Coal seam roof hydraulic fracturing permeability enhancement and extraction method for coal roadway driving face

Abstract

The present application relates to a kind of coal roadway excavation working face coal seam roof hydraulic fracturing permeability enhancement extraction method, belong to coal mine underground hydraulic fracturing permeability enhancement technical field.The method present application is a kind of coal roadway excavation working face coal seam roof hydraulic fracturing permeability enhancement extraction method, according to coal seam thickness, coal seam firmness coefficient, roof firmness coefficient, coal roadway planned excavation month footage etc.Parameter, by the alternate arrangement drill site construction offset coal roadway a certain distance of roof directional long borehole and carry out hydraulic fracturing, press through roof and make fissure expand to coal seam, improve coal roadway area coal seam permeability, improve the extraction range of directional long borehole.The method can not only ensure that fracturing range can cover planned excavation coal roadway, but also can prevent directly fracturing damage roof after coal roadway above and affect excavation and support, avoid excavation and extraction alternately and extraction borehole is not damaged in the process of excavation, coal seam roof rock directional drilling horizon is easy to control, pore-forming property is good, need not worry about hole collapse problem.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of coal mine underground hydraulic fracturing permeability enhancement, and relates to a coal seam roof hydraulic fracturing permeability enhancement and extraction method for a coal roadway driving working face. BACKGROUND

[0002] With the improvement of coal mining technology and gas control technology in China, the development of coal resources in China is moving towards safe and efficient mining. Under the premise of safety, the coal production is increasing year by year, providing the most stable and reliable energy supply guarantee for various industries. However, with the increase of mining depth, the ground stress and gas pressure increase, and the permeability decreases, which brings great challenges to safe mining. Gas control is still one of the most important work in gas mines, and the quality of gas control directly affects the coal mining production. The gas control of coal roadway driving is a major problem. Since coal roadway driving is directly carried out in the coal seam, if the working face needs to be quickly arranged to ensure normal production connection of the mine and improve the economic benefit of the coal mine, the coal roadway driving speed must be improved. The gas drainage borehole of the coal roadway driving working face needs sufficient time for drainage or extraction, otherwise, gas overrun or coal and gas outburst accidents may occur during driving, causing personnel casualties. Therefore, there is a contradiction between driving speed and gas control.

[0003] At present, the method of constructing a bottom drainage roadway in the coal seam floor and using a through-hole drilling to extract gas during coal roadway driving can solve the contradiction between driving and gas control in time and space. However, this method has a huge amount of engineering, high cost, low utilization rate of gas drilling, and is not suitable for large-scale promotion. SUMMARY

[0004] Therefore, the purpose of the present application is to provide a coal seam roof hydraulic fracturing permeability enhancement and extraction method for a coal roadway driving working face, which solves the problem of contradiction between coal roadway driving speed and gas control in coal mines and the problem of large amount of engineering and high cost in current coal roadway driving gas control.

[0005] To achieve the above purpose, the present application provides the following technical scheme:

[0006] A coal seam roof hydraulic fracturing permeability enhancement and extraction method for a coal roadway driving working face, comprising the following steps:

[0007] Step 1, obtaining the coal seam thickness h, the coal seam firmness coefficient f1, the roof firmness coefficient f2, the planned coal roadway driving length D, and the length B required for the planned driving drilling field z , the monthly footage v of the planned coal roadway driving;

[0008] Step 2, designing a planned driving drilling field, n planned driving drilling fields are alternately arranged along the driving direction of the planned coal roadway driving, and the distance between the adjacent two planned driving drilling fields is S z , S z, n are respectively calculated as follows:

[0009]

[0010]

[0011] In the formula, v is the monthly footage of the planned coal roadway excavation, f2 is the roof solidity coefficient, D is the planned coal roadway excavation length, S z The calculation result is rounded to an integer after the first decimal place, and n is rounded to an integer;

[0012] Step 3, drilling a directional long borehole in the direction of the planned coal roadway excavation in the coal seam parallel to the direction of the planned coal roadway excavation, the horizontal section of the directional long borehole in the roof is H k from the coal seam, the horizontal projection is P k from the planned coal roadway excavation, and the distance of the final hole point from the next planned drilling site is C k , H k , P k , and C k are respectively calculated as follows:

[0013]

[0014]

[0015]

[0016] In the formula, h is the coal seam thickness, f1 is the coal seam solidity coefficient, f2 is the roof solidity coefficient, and v is the monthly footage of the planned coal roadway excavation, and the calculation result is rounded to an integer after the first decimal place.

[0017] Step 4, performing staged hydraulic fracturing of the directional long borehole in the roof of the drilled site in step 3, connecting the extraction pipeline after the fracturing is completed and the water is drained to perform extraction.

[0018] Cyclically performing steps 3-4 until the fracturing of the directional long borehole in the roof of the nth drilled site is completed and the water is drained to connect the extraction pipeline to perform extraction.

[0019] Optionally, the coal roadway excavation operation is combined with the directional long borehole construction, the staged hydraulic fracturing construction, and the directional long borehole drainage operation.

[0020] Optionally, after the drilled coal roadway exceeds the design position of the planned drilling site, the planned drilling site is excavated, and after the excavation is completed, the drilling site becomes a drilled site.

[0021] The beneficial effects of the present application are as follows:

[0022] The coal seam roof hydraulic fracturing permeability increasing and extraction method of the coal roadway tunneling working face of the application, through the alternate arrangement of the drill field construction directional long drill hole and the hydraulic fracturing, the coal seam permeability of the coal roadway region is improved, and the extraction range of the directional long drill hole is improved. The alternate arrangement method can ensure that the fracturing range covers the planned tunneling coal roadway, and can ensure that the two drill fields are ahead in space without hole jumping, and the arrangement method of deviating from the roadway by a certain distance can prevent the direct fracturing of the roof above the coal roadway from affecting the tunneling and supporting after the roof is damaged, and avoids the alternation of tunneling and extraction and ensures that the extraction drill hole is not damaged during the tunneling process.

[0023] Other advantages, objects, and features of the present application will be understood by those skilled in the art from the following specification in conjunction with the accompanying drawings. The present application's objects and other advantages will be realized and attained by means of the following specification. BRIEF DESCRIPTION OF DRAWINGS

[0024] In order to make the objects, technical solutions, and advantages of the present application clearer, the preferred detailed description of the present application will be combined with the drawings as follows, in which:

[0025] Fig. 1 The dynamic arrangement plane schematic diagram of the drill field and the roof directional long drill hole of the present application;

[0026] Fig. 2 The horizon profile schematic diagram of the roof directional long drill hole of the present application. DETAILED DESCRIPTION

[0027] The embodiments of the present application are described below through specific specific examples, and those skilled in the art can easily understand other advantages and effects of the present application from the disclosure of the specification. The present application can also be implemented or applied through other different specific embodiments, and the details in the specification can be modified or changed based on different views and applications without departing from the spirit of the present application. It should be noted that the diagrams provided in the following examples only illustrate the basic concept of the present application in a schematic manner, and the following examples and features in the examples can be combined with each other without conflict.

[0028] The drawings are only used for illustrative explanation, and the representation is only a schematic diagram, not a physical diagram, and cannot be understood as a limitation of the present application; in order to better illustrate the embodiments of the present application, some components in the drawings are omitted, enlarged, or reduced, and do not represent the size of the actual product; for those skilled in the art, it can be understood that some known structures and their descriptions in the drawings can be omitted.

[0029] The same or similar reference numerals in the drawings of the embodiments of the present application correspond to the same or similar components; in the description of the present application, it is understood that if the orientations or positional relationships indicated by the terms "upper", "lower", "left", "right", "front", "back", etc. are based on the orientations or positional relationships shown in the drawings, they are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, therefore the terms describing the positional relationships in the drawings are only used for exemplary illustration and cannot be understood as a limitation on the present application, for those skilled in the art, the specific meanings of the above terms can be understood according to the specific circumstances.

[0030] Please refer to Figs. 1-2 , assuming that the thickness of the coal seam h=2m, the coal seam solidity coefficient f1=1, the roof solidity coefficient f2=3, the planned excavation coal roadway length D=1500m, the length B z =9m required for the planned excavation drill field, and the monthly footage v=60m of the planned excavation coal roadway.

[0031] The n planned excavation drill fields are alternately arranged on both sides of the planned excavation coal roadway in the excavation direction, the distance between two adjacent planned excavation drill fields is S z , each planned excavation drill field is named as 1#, 2#, 3#, 4#...n# along the excavation direction of the coal roadway, and S z , n are calculated according to the following formulas respectively:

[0032]

[0033]

[0034] In the formula, v is the monthly footage of the planned excavation coal roadway, f2 is the roof solidity coefficient, D is the planned excavation coal roadway length, S z The calculation result is kept to one decimal place, and n is rounded to an integer, and through the calculation, S z =360.0m, n=4.

[0035] After starting excavation, when the coal roadway exceeds the design position of the 1# planned excavation drill field, the 1# planned excavation drill field is started to be excavated, and after the excavation is completed, the drill field becomes the 1# excavated drill field.

[0036] The roof directional long drill hole is constructed in the 1# excavated drill field parallel to the coal seam and the planned excavation coal roadway in the excavation direction, the distance between the horizontal section of the roof directional long drill hole and the coal seam is H k , the distance between the horizontal projection and the planned excavation coal roadway is P k , and the distance between the terminal hole point and the 2# planned excavation drill field is C k , H k , P k, C k The calculation is made according to the following formula respectively:

[0037]

[0038]

[0039]

[0040] In the formula, h is the thickness of the coal seam, f1 is the firmness coefficient of the coal seam, f2 is the firmness coefficient of the roof, and v is the planned daily advance of the coal roadway. The calculation result is rounded to one decimal place. After calculation, H k = 6.0 m, P k = 12.0 m, and C k = 30.0 m.

[0041] After the roof directional long hole construction is completed, the roof directional long hole in the 1# drilled field is subjected to staged hydraulic fracturing, and after the fracturing is completed and the water is drained, the extraction pipeline is connected to perform extraction.

[0042] When the roof directional long hole construction, staged hydraulic fracturing construction, and roof directional long hole drainage are performed in the above 1# drilled field, the coal roadway excavation is still in parallel operation. When the coal roadway exceeds the design position of the 2# planned excavation field, the roof directional long hole is constructed in the 2# drilled field in the direction parallel to the coal seam and the planned excavation coal roadway. The distance between the horizontal section of the roof directional long hole and the coal seam is still H k = 6.0 m, the distance between the horizontal projection and the planned excavation coal roadway is still P k = 12.0 m, and the distance from the final hole point to the 3# planned excavation field is still C k = 30.0 m.

[0043] After the roof directional long hole construction in the 2# drilled field is completed, the roof directional long hole in the 2# drilled field is subjected to staged hydraulic fracturing, and after the fracturing is completed and the water is drained, the extraction pipeline is connected to perform extraction.

[0044] By analogy, until the roof directional long hole fracturing in the nth drilled field is completed and the water is drained, the extraction pipeline is connected to perform extraction, and the coal seam roof hydraulic fracturing and permeability enhancement extraction of the entire coal roadway excavation working face are completed.

[0045] Finally, it should be pointed out that the above examples are only used to illustrate the technical solutions of the present application and are not limiting. Although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or replaced equivalently without departing from the purpose and scope of the technical solutions, and they should be covered in the scope of the claims of the present application.

Claims

1. A coal seam roof hydraulic fracturing permeability enhancement and extraction method for a coal roadway driving face, characterized in that, Comprising the following steps: Step 1, obtain the seam thickness h of the coal roadway to be excavated, the seam firmness coefficient f1, the roof firmness coefficient f2, the planned excavating coal roadway length D, the length B required for the planned excavating drill field z , the monthly footage v of the planned excavating coal roadway Step 2, design a planned excavation drill field, n planned excavation drill fields are alternately arranged along the excavation direction of the planned excavation coal roadway, the spacing between two adjacent planned excavation drill fields is S z , S z , and n are respectively calculated according to the following formula: In the formula, v is the monthly footage of the coal roadway planned to be excavated, f2 is the roof firmness coefficient, D is the planned excavation length of the coal roadway, S z The calculation result is retained to one decimal place, and n is rounded to an integer. Step 3, drilling the directional long borehole in the direction parallel to the coal seam and the roof of the planned coal roadway in the direction of excavation in the excavated drilling field, the horizontal section of the directional long borehole and the coal seam is H k , the horizontal projection and the planned coal roadway is P k , the distance of the final hole point beyond the next planned drilling field is C k , H k , P k , C k are respectively calculated according to the following formula: In the formula, h is the thickness of the coal seam, f1 is the coal seam firmness coefficient, f2 is the roof firmness coefficient, v is the planned monthly footage of the coal roadway driving, and the calculation result is rounded to one decimal place; Step 4, the roof directional long borehole in the drilled field in step 3 is subjected to staged hydraulic fracturing, after fracturing and drainage, the extraction pipeline is connected to perform extraction; Cyclic steps 3-4 until the roof directional long borehole in the nth drilled field is fractured and drained, and the extraction pipeline is connected to perform extraction.

2. The coal seam roof hydraulic fracturing permeability enhancement and drainage method for a coal roadway drivage face according to claim 1, characterized in that: The coal roadway driving operation, the roof directional long borehole construction, the staged hydraulic fracturing construction, and the roof directional long borehole drainage operation.

3. The coal seam roof hydraulic fracturing permeability enhancement and drainage method for coal roadway drivage working face of claim 1, characterized in that: After the coal roadway driving exceeds the planned driving field design position, the planned driving field is driven, and after the driving is completed, the field becomes a drilled field.

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