CN116971775A - Shallow coal seam mining-along-filling coal mining method based on deflagration fracturing roof horizontal well - Google Patents
Shallow coal seam mining-along-filling coal mining method based on deflagration fracturing roof horizontal well Download PDFInfo
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- 239000003245 coal Substances 0.000 title claims abstract description 139
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- 238000004200 deflagration Methods 0.000 title claims abstract description 31
- 239000011435 rock Substances 0.000 claims abstract description 16
- 238000005553 drilling Methods 0.000 claims description 81
- 239000002002 slurry Substances 0.000 claims description 33
- 238000005474 detonation Methods 0.000 claims description 22
- 238000010276 construction Methods 0.000 claims description 15
- 239000004568 cement Substances 0.000 claims description 11
- 238000005086 pumping Methods 0.000 claims description 11
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- E—FIXED CONSTRUCTIONS
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- E—FIXED CONSTRUCTIONS
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- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21F—SAFETY DEVICES, TRANSPORT, FILLING-UP, RESCUE, VENTILATION, OR DRAINING IN OR OF MINES OR TUNNELS
- E21F15/00—Methods or devices for placing filling-up materials in underground workings
- E21F15/06—Filling-up mechanically
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- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21F—SAFETY DEVICES, TRANSPORT, FILLING-UP, RESCUE, VENTILATION, OR DRAINING IN OR OF MINES OR TUNNELS
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Abstract
The application discloses a mining-along-mining and filling coal mining method for a shallow coal seam based on a deflagration fracturing roof horizontal well. According to the application, cracks are generated in the rock stratum through deflagration and fracturing, so that the roof can collapse in time after coal mining, synchronous operation of coal mining and goaf filling can be realized, the influence of filling operation on coal mining operation is avoided, the goaf can be treated in time, the problem of ground subsidence is solved, and the problems of ground building damage, ground ecological environment damage, cultivated land damage and the like caused by the problems are avoided.
Description
Technical Field
The application belongs to the technical field of coal mining, and particularly relates to a mining-along-filling coal mining method for a shallow coal seam based on a deflagration fracturing roof horizontal well.
Background
The first coal-producing country in the world is China, and coal is taken as important basic energy and raw material, and has the dual properties of energy and resources. Coal accounts for about 76% and 69% in the primary energy production and consumption structure of China, so that the development of national economy and society is strongly supported. At present, the underground mining is still the main mining mode of coal mines in China. The goaf is formed underground after coal is excavated out of the ground, if the goaf is not filled, the ground surface collapses and forms ground cracks under the gravity action of an overlying rock layer, so that the construction and the cultivated land on the ground are damaged, and the ecological environment protection concept is violated.
In order to solve the problem, filling mining is proposed as a way for solving the settlement of overburden in a mining area, and the aim of controlling the settlement is achieved by injecting slurry into a goaf to support an upper rock stratum.
The technical method for filling and mining gangue by using ground directional drilling (CN 202110313271.2) discloses a method for filling processed gangue into a separation layer and a goaf by taking L-shaped ground drilling as a channel, so as to achieve the purposes of filling along with the mining and zero emission of the gangue. However, the technology needs to construct a new drilling hole when the coal mining machine moves forwards for 8-20m, and the single working face filling engineering amount is large and the cost is high.
The method of coal seam roof sleeve horizontal long drilling along with mining along with filling ecological (CN 202110423554.2) discloses a method of filling paste by using the coal seam roof sleeve horizontal long drilling as a filling channel of the paste, stoping a working face, directly pushing rock stratum along with mining along with caving, and injecting the filling paste into a goaf after the front end of the sleeve in the direct pushing rock stratum is exposed out of the goaf due to the caving of the direct pushing rock stratum. The method provides a new idea for the coal mine to fill along with the mining, and can realize long-distance filling by using a single long drilling hole, but also faces the problem that the sleeve cannot be exposed when the top plate cannot collapse. And for shallow coal beds, the construction water-to-vertical ratio of the horizontal section of the horizontal well is large due to the shallow vertical depth, and the construction difficulty is high.
Disclosure of Invention
Aiming at the defects existing in the prior art, the application aims to provide a mining method of shallow coal seam mining along with filling based on a deflagration fracturing roof horizontal well, so as to realize the mining along with filling control sinking in the coal mining process, solve the problem of goaf sedimentation and achieve the purpose of green coal mining.
In order to solve the technical problems, the application adopts the following technical scheme:
the method for mining coal while mining and while filling of the shallow coal seam based on the deflagration fracturing roof horizontal well comprises the following steps:
step 1, constructing an inclined horizontal well in a coal seam roof stratum at the top of a target working surface by adopting a three-well structure;
step 2, implementing segment detonation fracturing on the horizontal section of the inclined horizontal well: perforating the inclined horizontal well by adopting a multistage perforating gun to complete the whole-well section perforating operation, so as to obtain a plurality of perforating sections; connecting the detonation fracturing tool strings, and transmitting the connected detonation fracturing tool strings to the perforating segments by adopting oil pipe transmission to finish detonation fracturing operation of all the perforating segments;
step 3, ground crushed coal gangue is used for preparing filling slurry: coal gangue generated in the coal mining process is crushed and screened and then mixed with wastewater to prepare slurry;
step 4, working face stoping is started, along with working face coal mining pushing, the hydraulic support moves forward, a goaf roof stratum collapses under the action of gravity, the sleeve is exposed under the action of gravity, and the front end of the sleeve is positioned on the goaf;
step 5, filling slurry is injected from a ground wellhead, and a goaf is formed after the hydraulic support is filled: pumping the filling slurry prepared in the step 3 into a horizontal well through a ground pump; the injected filling slurry and the caving coal seam roof rock are mixed and piled up in the goaf to form a support for the rock stratum at the upper part of the goaf;
and 6, continuously stoping the working face, moving the hydraulic support forwards, and repeating the steps 4-5 until the continuous stoping and continuous filling operation of the whole working face is completed.
The application also comprises the following technical characteristics:
specifically, the step 1 includes: drilling to the position below the aquifer at an initial drilling well bevel angle of 10-30 degrees, casing well cementation, and returning cement to the ground; beginning to make a deviation after drilling to a deviation point, stably and obliquely drilling a pilot hole well for detecting coal when the well deviation is 40-60 degrees, lifting the drill after the pilot hole well is detected to a target coal bed, filling cement and backfilling the pilot hole, then continuing to drill to a landing point in an inclination increasing way, setting a sleeve, and returning cement to the ground; and thirdly, drilling into the depth of the final hole, casing and cementing, and returning cement to the ground to obtain the inclined horizontal well.
Specifically, in the step 1, the vertical distance between the horizontal section of the inclined horizontal well and the top surface of the coal seam is 2-5m.
Specifically, in the step 1, when the burial depth H of the coal seam satisfies: H-H m When R+h is less than or equal to R+h, adopting an inclined vertical well drilling machine to perform drilling construction operation;
in the above formula, h is a drilling depth, m; h is a m The vertical distance between the horizontal section of the inclined horizontal well and the top surface of the coal seam is m; r is the minimum curvature radius of the inclined horizontal well bore, and the calculation formula is as follows:
wherein d is the outer diameter of the sleeve, m; k (k) 1 Is a safety coefficient; k (k) 2 Is the stress concentration coefficient of the thread; t is the yield strength of the steel of the sleeve body and MPa.
Specifically, in the step 2, the oil pipe transmits the multistage perforating gun to the perforation with the preset depth, the length of a single perforation section is 1m-2m, the perforation density is not less than 10 holes/m, and the interval between adjacent perforation sections is not less than 20m.
Specifically, in the step 2, the detonation fracturing tool string includes sequentially connected from top to bottom: the device comprises a joint, a mechanical packer, a magnetic positioner, a centralizer, a heat insulation ring, an impact igniter, deflagration fracturing powder columns, a centralizer and a guide shoe.
Specifically, completing the deflagration fracturing operation of all perforation segments includes: connecting a detonation fracturing tool string, conveying the connected detonation fracturing tool string to a first perforating section by adopting oil pipe transmission, and calibrating the depth by using a magnetic positioner to enable fracturing bullets to be aligned to the perforating section; setting the mechanical packer and installing a wellhead blowout preventer; throwing an impact rod into an oil pipe from a wellhead to ignite and detonate a fracturing bomb; deblocking the mechanical packer, and lifting out an operation tubular column in the well; repeating the operation until the deflagration fracturing operation of all perforation segments is completed.
Specifically, in the step 3, the particle size is not more than 4mm after crushing the gangue, and the slurry density is 1.15-1.20g/cm 3 。
Specifically, in the step 5, the pumping displacement of pumping the filling slurry is 2-5m 3 /min。
Compared with the prior art, the application has the following technical effects:
(1) The application can realize synchronous operation of coal mining and goaf filling, avoid the influence of filling operation on coal mining operation, and can timely treat the goaf, solve the problem of ground subsidence, thereby avoiding the problems of ground building damage, ground ecological environment damage, cultivated land damage and the like caused by the ground subsidence.
(2) The application constructs the shallow horizontal well by means of the inclined vertical well drilling machine, can reduce the construction difficulty of the horizontal well, improves the horizontal section length of the shallow horizontal well, and reduces the construction quantity of filling and drilling.
(3) According to the application, staged deflagration fracturing construction is carried out on the horizontal section of the inclined horizontal well, a large number of cracks can be formed in the top plate before coal mining, on one hand, the strength of the top plate can be weakened, the top plate is ensured to collapse, the sleeve is promoted to be exposed to serve as a slurry conveying channel, on the other hand, the top plate can be weakened, and the rock burst problem caused by large-area suspended roof of the hard top plate is solved.
(4) According to the application, the filling slurry is prepared after the coal gangue is crushed, so that the problem of environmental pollution caused by stacking the gangue formed in the coal mining process can be solved, and the aim of zero emission of the gangue is fulfilled.
Drawings
FIG. 1 is a flow chart of the method of the present application;
FIG. 2 is (a) a conventional vertical well rig drilling schematic (b) an inclined vertical well rig drilling schematic;
FIG. 3 is a schematic view of a well bore structure of an inclined horizontal well according to the present application;
FIG. 4 is a schematic illustration of a staged detonation fracture of an inclined horizontal well in accordance with the present application;
FIG. 5 is a schematic illustration of the deflagration fracture morphology of the present application;
FIG. 6 is a schematic representation of the morphology of (a) deflagration fracturing of the present application and (b) conventional hydraulic fracturing fractures;
FIG. 7 is a schematic illustration of the grouting filling of an inclined horizontal well according to the present application.
The meaning of each reference numeral in the figures is:
1-target coal mining; 2-coal seam roof strata; 3-overlying strata on a roof of the coal bed; 4-coal seam floor strata; 5-an inclined horizontal well; 6-three casing pipes of the inclined horizontal well; 7-radial cracks formed by deflagration fracturing; 8-hydraulically fracturing the formed fracture; 9-filling the slurry; 10-roof strata collapse rock mass; 11-hydraulic support.
Detailed Description
The application provides a mining-along-filling coal mining method for a shallow coal seam based on a deflagration fracturing roof horizontal well. As shown in fig. 1 to 7, the method comprises the following steps:
step 1, performing inclined horizontal well drilling in a roof stratum at the top of a target working surface:
constructing an inclined horizontal well on the ground by using an inclined vertical well drilling machine and adopting a three-well structure; drilling to the position below the aquifer at an initial drilling well bevel angle of 10-30 degrees, casing well cementation, and returning cement to the ground; beginning to make a deviation after drilling to a deviation point, and stably drilling a pilot hole well to detect coal when the well deviation is 40-60 degrees, lifting the drill after the pilot hole well is detected to a target coal bed, and logging to obtain coal bed information; cementing backfill the pilot hole well, and then continuing to drill to the landing site in an inclination increasing way; casing well cementation, and returning cement to the ground; and thirdly, drilling into the depth of the final hole, casing and cementing, and returning cement to the ground to obtain the inclined horizontal well.
The inclined horizontal well is drilled by adopting an inclined vertical well drilling machine, and compared with a conventional vertical well drilling machine, the inclined horizontal well drilling machine has the advantages that the coal bed is shallow in burial, the deflecting point is shallow, the distance from the surface soil layer is relatively short, and the construction quality is not easy to control; and because the coal seam is shallow to be buried, in order to achieve horizontal section well deviation at the landing site, high slope drilling is required to be maintained, and the casing is not beneficial to being put into. The inclined vertical well drilling machine is used for drilling, so that a larger horizontal section length can be obtained, the difficulty in the processes of directional deflecting, inclination increasing and the like in the drilling construction process is reduced, and the adaptability to large water drop of the shallow coal seam is stronger than that of horizontal well drilling.
The two-open drilling guide hole can achieve the purpose of coal detection, so that accurate data is provided for three-open horizontal section drilling, and control of horizontal well drilling tracks is facilitated. The mine with perfect geological data and detailed coal seam geological data can be directly drilled to the landing site without drilling a guide hole.
Wherein the vertical distance between the horizontal section of the inclined horizontal well and the top surface of the coal seam is 2-5m.
The drilling of the horizontal section of the inclined horizontal well can also adopt a reaming while drilling technology, so that the drilling holes of the horizontal section of the horizontal well are increased under the condition that a drill bit is not replaced, the slurry input displacement is increased, and the wellhead pressure during slurry injection is reduced.
The roller type centralizer is adopted when the three-opening casing pipe is put down, so that the casing pipe is guaranteed to be centered on one hand, and the resistance of the casing pipe to pushing is reduced on the other hand.
Preferably adopting an inclined straight well drilling machine to carry out shallow coal seam roof horizontal well construction; the method is characterized in that the target coal seam is shallow in vertical burial, and in a limited vertical depth range, the deflecting from the vertical direction to the horizontal direction needs to be realized, so that the deflecting rate requirement in drilling is high, and the method is unfavorable for the subsequent casing running.
According to the maximum curvature of the well bore allowed to pass through by the casing, the calculation method for obtaining the minimum curvature radius of the well bore of the inclined horizontal well comprises the following steps:
wherein d is the outer diameter of the sleeve, m; k (k) 1 As a safety factor, API recommendation is 1.8; k (k) 2 API recommended to be 3.0 for thread stress concentration factor; t is the yield strength of the steel of the sleeve body and MPa.
When the burial depth H of the coal seam meets the following conditions:
H-h m ≤R+h
the drilling construction operation should be performed by using an inclined vertical well drilling machine.
Wherein h is an open drilling depth, m; h is a m And m is the vertical distance between the horizontal section of the inclined horizontal well and the top surface of the coal seam.
As shown in FIG. 2, if the conventional vertical drilling machine is used for drilling, the drilling depth of one drill is H, the drilling depth of one drill cannot be inclined within the range of the drilling depth of one drill, and if the drilling depth of two drills is directly inclined at the bottom of one drill, the drilling depth of one drill is H-H m When R+h is less than the threshold value, the steering of the well track from the deflecting point to the landing point from the vertical 90 degrees to the horizontal 0 degrees can not be realized in a limited depth range, namely the steering from the vertical to the horizontal can not be realized in a limited vertical depth range, so that the drilling failure of the horizontal well of the top plate is caused, and the subsequent filling and mining operation is influenced. If an inclined vertical well drilling machine is adopted, the initial drilling is performed, namely, the stratum is drilled with a certain well inclination angle, the requirement for deflecting is reduced, the initial drilling well inclination angle is assumed to be 10-30 degrees, and the steering requirement is reduced from 90 degrees to 0 degrees to 80-60 degrees to 0 degrees. Therefore, when the buried depth of the coal seam is shallow, an inclined vertical well drilling machine is adopted.
Taking a certain target coal seam with a buried depth of 330m as an example, the first drilling depth of the region is 20m, the vertical distance between the horizontal section of the inclined horizontal well and the top surface of the coal seam is 5m, and the outside diameter of a casing is planned to be put inInner diameter->The tensile strength of the sleeve body with the steel grade of N80 is 177MPa, and the minimum curvature radius R allowing the sleeve to pass through is calculated as follows:
the buried depth of the coal seam (H-5 m=325 m) is less than or equal to (390.65m+20m= 410.65 m), and a top plate horizontal well needs to be constructed by adopting an inclined vertical well drilling machine. The inclined vertical well drilling machine can reduce the requirement of the borehole curvature in the working hour of horizontal well deflecting Duan Shi, improve the construction safety and facilitate the casing running.
Also taking a certain target coal seam with a buried depth of 330m as an example, the first drilling depth in the area is 20m, the vertical distance between the horizontal section of the inclined horizontal well and the top surface of the coal seam is 5m, and the outside diameter of a casing is planned to be put inInner diameter->The tensile strength of the sleeve body with the steel grade of N80 is 483MPa, and the minimum curvature radius R allowing the sleeve to pass through is calculated as follows:
the buried depth of the coal seam (H-5 m=325 m) > (281.82m+20m=301.82 m), a top plate horizontal well can be constructed by adopting an inclined vertical well drilling machine or a conventional vertical well drilling machine, and when the inclined vertical well drilling machine is adopted, the requirement on the curvature of a well hole in the process of deflecting the horizontal well for Duan Shi hours can be reduced, so that the construction safety is improved.
Fig. 3 is a schematic diagram of a well bore structure of an inclined horizontal well, wherein the shallow coal seam is sequentially provided with a coal seam roof overburden layer 3, a coal seam roof layer 2, a target mining coal seam 1 and a coal seam floor layer 4 from top to bottom; drilling in the coal seam roof strata 2 results in a slanted horizontal well 5.
Step 2, implementing staged detonation fracturing on the inclined horizontal well:
2.1, perforating an inclined horizontal well by adopting a multi-stage perforating gun, transmitting an oil pipe to a preset depth for perforation, wherein the length of a single perforation section is 1-2 m, the perforation density is not less than 10 holes/m, the interval between adjacent perforation sections is not less than 20m, and completing the perforation operation of the whole well section;
2.2, connecting a detonation fracturing tool string, wherein the detonation fracturing tool string comprises a plurality of connecting parts sequentially from top to bottom: the device comprises a joint, a mechanical packer, a magnetic positioner, a centralizer, a heat insulation ring, an impact igniter, deflagration fracturing powder columns, a centralizer and a guide shoe, wherein the powder adopts solid powder, and the charging length and the charging amount are carried out according to an optimal design;
2.3, using oil pipe transmission to serially send the detonation fracturing tool connected in the step 2.2 to a designed first perforation section of the inclined horizontal well, and using a magnetic positioner to calibrate the depth so as to align the fracturing bomb to the perforation section;
2.4, setting the mechanical packer and installing a wellhead blowout preventer;
2.5, throwing an impact rod into the oil pipe from the wellhead to ignite and detonate the fracturing bomb;
2.6, deblocking the packer, and taking out the operation pipe column in the well;
and 2.7, repeating the steps 2.2-2.6, and sequentially fracturing the second perforating section, the third perforating section, the … … and the nth perforating section until the deflagration fracturing operation of all the perforating sections is completed.
Fig. 4 is a schematic diagram of a staged detonation fracturing fracture of a slant horizontal well, wherein a triple casing 6 of the slant horizontal well and a radial fracture 7 formed by detonation fracturing are included. FIG. 5 is a schematic representation of the deflagration fracture morphology of the present application.
After deflagration and fracturing, a complex seam network which is not controlled by ground stress can be formed around the well hole, so that the top plate can be weakened, and the top plate is facilitated to collapse and the casing is exposed.
The vertical stress of the shallow coal seam is low, and if the hydraulic fracturing technology is adopted to fracture the top plate, horizontal seams can be formed, so that the explosion fracturing technology is more suitable for the shallow coal seam.
At present, the existing common fracturing technology is mainly hydraulic fracturing technology, a high-pressure fracturing pump is utilized to inject the fracturing fluid into a well at a displacement exceeding the stratum absorption capacity, high pressure is held down at the bottom of the well, and when the pressure is greater than the ground stress near the well wall and the stratum rock tensile strength, cracks are generated in the stratum near the bottom of the well. The ground stress in the stratum can be decomposed into vertical stress, maximum horizontal principal stress and minimum horizontal principal stress along three directions, and the ground stress field types can be generally divided into 3 types according to the relative sizes of the three-dimensional principal stress: class I-vertical principal stress maximum (sigma v >σ H >σ h ) Is positive fracture layer type, type II-vertical main stress minimum (sigma H >σ h >σ v ) Is reverse-layer-broken type; class III-vertical principal stress centering (sigma H >σ v >σ h ) Is a sliding layer-breaking type. Under the ground stress state of class I and class III, the minimum horizontal main stress is three-way minimum main stress, and the hydraulic fracturing mainly develops vertical joints; in the class II ground stress state, the vertical main stress is the minimum main stress, and the hydraulic fracturing mainly develops horizontal joints.
The application preferably adopts deflagration fracturing technology, and mainly aims at the characteristics of shallow coal seams. The shallow coal seam is shallow in depth and low in vertical stress, and the ground stress is generally characterized in that the vertical stress is less than the minimum horizontal main stress and less than the maximum horizontal main stress, namely, the reverse fracture layer is formed, so that if the hydraulic fracturing technology is directly adopted, horizontal seams are formed in the stratum, the deformation of a sleeve is easily caused when the stratum of the roof of the coal seam collapses, and a slurry conveying channel is not smooth.
FIG. 6 (a) is a cross-sectional view of a deflagration-fracture of the present application, including a radial fracture 7 formed by deflagration fracturing; and (b) conventional hydraulic fracture profile, including hydraulic fracture-formed fracture 8.
Accordingly, the present application preferably employs deflagration fracturing techniques for such ground stress conditions. The crack extension of the deflagration fracturing technology is not influenced by the ground stress state, 3-8 cracks can be formed along perforation holes in deflagration fracturing construction, the crack length can reach 1-15 m, and the cracks are along the radial direction of a shaft. After deflagration fracturing, the roof of the coal bed is broken, and after the lower coal bed is mined, roof strata is weakened and can smoothly collapse in a fragment shape, so that the sleeve is exposed and is used as a conveying channel for filling slurry.
Step 3, ground crushed coal gangue is used for preparing filling slurry:
coal gangue produced in the coal mining process is crushed, screened to grain size not larger than 4mm, and then mixed with waste water to prepare slurry with density of about 1.15-1.20g/cm 3 。
Wherein, the crushing and screening particle size is not more than 4mm to ensure that the filling slurry does not generate sedimentation, separation layers and the like in the conveying process.
Step 4, stoping of the working face is started, after stoping is carried out to a certain distance, along with coal mining and pushing of the working face, the hydraulic support moves forwards, the roof strata of the goaf collapses under the action of gravity, the sleeve is exposed under the action of gravity, and the front end of the sleeve is positioned on the goaf;
step 5, filling slurry is injected from a ground wellhead, and a goaf is formed after the hydraulic support is filled:
pumping the filling slurry prepared in the step 3 into a horizontal well by a ground pump, wherein the pumping discharge capacity is 2-5m 3 And/min. The specific pumping displacement is determined in accordance with the rated operating pressure and rated power of the surface injection pump. The filling slurry injected through the conveying channel is mixed with the caving coal seam roof rock blocks and accumulated in the goaf, and the rock layer at the upper part of the goaf is supported. The hydraulic support belongs to coal mining equipment, and after coal is cut by the coal cutting machine, the hydraulic support temporarily supports a goaf, and along with the pushing of coal mining of the coal cutting machine, the hydraulic support moves forward along with the coal cutting machine.
Fig. 7 is a schematic diagram of the grouting and filling of the inclined horizontal well, which comprises a filling slurry 9, a roof strata collapse rock block 10 and a hydraulic bracket 11 of coal mining equipment.
And 6, continuously stoping the working face, moving the hydraulic support forwards, and repeating the steps 4-5 until the continuous stoping and continuous filling operation of the whole working face is completed.
The following specific embodiments of the present application are provided, and it should be noted that the present application is not limited to the following specific embodiments, and all equivalent changes made on the basis of the technical scheme of the present application fall within the protection scope of the present application.
Examples:
the embodiment provides a method for constructing a filling slurry conveying channel of a shallow coal seam along with mining, which takes a certain coal mine in the north of Shanxi province as an example, wherein the burial depth of the coal seam is 200-230m, the width of a working face is 200m, the length is 600m, and the average thickness of the coal seam is 3.5m. In order to achieve the aim of green coal mining, the method for mining coal mining while filling coal mining of the shallow coal seam based on the deflagration fracturing roof horizontal well is adopted to carry out the mining while filling operation.
Step 1: and constructing an inclined horizontal well in the roof stratum above the target working surface, and designing the horizontal section length of the horizontal long drilling hole to be 600m for covering one working surface, wherein the distance from the horizontal section length to the top surface of the coal seam is 3m in the longitudinal direction. The horizontal well drilling adopts an MZJ-90XY full-hydraulic inclined vertical well drilling machine. The maximum drilling depth of the drilling machine is 1:500 m, and the maximum inclination angle of the derrick is 45 degrees. The initial drilling angle of the inclined horizontal well is 15 degrees, the horizontal well adopts a three-well structure and one drill bitTwo-way drill bit->Three-open drill bitBecause the coal bed in the area has simple structure and complete geological data of the coal bed, no pilot hole drilling is constructed in the two-stage drilling process. The three openings are N80 steel sleeves.
Step 2: and the horizontal section of the inclined horizontal well carries out sectional detonation fracturing to weaken the top plate. And (3) perforating by adopting an oil pipe to transmit a perforating gun, wherein the segment spacing of the perforating segments is 30m. And (3) adopting an oil pipe transmission mode to implement detonation fracturing on each perforation section, and forming a radially expanded complex seam network around the well bore.
Step 3: the solid waste formed by mining coal mine is crushed, screened and sized with the grain diameter not more than 4mm, and then mixed with wastewater to prepare slurry with the density of about 1.15-1.20g/cm 3 。
Step 4: the working face is provided with a coal cutter and a hydraulic support, and coal seam stoping of the working face is started. The roof strata collapse after the coal seam is mined back for 5-6m, the sleeve is exposed and is suspended above the goaf in an arc shape under the action of gravity.
Step 5: pumping the filling slurry prepared in the step 3 into a horizontal well through a ground pump, wherein the pumping discharge capacity is 3m 3 /min。
Step 6: and observing the filling condition of the goaf through a monitoring system behind the hydraulic support, stopping filling after the design requirement is met, cutting the sleeve, repeating the steps, and continuing to perform coal seam stoping and slurry filling operation until the continuous mining and continuous filling operation of the whole working face is completed.
Claims (9)
1. The method for mining coal while mining and while filling of the shallow coal seam based on the deflagration fracturing roof horizontal well is characterized by comprising the following steps of:
step 1, constructing an inclined horizontal well in a coal seam roof stratum at the top of a target working surface by adopting a three-well structure;
step 2, implementing segment detonation fracturing on the horizontal section of the inclined horizontal well: perforating the inclined horizontal well by adopting a multistage perforating gun to complete the whole-well section perforating operation, so as to obtain a plurality of perforating sections; connecting the detonation fracturing tool strings, and transmitting the connected detonation fracturing tool strings to the perforating segments by adopting oil pipe transmission to finish detonation fracturing operation of all the perforating segments;
step 3, ground crushed coal gangue is used for preparing filling slurry: coal gangue generated in the coal mining process is crushed and screened and then mixed with wastewater to prepare slurry;
step 4, working face stoping is started, along with working face coal mining pushing, the hydraulic support moves forward, a goaf roof stratum collapses under the action of gravity, the sleeve is exposed under the action of gravity, and the front end of the sleeve is positioned on the goaf;
step 5, filling slurry is injected from a ground wellhead, and a goaf is formed after the hydraulic support is filled: pumping the filling slurry prepared in the step 3 into a horizontal well through a ground pump; the injected filling slurry and the caving coal seam roof rock are mixed and piled up in the goaf to form a support for the rock stratum at the upper part of the goaf;
and 6, continuously stoping the working face, moving the hydraulic support forwards, and repeating the steps 4-5 until the continuous stoping and continuous filling operation of the whole working face is completed.
2. The method for mining coal while mining and while filling of a shallow coal seam based on a deflagration-fracture roof horizontal well as claimed in claim 1, wherein the step 1 comprises: drilling to the position below the aquifer at an initial drilling well bevel angle of 10-30 degrees, casing well cementation, and returning cement to the ground; beginning to make a deviation after drilling to a deviation point, stably and obliquely drilling a pilot hole well for detecting coal when the well deviation is 40-60 degrees, lifting the drill after the pilot hole well is detected to a target coal bed, filling cement and backfilling the pilot hole, then continuing to drill to a landing point in an inclination increasing way, setting a sleeve, and returning cement to the ground; and thirdly, drilling into the depth of the final hole, casing and cementing, and returning cement to the ground to obtain the inclined horizontal well.
3. The method for mining coal while mining and while filling of a shallow coal seam based on a deflagration-fracture roof horizontal well as claimed in claim 1, wherein in the step 1, the vertical distance between the horizontal section of the inclined horizontal well and the top surface of the coal seam is 2-5m.
4. The method for mining coal while mining and while filling of a shallow buried coal seam based on a deflagration-fracturing roof horizontal well according to claim 3, wherein in the step 1, when the depth of burial H of the coal seam is as follows: H-H m When R+h is less than or equal to R+h, adopting an inclined vertical well drilling machine to perform drilling construction operation;
in the above formula, h is a drilling depth, m; h is a m The vertical distance between the horizontal section of the inclined horizontal well and the top surface of the coal seam is m; r is the minimum curvature radius of the inclined horizontal well bore, and the calculation formula is as follows:
wherein d is the outer diameter of the sleeve, m; k (k) 1 Is a safety coefficient; k (k) 2 Is the stress concentration coefficient of the thread; t is the yield strength of the steel of the casing pipe body,MPa。
5. the method for mining coal while mining and filling shallow coal seam based on deflagration-fracturing roof horizontal well according to claim 1, wherein in the step 2, the oil pipe transmits the multi-stage perforating gun to the perforation of the preset depth, the length of a single perforation section is 1m-2m, the perforation density is not less than 10 holes/m, and the interval between the adjacent perforation sections is not less than 20m.
6. The method for mining coal while mining and while mining shallow coal seam based on deflagration fracturing roof horizontal well as claimed in claim 1, wherein in the step 2, deflagration fracturing tool string comprises sequentially connected from top to bottom: the device comprises a joint, a mechanical packer, a magnetic positioner, a centralizer, a heat insulation ring, an impact igniter, deflagration fracturing powder columns, a centralizer and a guide shoe.
7. The method of mining while mining and while filling coal of a shallow coal seam based on a deflagration-fracture roof horizontal well of claim 6, wherein completing deflagration-fracturing operations of all perforation segments comprises: connecting a detonation fracturing tool string, conveying the connected detonation fracturing tool string to a first perforating section by adopting oil pipe transmission, and calibrating the depth by using a magnetic positioner to enable fracturing bullets to be aligned to the perforating section; setting the mechanical packer and installing a wellhead blowout preventer; throwing an impact rod into an oil pipe from a wellhead to ignite and detonate a fracturing bomb; deblocking the mechanical packer, and lifting out an operation tubular column in the well; repeating the operation until the deflagration fracturing operation of all perforation segments is completed.
8. The method for mining coal while mining and filling in shallow coal seam based on deflagration-fracturing roof horizontal well as claimed in claim 1, wherein in the step 3, the particle size of the crushed gangue is not more than 4mm, and the slurry density is 1.15-1.20g/cm 3 。
9. The method for mining coal while mining and while filling in shallow coal seam based on deflagration-fracturing roof horizontal well as recited in claim 1, wherein in step 5, pumping displacement of pumping filling slurry is 2-5m 3 /min。
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| CN118292885A (en) * | 2024-06-05 | 2024-07-05 | 山西鸿太旭飞建设有限公司 | Mining method for preventing earth surface subsidence by mining underground resources without coal pillars |
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| CN118292885A (en) * | 2024-06-05 | 2024-07-05 | 山西鸿太旭飞建设有限公司 | Mining method for preventing earth surface subsidence by mining underground resources without coal pillars |
| CN118292885B (en) * | 2024-06-05 | 2024-08-09 | 山西鸿太旭飞建设有限公司 | Mining method for preventing earth surface subsidence by mining underground resources without coal pillars |
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