CN111005723B - Ground large-range rock stratum pre-splitting area anti-impact method based on up-down combined arrangement - Google Patents
Ground large-range rock stratum pre-splitting area anti-impact method based on up-down combined arrangement Download PDFInfo
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Abstract
The invention discloses a ground large-range rock stratum pre-splitting area anti-impact method based on up-down combined arrangement, which comprises the steps of determining a target rock stratum needing to be modified and decompressed in an area with hidden danger of rock burst; determining the hole distribution direction of a horizontal hole in a target rock stratum, and drilling a hole underground; drilling a vertical hole in the middle of a special roadway facing a target stratum from the ground; and performing directional cracking on the horizontal holes after hole distribution. The invention can form a plurality of reticular cracks with different directions and lengths in the rock stratum with good integrity, thereby greatly reducing the overall strength of the rock stratum, reducing the stress distribution of the coal bed with high impact risk below the rock stratum and fundamentally eliminating the serious impact disaster risk during the coal bed mining.
Description
Technical Field
The invention relates to the technical field of coal mine safety mining, in particular to a ground large-range rock stratum pre-splitting area anti-impact method based on up-down combined arrangement.
Background
In the coal mining process, a large-area suspended roof structure is easily formed on a high-level thick-layer roof above a coal seam, the suspended roof without collapse causes stress concentration of a stope, and strong dynamic load disturbance is generated on the stope when the roof is suddenly broken, so that a rock burst disaster is easily induced. At present, the effective range of underground roof treatment is within 50m above a coal seam, and the threat of inducing stope rock burst by a high-level thick-layer roof cannot be eliminated. The ground fracturing technology utilizes an artificial channel between the ground and the thick-layer top plate to press high-pressure liquid into the thick-layer top plate, so that a large number of artificial cracks are generated, the strength and the integrity of the thick-layer top plate are weakened in the region, the stress concentration and dynamic load disturbance of a stope are reduced, and the purpose of treating rock burst at the source can be realized.
In the prior art, all artificial channels adopted during ground fracturing are drilled holes constructed downwards from the ground, in order to improve the fracturing range, a series of drilled holes are required to be constructed on the ground to realize large-range fracturing on a top plate, the ground construction occupied area is large, the environment is seriously damaged, the construction difficulty is large, and the cost is high. For this reason, the patent proposes a method for preventing scour in a large-scale ground rock stratum pre-splitting area based on the combined arrangement of the upper part and the lower part of a well.
Disclosure of Invention
In order to solve the technical problem, the invention provides an anti-impact method for a ground large-range rock stratum pre-splitting area based on up-down combined arrangement.
According to one aspect of the invention, a ground wide rock stratum pre-splitting area anti-impact method based on up-down combined arrangement is provided, and comprises the following steps:
determining a target rock stratum needing modification and pressure relief in an area with the potential risk of rock burst;
determining the hole distribution direction of a horizontal hole in a target stratum, and drilling a hole underground;
drilling a vertical hole in the middle of a special roadway facing a target stratum from the ground;
and performing directional cracking on the horizontal holes after hole distribution.
Further, the step of determining the target rock stratum needing modified pressure relief in the area with the potential rock burst hazard comprises the following steps:
and determining a target rock stratum needing modification and pressure relief by adopting a main control key layer for coal mining and a main control key layer analysis method for energy transfer response analysis and/or microseismic monitoring based on mine geological data above the rock burst hidden danger area.
Further, the analysis of the key layer of the main control by using microseismic monitoring comprises the following steps: acquiring microseismic events with different energy levels for representing the activity of the surrounding rock in the rock stratum;
analyzing and using the microseismic events with different energy levels to represent whether the activity of the surrounding rock mainly occurs in the roof rock stratum or not;
and if so, analyzing the distributed layer positions of the high-energy events on the roof rock stratum, and determining the layer positions of the high-energy events which occur in a concentrated mode as the ground fracturing target rock stratum.
Further, the analyzing of microseismic events according to the different energy levels to characterize whether the surrounding rock activity occurs primarily in the roof strata comprises:
analyzing the proportion of microseismic events or the energy of the top rock stratum, the coal bed and the bottom rock stratum;
and when the number of the microseismic events of the top plate rock stratum is greater than the number of the microseismic events of the bottom plate rock stratum and/or the number of the microseismic events of the coal bed, or the energy of the microseismic events of the top plate rock stratum is greater than the energy of the microseismic events of the bottom plate rock stratum and/or the microseismic events of the coal bed, determining that the activity of the surrounding rock is mainly generated in the top plate rock stratum.
Further, the analyzing the distributed horizons of the high-energy events in the roof rock stratum, and the determining the horizons occurring in the high-energy event set as the target rock stratum includes:
and according to the microseismic events monitored by the up-and-down combined microseisms and the monitored microseismic event energy level, projecting the maximum energy level event to the roof rock stratum, and determining the rock stratum with the maximum microseismic event occupation ratio of the maximum energy level in the roof rock stratum as a ground fracturing target rock stratum.
Further, the determining the layer position of the roof strata distribution, which is the layer position of the high-energy event set as the ground fracture target strata, further comprises:
when the maximum energy level occurrence quantity is not enough to determine the ground fracturing target rock stratum, continuously analyzing the secondary maximum energy level events to the rock stratum position where the large energy events can be determined to be concentrated, and determining the target rock stratum; the insufficient maximum energy level occurrence quantity is that the energy events have distribution in different lithologies, and the contrast difference of the distributed rock layers is small.
Further, the analysis of the main control key layer and the energy transfer response of the coal mining comprises the following steps: calculating a plurality of pre-ground fractured rock layers with the fracturing performance by utilizing a key layer theory;
and judging whether the target rock stratum is a final ground fracturing target rock stratum or not according to the residual energy transferred to the working face coal seam from the plurality of pre-ground fracturing rock stratums.
Further, still include: determining remaining energy transferred to a face coal seam from the plurality of pre-surface fractured rock formations; the method specifically comprises the following steps:
and according to the plurality of pre-ground fractured rock layers, calculating the residual energy transferred to the coal bed of the working face by utilizing the rock layer released energy attenuation characteristics.
Further, the calculating the remaining energy transferred to the working face coal seam from the plurality of pre-surface fractured rock formations by using the rock formation released energy attenuation characteristics comprises:
performing bending energy calculation on the plurality of pre-ground fractured rock layers to obtain rock layer release energy of the plurality of pre-ground fractured rock layers;
and calculating the residual energy transmitted to the working face coal seam by the rock stratum release energy of the plurality of pre-ground fractured rock strata according to the rock stratum release energy of the plurality of pre-ground fractured rock strata.
Further, determining a surface fracturing target rock stratum according to the residual energy transferred to the working surface coal seam from the plurality of pre-surface fracturing rock strata comprises:
and determining the pre-ground fractured rock stratum with the maximum residual energy as a ground fractured target rock stratum by comparing the residual energy transferred to the working face coal seam by the plurality of pre-ground fractured rock strata.
Further, the determining a hole distribution direction of a horizontal hole in the target rock stratum and drilling the hole downhole comprises:
determining the hole distribution direction of the horizontal hole according to the direction of the ground stress of the target rock stratum;
and drilling underground according to the determined hole distribution direction of the horizontal hole.
Further, the determining the hole distribution direction of the horizontal well according to the direction of the ground stress of the target rock stratum comprises the following steps:
punching a hole in a target rock stratum in a coal seam roadway, conveying hydraulic fracturing equipment to the bottom of the hole, and sealing the upper end and the lower end of a fracturing section by using a packer;
breaking the rock and taking the initial breaking direction as the direction of the maximum horizontal principal stress;
taking the direction vertical to the direction of the maximum horizontal principal stress as the direction of the minimum horizontal principal stress; and taking the direction of the minimum horizontal main stress as the hole distribution direction of the horizontal hole.
Further, the drilling downhole according to the determined hole distribution direction of the horizontal hole comprises:
digging bypasses into a target rock stratum in a large transportation roadway and a large air return roadway in a coal layer with impact risk respectively, and digging a special roadway in the target rock stratum to communicate the two bypasses, thereby forming a smooth closed loop;
and constructing a plurality of groups of horizontal holes in a special roadway in the target stratum along the direction of the minimum horizontal main stress.
Further, the method also comprises the step of cementing the well in the horizontal hole construction process, and specifically comprises the following steps:
and (3) lowering the sleeve to the bottom of the hole, continuously pressing plugging materials into the sleeve, and pressing the plugging materials into an annular space between the sleeve and the hole wall until the hole opening, so that the sleeve and the hole wall form a whole.
Further, the directional fracturing of the horizontal hole after hole distribution comprises:
conveying the perforating equipment to the bottom of a horizontal hole in a target rock stratum roadway, and starting a perforating device to perforate on the hole wall;
sending fracturing equipment to the bottom of the horizontal hole, adopting the packer to set the injection hole section, injecting fracturing fluid into the injection hole section along the fracturing pipeline, making the crack expand to the rock stratum is inside, accomplishing first fracturing, the deblocking at last, removing the fracturing pipeline to other positions of treating the fracturing, repeatedly setting and fracturing to the fracturing construction of accomplishing a bite horizontal hole, repeating the fracturing construction of other horizontal holes of directional fracturing process completion of high pressure water conservancy again, making the target rock stratum form the netted crack that link up each other.
According to the ground large-range rock stratum pre-splitting area anti-impact method based on the up-down combined arrangement, the ground fracturing method of the up-down drilling is adopted to modify and relieve the pressure of the thick-layer hard top plate, so that a plurality of reticular cracks with different directions and lengths are formed in the rock stratum with good integrity, the overall strength of the rock stratum is greatly reduced, the stress distribution of a strong impact dangerous coal bed below the rock stratum is reduced, and the serious impact disaster risk during the coal bed mining is fundamentally eliminated.
Drawings
FIG. 1 is a schematic flow chart of a method for preventing scour in a large-scale ground rock formation pre-splitting area based on a downhole and uphole combined arrangement according to an embodiment of the present invention;
FIG. 2 is a schematic diagram of a target rock stratum selection in a surface large-scale rock stratum pre-splitting area scour prevention method based on a downhole and uphole combined arrangement, provided by an embodiment of the invention;
FIG. 3 is a schematic diagram of a fractured well arrangement in a method for preventing shock in a large-scale ground rock stratum pre-fractured region based on the downhole and uphole combined arrangement provided by the embodiment of the invention;
FIG. 4 is a schematic diagram of horizontal hole cementing in a method for preventing shock in a ground large-scale rock stratum pre-splitting area based on downhole and uphole combined arrangement according to an embodiment of the invention;
FIG. 5 is a schematic diagram illustrating the effect of horizontal hole staged fracturing in a method for preventing scour in a ground large-scale rock stratum pre-fractured region based on downhole and uphole combined arrangement according to an embodiment of the present invention;
fig. 6 is a schematic diagram illustrating an influence of a top plate not weakened in an anti-impact method for a ground large-scale rock stratum pre-splitting area based on downhole and uphole combined arrangement on rock burst pressure of a roadway;
fig. 7 is a schematic diagram of an influence of weakened top plates on rock burst of a roadway in an anti-impact method for a ground large-scale rock stratum pre-fractured region based on combined up-and-down arrangement provided by an embodiment of the invention.
Fig. 8 is a layout diagram of an uphole and downhole microseismic joint monitoring system in the method for preventing shock in a ground large-scale rock stratum pre-splitting area based on uphole and downhole joint arrangement provided by the embodiment of the invention.
Detailed Description
Referring to fig. 1, an embodiment of the present invention provides a method for protecting a large-scale ground rock formation pre-fractured area from impact, which is based on downhole combined arrangement, and includes:
the determination of the area with the potential rock burst hazard can be determined according to the occurrence history of rock burst of the mine or an adjacent mine, the geological conditions of the mine, the current mining condition, the recent planning and the like; referring to fig. 2, the lowest layer is a coal seam with a risk of impact, and the coal seam is the potential area of the rock burst. The rock stratum above the coal seam is called as a top plate, after the coal seam is mined out, the top plate above the coal seam is damaged under the action of gravity, and a top plate overlying rock three zones are sequentially formed from bottom to top, namely a caving zone, a fracture zone and a bending subsidence zone from bottom to top.
The target rock stratum can be determined by adopting methods such as main control key layers of coal seam mining, energy transfer response analysis, main control rock stratum analysis of microseismic monitoring and the like, for example, the rock stratum which is mainly used for inducing rock burst and has the combined thickness of more than 20m of single layer or multiple layers within the range of more than 50m above the coal seam can be determined as the target rock stratum, and the target rock stratum has the characteristics of larger thickness, good integrity and difficult collapse after the coal seam is mined.
Wherein, the analysis of the main control key layer and the energy transfer response comprises the following steps: calculating a plurality of pre-ground fractured rock layers with the fracturing performance by utilizing a key layer theory; and judging whether the target rock stratum is a final ground fracturing target rock stratum or not according to the residual energy transferred to the working face coal seam from the plurality of pre-ground fracturing rock stratums.
Wherein the determination of the remaining energy transferred from the plurality of pre-surface fractured rock formations to the face coal seam comprises: and according to the plurality of pre-ground fractured rock layers, calculating the residual energy transferred to the coal bed of the working face by utilizing the rock layer released energy attenuation characteristics.
Calculating the remaining energy transferred to the working face coal seam by the plurality of pre-ground fractured rock layers by utilizing the rock layer released energy attenuation characteristics, wherein the method comprises the following steps: performing bending energy calculation on the plurality of pre-ground fractured rock layers to obtain rock layer release energy of the plurality of pre-ground fractured rock layers; and calculating the residual energy transmitted to the working face coal seam by the rock stratum release energy of the plurality of pre-ground fractured rock strata according to the rock stratum release energy of the plurality of pre-ground fractured rock strata.
Determining a surface fracture target formation from remaining energy transferred to the face coal seam from the plurality of pre-surface fracture formations comprises: and determining the pre-ground fractured rock stratum with the maximum residual energy as a ground fractured target rock stratum by comparing the residual energy transferred to the working face coal seam by the plurality of pre-ground fractured rock strata.
The key layer theory calculation method can refer to general mechanical analysis and 2.2 section key layer discrimination methods in chapter 2 and 2.3 section key layer theories in key layer theory of rock layer control compiled by high-grade Mingming and the related contents of key layer theory of chapter 6 and second section rock layer control in mine pressure and rock layer control, so that residual energy which is transmitted to a working face coal seam according to a plurality of pre-ground fractured rock layers is convenient to obtain a ground fractured target rock layer which influences the rock burst, namely a rock burst main control rock layer.
The analysis of the primary rock formation for microseismic monitoring includes:
firstly, acquiring microseismic events with different energy levels for representing the activity of surrounding rocks in a rock stratum; the method can be specifically obtained by adopting an uphole and downhole micro-seismic combined monitoring system, an uphole and downhole micro-seismic combined monitoring system or a downhole micro-seismic combined monitoring system. As a preferred embodiment, the uphole and downhole microseismic joint monitoring system shown in fig. 8 (ARP 2000 surface microseismic monitoring system of polish) can be specifically utilized, wherein the application of the ARP system realizes "armamis M/E downhole microseismic monitoring system + ARP2000P surface microseismic monitoring system" uphole and downhole joint monitoring.
Second, microseismic event analysis based on different energy levels is used to characterize whether the wall rock activity occurs primarily in the roof strata. The method specifically comprises the steps of analyzing the ratio of microseismic events or the energy of the microseismic events occurring in a top rock stratum, a coal bed and a bottom rock stratum; and when the number of the microseismic events of the top plate rock stratum is greater than the number of the microseismic events of the bottom plate rock stratum and/or the number of the microseismic events of the coal bed, or the energy of the microseismic events of the top plate rock stratum is greater than the energy of the microseismic events of the bottom plate rock stratum and/or the microseismic events of the coal bed, determining that the activity of the surrounding rock is mainly generated in the top plate rock stratum.
And thirdly, when the method is used for representing that the surrounding rock activities mainly occur in the roof rock stratum, analyzing the distributed horizons of the high-energy events in the roof rock stratum, and determining the horizons of the high-energy events which occur in a concentrated mode as the ground fracturing target rock stratum. The method specifically comprises the following steps: and according to the microseismic events monitored by the up-and-down combined microseisms and the monitored microseismic event energy level, projecting the maximum energy level event to the roof rock stratum, and determining the rock stratum with the maximum energy level microseismic event occupation ratio in the roof rock stratum as a target rock stratum.
In addition, when the maximum energy level occurrence quantity is not enough to determine the target rock stratum, continuously analyzing the secondary maximum energy level events to the rock stratum positions where the large energy events can be concentrated, and determining the target rock stratum; the insufficient number of maximum energy level occurrences is that the energy events have distributions in different lithologies (e.g., medium sandstone, fine sandstone, and/or coarse sandstone formations), and the distributions have small contrasts from formation to formation.
The microseismic monitoring master rock formation analysis and the master key layer and energy transfer response analysis can be used for determining the target rock formation independently or in combination, namely: after the main control key layer and the energy transfer response analysis are used for determining the target rock stratum, the target rock stratum determined by the main control rock stratum analysis of the microseismic monitoring is used for verifying the main control key layer and the target rock stratum determined by the energy transfer response analysis; or after the target rock stratum is determined by using the master control rock stratum analysis of the microseismic monitoring, the target rock stratum determined by the master control key layer and the target rock stratum determined by the energy transfer response analysis is verified. Through the mode of verifying whether the rock formation is consistent or not, if so, the determined target rock formation is proved to have no problem, so that the accuracy of prediction of the target rock formation is realized, and a foundation is laid for subsequent well arrangement and rock burst treatment.
And step 20, determining the hole distribution direction of the horizontal hole in the target rock stratum, and drilling the hole underground. The method specifically comprises the following steps:
step 201, determining a hole distribution direction of a horizontal hole according to a ground stress direction of a target rock stratum, wherein the step specifically comprises the following steps: punching a hole in a target rock stratum in a coal seam roadway, conveying hydraulic fracturing equipment to the bottom of the hole, and sealing the upper end and the lower end of a fracturing section by using a packer; injecting high-pressure liquid, pressurizing until the rock is cracked, and taking the initial cracking direction as the direction of the maximum horizontal principal stress; taking the direction vertical to the direction of the maximum horizontal principal stress as the direction of the minimum horizontal principal stress; and taking the direction of the minimum horizontal main stress as the hole distribution direction of the horizontal hole.
And 202, drilling according to the hole distribution direction of the horizontal hole determined in the step 201. Referring to fig. 3, detours are respectively excavated in a large transportation roadway and a large return air roadway in a coal layer with risk of impact to a target rock stratum, a special roadway is excavated in the target rock stratum to communicate the two detours, so that a smooth closed loop is formed, and the width of the roadway can meet the requirements of ventilation, pedestrians and construction. And constructing a plurality of groups of horizontal holes in a special roadway in the target stratum along the direction of the minimum horizontal main stress. The horizontal hole construction process may encounter soft and broken zone rock mass, needs well cementation at the moment, and the purpose of well cementation is to separate the drill hole from external media and prevent the drill hole from collapsing and deforming. Referring to fig. 4, during well cementation, the casing is lowered to the bottom of the hole, cement slurry is continuously pressed into the casing, and the cement slurry is pressed into an annular space between the casing and the hole wall until the hole opening, so that the casing and the hole wall form a whole, and the exposed hole wall is sealed and reinforced, and thus the well cementation process from inside to outside is completed. After the well cementation work is finished, a small first drilling tool is adopted to continue to construct the horizontal hole forwards until the deep part of the target rock stratum, and the whole drilling process needs to finish the well logging work so as to obtain the geological parameters (such as lithology, natural gamma, compensation density and the like) of the target rock stratum.
And step 30, drilling a vertical hole in the middle of the special roadway facing the ground into the target rock stratum. The method specifically comprises the following steps: and vertically drilling a hole on the ground by using drilling equipment until a special roadway communicated with a target rock stratum is reached. The process also encounters the work of well cementation and well logging, and the construction method is the same as the well cementation and well logging process of the horizontal hole.
And step 40, performing directional fracturing on the horizontal holes after hole distribution. As an embodiment, a high-pressure hydraulic directional fracturing method can be specifically adopted, namely the method comprises the following steps: and conveying the perforation equipment to the bottom of the horizontal hole in the target rock stratum roadway, starting a perforation device to perforate on the hole wall, and taking out the equipment after perforation. Laying a high-pressure rubber pipe along a vertical hole and a roadway special for a target rock stratum to connect a ground high-pressure pump truck with fracturing equipment in the roadway of the target rock stratum, then conveying the fracturing equipment to the bottom of a horizontal hole, setting the injection hole section by adopting a packer, opening the ground high-pressure pump truck to inject fracturing fluid into the injection hole section along a fracturing pipeline, expanding the fracture to the inside of the rock stratum, completing first fracturing, finally deblocking, moving the fracturing pipeline to other positions to be fractured, repeating the setting and fracturing till completing fracturing construction of one horizontal hole, repeating the high-pressure hydraulic directional fracturing procedure to complete fracturing construction of other horizontal holes, and forming mutually-through reticular fractures in the target rock stratum. Referring specifically to fig. 5, the perforating apparatus is pushed to the horizontal bottom of the hole, and the perforating device is opened to generate high-pressure gas or liquid, which is ejected from the nozzle of the perforating device, and the pressure of the high-pressure gas or liquid far exceeds the sum of the shear strength and the maximum horizontal stress of the hole wall (including casing, cement and rock), so that a crack perpendicular to the fractured well is formed at the nozzle position of the hole wall. And taking out the perforating device, conveying the fracturing device to the perforating section, pressurizing the packers at the two ends to expand and extrude the hole wall, and finishing setting so that the perforating section forms a closed space. And starting the ground high-pressure pump, continuously injecting fracturing fluid into the perforating section along the high-pressure pipeline, preparing the fracturing fluid by water and chemical agents according to a certain proportion, expanding the cracks formed by perforating towards the deep part under the action of the high-pressure fluid, forming reticular cracks with different directions, widths and lengths on the periphery of the main cracks, and closing the high-pressure pump to finish primary fracturing after the designed fracturing time is reached or the pressure is reduced to a certain value. And releasing the pressure of the packer to separate the packer from the hole wall, completing deblocking, and dragging the fracturing pipeline to move back to the next fracturing position after deblocking. And repeating the fracturing process to complete the fracturing process of the whole horizontal hole in sequence.
And completing the drilling and fracturing construction process of other wells according to the method.
Referring to fig. 6 and 7, through the modification and pressure relief of the large-area roof, a large number of interconnected network-shaped fractures are formed in the target rock stratum, the overall strength of the rock stratum is greatly reduced, and when the stress of the rock stratum above the target rock stratum is transferred downwards, the hard transfer before modification is converted into soft transfer, so that the overall stress level of the coal stratum below the target rock stratum is reduced.
In the illustrated example, the coal seam mining sequence is: firstly mining a 101 working face, then mining a 103 working face and finally mining a 102 working face, and analyzing the influence of roof modification pressure relief on roadway rock burst by taking the impact risk during mining of the 102 working face as an example.
After the 101 working face is mined out, part of the pressure of the top plate above the 101 working face acts on the 102 return air gateway, and after the 103 working face is mined out, part of the pressure of the top plate above the 103 working face acts on the 102 transportation gateway, so that lateral stress concentration areas are formed near the 102 return air gateway and the transportation gateway respectively; meanwhile, the 102 working face is mining and is influenced by continuous mining of the coal seam, and part of the pressure of the top plate of the rear goaf acts on the coal body in front of the goaf, so that a strike stress concentration area is formed in the area where the two gate roads are close to the 102 goaf. The higher the stress concentration, the higher the probability of rock burst occurring, and the higher the energy released by rock burst.
Referring to fig. 6, because the thick-layer hard top plate is not modified for pressure relief, the top plate has high strength and good integrity, so that after coal is mined, the top plate is not easy to collapse to form a large-area suspended roof, the larger the suspended roof area is, the higher the stress acting on coal bodies near 102 two gate roads is, and meanwhile, the large-area suspended roof is suddenly broken to generate a strong dynamic pressure effect, so that the stress of the coal bodies near a roadway is suddenly increased, and when the stress of the coal bodies exceeds the critical stress triggering rock burst, the elastic energy accumulated in the coal bodies is suddenly released, and the roadway damage, equipment damage and casualties are caused in serious cases.
Referring to fig. 7, because the thick-layer hard top plate is modified and decompressed in advance, the strength and the integrity of the rock stratum are greatly reduced, the top plate can collapse in time along with the mining of coal to fill a goaf, so that the upper rock stratum is supported, partial stress of coal bodies around a roadway is shared, and the stress of the coal bodies is always below the critical stress of rock burst, thereby fundamentally eliminating the serious threat of the rock burst to the safety production.
Compared with the conventional ground fracturing technology, the ground large-range rock stratum pre-splitting area anti-impact method based on the up-down combined arrangement has the advantages of high construction efficiency, low cost, easiness in control and the like. The thick-layer hard top plate is modified and decompressed by adopting a ground fracturing method of drilling holes up and down, so that a plurality of reticular cracks with different directions and lengths are formed in a rock stratum with good integrity, the overall strength of the rock stratum is greatly reduced, the stress distribution of a strong impact dangerous coal bed below the rock stratum is reduced, and the serious impact disaster risk during coal bed mining is fundamentally eliminated. In addition, the ground large-range rock stratum pre-splitting area anti-impact method based on up-down combined arrangement belongs to strategic treatment measures of rock burst, has important significance on the progress of the rock burst prevention and treatment technology and concept in China, and has remarkable social and economic benefits.
Finally, it should be noted that the above embodiments are only for illustrating the technical solutions of the present invention and not for limiting, and although the present invention has been described in detail with reference to examples, it should be understood by those skilled in the art that modifications or equivalent substitutions may be made on the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, which should be covered by the claims of the present invention.
Claims (7)
1. A ground large-range rock stratum pre-splitting area anti-impact method based on up-down combined arrangement is characterized by comprising the following steps:
determining an area with potential rock burst hazards according to the occurrence history of rock burst of the mine or an adjacent mine, the geological conditions of the mine, the current mining condition and recent planning;
determining a target rock stratum needing modified pressure relief in an area with a potential rock burst hazard, wherein the target rock stratum comprises: determining a target rock stratum needing modification and pressure relief by adopting a main control key layer for coal mining and a main control key layer analysis method for energy transfer response analysis and microseismic monitoring on the basis of mine geological data above an area with the potential risk of rock burst;
wherein the master key layer and energy transfer response analysis comprises: calculating a plurality of pre-ground fractured rock layers with the fracturing performance by utilizing a key layer theory; performing bending energy calculation on the plurality of pre-ground fractured rock layers to obtain rock layer release energy of the plurality of pre-ground fractured rock layers; calculating the residual energy transmitted to the working face coal seam by the rock stratum release energy of the plurality of pre-ground fractured rock strata according to the rock stratum release energy of the plurality of pre-ground fractured rock strata; determining the pre-ground fractured rock stratum with the maximum residual energy as a ground fractured target rock stratum by comparing the residual energy transferred to the working face coal seam by the plurality of pre-ground fractured rock strata;
wherein, the analysis of the key layer of the main control of the microseismic monitoring comprises the following steps: acquiring microseismic events with different energy levels for representing the activity of the surrounding rock in the rock stratum; analyzing whether the microseismic events used for representing the activities of the surrounding rock mainly occur in the roof rock stratum or not according to the microseismic events with different energy levels; when the microseismic events for representing the activity of the surrounding rock mainly occur in the roof rock stratum, analyzing the distribution layer of the high-energy microseismic events in the roof rock stratum, and determining the layer in which the high-energy microseismic events occur in a concentrated manner as a ground fracturing target rock stratum;
determining the hole distribution direction of a horizontal hole in a target stratum, and drilling a hole underground;
drilling a vertical hole in the middle of a special roadway facing a target stratum from the ground;
and performing directional cracking on the horizontal holes after hole distribution.
2. The method of claim 1, wherein determining a hole placement direction of a horizontal hole in the target formation and drilling a hole downhole comprises:
determining the hole distribution direction of the horizontal hole according to the direction of the ground stress in the target rock stratum;
and drilling underground according to the determined hole distribution direction of the horizontal hole.
3. The method of claim 2, wherein determining the hole distribution direction of the horizontal well according to the direction of the ground stress of the target rock formation comprises:
punching a hole in a target rock stratum in a coal seam roadway, conveying hydraulic fracturing equipment to the bottom of the hole, and sealing the upper end and the lower end of a fracturing section by using a packer;
breaking the rock and taking the initial breaking direction as the direction of the maximum horizontal principal stress;
taking the direction vertical to the direction of the maximum horizontal principal stress as the direction of the minimum horizontal principal stress; and taking the direction of the minimum horizontal main stress as the hole distribution direction of the horizontal hole.
4. The method of claim 2, wherein drilling downhole according to the determined hole placement direction of the horizontal hole comprises:
digging bypasses into a target rock stratum in a large transportation roadway and a large air return roadway in a coal layer with impact risk respectively, and digging a special roadway in the target rock stratum to communicate the two bypasses, thereby forming a smooth closed loop;
and constructing a plurality of groups of horizontal holes in a special roadway in the target stratum along the direction of the minimum horizontal main stress.
5. The method according to claim 4, further comprising the step of cementing during horizontal bore construction, in particular comprising:
and (3) lowering the sleeve to the bottom of the hole, continuously pressing plugging materials into the sleeve, and pressing the plugging materials into an annular space between the sleeve and the hole wall until the hole opening, so that the sleeve and the hole wall form a whole.
6. The method of claim 1, wherein directionally fracturing the horizontal hole after perforating comprises:
conveying the perforating equipment to the bottom of a horizontal hole in a target rock stratum roadway, and starting a perforating device to perforate on the hole wall;
sending fracturing equipment to the horizontal hole bottom, adopting the packer to set the perforation section, injecting fracturing fluid into the perforation section along the fracturing pipeline, making the crack to the inside extension of rock stratum, accomplishing first fracturing, the deblocking at last removes the fracturing pipeline to other positions of treating the fracturing, and repeated setting and fracturing are to the fracturing construction of accomplishing a mouthful of horizontal hole.
7. The method of claim 6, further comprising: and performing directional fracturing on the horizontal holes after hole distribution, and repeating the high-pressure hydraulic directional fracturing process to complete fracturing construction of other horizontal holes, so that mutually communicated reticular fractures are formed in the target rock stratum.
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| CN201811518097.XA CN109736805A (en) | 2018-12-12 | 2018-12-12 | A kind of method of the modified release watershed management bump of thick-layer tight roof |
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| CN201911277065.XA Active CN111005723B (en) | 2018-12-12 | 2019-12-12 | Ground large-range rock stratum pre-splitting area anti-impact method based on up-down combined arrangement |
| CN201911276513.4A Active CN111005722B (en) | 2018-12-12 | 2019-12-12 | Well arrangement method for governing rock burst at pressure relief source of ground fracturing area |
| CN201911276023.4A Active CN110939442B (en) | 2018-12-12 | 2019-12-12 | Method for treating rock burst by pressure relief source in ground fracturing area |
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| CN110939442B (en) | 2021-07-27 |
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| CN109736805A (en) | 2019-05-10 |
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| CN111005723A (en) | 2020-04-14 |
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