized in that: The pulse pump includes a diaphragm pump, a peristaltic pump, a rotary piston pump, a plunger pump or a vane pump.

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