Determination method of water storage coefficient of underground reservoir in coal mine and underground reservoir model

Abstract

The present invention provides a method for determining the water storage coefficient of a coal mine underground reservoir and an underground reservoir model, wherein the method for determining the water storage coefficient of a coal mine underground reservoir includes: obtaining the area of ​​the underground reservoir; injecting water into the underground reservoir multiple times until the underground reservoir is full, recording the cumulative water injection volume each time and the height of the aquifer corresponding to each water injection; determining the water storage coefficient of the aquifer for each water injection based on the area, the cumulative water injection volume each time, and the height of the aquifer corresponding to each water injection; obtaining a change curve between the cumulative water injection volume each time and the water storage coefficient of the aquifer based on the water storage coefficient of the aquifer for each water injection; and determining the water storage coefficient of the coal mine underground reservoir based on the inflection point of the change curve. The technical solution of the present application effectively solves the problems of poor numerical reliability and high operational difficulty in determining the water storage coefficient in the related art.

Description

Technical Field

[0001] The present invention relates to the technical field of mine hydrogeological monitoring, and in particular to a method for determining a water storage coefficient of a coal mine underground reservoir and an underground reservoir model. Background Art

[0002] Some mining areas in my country, located at the border of the Maowusu Desert and the Loess Plateau, experience a typical semi-arid, semi-desert, plateau continental climate, resulting in extremely scarce water resources. To address the widespread conditions in these areas, where large-scale, high-intensity coal mining creates extensive goafs and large quantities of mine water, a technical solution for storing and utilizing mine water in underground coal mine reservoirs has been proposed. From the perspective of water resource conservation, underground coal mine reservoirs are a construction model for improving mine water utilization. They connect discontinuous coal pillars through the construction of artificial dams to form underground reservoirs. Water is stored in the free spaces between collapsed rock masses in the goaf. Mine water is injected into the goaf for sedimentation, filtration, and adsorption, and then used as a source of water for production and daily life in the mining area, achieving natural storage and purification of mine water. Because underground coal mine reservoirs are built underground, the internal rock collapse accumulation is unknown, and the space available for human intervention is very limited. This poses unprecedented challenges in determining the performance parameters of the reservoir's internal structure.

[0003] Water storage capacity is a key indicator for evaluating the success of constructed coal mine underground reservoirs. The water storage coefficient (equivalent to porosity) has attracted considerable attention as a key factor characterizing the water storage capacity of coal mine underground reservoirs. Academician Gu Dazhao pointed out that the water storage coefficient depends on the rock mass porosity, changes dynamically over time, and is influenced by factors such as overburden structure, mining parameters, mine pressure, and rock mass fragmentation. Chen Sushe and other scholars believe that the water storage space of coal mine underground reservoirs is composed of collapse zones and fracture zones, and the corresponding water storage coefficient is equal to the porosity of the collapse zone or the porosity of the fracture zone. Li Quansheng and other scholars have established a mathematical relationship between the water storage coefficient and the coefficient of expansion of the fractured rock mass in the goaf. Furthermore, other researchers have conducted physical simulations using large-scale three-dimensional vibration simulation test rigs and, in combination with mining area pumping and drainage engineering tests, have determined the specific value of the water storage coefficient.

[0004] However, in actual engineering applications, the values ​​of the water storage coefficient are mostly derived from the empirical value range or simple pumping and drainage engineering tests in mining areas. Due to the poor numerical reliability and difficulty in determining the water storage coefficient, it cannot truly reflect the porosity of the rock mass of the coal mine underground reservoir and has great limitations. Summary of the Invention

[0005] The main purpose of the present invention is to provide a method for determining the water storage coefficient of a coal mine underground water reservoir and an underground water reservoir model, so as to solve the problems of poor numerical reliability and high operational difficulty in determining the water storage coefficient in related technologies.

[0006] To achieve the above object, according to one aspect of the present invention, a method for determining the water storage coefficient of a coal mine underground reservoir is provided, comprising: obtaining the area occupied by the underground reservoir;

[0007] Inject water into the underground reservoir multiple times until it is full, and record the cumulative volume of water injected each time and the height of the aquifer corresponding to each injection;

[0008] Determine the water storage coefficient of the aquifer for each injection based on the land area, the cumulative water injection volume each time, and the height of the aquifer corresponding to each injection;

[0009] According to the water storage coefficient of the aquifer injected each time, a curve of the relationship between the cumulative injection volume of each injection and the water storage coefficient of the aquifer is obtained;

[0010] The water storage coefficient of the coal mine underground water reservoir is determined according to the inflection point of the change curve.

[0011] Furthermore, the step of determining the water storage coefficient of the aquifer for each water injection based on the area, the cumulative water injection volume each time, and the height of the aquifer corresponding to each water injection includes: obtaining the water storage coefficient of the aquifer for each water injection by the following formula: C = V / (S×H); wherein C is the water storage coefficient of the aquifer for each water injection, V is the cumulative water injection volume, S is the area of ​​the groundwater reservoir, and H is the height of the aquifer.

[0012] Furthermore, the underground reservoir is an actual underground reservoir.

[0013] Furthermore, the underground reservoir is a model of an underground reservoir.

[0014] Furthermore, between the step of obtaining the floor area S of the underground reservoir and the step of injecting water into the underground reservoir multiple times until the underground reservoir is full, and recording the cumulative water injection volume each time and the height of the aquifer corresponding to each water injection, the method for determining the water storage coefficient of the coal mine underground reservoir also includes: drilling injection holes on the side wall of the underground reservoir, and injecting water into the underground reservoir through the injection holes.

[0015] Furthermore, the step of drilling water injection holes on the side wall of the underground reservoir includes: drilling a plurality of water injection holes at equal intervals on the side wall of the underground reservoir in the up-down direction.

[0016] Furthermore, the step of obtaining the height of the aquifer corresponding to each water injection includes: obtaining the height of the aquifer corresponding to each water injection by means of liquid level gauges at different heights.

[0017] According to another aspect of the present invention, an underground water reservoir model is provided for implementing the above-mentioned method for determining the water storage coefficient of the coal mine underground water reservoir. The underground water reservoir model includes: a containing box, in which a tortuous circuitous passage is provided; an injection pipe, which is provided through the head of the containing box and is connected to the tortuous circuitous passage; and a plurality of sampling tubes, which are provided through the side wall of the containing box and are connected to the tortuous circuitous passage, and the plurality of sampling tubes are evenly arranged along the upper and lower directions of the containing box.

[0018] Furthermore, an overflow pipe communicating with the meandering channel is provided at the top of the tail portion of the container box, and / or an emergency discharge pipe communicating with the meandering channel is provided at the bottom of the side wall of the container box.

[0019] Furthermore, the underground reservoir model also includes a drainage pipe, which is arranged at the tail end of the receiving box and is connected with the winding channel. The drainage pipe is located below the water injection pipe.

[0020] Applying the technical solution of the present invention, the method for determining the water storage coefficient of the underground water reservoir of a coal mine includes: obtaining the floor area of ​​the underground water reservoir; injecting water into the underground water reservoir multiple times until the underground water reservoir is full, recording the cumulative water injection volume each time and the height of the aquifer corresponding to each water injection; determining the water storage coefficient of the aquifer injected each time according to the floor area, the cumulative water injection volume each time and the height of the aquifer corresponding to each water injection; obtaining a change curve between the cumulative water injection volume of each water injection and the water storage coefficient of the aquifer according to the water storage coefficient of the aquifer injected each time; and determining the water storage coefficient of the underground water reservoir of a coal mine according to the inflection point of the change curve. The method for determining the water storage coefficient of the underground water reservoir of a coal mine according to the present application can directly obtain the floor area of ​​the underground water reservoir to determine the water storage coefficient of the underground water reservoir of a coal mine. It is highly targeted, reliable, and easy to operate, and can truly evaluate the water storage coefficient of the underground water reservoir of a coal mine. Therefore, the technical solution of the present application effectively solves the problems of poor numerical reliability and high operational difficulty in determining the water storage coefficient in the related art. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The accompanying drawings, which constitute part of this application, are intended to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are intended to explain the present invention and do not constitute an undue limitation of the present invention. In the accompanying drawings:

[0022] Figure 1 A flow chart showing an embodiment of a method for determining a water storage coefficient of a coal mine underground water reservoir according to the present invention is shown;

[0023] Figure 2 Shown Figure 1 The method for determining the water storage coefficient of the coal mine underground water reservoir is a curve diagram showing the change between the cumulative injection volume of each injection and the water storage coefficient of the aquifer;

[0024] Figure 3A schematic diagram of the three-dimensional structure of the front side of an embodiment of an underground reservoir model according to the present invention is shown;

[0025] Figure 4 Shown Figure 3 A schematic diagram of the three-dimensional structure of the rear side of the underground reservoir model;

[0026] Figure 5 Shown Figure 3 Schematic top view of the underground reservoir model.

[0027] The above drawings include the following reference numerals:

[0028] 10. Container; 11. Bend and circuitous passage; 21. Water injection pipe; 22. Sampling pipe; 23. Overflow pipe; 24. Emergency discharge pipe; 25. Drain pipe. DETAILED DESCRIPTION

[0029] The following will be combined with the accompanying 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 embodiments described are only part of the embodiments of the present invention, rather than all the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is in no way intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0030] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0031] Unless otherwise specifically stated, the relative arrangement of the parts and steps, the numerical expressions and the numerical values ​​set forth in these embodiments do not limit the scope of the present invention. At the same time, it should be understood that, for ease of description, the sizes of the various parts shown in the drawings are not drawn according to the actual proportional relationship. The techniques, methods and equipment known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, the techniques, methods and equipment should be considered as part of the authorization specification. In all examples shown and discussed here, any specific values ​​should be interpreted as being merely exemplary and not as limiting. Therefore, other examples of the exemplary embodiments may have different values. It should be noted that similar numbers and letters represent similar items in the following figures, and therefore, once an item is defined in one figure, it does not need to be further discussed in subsequent figures.

[0032] like Figure 1 and Figure 2 As shown, the method for determining the water storage coefficient of the coal mine underground water reservoir in this embodiment includes: obtaining the floor area of ​​the underground water reservoir; injecting water into the underground water reservoir multiple times until the underground water reservoir is full, recording the cumulative water injection volume each time and the height of the aquifer corresponding to each water injection; determining the water storage coefficient of the aquifer for each water injection based on the floor area, the cumulative water injection volume each time and the height of the aquifer corresponding to each water injection; obtaining a change curve between the cumulative water injection volume for each water injection and the water storage coefficient of the aquifer based on the water storage coefficient of the aquifer for each water injection; and determining the water storage coefficient of the coal mine underground water reservoir based on the inflection point of the change curve.

[0033] Applying the technical solution of this embodiment, the method for determining the water storage coefficient of the underground water reservoir of a coal mine includes: obtaining the floor area of ​​the underground water reservoir; injecting water into the underground water reservoir multiple times until the underground water reservoir is full, recording the cumulative water injection volume each time and the height of the aquifer corresponding to each water injection; determining the water storage coefficient of the aquifer injected each time according to the floor area, the cumulative water injection volume each time and the height of the aquifer corresponding to each water injection; obtaining a change curve between the cumulative water injection volume of each water injection and the water storage coefficient of the aquifer according to the water storage coefficient of the aquifer injected each time; and determining the water storage coefficient of the underground water reservoir of a coal mine according to the inflection point of the change curve. The method for determining the water storage coefficient of the underground water reservoir of a coal mine according to the present application can directly obtain the floor area of ​​the underground water reservoir to determine the water storage coefficient of the underground water reservoir of a coal mine. It is highly targeted, reliable, and easy to operate, and can truly evaluate the water storage coefficient of the underground water reservoir of a coal mine. Therefore, the technical solution of this embodiment effectively solves the problems of poor numerical reliability and high operational difficulty in determining the water storage coefficient in the related art.

[0034] The method for determining the water storage coefficient of a coal mine underground reservoir in this embodiment is based on the following principles: Because physical and chemical reactions such as filtration, adsorption, and ion exchange can only occur when mine water comes into contact with the rock mass of the goaf, thereby purifying the mine water by the rock mass of the coal mine underground reservoir, the effective water storage space within the underground reservoir is the space where the rock mass is distributed, and the void volume of the rock mass is the effective water storage volume. As water is continuously injected into the underground reservoir, the voids in the rock mass within the underground reservoir are gradually filled. In the initial stages of injection, the mine water can be absorbed by the dry surface of the rock and a certain amount of voids, resulting in an overly high water storage coefficient for the measured aquifer. Consequently, the measured water storage coefficient for the aquifer gradually decreases with increasing cumulative injection volume or injection height until the mine water is saturated, at which point the measured water storage coefficient gradually stabilizes. Continue to inject water into the underground reservoir. Because there may be no rockfall in the top space of the underground reservoir, the entire space can store a large amount of water, causing the measured water storage coefficient of the aquifer to gradually increase. However, since the mine water in the space without rockfall cannot come into contact with the rock and thus cannot be purified, the water storage volume in the top space cannot be used as the effective water storage volume. Ultimately, the curve between the cumulative injection volume of each injection and the water storage coefficient of the aquifer will show a trend of first decreasing and then increasing. The water storage coefficient at the inflection point is the water storage coefficient of the coal mine underground reservoir, which is also the effective water storage coefficient of the entire coal mine underground reservoir.

[0035] like Figure 1 and Figure 2 As shown, in order to accurately obtain the water storage coefficient of the aquifer for each water injection, the step of determining the water storage coefficient of the aquifer for each water injection based on the land area, the cumulative water injection volume for each injection, and the height of the aquifer corresponding to each water injection includes: obtaining the water storage coefficient of the aquifer for each water injection using the following formula: C = V / (S × H). Where C is the water storage coefficient of the aquifer for each water injection, V is the cumulative water injection volume, S is the land area of ​​the groundwater reservoir, and H is the height of the aquifer.

[0036] like Figure 1 and Figure 2 As shown, the step of recording each cumulative water injection volume includes: obtaining each cumulative water injection volume by summing the product of each water injection flow rate and the corresponding water injection time.

[0037] like Figure 1 and Figure 2 In order to directly obtain the area of ​​the groundwater reservoir, the groundwater reservoir is the actual groundwater reservoir. The actual groundwater reservoir can be determined based on the existing excavation drawings of the mined-out area and relevant geological data.

[0038] like Figure 1 and Figure 2 As shown, for the sake of simplicity, the underground reservoir is an underground reservoir model. The specific operation steps are as follows:

[0039] Step S1: Determine the floor area of ​​the underground reservoir model as 1.268m based on the design drawings. 3 .

[0040] Step S2: Cumulatively inject 20 L, 40 L, 60 L, 80 L, 100 L, 120 L, 130 L, 135 L, and 136 L of mine water into the underground reservoir model, and record the cumulative injection volume and the height H of the aquifer corresponding to each injection (see Table 1 for parameters).

[0041] Table 1

[0042]

[0043] Step S3: Draw a curve showing the change between the cumulative injection volume of each injection and the water storage coefficient of the aquifer, find the inflection point of the curve at 120L of cumulative injection volume, and determine its water storage coefficient to be 0.52228, which is the water storage coefficient of the coal mine underground reservoir.

[0044] Of course, the above-mentioned floor area may also be the net bottom area, and the above-mentioned height of the aquifer may also be the liquid level height.

[0045] like Figure 1 and Figure 2 As shown, between the step of obtaining the area S of the underground reservoir and the step of repeatedly injecting water into the underground reservoir until the underground reservoir is full, and recording the cumulative injection volume and the height of the aquifer corresponding to each injection, the method for determining the water storage coefficient of the coal mine underground reservoir further includes: drilling injection holes in the side wall of the underground reservoir and injecting water into the underground reservoir through the injection holes to facilitate injection into the underground reservoir.

[0046] like Figure 1 and Figure 2 As shown, in order to conveniently determine the cumulative water injection volume each time and the height of the aquifer injected each time, the step of drilling water injection holes on the side wall of the underground reservoir includes: drilling multiple water injection holes at equal intervals on the side wall of the underground reservoir in the up and down directions.

[0047] like Figure 1 and Figure 2 As shown, in order to accurately record the height of the aquifer for each water injection, the step of obtaining the height of the aquifer for each water injection includes: obtaining the height of the aquifer for each water injection by using liquid level gauges at different heights.

[0048] This application also provides a groundwater reservoir model, such as Figures 3 to 5As shown, the underground reservoir model of this embodiment is used to implement the above-mentioned method for determining the water storage coefficient of a coal mine underground reservoir. The underground reservoir model includes: a container box 10, an injection pipe 21, and multiple sampling pipes 22. A curved circuitous passage 11 is provided within the container box 10. The injection pipe 21 is disposed through the head of the container box 10 and communicates with the curved circuitous passage 11. Water can be injected into the container box 10 through the injection pipe 21. Multiple sampling pipes 22 are disposed through the side walls of the container box 10 and communicate with the curved circuitous passage 11. The multiple sampling pipes 22 are evenly arranged along the upper and lower sides of the container box 10. The multiple sampling pipes 22 enable sampling to be performed through any of the sampling pipes 22 during the method for determining the water storage coefficient of a coal mine underground reservoir, thereby analyzing and testing water quality indicators. Because the above-mentioned method for determining the water storage coefficient of a coal mine underground reservoir can solve the problems of poor numerical reliability and high operational difficulty in determining the water storage coefficient in related technologies, the underground reservoir model used to implement the above-mentioned method for determining the water storage coefficient of a coal mine underground reservoir can also solve the same technical problems.

[0049] It should be noted that when water is injected into the container 10 through the water injection pipe 21, it first enters the container 10 from the head portion, passes through the middle portion of the container 10, and then flows to the tail portion of the container 10. The head portion of the container 10 is the starting point for the water in the container 10 to flow to other locations in the container 10.

[0050] like Figures 3 to 5 As shown, when water fills the winding channel 11, an overflow pipe 23 is provided at the top of the tail portion of the container 10 for safety reasons. This overflow pipe is connected to the winding channel 11. When inspecting the underground reservoir model or discharging an emergency, an emergency discharge pipe 24 is provided at the bottom of the side wall of the container 10 for safety reasons. The tail portion of the container 10 is the portion of the container 10 where the water within the container 10 stops flowing downward after reaching a certain point within the container 10.

[0051] In an embodiment not shown in the figures, an overflow pipe communicating with the meandering channel is provided at the top of the side wall of the container box, or an emergency discharge pipe communicating with the meandering channel is provided at the bottom of the side wall of the container box.

[0052] like Figures 3 to 5 As shown, in order to facilitate the discharge of water in the winding channel 11 of the underground reservoir model, the underground reservoir model also includes a drainage pipe 25. The drainage pipe 25 is arranged at the tail of the containing box 10 and is connected to the winding channel 11. The drainage pipe 25 is located below the water injection pipe 21.

[0053] In the description of the present invention, it should be understood that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "horizontal, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the device or element referred to must have a specific direction or be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the scope of protection of the present invention; the directional words "inside and outside" refer to the inside and outside relative to the outline of each component itself.

[0054] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used herein to describe the spatial positional relationship of a device or feature to other devices or features as shown in the figures. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figures. For example, if the device in the drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0055] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of the present invention.

[0056] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A method for determining the water storage coefficient of a coal mine underground reservoir, characterized in that: include: Obtain the area occupied by the groundwater reservoir; injecting water into the underground reservoir multiple times until the underground reservoir is filled, and recording the cumulative volume of water injected each time and the height of the aquifer corresponding to each water injection; Determine the water storage coefficient of the aquifer for each water injection according to the land area, the cumulative water injection volume for each time, and the height of the aquifer corresponding to each water injection; According to the water storage coefficient of the aquifer at each water injection, a variation curve between the cumulative water injection volume at each water injection and the water storage coefficient of the aquifer is obtained; Determining the water storage coefficient of the coal mine underground water reservoir according to the inflection point of the change curve; The step of determining the water storage coefficient of the aquifer for each water injection according to the land area, the cumulative water injection volume for each injection, and the height of the aquifer corresponding to each water injection comprises: The water storage coefficient of the aquifer for each water injection is obtained by the following formula: C = V / (S × H); Wherein, C is the water storage coefficient of the aquifer at each water injection, V is the cumulative water injection volume, S is the area occupied by the underground reservoir, and H is the height of the aquifer; The underground reservoir is an underground reservoir model; the method for determining the water storage coefficient of the coal mine underground reservoir is applied to the underground reservoir model, and the underground reservoir model includes: A accommodating box (10), wherein a curved circuitous channel (11) is provided in the accommodating box (10); A water injection pipe (21) is provided through the head of the containing box (10) and is in communication with the curved circuitous channel (11); A plurality of sampling tubes (22) are provided through the side wall of the accommodating box (10) and communicate with the bending circuitous channel (11); the plurality of sampling tubes (22) are evenly arranged in the vertical direction of the accommodating box (10).

2. The method for determining the water storage coefficient of a coal mine underground reservoir according to claim 1, characterized in that: The underground reservoir is an actual underground reservoir.

3. The method for determining the water storage coefficient of a coal mine underground reservoir according to claim 1, characterized in that: Between the steps of obtaining the area S of the underground reservoir and injecting water into the underground reservoir multiple times until the underground reservoir is full, and recording the cumulative water injection volume of each injection and the height of the aquifer corresponding to each injection, the method for determining the water storage coefficient of the coal mine underground reservoir further includes: Water injection holes are drilled on the side walls of the underground reservoir, and water is injected into the underground reservoir through the water injection holes.

4. The method for determining the water storage coefficient of a coal mine underground reservoir according to claim 3, characterized in that: The step of drilling a water injection hole on the side wall of the underground reservoir comprises: A plurality of water injection holes are drilled on the side wall of the underground reservoir at equal intervals along the up and down directions.

5. The method for determining the water storage coefficient of a coal mine underground reservoir according to claim 1, characterized in that: The step of obtaining the height of the aquifer corresponding to each water injection includes: obtaining the height of the aquifer corresponding to each water injection by using liquid level gauges at different heights.

6. The method for determining the water storage coefficient of a coal mine underground reservoir according to claim 1, characterized in that: An overflow pipe (23) communicating with the bent circuitous channel (11) is provided at the top of the tail of the container box (10), and / or an emergency discharge pipe (24) communicating with the bent circuitous channel (11) is provided at the bottom of the side wall of the container box (10).

7. The method for determining the water storage coefficient of a coal mine underground reservoir according to claim 1, characterized in that: The underground reservoir model further comprises a drainage pipe (25), the drainage pipe (25) being arranged through the tail of the housing box (10) and communicating with the meandering channel (11), and the drainage pipe (25) being located below the water injection pipe (21).

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