Device and method for groundwater multilevel rapid sampling by multi-layer simultaneous displacement

Abstract

A device for groundwater multilevel rapid sampling by multi-layer simultaneous displacement. The device comprises a compressed gas source 3, an exhaust pipe 5, a plurality of sampling bottles 6, and a plurality of layered units 2 distributed along a depth of a well hole. Each sampling bottle is connected with a sample-taking pipe 7, and each sample-taking pipe extends into the well hole and corresponds to one layered unit. The compressed gas source is connected with a gas supply pipe 4, and the gas supply pipe and the gas exhaust pipe separately extend into the well hole. A downhole fluid storage container (8, Fig 2) is arranged in each layered unit and an upper end of the downhole fluid storage container is connected with a check valve (9, Fig 2) and a semipermeable membrane element through pipelines. A pipeline where the check valve is located is connected to the gas supply pipe, and a pipeline where the semipermeable membrane element is located is connected to the gas exhaust pipe. A lower end of the downhole fluid storage container is connected with a filtration and dialysis component, and a pipeline between the filtration and dialysis component 11 and the downhole fluid storage container is connected to the sample-taking pipe through a tee-junction. Each of the gas supply pipe, the gas exhaust pipe and the sample-taking pipes is provided with a valve 12. A method comprising the device is also described.

Description

09 01 24 TECHNICAL FIELD

[0001] The present invention relates to the technical fields of hydrogeology and water resources, site soil and groundwater pollution, and in particular to a device and method for groundwater multilevel rapid sampling by multi-layer simultaneous displacement. BACKGROUND ART

[0002] With the rapid industrialization of the world, mining and solid waste landfills, municipal domestic waste landfill sites, chemical industrial sites are springing up all over the world, resulting in increasingly serious groundwater pollution, hindering green and high-quality economic development and negatively impacting the health of local human-animal-environment. The groundwater pollution is mainly caused by the infiltration of pollutants from surface water leaching and the rapid movement and spread of stratum leakage channels. International development experience shows that the polluted sites are the result of urbanization and industrialization, and the investigation and remediation of the polluted sites are related to the sustainable development of ecological environment. The general shrinkage, pollution and abandonment of industrial zones in central cities of some developed countries or regions have resulted in a wide range of brownfields, the so-called "Rust Belt".

[0003] Environmental layered monitoring of groundwater should be carried out in combined with the level of technological progress according to relevant policies, regulations and technical specifications issued in recent years. For example, Specification for Hydrogeological Survey (1:50 000) DZ / T 0282-2015, Guidance on the design and installation of groundwater quality monitoring points (Environment Agency, UK, SC020093-2006) notes that main aquifers in multilayer aquifer distribution areas should be monitored separately, and groundwater multilevel monitoring wells should be provided where conditions are available.

[0004] There has been a series of domestic and international research and development on groundwater multilevel sampling and monitoring technologies. For example, the invention patents "Gas-driven Underground Fluid Multilevel sampling Apparatus" (publication No. CN 103967486 B) and "Underground Fluid Multilevel sampling Apparatus and Method based on U-tube technology" (publication No. CN 105298490B), and the like provide the groundwater multilevel sampling technology based on the U-tube principle, and have developed three series of groundwater multilevel sampling apparatus with U-tubes on shallow (30 m), medium (200 m) and deep (2000 m) sites. However, the arrangement of all the U-tube in each layer of a shaft, an inlet and outlet connecting pipe of the U-tube and piping components thereof must occupy sectional space of the shaft. As a result, the number of layers is limited due to the restricted shaft diameter. For another instance, the invention patent "Pipe-in-pipe Underground Fluid Multilevel Sampling Apparatus" (publication No. CN 104929629A) and the utility patent “Groundwater multilevel monitoring Well for Multiple Aquifers" (publication No. CN 208350783U) provide gas-driven groundwater multilevel sampling technology based on the pipe-in-pipe principle, which doubles the number of layers of environmental layered monitoring of groundwater under the original conditions compared with the U-tube technology.

[0005] However, the above solutions still have technical problems that groundwater multilevel sampling efficiency is required to be improved, the number of layers is required to be further increased, and the like. Especially, under the premise of IL groundwater sampling volume, the total time to purging and sampling in multiple layers should be controlled within 60 min, but the above existing technologies cannot meet the demand. SUMMARY OF THE INVENTION

[0006] The present invention solved technical problems through achieving groundwater multilevel sampling by multi-layer simultaneous displacement technology, thus increasing the number of layers, and improving efficiency of the groundwater multilevel sampling.

[0007] The technical solutions of the present invention for solving the above technical problems are as follows.

[0008] The present invention provides a device for groundwater multilevel rapid sampling by multi-layer simultaneous displacement. The device includes: a compressed gas source, an exhaust pipe, a plurality of sampling bottles, and a plurality of layered units distributed along the depth of a well hole, wherein each sampling bottle is connected with a sample-taking pipe, and each sample-taking pipe extends into the well hole and corresponds to one layered unit; the compressed gas source is connected with a gas supply pipe, and the gas supply pipe and the gas exhaust pipe separately extend into the well hole; a downhole fluid storage container is arranged in each layered unit, the upper end of the downhole fluid storage container is connected with a check valve and a semipermeable membrane element through pipelines, a pipeline where the check valve is located is connected to the gas supply pipe, and a pipeline where the semipermeable membrane element is located is connected to the gas exhaust pipe, the low'er end of the downhole fluid storage container is connected with a filtration and dialysis component, and a pipeline between the filtration and dialysis component and the downhole fluid storage container is connected to the sample-taking pipe through a tee-junction; and each of the gas supply pipe, the gas exhaust pipe and the sample-taking pipes is provided with a valve.

[0009] The present invention has the following beneficial effects,

[0010] 1 By operating the valves on the gas supply pipe, the gas exhaust pipe and the sampletaking pipes, the groundwater in the plurality of layered units can simultaneously sampled by displacement, so that the groundwater in positions of a plurality of layers with different depths can simultaneously purge and be simultaneously sampled, thereby improving the working efficiency; and in addition, the more the layers of groundwater multilevel sampling are, the more obvious the saving of total sampling time is.

[0011] 2 The groundwater samples acquired by in-si tu weak disturbance are more representative. Displacement sampling is carried out in the downhole fluid storage container based on gas drive principle, and the interference of the sampling process to a stratum is reduced by the filtration and dialysis component, which ensures the characteristics of lew sampling disturbance on the premise of high-efficiency sampling. Through the check valve and the semipermeable membrane element, the mixing of the groundwater in different layer positions along the pipelines is avoided.

[0012] The present invention may also be improved as follows based on the above technical solutions.

[0013] 3. The number of groundwater multilevel layers are effectively increased. Compared with the U-tube groundwater multilevel sampling technology, 2N pipelines for sample taking in an original N-layer is reduced to N+2 pipelines. For example, in one-hole six-layer multilevel sampling of groundwater, twelve pipelines are reduced to eight pipelines; and in one-hole nine-layer multilevel sampling of groundwater, eighteen pipelines are reduced to eleven pipelines. When it is required to increase the number of layered layers, the number of layered layers of groundwater can be doubled with the same pipeline input.

[0014] Further, the layered unit includes a wellbore solid pipe and a wellbore sieve pipe; the wellbore sieve pipe is fixed to the lower end of the wellbore solid pipe; the upper end of the wellbore solid pipe and the lower end of the wellbore sieve pipe are closed; and the filtration and dialysis component and the downhole fluid storage container are both arranged in an accommodating cavity formed by the wellbore solid pipe and the wellbore sieve pipe.

[0015] By adopting this further solution, the groundwater at limited stratum depths enters the wellbore sieve pipe through small holes in the side wall of the wellbore sieve pipe, so that most of the sediment is blocked, ensuring the long-term effective operation of the well hole and a sampling device. Through the weak-disturbance sample injection with the wellbore sieve pipe, the groundwater is characterized by fine vertical layering, and is more representative. 09 01 24

[0016] Further, annular packers are arranged on outer ring surfaces at two ends of the wellbore sieve pipe, and are in contact with a side wall of the well hole.

[0017] By adopting this solution further, the groundwater in different strata at the peripheries of the layered units is isolated from each other, so that the groundwater is prevented from flowing up and down along the outer walls of the wellbore solid pipe and the wellbore sieve pipe, as well as mixing, thereby improving the layering representativeness of groundwater samples.

[0018] Further, the packer is inflated by air-driving.

[0019] By adopting this solution further, it is convenient to mount first and then inflate for packing, so that the operation is facilitated and the adaptability is excellent.

[0020] Further, three to nine layered units are distributed along the depth of the well hole.

[0021] Further, six to nine layered units are distributed along the depth of the well hole.

[0022] Three to nine layers of groundwater are simultaneously sampled.

[0023] Further, a pressure gauge is arranged at the end of each gas supply pipe and gas exhaust pipe that extend out of the wellhead.

[0024] By adopting this further solution, it is convenient to monitor the pressures of the gas supply pipe and the gas exhaust pipe, ensuring the effective operation of the device.

[0025] Further, a check valve is arranged on a pipeline between the filtration and dialysis component and the tee-junction.

[0026] By adopting this further solution, the groundwater sample stored in the downhole fluid container is prevented from reversely entering the layered unit in a process that the compressed gas source is started to pressurize the downhole fluid storage container for displacement, so that the disturbance is reduced.

[0027] Further, the compressed gas source is driven by a nitrogen cylinder.

[0028] By adopting this further solution, reaction between compressed gas and groundwater samples is avoided because the nitrogen is an inert gas, ensuring that a sampling result is more representative.

[0029] The present invention provides a method for groundwater multilevel rapid sampling by multi-layer simultaneous displacement, wherein the method is implemented using the above device for groundwater multilevel sampling by the multi-layer simultaneous displacement, and includes the following steps:

[0030] step 1, drilling a borehole in a selected site, and install the device of groundwater multilevel rapid sampling;

[0031] step 2, opening the valve on the gas supply pipe to pressurize the gas supply pipe to 0.5 KPa, closing the valve on the gas exhaust pipe, adjusting the valve on each sample-taking pipe so that groundwater at different depths is simultaneously discharged from the respective sample taking pipes until no groundwater is discharged from each sample-taking pipe to achieve emptying of downhole residual liquid, and closing the valves on the sample-taking pipes and the valve on the gas supply pipe;

[0032] step 3, opening the valve on the gas exhaust pipe, groundwater infiltrate from formation into the downhole fluid storage container by the differential pressure between formation pressure and atmospheric pressure. Meanwhile, the gas in the downhole fluid storage container would exhaust out completely through the semipermeable membrane element and the gas exhaust pipe;

[0033] step 4, repeating steps 2 and 3 to purge groundwater with 3 to 5 times a volume of the downhole residual liquid; and

[0034] step 5, connecting the sampling bottle to each sample-taking pipe, and opening the valves on the gas supply pipe and on the respective sample-taking pipes to acquire representative multilevel groundwater samples.

[0035] By adopting the method provided by the present invention, the influence of borehole drilling is avoided through purging operation from step 2 to step 4, and multilevel groundwater representative sample is achieved through one-hole. Through multi-layer simultaneous displacement sampling technology, it is achieved that the total time to complete borehole purging duration and multilevel groundwater sampling should be controlled within 60 min under the premise of IL volume. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] FIG, 1 is a schematic structural diagram of the present invention;

[0037] FIG. 2 is a working principle diagram of single-layer sampling of groundwater according to the present invention;

[0038] FIG. 3 is a schematic structural diagram of one-hole three-layer rapid sampling of groundwater according to the present invention;

[0039] FIG. 4 is a schematic structural diagram of one-hole six-layer rapid sampling of groundwater according to the present invention; and

[0040] FIG, 5 is a schematic structural diagram of one-hole nine-layer rapid sampling of groundwater according to the present invention.

[0041] In the accompanying drawings, the technical features represented by reference numerals are as follows: 1, well hole; 2, layered unit; 3, compressed gas source; 4, gas supply pipe; 5, exhaust pipe; 6, sampling bottle; 7, sample-taking pipe; 8, downhole fluid storage container; 9, check valve; 10, semipermeable membrane element; 11, filtration and dialysis component; 12, valve; 13, wellbore solid tube; 14, wellbore sieve pipe; 15, packer; and 16, pressure gauge. DETAILED DESCRIPTION

[0042] The principles and features of the present invention are described below, and the examples given are only intended to explain the present invention, rather than limiting the scope of the present invention.

[0043] Embodiment 1 is as shown in FIGs. 1 and 2.

[0044] The present invention provides a device for groundwater multilevel rapid sampling by multi-layer simultaneous displacement. The device includes a compressed gas source 3, an exhaust pipe 5, a plurality of sampling bottles 6, and a plurality of layered units 2 distributed along the depth of a well hole 1. Each sampling bottle 6 is connected with a sample-taking pipe 7, and each sample-taking pipe 7 extends into the well hole 1 and corresponds to one layered unit 2. The compressed gas source 3 is connected with a gas supply pipe 4, and the gas supply pipe 4 and the gas exhaust pipe 5 separately extend into the well hole 1. A downhole fluid storage container 8 is arranged in each layered unit 2, the upper end of the downhole fluid storage container 8 is connected with a check valve 9 and a semipermeable membrane element 10 through pipelines, a pipeline where the check valve 9 is located is connected to the gas supply pipe 4, and a pipeline where the semipermeable membrane element 10 is located is connected to the gas exhaust pipe 5. The lower end of the downhole fluid storage container 8 is connected with a filtration and dialysis component II, and a pipeline between the filtration and dialysis component 11 and the downhole fluid storage container 8 is connected to the sample-taking pipe 7 through a tee-junction. Each of the gas supply pipe 4, the gas exhaust pipe 5 and the sample-taking pipes 7 is provided with a valve 12.

[0045] The principle is as follows. The working principle of single-layer sampling of groundwater is shown in FIG. 2, and includes three stages: in-situ weak disturbance sample injection of groundwater, sampling of groundwater by displacement with compressed nitrogen, and gas discharging of the downhole fluid storage container 8 by filling of the downhole fluid storage container 8 with groundwater. In the first stage, under the action of a plurality of layered units 2, the layered units 2 receive injected dialyzed samples of groundwater in a stratum with a defined depth, and the groundwater passes through the filtration and dialysis component 11 and enters the downhole fluid storage container 8 in a corresponding layer until the sample injection is completed when a pipeline is filled with the groundwater. In the second stage, during sampling operation, the valve 12 on the gas supply pipe 4 is opened for pressurization, and the valve 12 on the gas exhaust pipe 5 is closed, so that compressed gas enters the downhole fluid storage container 8 for pressurized displacement, and a groundwater sample enters the sampling bottle 6 on the ground through the sample-taking pipe 7, thereby acquiring the groundwater sample in this layer position. It is worth pointing out that the resistance of the filtration and dialysis component 11 itself has a check effect on the reverse entry’ of the groundwater into the layered unit 2. The compressed gas cannot enter the gas exhaust pipe 5 upon closing the valve 12 on the gas exhaust pipe 5. In the third stage, the valves 12 on the gas supply pipe 4 and the sampletaking pipe 7 are closed, and the valve 12 on the gas exhaust pipe 5 is opened, so that the groundwater enters the downhole fluid storage container 8 for gas discharging by displacement under the action of a differential pressure, and the gas in the downhole fluid storage container 8 is discharged out of the well hole 1 through the gas exhaust pipe 5, and a sample of the groundwater is continuously injected to fill the downhole fluid storage container 8, thereby completing the next in-situ weak disturbance sample injection of the groundwater.

[0046] It should be noted that the filtration and dialysis component 11 functions to filter sediment, and is communicated in one direction. It is an unconventional filter and can be customized at a filter manufacturer. The semipermeable membrane element 10 functions to allow gas but not water to pass therethrough, and can be customized at a semipermeable membrane element manufacturer.

[0047] To sum up, the present invention has the following advantages. 1. By operating the valves 12 on the gas supply pipe 4, the gas exhaust pipe 5 and the sample-taking pipes 7, the groundwater in the plurality of layered units 2 can simultaneously sampled by displacement, so that the groundwater in positions of a plurality of layers with different depths can simultaneously be purged and sampled, thus improving the sampling efficiency; and in addition, the more the layers of groundwater multilevel sampling are, the more obvious the saving of total sampling time is.

[0048] 2 The groundwater samples acquired by in-situ weak disturbance are more representative. Displacement sampling is carried out in the downhole fluid storage container 8 based on the gas drive principle, and the interference of the sampling process to a stratum is reduced by the filtration and dialysis component 11, which ensures the characteristics of low sampling disturbance on the premise of high-efficiency sampling. Through the check valve 9 and the semipermeable membrane element 10, the mixing of the groundwater in different layer positions along the pipelines is avoided.

[0049] 3 The number of layered layers of groundwater is effectively increased. Compared with the U-tube multilevel sampling technology of groundwater, 2N pipelines for sample taking in an original N-layer is reduced to N+2 pipelines. For example, in one-hole six-layer multilevel sampling of groundwater, twelve pipelines are reduced to eight pipelines, and in one-hole nine-layer multilevel sampling of groundwater, eighteen pipelines are reduced to eleven pipelines. When it is required to increase the number of layered layers, the number of layered layers of groundwater can be doubled with the same pipeline input.

[0050] The present invention is mainly applicable to the field of investigation and remediation of groundwater in polluted sites at the depth of 50m or less, and can efficiently and rapidly acquire a plurality of representative groundwater samples at different depths below the groundwater level interface to depict and characterize spatial distribution of pollutants in a vertical structure of an aquifer in the stratum, so as to reveal the dynamic change rule of chemical characteristics of groundwater in vertical three-dimensional space with time and stratum depth. It is especially suitable for ecological environment monitoring and law enforcement screening, accurate investigation and restoration of environmental risks such as mine solid waste landfills, contaminated sites in chemical parks and industrial solid waste landfills, traceability identification of groundwater pollution, acceptance monitoring of contaminated land remediation projects, retrospective assessment monitoring of contaminated land sites, monitoring of a natural attenuation remediation process of the contaminated land sites, and other application scenarios.

[0051] Further, the layered unit 2 includes a wellbore solid pipe 13 and a wellbore sieve pipe 14; the wellbore sieve pipe 14 is fixed to the lower end of the wellbore solid pipe 13; the upper end of the wellbore solid pipe 13 and the lower end of the wellbore sieve pipe 14 are closed; and the filtration and dialysis component 11 and the downhole fluid storage container 8 are both arranged in an accommodating cavity formed by the wellbore solid pipe 13 and the wellbore sieve pipe 14.

[0052] By adopting this further solution, the groundwater at limited stratum depths enters the wellbore sieve pipe 14 through small holes in the side wall of the wellbore sieve pipe 14, so that most of the sediment is blocked, ensuring the long-term effective operation of the well hole 1 and the sampling device. Through the weak-disturbance sample injection with the wellbore sieve pipe 14, the groundwater is characterized by fine vertical layering, and is more representative.

[0053] Further, annular water-stop packers 15 are arranged on outer ring surfaces at two ends of the wellbore sieve pipe 14, and are in contact with a side wall of the well hole 1.

[0054] By adopting this further solution, the groundwater in different strata at the peripheries of the layered units 2 is isolated from each other, so that the groundwater is prevented from flowing up and down along the outer walls of the wellbore solid pipe 13 and the wellbore sieve pipe 14, as well as mixing, thereby improving the layering representativeness of groundwater samples.

[0055] Further, the water-stop packer 15 is an air bag packer.

[0056] By adopting this further solution, it is convenient to mount first and then inflate for packing, so that the operation is facilitated and adaptability is excellent.

[0057] Further, there are three to nine layered units 2 distributed along the depth of the well hole 1.

[0058] Further, there are six to nine layered units 2 distributed along the depth of the well hole 1.

[0059] FIGs. 3, 4 and 5 are schematic diagrams showing three, six and nine layered units 2 respectively, in which three to nine layers of groundwater are simultaneously sampled.

[0060] Further, a pressure gauge 16 is further arranged at each of an end of the gas supply pipe 4 and an end of the gas exhaust pipe 5 that extend out of the well hole 16.

[0061] By adopting this further solution, it is convenient to monitor the pressures of the gas supply pipe 4 and the gas exhaust pipe 5, ensuring the effective operation of the device.

[0062] Further, a check valve 9 is further arranged on a pipeline between the filtration and dialysis component 11 and the tee-junction.

[0063] By adopting this further solution, the groundwater in the downhole fluid storage container 8 is prevented from reversely entering the layered unit 2 in a process that the compressed gas source 3 is started to pressurize the downhole fluid storage container 8 for displacement, so that the disturbance is reduced.

[0064] Further, the compressed gas source 3 is a nitrogen bottle.

[0065] By adopting this further solution, reaction between compressed gas and ground water samples is avoided because the nitrogen is an inert gas, ensuring that a sampling result is more representative.

[0066] Embodiment 2 is as shown in FIGs. 3 and 5.

[0067] The present invention provides a method for groundwater multilevel rapid sampling by multi-layer simultaneous displacement, wherein the method is implemented based on the above device for groundwater multilevel rapid sampling by the multi-layer simultaneous displacement, and includes the following steps:

[0068] step 1, drilling a well hole 1 in a selected site, and mounting the device for groundwater multilevel rapid sampling by the multi-layer simultaneous displacement,

[0069] step 2, opening the valve 12 on the gas supply pipe 4 to pressurize the gas supply pipe 4 to 0.5 KPa, closing the valve 12 on the gas exhaust pipe 5, adjusting the valve 12 on each sample-taking pipe 7 so that groundwater at different depths is simultaneously discharged from the respective sample-taking pipes 7 until no groundwater is discharged from each sample-taking pipe 7 to achieve emptying of downhole residual liquid, and closing the valves 12 on the sample-taking pipes 7 and the valve 12 on the gas supply pipe 4,

[0070] step 3, opening the valve 12 on the gas exhaust pipe 5 to enable the groundwater in the layered unit 2 of each corresponding layer to enter the downhole fluid storage container 8 through the filtration and dialysis component 11 under the action of a difference between a stratum pore water pressure and an atmospheric pressure so that gas in the downhole fluid storage container 8 passes through the semipermeable membrane element 10 to enter the gas exhaust pipe 5 and then is discharged until the downhole fluid storage container 8 in each layered unit 2 completes sample injection and the gas therein is completely discharged;

[0071] step 4, repeating steps 2 and 3 to discharge groundwater with 3 to 5 times a volume of the downhole residual liquid; and

[0072] step 5, connecting the sampling bottle 6 to each sample-taking pipe 7, and opening the valve 12 on the gas supply pipe 4 and the valves 12 on the respective sample-taking pipes 7 to acquire representative samples of the groundwater in multiple layer positions.

[0073] By adopting the method provided by the present invention, the influence of drilling on the sampling result is avoided through a well washing operation from step 2 to step 4, and the one-hole multi-layer in-situ weak disturbance dialysis sample injection of the groundwater is achieved, so that the groundwater sample is more representative. Through multi-layer simultaneous displacement sampling, it is achieved that the total time to complete groundwater well washing and sampling in multiple layer positions should be controlled within 60 min under the premise of IL groundwater sampling volume.

[0074] In the description of the present invention, it should be understood that the terms indicating orientation, direction or position relationships (such as “center”, “longitudinal”, “transverse”, “length”, “width”, “thickness”, “upper”, “lower”, “front”, “rear”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “internal”, “external”, “clockwise”, “anti-clockwise”, “axial”, “radial”, “circumferential” and the like) refer to the orientation, direction or position relationships shown in the drawings, and are merely intended to describe the present invention conveniently and simplify the description, rather than to indicate or imply that the referred part, element or entire device must has a specific orientation and must be configured and operated at the specific orientation. Therefore, such terms should not be construed as limiting the present invention.

[0075] Moreover, the terms describing a sequence such as “first” and “second” are only for the purpose of facilitating understanding or simplifying the description. For example, to distinguish multiple technical features having the same type or function, when one of these multiple technical feature needs to be mentioned separately, these technical features may be distinguished by using prefixes or suffixes to the terms describing a sequence in the present description. Thus, such terms describing a sequence should not be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined with “first” and “second” may explicitly or implicitly comprise at least one of the features. In the description of the present invention, “a plurality of / multiple” means at least two, for example, two or three, unless otherwise particularly defined.

[0076] In the present invention, it should be noted that the terms for describing relative actions among the structures such as “mounted”, “connected with”, “connected to”, “fixed” and the like should be broadly understood unless explicitly defined or limited otherwise. For example, the terms such as “mounted”, “connected with” and “connected to” may refer to a fixed connection, a detachable connection or an integrated connection, or a mechanical connection or an electrical connection, or a direct connection or an indirect connection via an intermediary, or an internal communication of two elements or mutual actions between two elements, unless otherwise particularly defined. The term “fixed” may refer to an integrated fixing manner, a detachable fixing manner through a fixture, a direct fixing manner, or a fixing manner using an intermediate medium, unless otherwise particularly defined. Those skilled in the art can understand the specific meaning of the above terms in the present invention according to specific conditions, the context or the contextual coherence of the previous and followed text.

[0077] In the present invention, if there is a descriptive term containing subsidiary or connecting meanings, for example, if the first feature is "above" or “below” the second feature, unless otherwise expressly specified, it should not be understood in a limiting manner. For example, the term "above" or “below” may refer to direct contact between the first and second features, or may mean that the first feature and the second feature indirect contact with each other through an intermediate medium. For those of ordinary skill in the art, the specific meaning of the above descriptive terms in the present invention may be understood according to specific conditions, the context or the contextual coherence of the previous and followed text.

[0078] Further, if the first feature is "above" or "on" the second feature, it may mean that the first feature is directly above the second feature or above the second feature in a staggered manner, or it may simply indicate that the horizontal height of the first feature is higher than that of the second feature. If the first feature is "below" or "under" the second feature, it may mean that the first feature is directly below the second feature or below the second feature in a staggered manner, or it may simply indicate that the horizontal height of the first feature is less than that of the second feature.

[0079] In the description of the present invention, the reference term “one embodiment”, “some embodiments”, “an example”, “a particular example”, “some examples” or the like means that particular features, structures, materials or characteristics described in combination with the embodiment or example are included in at least one embodiment or example of the present invention. In this description, the schematic representation of the terms does not necessarily refer to the same embodiment or example. Furthermore, the described specific features, structures, materials, or characteristics may be combined in any suitable manner in any one or more embodiments or examples. In addition, in the absence of mutual contradiction, different embodiments or examples described and features of the different embodiments or examples in this description may be combined by those skilled in the art. Such combinations shall fall within the scope summarized by the present invention.

[0080] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are illustrative and should not be construed as limitations of the present invention, and those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the information disclosed herein.

Claims

1. A device for groundwater multilevel rapid sampling by multi-layer simultaneous displacement, comprising: a compressed gas source (3), an exhaust pipe (5), a plurality of sampling bottles (6), and a plurality of layered units (2) distributed along a depth of a well hole (1), wherein each sampling bottle (6) is connected with a sample-taking pipe (7), and each sample-taking pipe (7) extends into the well hole (1) and corresponds to one layered unit (2); the compressed gas source (3) is connected with a gas supply pipe (4), and the gas supply pipe (4) and the gas exhaust pipe (5) separately extend into the well hole (1); a downhole fluid storage container (8) is arranged in each layered unit (2), an upper end of the downhole fluid storage container (8) is connected with a check valve (9) and a semipermeable membrane element (10) through pipelines, a pipeline where the check valve (9) is located is connected to the gas supply pipe (4), and a pipeline where the semipermeable membrane element (10) is located is connected to the gas exhaust pipe (5); a lower end of the downhole fluid storage container (8) is connected with a filtration and dialysis component (11), and a pipeline between the filtration and dialysis component (11) and the downhole fluid storage container (8) is connected to the sample-taking pipe (7) through a tee-junction; and each of the gas supply pipe (4), the gas exhaust pipe (5) and the sample-taking pipes (7) is provided with a valve (12).

2. The device for groundwater multilevel rapid sampling by the multi-layer simultaneous displacement according to claim 1, wherein the layered unit (2) comprises a wellbore solid pipe (13) and a wellbore sieve pipe (14); the wellbore sieve pipe (14) is fixed to a lower end of the wellbore solid pipe (13); an upper end of the wellbore solid pipe (13) and a lower end of the wellbore sieve pipe (14) are closed; and the filtration and dialysis component (11) and the downhole fluid storage container (8) are both arranged in an accommodating cavity formed by the wellbore solid pipe (13) and the wellbore sieve pipe (14).

3. The device for groundwater multilevel rapid sampling by the multi-layer simultaneous displacement according to claim 2, wherein annular packers (15) are arranged on outer ring surfaces at two ends of the wellbore sieve pipe (14), and are in contact with a side wall of the well hole (1).

4. The device for groundwater multilevel rapid sampling by the multi-layer simultaneous displacement according to claim 3, wherein the packer (15) is air-driving.09 01 245. The device for groundwater multilevel rapid sampling by the multi-layer simultaneous displacement according to claim 1, wherein three to nine layered units (2) are distributed along the depth of the well hole (1).

6. The device for groundwater multilevel rapid sampling by the multi-layer simultaneous displacement according to claim 5, wherein six to nine layered units (2) are distributed along the depth of the well hole (1).

7. The device for groundwater multilevel rapid sampling by the multi-layer simultaneous displacement according to claim 1, wherein a pressure gauge (16) is further arranged at each of an end of the gas supply pipe (4) and an end of the gas exhaust pipe (5) that extend out of the well hole (1).

8. The device for groundwater multilevel rapid sampling by the multi-layer simultaneous displacement according to claim 1, wherein a check valve (9) is further arranged on a pipeline between the filtration and dialysis component (11) and the tee-junction.

9. The device for groundwater multilevel rapid sampling by the multi-layer simultaneous displacement according to claim 1, wherein the compressed gas source (3) is a nitrogen bottle.

10. A method for groundwater multilevel rapid sampling by multi-layer simultaneous displacement, wherein the method is implemented using the device for groundwater multilevel rapid sampling by the multi-layer simultaneous displacement according to any one of claims 1 to 9, and comprises the following steps:step 1, drilling a well hole (1) in a selected site, and mounting the device for groundwater multilevel rapid sampling by the multi-layer simultaneous displacement;step 2, opening the valve (12) on the gas supply pipe (4) to pressurize the gas supply pipe (4), closing the valve (12) on the gas exhaust pipe (5), adjusting the valve (12) on each sampletaking pipe (7) so that groundwater at different depths is simultaneously discharged from the respective sample-taking pipes (7) until no groundwater is discharged from each sample-taking pipe (7) to achieve emptying of downhole residual liquid, and closing the valves (12) on the sample-taking pipes (7) and the valve (12) on the gas supply pipe (4);step 3, opening the valve (12) on the gas exhaust pipe (5) to enable the groundwater in the layered unit (2) of each corresponding layer to enter the downhole fluid storage container (8) through the filtration and dialysis component (11) under an action of a difference between astratum pore water pressure and an atmospheric pressure so that gas in the downhole fluid storage container (8) passes through the semipermeable membrane element (10) to enter the gas exhaust pipe (5) and then is discharged until the downhole fluid storage container (8) in each layered unit (2) completes sample injection and the gas in the downhole fluid storage container (8) is completely discharged;step 4, repeating steps (2) and (3) to discharge groundwater with 3 to 5 times a volume of the downhole residual liquid; andstep 5, connecting the sampling bottle (6) to each sample-taking pipe (7), and opening the valve (12) on the gas supply pipe (4) and the valves (12) on the respective sample-taking pipes (7) to acquire representative samples of the groundwater in multiple layer positions.09 01 24

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