CN108343418B - Method for controlling mining influence range from surface directional hydraulic fracturing pre-cracked bedrock - Google Patents
Method for controlling mining influence range from surface directional hydraulic fracturing pre-cracked bedrock Download PDFInfo
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- CN108343418B CN108343418B CN201810191336.9A CN201810191336A CN108343418B CN 108343418 B CN108343418 B CN 108343418B CN 201810191336 A CN201810191336 A CN 201810191336A CN 108343418 B CN108343418 B CN 108343418B
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- 238000005065 mining Methods 0.000 title claims abstract description 40
- 238000000034 method Methods 0.000 title claims abstract description 17
- 238000005553 drilling Methods 0.000 claims abstract description 32
- 239000011435 rock Substances 0.000 claims abstract description 30
- 238000010276 construction Methods 0.000 claims abstract description 3
- 239000003245 coal Substances 0.000 claims description 13
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 6
- 230000002829 reductive effect Effects 0.000 claims description 3
- 230000005540 biological transmission Effects 0.000 claims description 2
- 230000000149 penetrating effect Effects 0.000 claims description 2
- 238000007789 sealing Methods 0.000 claims description 2
- 239000011159 matrix material Substances 0.000 claims 2
- 238000013459 approach Methods 0.000 description 2
- 230000006378 damage Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 230000036961 partial effect Effects 0.000 description 2
- 230000001681 protective effect Effects 0.000 description 2
- 238000000926 separation method Methods 0.000 description 2
- 230000007547 defect Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 230000000977 initiatory effect Effects 0.000 description 1
- 229910052500 inorganic mineral Inorganic materials 0.000 description 1
- 238000002955 isolation Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 239000011707 mineral Substances 0.000 description 1
- 230000002441 reversible effect Effects 0.000 description 1
- 239000004576 sand Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- 238000012546 transfer Methods 0.000 description 1
- 230000003313 weakening effect Effects 0.000 description 1
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- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B43/00—Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
- E21B43/25—Methods for stimulating production
- E21B43/26—Methods for stimulating production by forming crevices or fractures
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- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21C—MINING OR QUARRYING
- E21C41/00—Methods of underground or surface mining; Layouts therefor
- E21C41/16—Methods of underground mining; Layouts therefor
- E21C41/18—Methods of underground mining; Layouts therefor for brown or hard coal
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- Engineering & Computer Science (AREA)
- Mining & Mineral Resources (AREA)
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- Geology (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geochemistry & Mineralogy (AREA)
- Physics & Mathematics (AREA)
- Environmental & Geological Engineering (AREA)
- Fluid Mechanics (AREA)
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- Investigation Of Foundation Soil And Reinforcement Of Foundation Soil By Compacting Or Drainage (AREA)
- Earth Drilling (AREA)
Abstract
The invention relates to a method for controlling the mining influence range from the earth surface directional hydraulic fracturing pre-cracked bedrock, which comprises the following steps: 1) obtaining overburden in a pre-fractured zoneAnalyzing and determining the moving basin boundary of the earth surface according to the geological condition, wherein the geological condition of the overlying strata comprises the rock horizon of the overlying strata, the thickness of the strata and the thickness h of the unconsolidated layer1Formation strength and ground stress; 2) determining the width D of the guard band according to the protection grade of a building needing to protect the earth surface; 3) determining the layout distance L of the drilled holes from the building (structure) according to the width of the guard band determined in the step 2) and the safety coefficient q of the building (structure), wherein L = q × D; 4) determining a presplitting depth h2= S tan δ; 5) determining borehole depth H = H1+h2(ii) a 6) And drilling, hydraulic fracturing and other operations are carried out according to the drilling position and the drilling depth. The method can effectively control the influence of the mining range during underground mining, and can greatly reduce the construction difficulty by adopting the surface directional hydraulic fracturing method.
Description
Technical Field
The invention particularly relates to a method for controlling mining influence range and optimizing a mining stopping line from an earth surface directional hydraulic fracturing pre-cracked bedrock, and belongs to the technical field of mining methods.
Background
Coal is a main energy source in the current society, and with the development of the society and the progress of production technology, the demand of people for energy sources is more and more large. After the coal is mined from the underground, the overlying strata above the coal is not supported, the original stress balance state in the rock mass is damaged, the redistribution of the internal stress of the rock mass is caused, and the rock mass around the goaf is displaced, deformed and damaged. When the area of the goaf reaches a certain range, the earth surface above the goaf is caused to move and deform. The movement and deformation of the earth's surface affect the foundation of the building, resulting in the movement and deformation of the building, even the destruction.
The main technical approaches for controlling and relieving surface subsidence at present are filling mining, partial mining, overburden zona isolation grouting filling and the like. The filling mining is to fill a goaf formed after mineral resources are mined by adopting external materials, including water sand filling, gangue filling and the like, but the method has high cost and complex process, and is rarely used in a coal system in China at present. The grouting, filling and subsidence reducing of a overburden separation zone is a new ground surface subsidence control method which is provided in recent years, and the essence of the method is that a separation space formed in overburden in the grouting, filling and mining process prevents upward transfer of a mining space, prevents and slows down continuous subsidence of an overlying strata, and achieves the purpose of slowing down ground subsidence. Partial mining, which mainly includes chamber mining and strip mining, uses a remaining rectangular or strip coal pillar to support the overburden to control surface subsidence. The strip mining is the main technical approach for controlling the coal mining surface subsidence under the domestic buildings at present, and the biggest defect is that the permanent loss rate of coal is higher. In actual production, the boundary of the earth surface moving basin is mostly defined according to the angle of the earth surface moving basin boundary. The method can only estimate and demarcate the subsidence area, can not actively control the surface subsidence area, and can not play an active protection role on buildings (structures) in the surface subsidence area.
Disclosure of Invention
The invention aims to provide a method for controlling mining influence range and optimizing a mining stop line from an earth surface directional hydraulic fracturing pre-cracked bedrock, which comprises the following steps:
1) acquiring geological conditions of an overlying rock stratum in a pre-splitting area, and analyzing and determining a surface mobile basin boundary, wherein the geological conditions of the overlying rock stratum comprise an overlying rock layer position, a rock stratum thickness and a loose layer thickness h1Formation strength and ground stress;
2) determining the width D of the guard band according to the protection grade of a building needing to protect the earth surface;
3) determining the layout distance L of the drilled holes from the building (structure) according to the width of the guard band determined in the step 2) and the safety coefficient q of the building (structure), wherein L = q × D;
4) determining a trend moving angle delta and a stopping and mining line horizontal moving distance S according to the ground surface moving basin determined in the step 1), and determining a pre-splitting depth h2= S*tanδ；
5) Thickness h of the bulk layer determined in accordance with step 1)1And step 4) determining the pre-splitting depth h of the drilled hole2Determining borehole depth H = H1+ h2；
6) And performing drilling, hydraulic fracturing and other operations according to the drilling position determined in the step 3) and the drilling depth determined in the step 5).
Further, the hydraulic fracturing operation in step 6) comprises the following steps:
61) determining drilling parameters according to the geological condition of the overlying rock stratum and the pre-splitting depth;
62) drilling holes on the ground surface according to the drilling parameters determined in the step 61);
63) according to the geological condition of the overlying rock stratum and the hole depth of the drilled hole, slotting at a preset distance of the drilled hole to obtain a plurality of slots;
64) sealing holes at the front and rear positions of each cutting groove, injecting high-pressure water into the drill hole, and enabling the high-pressure water to act on the cutting grooves to crack the two sides of the cutting grooves to form penetrating cracks and weaken the overall strength of the rock stratum;
65) after hydraulic fracturing, the mining stopping line of the working face extends from A to A, so that the size of a protective coal pillar of an earth surface building (structure) is reduced, and the mining rate of coal is improved.
Further, the drilling parameters in the step 61) include drilling position, drilling hole depth and drilling hole spacing.
The hydraulic fracturing technology is applied to the field of controlling the mining influence range and optimizing the mining stop line, namely, the strength of a rock body is weakened through directional hydraulic fracturing, and the transmission of the overlying strata fracture to the mining direction of a working face is cut off, so that the aim of controlling the mining influence range is fulfilled. The weakening of rock mass by hydraulic fracturing is mainly embodied in two aspects: firstly, the macroscopic and microscopic structure of the rock mass is reformed through the initiation and expansion of hydraulic fractures, and the mechanical property of the rock mass is weakened; and secondly, the mechanical property of the rock is reduced through the physical and chemical action of water on the rock. The two act together to weaken the mechanical property of the rock mass and reduce the overall strength of the roof rock. The invention optimizes the position of the stoping line on the premise of ensuring that the surface building is not influenced by mining damage, reduces the size of a protective coal pillar reserved for protecting the surface building, and improves the coal mining rate.
The invention carries out hydraulic fracturing operation on the overburden from the earth surface to the downward hole, can greatly reduce the construction difficulty compared with underground fracturing, has high safety, can directly cut off the bedrock of the overburden which has larger influence on the earth surface, and has higher reliability when being used for controlling the influence of the mining range.
Drawings
FIG. 1 is a schematic diagram of the present invention for determining the pre-crack height;
FIG. 2 is a schematic diagram of the present invention for determining the location of the drill hole;
fig. 3 is a schematic view of the drilling arrangement of the present invention.
Detailed Description
A certain mine 5304 working surface is to be selected as a test area. As shown in figures 1-3, a building is built in front of a working face, the geological condition of the overburden in the area where the building is located is obtained, the boundary of a moving basin of the ground surface is analyzed and determined, the moving angle of the moving basin of the ground surface and the thickness h of a loose layer are determined1(ii) a Determining the arrangement distance L and the presplitting depth h of a drilling hole from a building (structure)2And then determines the drilling depth H. And vertically drilling at the determined presplitting position, uniformly arranging the drilling belts along the guard belt and the mining area, and drilling according to the presplitting depth, wherein the distance between the drilling holes is 10 m. A KZ54 type grooving drill bit is adopted, a transverse grooving is prefabricated in a rock stratum, a reverse fracturing method is adopted for hydraulic fracturing holes, and fracturing is carried out once every 1.5-2 m from the bottom of a drilled hole to the outside. A fracture zone is formed between the building (structure) and the mining area after pre-splitting, and the mining stopping line is moved from A to A'.
Claims (2)
1. A method of controlling the range of mining impacts from a surface oriented hydrofracturing of a pre-fractured matrix, comprising the steps of:
1) acquiring geological conditions of an overlying rock stratum in a pre-splitting area, and analyzing and determining a surface mobile basin boundary, wherein the geological conditions of the overlying rock stratum comprise an overlying rock layer position, a rock stratum thickness, a loose layer thickness h1, a rock stratum strength and a ground stress;
2) determining the width D of the enclosure belt according to the protection level of the earth surface structure to be protected;
3) determining the layout distance L of the drilled holes from the building according to the width of the guard band determined in the step 2) and the safety coefficient q of the building, wherein L = q × D;
4) determining a trend moving angle delta and a stopping and mining line horizontal moving distance S according to the ground surface moving basin determined in the step 1), and determining a pre-splitting depth h2 = S tan delta;
5) determining the drilling depth H = H1+ H2 according to the loose layer thickness H1 determined in the step 1) and the drilling pre-splitting depth H2 determined in the step 4);
6) drilling and hydraulic fracturing operation are carried out according to the drilling position determined in the step 3) and the drilling depth determined in the step 5), the strength of a rock body is weakened through directional hydraulic fracturing, the transmission of the overburden rock fracture to the mining direction of a working face is cut off, and the purpose of controlling the mining influence range is achieved, wherein the hydraulic fracturing operation comprises the following steps:
61) determining drilling parameters according to the geological condition of the overlying rock stratum and the pre-splitting depth;
62) drilling holes on the ground surface according to the drilling parameters determined in the step 61);
63) according to the geological condition of the overlying rock stratum and the hole depth of the drilled hole, slotting at a preset distance of the drilled hole to obtain a plurality of slots;
64) sealing holes at the front and rear positions of each cutting groove, injecting high-pressure water into the drill hole, and enabling the high-pressure water to act on the cutting grooves to crack the two sides of the cutting grooves to form penetrating cracks and weaken the overall strength of the rock stratum;
65) after the hydraulic fracturing, the mining stopping line of the working face extends from A to A, so that the size of a surface construction object protection coal pillar is reduced, and the mining rate of coal is improved.
2. The method of controlling the range of mining impacts by directional hydraulic fracturing of a pre-fractured matrix from the surface of claim 1, wherein: the drilling parameters in the step 61) comprise drilling position, drilling hole depth and drilling distance.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201810191336.9A CN108343418B (en) | 2018-03-08 | 2018-03-08 | Method for controlling mining influence range from surface directional hydraulic fracturing pre-cracked bedrock |
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| CN201810191336.9A CN108343418B (en) | 2018-03-08 | 2018-03-08 | Method for controlling mining influence range from surface directional hydraulic fracturing pre-cracked bedrock |
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| CN108343418A CN108343418A (en) | 2018-07-31 |
| CN108343418B true CN108343418B (en) | 2020-04-03 |
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| CN109594985A (en) * | 2018-11-22 | 2019-04-09 | 太原理工大学 | A kind of rockmass and surface subsidence distribution control method of mining overburden hydraulic slotted liner technique |
| CN110512588B (en) * | 2019-08-13 | 2021-05-25 | 安徽理工大学 | Protection method for tension fracture belt type protection zone crossing mine surface |
| CN111075507A (en) * | 2019-12-06 | 2020-04-28 | 华亭煤业集团有限责任公司 | Method and device for determining stoping line of coal mine stoping working face |
| CN112879011B (en) * | 2021-01-26 | 2021-10-12 | 中煤科工开采研究院有限公司 | Method for controlling height of water guide crack zone by hard overburden rock pre-cracking weakening under aquifer |
| CN113622913B (en) * | 2021-08-20 | 2022-05-06 | 中国矿业大学 | Deformation control method for mining tunnel surrounding rock integrated with underground and up-down tunnel by full-caving method |
| CN114278301A (en) * | 2021-12-23 | 2022-04-05 | 扬州中矿建筑新材料科技有限公司 | Method for dynamically controlling surface subsidence based on hydraulic fracturing and roof cutting |
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| CN106014407B (en) * | 2016-06-30 | 2018-09-11 | 太原理工大学 | Utilize the roof fracture water method that reduction master control coal rock layer controls disaster in situ |
| CN106368701B (en) * | 2016-09-27 | 2019-04-23 | 天地科技股份有限公司 | The method and device in lane is stayed using hydraulic fracturing release control stope drift active workings |
| CN206957683U (en) * | 2017-06-13 | 2018-02-02 | 中铁十九局集团矿业投资有限公司 | A kind of coal seam pressure relief and permeability improvement system |
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Inventor after: Guo Wenbing Inventor after: Feng Zhanjie Inventor after: Tan Yi Inventor after: Yang Daming Inventor after: Xu Feiya Inventor before: Feng Zhanjie Inventor before: Guo Wenbing Inventor before: Tan Yi Inventor before: Yang Daming Inventor before: Xu Feiya |
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