Dynamic drainage method for coal seam roof separation water area
By employing directional comb-shaped borehole groups and in-stratum drilling on the ground, connecting the abscess water accumulation areas in series, and dynamically constructing short branch boreholes, the problem of insufficient abscess water drainage was solved, achieving safe and efficient abscess water drainage and avoiding water damage and rock bursts.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-02-12
- Publication Date
- 2026-04-10
AI Technical Summary
Existing technologies for draining delamination water suffer from several problems, including inflexible surface drilling layout, inaccurate detection of delamination water, insufficient draining, high draining costs, difficulty in underground drilling, and constraints on coal mining progress.
A ground-oriented comb-shaped hole group is adopted to drill in the layer and connect the water accumulation area of the delamination. The water drainage channel of the delamination area is formed by dynamically constructing short branch holes to realize the dynamic drainage of the delamination area.
It enables dynamic and full release of absorptive water, avoiding water damage and rock bursts caused by instantaneous release of absorptive water, reducing costs, and improving construction flexibility and safety.
Smart Images
Figure CN121827907A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application belongs to the technical field of coal mine water disaster prevention and control, more specifically relates to a coal seam roof separation water area dynamic drainage method. BACKGROUND
[0002] The coal seam roof separation is due to the difference in lithology and physical and mechanical properties of each rock layer overlying the coal seam, and a layered cavity is formed during the mining process of the working face. The separation cavity accumulates water to form separation water, which surges and discharges to the coal mining working face to form separation water disaster. The separation water disaster has the characteristics of unclear water inrush signs, large instantaneous water volume, great destructive power, periodicity, and associated rock burst disaster, so it is necessary to study the prevention and control method of separation water disaster.
[0003] The separation developed in the overburden rock after coal mining is not unique and fixed; with the coal mining, the separation area increases, the separation of the roof of the mining area moves forward in the horizontal direction, the separation development height in the vertical direction continuously rises, the upper separation gradually develops, and the lower separation gradually closes, and the approximate development shape is "trapezoidal".
[0004] At present, the prevention and control methods for separation water disaster mainly include ground straight-through diversion hole, underground diversion hole, and control of mining height. The ground straight-through diversion hole for treating separation water disaster needs to increase the drilling hole with the advance of the working face, and part of the complex terrain such as hilly and mountainous areas does not have the condition of hole arrangement on the ground. In addition, since the separation is dynamically developed, the straight hole cannot be accurately constructed in the center of the separation water body, resulting in insufficient drainage, so the method of ground straight-through diversion hole for draining separation water has the problems of inflexible implementation, large engineering quantity, large investment, and inaccurate positioning of separation water body; the underground separation water body diversion hole can avoid the disadvantages of ground drilling, but the broken overburden after mining disturbance leads to large difficulty in underground drilling construction, and the separation water drainage work restricts the coal mining progress; the control of mining height to avoid affecting the separation water body will inevitably cause waste of coal resources.
[0005] Therefore, in view of the problems of inflexible ground drilling arrangement, inaccurate separation water body exploration, insufficient drainage, high drainage cost, large difficulty in underground drilling construction, and restriction of coal mining progress, there is an urgent need for a flexible, safe, efficient, and economical roof separation water drainage method. SUMMARY
[0006] The present application aims to provide a coal seam roof separation water area dynamic drainage method to overcome the shortcomings of the prior art. The present application forms a separation water drainage channel by drilling a short branch hole through a ground directional comb hole group, which is connected in series with the separation water area, so that the separation area does not accumulate water, and the problems of water disaster and rock burst caused by instantaneous release of separation water are avoided.
[0007] The application adopts the following technical solutions: A coal seam roof separation water area dynamic drainage method, comprising the following steps: S10, determining the position of the separation water in the overburden rock; analyzing the drill columnar chart to identify all hard rock layers above the coal seam roof with large thickness and high uniaxial compressive strength; taking the lower part of the first hard rock layer above the water-conducting fractured zone as a separation water accumulation area; S20, constructing a bedding main hole in the separation water accumulation area in the lower part of the first aquifer; the main hole adopts a three-opening structure, the first opening reaches the complete bedrock, the second opening is directionally drilled to the lower part of the first hard rock layer, the first opening and the second opening are respectively isolated from the stratum by casing cementing, and the third opening is drilled along the separation water accumulation area and is a bare hole; S30, as the working face advances, a dynamic drainage branch hole is constructed according to a certain drilling spacing.
[0008] Further, in step S10, the height of the water-conducting fractured zone is predicted by using an empirical formula, an analogy method or a simulation method.
[0009] Further, the prediction of the height of the water-conducting fractured zone is selected according to the hardness of the overburden rock by using the following empirical formula: is the predicted height of the water-conducting fractured zone, and the unit is m; M is the mining height of the coal seam, and the unit is m; the application range is that the single layer mining thickness is 1-3 m, and the cumulative mining thickness does not exceed 15 m.
[0010] Further, the analogy method predicts the height of the water-conducting fractured zone of the working face to be mined, and the formula is as follows:
[0011] In the formula, is the predicted height of the water-conducting fractured zone, and the unit is m; M is the mining height of the coal seam, and the unit is m; is the ratio of the height of the water-conducting fractured zone to the mining height of the coal seam.
[0012] Further, in step S20, each hole group can cover 1-2 working faces; and in the same long working face, multiple hole groups can be constructed.
[0013] Further, in step S30, the drainage branch hole is dynamically constructed as the working face advances, the drilling spacing is 1 / 2 of the working face width, the construction is completed in advance at the rear of the working face, and the dynamic distance from the working face is 1 times the working face width.
[0014] Further, the drainage branch hole enters the water-conducting fractured zone, whether it enters the water-conducting fractured zone can be judged according to the drilling fluid leakage amount, and the separation water accumulation is discharged to the goaf through the drainage branch hole.
[0015] Compared with the prior art, the present application has the following beneficial effects: (1) The bedding drilling is used to connect the separation water accumulation areas in series, to connect the originally dynamic development relatively isolated separation water accumulation areas, and to realize the dynamic drainage of the separation water accumulation areas, so that the high pressure water accumulation cannot be formed, and the dynamic disasters caused by the separation water inrush and the high separation water pressure are effectively avoided.
[0016] (2) The dynamic and sufficient drainage of the separation water accumulation areas is realized through the bedding series connection of the separation water accumulation areas and the comb-shaped drainage short branch.
[0017] (3) One drainage hole group can cover 1-2 working face ranges, and the cost is reduced.
[0018] (4) The drainage branch hole is constructed in advance of the working face, that is, the drilling hole is constructed in the original complete stratum, and the problem of the difficult drilling construction caused by the broken overburden rock after the mining is avoided. BRIEF DESCRIPTION OF DRAWINGS
[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced below. Obviously, the drawings in the following description are only the embodiments of the present application, and other drawings can be obtained by the provided drawings without creative labor for those skilled in the art.
[0020] Figure 1 is a coal seam roof separation water drainage hole profile; Figure 2 is a single working face roof separation water drainage hole layout plan; Figure 3 is a two working face roof separation water drainage hole layout plan; Figure 4 is a drilling structure diagram; Figure 5 is a working face stratum columnar diagram.
[0021] Among them, 1, the first open well section; 2, the second open well section; 3, the first hard rock layer; 4, the separation water accumulation area; 5, the bedding main hole; 6, the drainage branch hole; 7, the coal seam; 8, the goaf; 9, the water flowing fractured zone; 10, the working face; 11, the first open casing; 12, the second open casing. DETAILED DESCRIPTION
[0022] With reference to the drawings of the embodiments of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments of the present application, all the other embodiments obtained by a person of ordinary skill in the art without creative effort belong to the scope of the present application.
[0023] Embodiment 1
[0024] Reference Figures 1-5 A coal seam roof separation water area dynamic drainage method, comprising the following steps: S10, determining the position of the separation water in the overburden rock; analyzing the borehole columnar diagram to identify all hard rock layers (such as thick sandstone, limestone) with large thickness and high uniaxial compressive strength above the coal seam roof; taking the lower part of the first hard rock layer above the water flowing fractured zone as the separation water accumulation area; Among them, the height of the water flowing fractured zone is predicted by using empirical formula, analogy method or simulation method.
[0025] Specifically, when the height of the water flowing fractured zone is predicted by using the empirical formula, the following empirical formula can be selected according to the hardness of the overburden rock: is the predicted height of the water flowing fractured zone, unit: m; M is the mining height of the coal seam, unit: m; the application range is single layer mining thickness 1-3 m, cumulative mining thickness not more than 15 m.
[0026] When the height of the water flowing fractured zone is predicted by using the analogy method, the analogy method is to use the ratio of the measured value of the height of the water flowing fractured zone after the coal seam mining under similar geological conditions to the mining height of the coal seam to predict the height of the water flowing fractured zone of the working face to be mined, and the formula is as follows:
[0027] In the formula, is the predicted height of the water flowing fractured zone, unit: m; M is the mining height of the coal seam, unit: m; is the ratio of the height of the water flowing fractured zone to the mining height of the coal seam.
[0028] S20, constructing a bedding main hole in the separation water accumulation area under the first aquifer, the main hole adopts a three-opening structure, the first opening is to the complete bedrock, the second opening is directional drilling to the lower part of the first hard rock layer, the first opening and the second opening respectively adopt casing well cementation to isolate the strata, and the third opening is drilling along the separation water accumulation area, which is a bare hole; For example Figure 3 Each hole group can cover 1-2 working faces to realize regional drainage; for example Figure 2 In the same long working face, multiple hole groups can be constructed.
[0029] For exampleFigure 4 The main hole adopts a three-opening structure, one opening with a diameter of 311 mm drilled to the complete bedrock, one casing with a Φ244.5 mm x 8.94 mm type oil casing, the second opening with a diameter of 215.9 mm, directional drilling to the lower part of the first hard rock layer, the second casing with a Φ177.8 mm x 8.05 mm type oil casing, and the casings all using cementing to isolate the strata, and the third opening drilling along the water separation layer zone, being a bare hole.
[0030] The drainage hole group is arranged along the center of the working face, and a plurality of hole groups can be constructed for a long working face.
[0031] S30, as the working face advances, the dynamic drainage branch holes are constructed according to a certain drilling spacing.
[0032] Specifically, the drainage branch holes are dynamically constructed as the working face advances, the drilling spacing is 1 / 2 of the working face width, and the construction is completed in advance at the rear of the working face, with a dynamic distance of 1 times the working face width from the working face.
[0033] In this embodiment, the drainage branch holes enter the water-conducting fractured zone, and whether to enter the water-conducting fractured zone can be judged according to the drilling fluid leakage amount, and the water separation layer water is discharged to the goaf through the drainage branch holes.
[0034] Example 2
[0035] This embodiment takes a working face of a coal mine in Guizhou as an example based on example 1, the working face width is 180 m, the 16 coal seam 7 is mined, the mining height is 3 m, and the working face stratum column is as shown in Figure 5 The interlayer of the coal seam is sandstone and mudstone interbedded with thin layer of limestone, and is overlying with hard thick limestone aquifer.
[0036] To prevent and control the water damage of the water separation layer in the working face mining process, the scheme is specifically as follows: Step S10: determining the position of the water separation layer developed in the overburden 1) predicting the height of the water-conducting fractured zone by using empirical formula, analogy or simulation method; The prediction of the height of the water-conducting fractured zone can be selected according to the hardness of the overburden rock by using the following empirical formula: is the predicted height of the water-conducting fractured zone, m; M is the mining height of the coal seam, m; and the formula is applicable to the single layer mining thickness of 1-3 m and the cumulative mining thickness of not more than 15 m.
[0037] The analogy method is to predict the height of the water-conducting fractured zone of the working face to be mined by using the ratio of the measured value of the height of the water-conducting fractured zone after the coal seam is mined under similar geological conditions to the mining height of the coal seam, and the formula is as follows:
[0038] In the formula: is the ratio of the height of the water flowing fractured zone to the mining height of the coal seam 7.
[0039] In the embodiment, the coal seam roof sandstone, mudstone and limestone composite stratum belongs to medium-hard overburden rock, and the height of the water flowing fractured zone is calculated by using the empirical formula.
[0040] According to the measured value of the water flowing fractured zone of the working face under similar stratum conditions, the ratio K of the height of the water flowing fractured zone to the mining height is 18, and the height of the water flowing fractured zone is calculated as .
[0041] According to the calculation results of the empirical formula method and the analogy method, the maximum value is 54 m.
[0042] 2) Analyze the borehole column chart, and identify all hard rock layers (such as thick sandstone and limestone) above the coal seam roof with large thickness and high uniaxial compressive strength; For example, Figure 5 the depth of the coal seam roof is 155.44 m, the height of the water flowing fractured zone is 54 m, and therefore the depth of the top of the water flowing fractured zone is calculated as 101.44 m, and two layers of hard limestone aquifers with thicknesses of 29.28 m and 55.70 m are distributed above the water flowing fractured zone in sequence.
[0043] 3) The lower part of the first hard rock layer 3 above the water flowing fractured zone is taken as the separation water accumulation area 4.
[0044] For example, Figure 5 the lower part of the limestone aquifer with a thickness of 29.8 m is taken as the separation water accumulation area 4.
[0045] Step two: a bedding main hole 5 is constructed in the separation water accumulation area below the first aquifer.
[0046] For example, Figure 4 the main hole adopts a three-opening structure, the borehole diameter of the first opening well section 1 is 311 mm, and the drilling is performed to the complete bedrock, the first opening casing 11 adopts a Φ244.5 mm×8.94 mm type oil casing, the borehole diameter of the second opening well section 2 is 215.9 mm, and the directional drilling is performed to the lower part of the first hard rock layer 3, the second opening casing 12 adopts a Φ177.8 mm×8.05 mm type oil casing, and the casings all adopt cementing for stratum isolation, and the third opening drilling in the water accumulation separation area is a bare hole.
[0047] For example, Figure 2 the drainage hole group is arranged along the center of the working face.
[0048] Step S30: with the advancement of the working face, dynamic construction drainage branch holes are constructed at a certain drilling spacing.
[0049] The drainage branch hole 6 is constructed dynamically with the advancing of the working face, the drilling hole interval is 1 / 2 of the working face width, that is, 90m, and the construction is completed in advance at the rear of the working face 10, the dynamic distance is 1 times of the working face width, that is, 180m.
[0050] The drainage branch hole 6 enters the water flowing fractured zone 9, the drilling hole enters the water flowing fractured zone 9 according to the full leakage phenomenon of the drilling fluid, and the separated water is discharged to the goaf 8 through the drainage branch hole 6.
[0051] The technical solutions of the present application are fully described above, it should be noted that the specific embodiments of the present application are not limited by the above description, all technical solutions formed by the ordinary skilled in the art according to the spirit and essence of the present application in structure, method or function, etc., all fall within the protection scope of the present application.
Claims
1. A method for dynamically releasing aquifer water from the roof of a coal seam, characterized in that, Includes the following steps: S10. Determine the location of abscission water in the overburden; analyze the borehole columnar section to identify all thick, hard rock layers with high uniaxial compressive strength above the coal seam roof; designate the lower part of the first hard rock layer above the water-conducting fracture zone as the abscission water accumulation zone. S20. Construct the main borehole in the water-accumulated area below the first aquifer. The main borehole adopts a three-section structure. The first section is drilled to the intact bedrock. The second section is directionally drilled to the lower part of the first hard rock layer. The first and second sections are respectively isolated by casing cementing. The third section is drilled in the water-accumulated area and is a bare borehole. S30. As the working face advances, branch holes are dynamically constructed and laid out according to a certain drilling spacing.
2. The method for dynamic drainage of aquifer water in the coal seam roof according to claim 1, characterized in that, In step S10, the height of the water-conducting fracture zone is predicted using empirical formulas, analogies, or simulation methods.
3. The method for dynamically releasing water from the coal seam roof aquifer area according to claim 2, characterized in that, The height of the water-conducting fracture zone is predicted using the following empirical formula based on the hardness of the overlying strata: It is a prediction of the height of the water-conducting fracture zone, in meters; M represents the coal seam mining height, measured in meters. It is applicable to single-layer mining thicknesses of 1 to 3 meters, with a cumulative mining thickness not exceeding 15 meters.
4. The method for dynamically releasing water from the coal seam roof aquifer area according to claim 2, characterized in that, The analogy method is used to predict the height of the water-conducting fracture zone in the working face to be mined, and the formula is as follows: In the formula: It is a prediction of the height of the water-conducting fracture zone, in meters; M is the coal seam mining height, in meters (m). It is the ratio of the height of the water-conducting fracture zone to the coal seam mining height.
5. The method for dynamically releasing water from the coal seam roof aquifer area according to claim 1, characterized in that, In step S20, each hole group can cover 1 to 2 working surfaces; multiple hole groups can be constructed on the same long working surface.
6. The method for dynamically releasing water from the coal seam roof aquifer area according to claim 1, characterized in that, In step S30, the branch holes are dynamically constructed as the working face advances, with a drilling spacing of 1 / 2 working face width; the construction is completed ahead of the working face, with a dynamic distance of 1 working face width from the working face.
7. The method for dynamically releasing water from the coal seam roof aquifer area according to claim 6, characterized in that, The drainage branch hole enters the water-conducting fracture zone. Whether it enters the water-conducting fracture zone can be determined based on the amount of drilling fluid loss. The delamination water is discharged to the goaf through the drainage branch hole.