CN115929304B - Method for preventing impact of artificial relief layer of stope face - Google Patents

Abstract

The invention discloses a method for preventing artificial liberation layer from scouring in a mining working face, which includes: determining the target rock layer where the artificial liberation layer is located above the stratum area with hidden risk of rock pressure; conducting numerical simulation and mining of the artificial liberation layer and its equivalent coal seam; Theoretical analysis is performed to obtain the stress σ _lib of the liberated layer under equivalent coal seam mining, and the stress σ _art of the liberated layer under artificial liberation layer mining; the equivalent stress liberation coefficient ξ is defined based on the ratio of σ _lib and σ _art , Based on the classification and determination of the thickness and coverage of the artificial liberation layer in the target rock formation; based on the classification and determination of the thickness and coverage of the artificial liberation layer, an artificial liberation layer evaluation model is established, and based on this model, ground fracturing wells are arranged and drilled. , cracking operation; make the width coverage of the artificial liberation layer corresponding to 30-50m more coverage on each side of the covered working face, and then carry out mining operations on the working face. The invention greatly reduces the probability of occurrence of rockburst disasters during mining of the working face.

Description

An anti-collision method for artificial liberation layer in mining working face

Technical field

The invention relates to the technical field of safe mining of coal mines, and in particular to a method for preventing erosion of an artificial liberation layer on a mining working face.

Background technique

The structure of the roof rock layer, especially the hard and thick sandstone roof above the coal seam, is one of the main factors affecting the occurrence of rockburst. The main reason is that the hard and thick sandstone roof easily accumulates a large amount of elastic energy. During the breaking or sliding process of the hard roof, a large amount of elastic energy is suddenly released, resulting in the emergence of rockbursts or mine earthquakes.

Mining of the liberated layer is a generally recognized method to prevent ground pressure. Mining of the liberated layer causes the rock layers of the roof and floor of the goaf to fall and shift, breaking the balance of the original geostress and causing the redistribution of geostress around the stope. The formation of a certain range of pressure relief zones in roof and floor slates and coal bodies has stresses lower than the original stress and liberation zones, reducing the risk of impact on the working face. It is the most effective regional preventive measure to fundamentally prevent ground pressure impact. The principle of liberation seam mining is to give priority to coal seams with low impact risk.

However, not every rockburst mine has the conditions to mine the liberation layer. The applicable conditions and selection principles for liberation layer mining, liberation layer mining design, protection scope and protection effect, pressure relief period and other conditions need to be met. In mines with dynamic disasters such as rock bursts, coal and gas outbursts, there are no predicaments that can be used as conditions for liberation layer mining, and it is difficult to implement regional preventive measures. The degree of disaster in the subsequent mining process is serious, which has a very negative impact on production safety. To this end, based on the idea of anti-collision at the source of the liberation layer, when the mining conditions of the liberation layer are not met and the application effect of traditional anti-collision methods is not obvious, this application proposes a construction method of artificial liberation layer to achieve the same impact prevention effect as the mining of the liberation layer. .

Contents of the invention

The present invention aims to solve one of the technical problems in the related art, at least to a certain extent.

In order to achieve the above objectives, the present invention proposes a method for preventing anti-collision of artificial liberation layers in mining working faces, which includes the following steps:

S1. Determine the target rock layer where the artificial liberation layer is located above the area where there is a potential risk of rock pressure, and measure the thickness of the target rock layer to obtain the thickness h of the target rock layer;

S2. Carry out numerical simulation and theoretical analysis of the mining of the artificial liberated layer and its equivalent coal seam to obtain the stress σ _lib of the liberated layer under the mining of the equivalent coal seam, and the stress σ _art of the liberated layer under the mining of the artificial liberated layer;

S3. Define the equivalent stress liberation coefficient ξ based on the ratio of σ _lib and σ _art , establish the artificial liberation layer evaluation criteria based on the equivalent stress liberation coefficient, and divide the thickness and coverage of the artificial liberation layer in the target rock layer based on this evaluation criterion. determination;

S4. Establish an artificial liberation layer evaluation model based on the determination of the thickness and coverage of the artificial liberation layer, and use this model to arrange surface fracturing wells, and perform drilling and fracturing operations to crack and relieve pressure in the target rock to form an artificial liberation layer. ;

S5. Complete the artificial liberation layer operation covering the working face, so that the width coverage of the artificial liberation layer corresponds to 30-50m more coverage on each side of the working face. Improve the stress environment during the mining operation of the working face before proceeding. Working face mining operations.

This invention destroys the integrity of the overlying roof in the impact risk area in advance, allowing the load to migrate to a more complete roof area, thereby providing a low-stress operating environment for underground excavation and mining, and also depriving the important load conditions for starting the impact rock pressure, and thus It can achieve the same effect as that of liberation layer mining, reduce or avoid rock pressure disasters during well construction, and significantly reduce the probability of rock pressure disasters during working face mining.

Optionally, in S1, based on the geological data of the location of the mine, the target rock layer where the artificial liberation layer is located is determined by using the main key layer analysis method of coal seam mining and energy transfer response analysis and/or the main key layer analysis method of microseismic monitoring.

Further, in S2, it specifically includes:

S21. Apply simulation calculation software or discrete unit method program to simulate, conduct numerical simulation and theoretical analysis of the structural form of the target rock layer and the stress state of the liberated layer, so that the target rock layer is in the caving zone and fissure zone of equivalent coal seam mining. , and be fully destroyed or the energy release of the target rock formation is effectively reduced;

S22. Analyze the stress changes, crack development and surrounding rock structural characteristics of the liberated layer after equivalent coal seam mining, and obtain the stress σ _lib of the liberated layer under equivalent coal seam mining;

S23. Analyze the stress changes and crack development of the liberated layer when the artificial liberation layer causes the target rock layer to be in the caving zone and fissure zone equivalent to coal seam mining and is fully damaged or when the energy release of the target rock layer is effectively reduced. and the structural characteristics of the surrounding rock, and obtain the stress σ _art of the liberated layer under the mining of the artificial liberated layer.

Further, in S3, the criterion for judging the artificial liberation layer is according to the definition of ξ as Its size determines whether the current artificial liberation layer simulated mining plan is suitable for dividing into artificial liberation layers into four categories, including:

Category I: When ξ<0.25, the equivalent stress coefficient ξ is at an inappropriate level;

Class II, when 0.25≤ξ<0.5, the equivalent stress coefficient ξ is at the general level;

Class III, when 0.5≤ξ<0.75, the equivalent stress coefficient ξ is at the appropriate level;

Category IV, when ξ ≥ 0.75, the equivalent stress coefficient ξ is at a good level.

Further, in S3, the steps for dividing and determining the thickness of the artificial liberation layer are:

S31. Use simulation calculation software or discrete unit method program to conduct numerical simulation of equivalent coal seam mining, simulate the mining process of different coal seam thicknesses, and obtain equivalent coal seam mining. When the liberated layer reaches the mining requirements, it will be liberated. The stress of the layer σ _lib ;

S32. Use simulation calculation software or discrete unit method program to conduct numerical simulation to simulate the mining process of different thicknesses of the artificial liberation layer, so that the target rock layer is in the caving zone and fissure zone of equivalent coal seam mining, and the target rock layer is fully destroyed. As the basis for discrimination, simulate the mining process of the artificial liberation layer when mining the same coal seam thickness as the equivalent coal seam. When the mining effect based on the discrimination is achieved, the stress σ _art of the liberated layer under human mining of the liberation layer at this time is obtained;

S33. Based on the size of ξ, determine the mining thickness of the artificial liberation layer when ξ is in Category III and above. This thickness is the equivalent thickness and represents the liberation effect when the thickness of the artificial liberation layer reaches the appropriate liberation layer thickness determined above. .

Further, the projection of the artificial liberation layer coverage range at the level where the working face is located continuously covers all working faces between the transportation lane and the return air lane;

The coverage of the artificial liberation layer is set along the direction of the projected width of the working surface from the transport lane to the return air lane. The projected width of the coverage of the artificial liberation layer on the working surface is greater than the distance between the transport lane and the return air lane;

The coverage of the artificial liberation layer is set along the length direction of the working surface, and the projection length of the coverage of the artificial liberation layer on the working surface is greater than the length of the working surface.

Further, in S4, an artificial liberation layer evaluation model is established to analyze, calculate and record the equivalent stress σ _eq , equivalent height _Heq and equivalent thickness _heq of the artificial liberation layer under current geological and terrain conditions to characterize the artificial liberation layer. The feasibility of the liberation layer and provide design criteria for the determination of the artificial liberation layer in step S4.

Furthermore, the equivalent stress σ _eq , equivalent height _Heq and equivalent thickness heq required to establish the artificial liberation _layer evaluation model are as follows:

The equivalent stress is Among them, ξ≥0.5; the equivalent height is _Heq =H+ _hd , where H is the distance between the target layer and the coal seam, _hd is the distance between the fracturing well position and the bottom of the target layer; the equivalent thickness is _heq = 2h _d ≤ h, h ≤ 30m, where h _d is the distance between the fracturing well position and the bottom of the target layer.

Further, in S4, fracturing well layout planning is carried out based on the artificial liberation layer coverage and rock formation thickness determined in S3, including the number and location of fracturing wells, where fracturing wells include horizontal wells and vertical wells. well;

The horizontal well includes a vertically arranged through-layer section, a horizontally arranged fracturing section in the target rock formation, and a steering section connecting the through-layer section and the fracturing section. The said through-layer section, fracturing section and steering section are in the same plane, Used to carry out large-scale fracturing operations on target rock formations;

The vertical well is installed on the side of the horizontal well penetration section away from the fracturing section to carry out fracturing operations in the blind fracturing zone where horizontal wells cannot be fracturing.

Furthermore, when the number of horizontal wells set up for the same target rock formation is 2 or more, two adjacent horizontal wells form a group and share a construction site, and the fracturing sections of the two horizontal wells extend in opposite directions and are in In the same plane, a vertical well is set between the two horizontal wells.

Further, in S4, in order to obtain the artificial liberation layer with composite requirements, the fracturing well layout needs to be comprehensively determined based on the formation lithology, fractability and height, and on this basis, combined with the artificial liberation layer effect requirements, The rock structure state and stress state of the liberated layer are used to determine the fracturing operation position of the fracturing well through numerical simulation.

Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.

Description of drawings

The above and/or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

Figure 1 is a schematic diagram of an overall method for preventing erosion of an artificial liberation layer on a mining working face according to the present invention;

Figure 2 is a schematic diagram of the specific steps S2 of a method for preventing erosion of artificial liberation layers on mining working faces according to the present invention;

Figure 3 is a schematic diagram of the specific steps of S3 of a method for preventing anti-collision of artificial liberation layers on mining working faces according to the present invention;

Figure 4 is a schematic diagram of the layout of the surface fracturing wells after the artificial liberation layer is determined according to a method for preventing scour of the artificial liberation layer on the mining working face according to the present invention;

Figure 5 is a schematic diagram of the cracking effect of the artificial liberation layer according to a method for preventing erosion of the artificial liberation layer on a mining working face according to the present invention;

Figure 6 is a schematic diagram of the effect after the artificial liberation layer is cracked according to a method for preventing erosion of the artificial liberation layer on a mining working face according to the present invention;

Figure 7(a) and Figure 7(b) are schematic diagrams of the arrangement of the tunnel protection artificial liberation layer according to a method for preventing erosion of the artificial liberation layer in a mining working face according to the present invention;

Figure 8(a) and Figure 8(b) are schematic diagrams of the arrangement of the artificial liberation layer for working face protection according to a method for anti-collision of an artificial liberation layer on a mining working surface according to the present invention;

Figure 9 is a schematic diagram of a construction method of a multi-working face artificial liberation layer according to a mining working face artificial liberation layer anti-collision method of the present invention;

Figure 10 is a schematic diagram of another construction method of the artificial liberation layer of multiple working faces according to the anti-collision method of the artificial liberation layer of the mining working face of the present invention;

Figure 11 is a schematic diagram of the construction of an artificial liberation layer on a mining working surface according to a method for preventing erosion of an artificial liberation layer on a mining working surface according to the present invention.

Detailed ways

The embodiments of the present invention are described in detail below. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. The embodiments described below with reference to the drawings are exemplary and are intended to explain the present invention and are not to be construed as limiting the present invention.

This application provides a method for preventing anti-collision of an artificial liberation layer on a mining working face, which will be described in detail below with reference to Figures 1 to 11.

An artificial liberation layer anti-collision method on a mining working face includes the following steps:

S1. Determine the target rock layer where the artificial liberation layer is located above the area where there is a potential risk of rock pressure, and measure the thickness of the target rock layer to obtain the thickness h of the target rock layer;

S2. Carry out numerical simulation and theoretical analysis of the mining of the artificial liberated layer and its equivalent coal seam to obtain the stress σ _lib of the liberated layer under the mining of the equivalent coal seam, and the stress σ _art of the liberated layer under the mining of the artificial liberated layer;

S3. Define the equivalent stress liberation coefficient ξ based on the ratio of σ _lib and σ _art , establish the artificial liberation layer evaluation criteria based on the equivalent stress liberation coefficient, and divide the thickness and coverage of the artificial liberation layer in the target rock layer based on this evaluation criterion. determination;

S4. Establish an artificial liberation layer evaluation model based on the determination of the thickness and coverage of the artificial liberation layer, and use this model to arrange surface fracturing wells, and perform drilling and fracturing operations to crack and relieve pressure in the target rock to form an artificial liberation layer. ;

S5. Complete the artificial liberation layer operation covering the working face, so that the width coverage of the artificial liberation layer corresponds to 30-50m more coverage on each side of the working face. Improve the stress environment during the mining operation of the working face before proceeding. Working face mining operations.

This invention destroys the integrity of the overlying roof in the impact risk area in advance, allowing the load to migrate to a more complete roof area, thereby providing a low-stress operating environment for underground excavation and mining, and also depriving the important load conditions for starting the impact rock pressure, and thus It achieves the same effect as liberation layer mining and greatly reduces the probability of rock burst disasters during working face mining.

Among them, in S1, the target rock formation where the artificial liberation layer is located is generally based on the geological data of the location of the mine and the actual mine operating environment. The physical and mechanical properties of the rock formation above the dangerous area of rock pressure are analyzed, and the main control key layers and The main control key rock layer analysis method of energy transfer response analysis and/or microseismic monitoring analyzes the rock layers above the dangerous area of the impact of ground pressure, and combines the key layer theory to determine the target rock layer where the artificial liberation layer is located.

When using the main control key layer and energy transfer response analysis, we first use the key layer theory to determine multiple key rock layers above the formation area with potential risk of rock pressure. Due to the impact of multiple key rock layers at different levels on the working face, Different pressure levels have different effects. Calculate the bending energy of multiple key rock layers, calculate the remaining energy from the bottom to the coal seam at the working face, and determine the energy transfer based on the energy release of each key rock layer. According to the multiple key rock layers, the energy is transferred to the working face. The remaining energy, energy transfer and bending energy of the coal seam determine the target rock formation where the artificial liberation layer is theoretically located.

If the main key rock layer analysis method of microseismic monitoring is adopted, microseismic events of different energy levels in the rock layer used to characterize surrounding rock activities are first obtained; secondly, microseismic events of different energy levels are analyzed to characterize whether surrounding rock activities mainly occur. In the roof rock layer; if so, analyze the distribution of large-energy events in the roof rock layer, and determine that the layer where large-energy events occur concentratedly is the target rock layer where the theoretical artificial liberation layer is located.

In some embodiments, a single analysis method or multiple analysis methods are selected according to the actual situation to determine the target rock layer where the artificial liberation layer is located. The selection of multiple analysis methods can further support each other, so that the target rock layer where the artificial liberation layer is located can be determined. Rock formation determination is more accurate and reliable.

After completing the determination of the rock layer where the artificial liberation layer is located, you need to enter step S2. In S2, in order to determine the equivalent stress of the artificial liberation layer, the following steps are specifically included:

S21. Apply simulation calculation software or discrete unit method program to simulate, conduct numerical simulation and theoretical analysis of the structural form of the target rock layer and the stress state of the liberated layer, so that the target rock layer is in the caving zone and fissure zone of equivalent coal seam mining. , and be fully destroyed or the energy release of the target rock formation is effectively reduced;

S22. Analyze the stress changes, crack development and surrounding rock structural characteristics of the liberated layer after equivalent coal seam mining, and obtain the stress σ _lib of the liberated layer under equivalent coal seam mining;

S23. Analyze the stress changes and crack development of the liberated layer when the artificial liberation layer causes the target rock layer to be in the caving zone and fissure zone equivalent to coal seam mining and is fully damaged or when the energy release of the target rock layer is effectively reduced. and the structural characteristics of the surrounding rock, and obtain the stress σ _art of the liberated layer under the mining of the artificial liberated layer.

Further, after completing the calculations of σ _lib and σ _art , enter step S3, and determine the liberated layer stress σ _{art caused by the artificial liberated layer through the ratio of the two, that is, the equivalent stress liberation coefficient ξ, to converge to the liberated layer stress σ art} caused by the equivalent coal seam mining. Liberated layer stress σ _lib , that is The closer the ratio of the two is to 1, the more the effect of the artificial liberation layer is similar to the equivalent coal seam mining effect. Therefore, it is necessary to divide the equivalent stress liberation coefficient ξ so that the liberation stress effect in the artificial liberation layer reaches the level of the unsealing layer. The stress effect of mining, thereby ensuring the feasibility of artificial liberation layers. In S3, the criterion for judging the artificial liberation layer is based on the definition of ξ as/> Its size determines whether the current artificial liberation layer simulated mining plan is suitable for dividing into artificial liberation layers into four categories, including:

Category I: When ξ<0.25, the equivalent stress coefficient ξ is at an inappropriate level;

Class II, when 0.25≤ξ<0.5, the equivalent stress coefficient ξ is at the general level;

Class III, when 0.5≤ξ<0.75, the equivalent stress coefficient ξ is at the appropriate level;

Category IV, when ξ ≥ 0.75, the equivalent stress coefficient ξ is at a good level.

According to the classification of equivalent stress coefficients, the rock layer where the artificial liberation layer is located can be analyzed to simulate the rock layer thickness of the artificial liberation layer, thereby providing data basis for the subsequent establishment of the artificial liberation layer evaluation model. The steps to classify and determine the thickness of the artificial liberation layer are:

S31. Apply simulation calculation software or discrete unit method program to conduct numerical simulation of equivalent coal seam mining, simulate the mining process of different coal seam thicknesses, and obtain equivalent coal seam mining. When the liberated layer reaches the mining requirements, it will be liberated. The stress of the layer σ _lib ;

S32. Use simulation calculation software or discrete unit method program to conduct numerical simulation to simulate the mining process of different thicknesses of the artificial liberation layer, so that the target rock layer is in the caving zone and fissure zone of equivalent coal seam mining, and the target rock layer is fully destroyed. As the basis for discrimination, simulate the mining process of the artificial liberation layer when mining the same coal seam thickness as the equivalent coal seam. When the mining effect based on the discrimination is achieved, the stress σ _art of the liberated layer under human mining of the liberation layer at this time is obtained;

S33. Based on the size of ξ, determine the mining thickness of the artificial liberation layer when ξ is in Category III and above. This thickness is the equivalent thickness and represents the liberation effect when the thickness of the artificial liberation layer reaches the appropriate liberation layer thickness determined above. .

After determining the thickness of the artificial liberation layer through step S3, it is also necessary to plan the area covered by the artificial liberation layer. The projection of the coverage of the artificial liberation layer at the level where the working surface is located continuously covers the area between the transportation lane and the return air lane. All work surfaces;

The coverage of the artificial liberation layer is set along the direction of the projected width of the working surface from the transport lane to the return air lane. The projected width of the coverage of the artificial liberation layer on the working surface is greater than the distance between the transport lane and the return air lane;

The coverage of the artificial liberation layer is set along the length direction of the working surface, and the projection length of the coverage of the artificial liberation layer on the working surface is greater than the length of the working surface;

When the artificial liberation layer covers a single or multiple tunnels, the width coverage of the artificial liberation layer must span the rock formation range corresponding to the single or multiple tunnels, and the width coverage of the artificial liberation layer must be 30 more than the boundary on each side of the covered tunnel. -50m coverage, preferably 50m in this embodiment;

When the artificial liberation layer covers a single or multiple working faces, the width coverage of the artificial liberation layer must span the range of rock formations corresponding to the single or multiple working faces, and the width coverage of the artificial liberation layer must cover the boundaries of each side of the working face. The coverage range is 30-50m longer, and in this embodiment, the coverage range is preferably 50m.

After completing the determination of the regional coverage of the artificial liberation layer and the depth of the rock layer, enter step S4. In S4, an artificial liberation layer evaluation model is established to analyze, calculate and record the equivalent stress σ eq of the artificial liberation layer under the current geological and terrain conditions _. , equivalent height _Heq and equivalent thickness _heq are used to characterize the feasibility of the artificial liberation layer and provide design criteria for the determination of the artificial liberation layer in step S4. In order to re-verify the feasibility of the artificial liberation layer, establish an artificial liberation layer evaluation model, verify and evaluate each data of the artificial liberation layer obtained above, characterize the feasibility of the artificial liberation layer, and provide guidance for the determination of the artificial liberation layer Provide design guidelines. Among them, the equivalent stress σ _eq , equivalent height _Heq and equivalent thickness heq required by the artificial liberation _layer flat plate model are as follows:

The equivalent stress is Among them, ξ≥0.5; the equivalent height is _Heq =H+ _hd , where H is the distance between the target layer and the coal seam, _hd is the distance between the fracturing well position and the bottom of the target layer; the equivalent thickness is _heq = 2h _d ≤ h, h ≤ 30m, where h _d is the distance between the fracturing well position and the bottom of the target layer.

After the establishment of the artificial liberation layer evaluation model is completed, not only the various data of the artificial liberation layer are calculated and inspected, but also the artificial liberation can be given based on the calculation results of equivalent stress σ _eq , equivalent height _Heq and equivalent thickness he _eq The design criteria for layer fracturing construction can be used to design subsequent artificial liberation layers in accordance with the design criteria given by the artificial liberation layer evaluation model during the subsequent construction process.

Specifically, when determining the protection coverage of the artificial liberation layer, the classification according to the construction site includes the artificial liberation layer for tunnel protection and the artificial liberation layer for working face protection;

Among them, referring to Figure 11, the artificial liberation layer for tunnel protection is mainly aimed at dangerous tunnels where mine impact ground pressure appears, and tunnels with greater impact risk are selected for protection. Based on this, the scope of the artificial liberation layer is smaller, making the artificial liberation layer It is enough for the layer to effectively cover the tunnel. After completing the arrangement of the artificial liberation layer, the tunnel will be in a low-stress area;

The artificial liberation layer for working face protection is mainly aimed at high-risk working faces. The impact risk does not have obvious regional characteristics. The overall impact risk of the working face is high, and there is a risk of mining earthquakes or the emergence of rock pressure. Therefore, it is necessary to effectively protect the entire range of the working surface. Therefore, the artificial liberation layer has a larger range and has more implementation plans. Refer to Figure 9 to Figure 10. For example: the artificial liberation layer for working surface protection can be constructed horizontally across multiple working surfaces. The artificial liberation layer can be constructed in this way to achieve a large-scale anti-scour effect in the mining area and solve the larger-scale source control of rock pressure in the mining area; artificial liberation can also be carried out in key areas by gradually covering the coverage of a single working face. layer construction, thereby gradually solving the source control of impact ground pressure at various working face scales;

However, no matter which implementation scheme is implemented, it is necessary to effectively cover the entire working surface. In some embodiments, the range of the artificial liberation layer can be liberated in zones according to the risk of impact, so that after the artificial liberation layer is arranged, the working surface is in a low-stress area, surrounded by Rock activity releases low-energy zones.

After determining the area covered by the artificial liberation layer and the depth of the rock formation, and after passing the feasibility check of the artificial liberation layer evaluation model, the layout of surface fracturing wells and subsequent fracturing operations can begin. Thus, cracking and pressure relief operations are carried out on the artificial liberation layer. After the cracking operation on the artificial liberation layer is completed, the stress in the coal seam that needs to be developed, tunneled or mined will change, and the high-pressure area will become a low-pressure area, and excavation can be carried out safely. Well establishment operations, excavation and collection operations, and mining face construction operations.

Therefore, in S4, the fracturing well layout planning is carried out based on the artificial liberation layer coverage and rock layer thickness determined in S3, including the number and location of fracturing wells, where fracturing wells include horizontal wells and vertical wells. straight well;

The horizontal well includes a vertically arranged through-layer section, a horizontally set fracturing section in the target rock formation, and a steering section connecting the through-layer section and the fracturing section. The through-layer section, fracturing section, and steering section are in the same plane, for Conduct large-scale fracturing operations on target rock formations;

The vertical well is installed on the side of the horizontal well penetration section away from the fracturing section to carry out fracturing operations in the blind fracturing zone where horizontal wells cannot be fracturing.

And when the number of horizontal wells set up for the same target rock formation is 2 or more, two adjacent horizontal wells form a group and share a construction site, and the fracturing sections of the two horizontal wells extend in opposite directions and are on the same plane. inside, and a vertical well is set between the two horizontal wells.

Specifically, the type and number of fracturing wells to be used are determined based on the occurrence status of the target rock formation, including:

Determine the number of horizontal wells according to A=[target rock layer length/1500]+a, where, when the remainder of the target rock layer length/1500 is greater than 500m, a takes 1; when the remainder of the target rock layer length/1500 is not greater than 500m, a takes 0, A is the number of horizontal wells;

Determine the number of staged fracturing of horizontal wells in the vertical direction according to B = [target rock layer thickness/100], where the remainder of target rock layer thickness/100 is 0, and B is the quotient of target rock layer thickness/100; when the target rock layer thickness/100 The remainder of 100 is not 0, B takes the integer quotient of target rock layer thickness/100 + 1;

Determine the number of vertical wells according to C=[(target rock layer length-1500·A)/500]+[A/2]+b, where in the formula: target rock layer length-1500·A only takes the value as a positive number The calculation result is that when (target rock formation length-1500·A)/500 is a positive fraction, b takes 1; when (target rock formation length-1500·A)/500 is a non-positive fraction, b takes 0.

Determining the location relationship of fracturing wellheads based on the number of fracturing wells includes:

When the number of horizontal wells A is equal to 0, the number of vertical wells C is equal to 1, and the wellhead of the vertical well is located on the ground corresponding to the center of the target rock formation;

When the number A of horizontal wells is equal to 1, if the number C of vertical wells is 0, the wellhead position of the horizontal well is on the ground corresponding to the boundary of the target rock layer; if the number C of vertical wells is 1, the position of the wellhead of the horizontal well is 1. The wellheads of the vertical well and the horizontal well are located on the ground corresponding to the target rock formation, and both share a ground construction site;

When the number A of horizontal wells is greater than or equal to 2, every two horizontal wells need to share a ground construction site, and a vertical well needs to be arranged between the two horizontal wells. The vertical well also shares a ground construction site with the two horizontal wells, and the remaining 1 vertical well or horizontal well and a separate construction site on the ground.

After completing the well layout, the construction personnel can carry out fracturing operations according to the fracturing positions obtained by numerical simulation. After completing the fracturing operations, the thick-layered roofs that are difficult to collapse and prone to high energy release can be modified to be easier to collapse, and after modification The thick roof has changed from a "high energy" disaster-causing rock layer to a "low energy zone". The thick roof has changed from long and large to short and small fracture characteristics. The mining stress environment under the thick roof has been reduced from "high stress" to "low energy zone". The "low pressure zone" realizes the liberation layer effect of the artificial liberation layer.

After completing the setting of the artificial liberation layer, that is, an artificial liberation layer is formed on the hard-to-collapse thick roof above the working surface, thereby improving the stress environment of the working surface, and step S5 can be carried out to work under low stress conditions. mining operations on the working surface, thereby significantly reducing or avoiding the probability of occurrence of rockburst disasters during mining on the working surface.

In the description of this specification, reference to the terms "one embodiment," "some embodiments," "an example," "specific examples," or "some examples" or the like means that specific features are described in connection with the embodiment or example. , structures, materials or features are included in at least one embodiment or example of the invention. In this specification, the schematic expressions of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the specific features, structures, materials or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, those skilled in the art may combine and combine different embodiments or examples and features of different embodiments or examples described in this specification unless they are inconsistent with each other.

In addition, the terms “first” and “second” are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of indicated technical features. Therefore, features defined as "first" and "second" may explicitly or implicitly include at least one of these features. In the description of the present invention, "plurality" means at least two, such as two, three, etc., unless otherwise expressly and specifically limited.

Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art will appreciate that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and purposes of the invention. The scope of the invention is defined by the claims and their equivalents.

Claims (11)

1. A method for preventing anti-collision of the artificial liberation layer in the mining working face, which is characterized in that it includes the following steps: S1. Determine the target rock layer where the artificial liberation layer is located above the area where there is a potential risk of rock pressure, and measure the thickness of the target rock layer to obtain the thickness h of the target rock layer; S2. Carry out numerical simulation and theoretical analysis of the mining of the artificial liberated layer and its equivalent coal seam to obtain the stress σ _lib of the liberated layer under the mining of the equivalent coal seam, and the stress σ _art of the liberated layer under the mining of the artificial liberated layer; S3. Define the equivalent stress liberation coefficient ξ based on the ratio of σ _lib and σ _art , establish the artificial liberation layer evaluation criteria based on the equivalent stress liberation coefficient, and divide the thickness and coverage of the artificial liberation layer in the target rock layer based on this evaluation criterion. determination; S4. Establish an artificial liberation layer evaluation model based on the determination of the thickness and coverage of the artificial liberation layer, and use this model to arrange surface fracturing wells, and perform drilling and fracturing operations to crack and relieve pressure in the target rock to form an artificial liberation layer. ; S5. Complete the artificial liberation layer operation covering the working face, so that the width coverage of the artificial liberation layer corresponds to 30-50m more coverage on each side of the working face. Improve the stress environment during the mining operation of the working face before proceeding. Working face mining operations. 2. A method for preventing erosion of artificial liberation layers in mining working faces as claimed in claim 1, characterized in that in S1, based on the geological data of the location of the mine, the main control key layer and energy transfer response of coal seam mining are adopted. The main key layer analysis method of analysis and/or microseismic monitoring determines the target rock layer where the artificial liberation layer is located. 3. An anti-collision method for artificial liberation layers in mining working faces as claimed in claim 1, characterized in that, in S2, it specifically includes: S21. Apply simulation calculation software or discrete unit method program to simulate, conduct numerical simulation and theoretical analysis of the structural form of the target rock layer and the stress state of the liberated layer, so that the target rock layer is in the caving zone and fissure zone of equivalent coal seam mining. , and be fully destroyed or the energy release of the target rock formation is effectively reduced; S22. Analyze the stress changes, crack development and surrounding rock structural characteristics of the liberated layer after equivalent coal seam mining, and obtain the stress σ _lib of the liberated layer under equivalent coal seam mining; S23. Analyze the stress changes and crack development of the liberated layer when the artificial liberation layer causes the target rock layer to be in the caving zone and fissure zone equivalent to coal seam mining and is fully damaged or when the energy release of the target rock layer is effectively reduced. and the structural characteristics of the surrounding rock, and obtain the stress σ _art of the liberated layer under the mining of the artificial liberated layer. 4. A method for preventing erosion of artificial liberation layers in mining working faces as claimed in claim 3, characterized in that, in S3, the criterion for determining the artificial liberation layers is according to the definition of ξ. Its size determines whether the current artificial liberation layer simulated mining plan is suitable for dividing into artificial liberation layers into four categories, including: Category I: When ξ<0.25, the equivalent stress coefficient ξ is at an inappropriate level; Class II, when 0.25≤ξ<0.5, the equivalent stress coefficient ξ is at the general level; Class III, when 0.5≤ξ<0.75, the equivalent stress coefficient ξ is at the appropriate level; Category IV, when ξ ≥ 0.75, the equivalent stress coefficient ξ is at a good level. 5. An anti-collision method for artificial liberation layers in mining working faces as claimed in claim 4, characterized in that, in S3, the step of dividing and determining the thickness of artificial liberation layers is: S31. Use simulation calculation software or discrete unit method program to conduct numerical simulation of equivalent coal seam mining, simulate the mining process of different coal seam thicknesses, and obtain equivalent coal seam mining. When the liberated layer reaches the mining requirements, it will be liberated. The stress of the layer σ _lib ; S32. Use simulation calculation software or discrete unit method program to conduct numerical simulation to simulate the mining process of different thicknesses of the artificial liberation layer, so that the target rock layer is in the caving zone and fissure zone of equivalent coal seam mining, and the target rock layer is fully destroyed. As the basis for discrimination, simulate the mining process of the artificial liberation layer when mining the same coal seam thickness as the equivalent coal seam. When the mining effect based on the discrimination is achieved, the stress σ _art of the liberated layer under human mining of the liberation layer at this time is obtained; S33. Based on the size of ξ, determine the mining thickness of the artificial liberation layer when ξ is in Category III and above. This thickness is the equivalent thickness and represents the liberation effect when the thickness of the artificial liberation layer reaches the appropriate liberation layer thickness determined above. . 6. An anti-collision method for an artificial liberation layer in a mining working face as claimed in claim 1, characterized in that the coverage range of the artificial liberation layer continuously covers the area between the transport lane and the return air lane in the projection of the layer where the working face is located. all working surfaces; The coverage of the artificial liberation layer is set along the direction of the projected width of the working surface from the transport lane to the return air lane. The projected width of the coverage of the artificial liberation layer on the working surface is greater than the distance between the transport lane and the return air lane; The coverage of the artificial liberation layer is set along the length direction of the working surface, and the projection length of the coverage of the artificial liberation layer on the working surface is greater than the length of the working surface. 7. An artificial liberation layer anti-collision method on a mining working face as claimed in claim 1, characterized in that, in S4, an artificial liberation layer evaluation model is established to analyze, calculate and record the artificial liberation layer under current geological and terrain conditions. The equivalent stress σ _eq , equivalent height _Heq and equivalent thickness _heq are used to characterize the feasibility of the artificial liberation layer and provide design criteria for the determination of the artificial liberation layer in step S4. 8. An anti-collision method for an artificial liberation layer in a mining working face as claimed in claim 7, characterized in that the equivalent stress σ _eq , the equivalent height _Heq and the equivalent thickness h required to establish the artificial liberation layer evaluation model are _eq is as follows: The equivalent stress is Among them, ξ≥0.5; the equivalent height is _Heq =H+ _hd , where H is the distance between the target layer and the coal seam, _hd is the distance between the fracturing well position and the bottom of the target layer; the equivalent thickness is _heq = 2h _d ≤ h, h ≤ 30m, where h _d is the distance between the fracturing well position and the bottom of the target layer. 9. An artificial liberation layer anti-collision method in a mining working face as claimed in claim 1, characterized in that, in said S4, fracturing wells are arranged according to the artificial liberation layer coverage and rock layer thickness determined in S3. Planning, including the number and location of fracturing wells, including horizontal wells and vertical wells; The horizontal well includes a vertically arranged through-layer section, a horizontally arranged fracturing section in the target rock formation, and a steering section connecting the through-layer section and the fracturing section. The said through-layer section, fracturing section and steering section are in the same plane, Used to carry out large-scale fracturing operations on target rock formations; The vertical well is installed on the side of the horizontal well penetration section away from the fracturing section to carry out fracturing operations in the blind fracturing zone where horizontal wells cannot be fracturing. 10. An artificial liberation layer anti-collision method in a mining working face as claimed in claim 9, characterized in that when the number of horizontal wells set for the same target rock formation is 2 or more, two adjacent horizontal wells As a group, they share a construction site. The fracturing sections of the two horizontal wells extend in opposite directions and are in the same plane, and there is a vertical well between the two horizontal wells. 11. A method for preventing erosion of artificial liberation layers in mining working faces as claimed in claim 10, characterized in that in S4, in order to obtain artificial liberation layers with composite requirements, the fracturing well layout needs to be based on the formation lithology and feasibility. The fracturing properties and rallies are comprehensively determined, and on this basis, combined with the requirements of the artificial liberation layer effect, the rock structure state and stress state of the liberated layer, the fracturing operation position of the fracturing well is determined through numerical simulation.