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Equipment and method for controlling industrial and mining limestone roof of well through acid fracturing

A technology for industrial and mining limestone and acid fracturing, which is applied in surface mining, earthwork drilling, underground mining, etc., can solve the problems of unsatisfactory limestone caving effect and high hydraulic fracturing construction pressure, and improve the caving of suspended ceiling. effect, reducing construction pressure, reducing the effect of limestone strength

Active Publication Date: 2021-04-13
CHINA UNIV OF MINING & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] In view of this, the present invention discloses equipment and methods for acid fracturing to control the limestone roof of an underground mine, so as to solve the problems of high hydraulic fracturing construction pressure on the hard and thick limestone roof, unsatisfactory effect of limestone roof suspension and caving after conventional hydraulic fracturing, etc. Thereby reducing the fracturing pressure of the hard and thick limestone roof and improving the effect of the suspended roof collapse after fracturing

Method used

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  • Equipment and method for controlling industrial and mining limestone roof of well through acid fracturing
  • Equipment and method for controlling industrial and mining limestone roof of well through acid fracturing
  • Equipment and method for controlling industrial and mining limestone roof of well through acid fracturing

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Effect test

Embodiment 1

[0047] Acid fracturing to control limestone suspended roof in goaf:

[0048] The average thickness of coal seam 1 in the construction coal mine is 3m, the inclination angle of coal seam 1 is 3-8°, the roof of coal seam 1 is limestone, with an average thickness of 8m, and the bottom plate 3 is mudstone, aluminous mudstone and sandy mudstone, with an average thickness of 4.69m. The design length of 6 cutting holes in the coal mining face is 150m, and it is a rectangular section with a net width of 7.0m, a net height of 3.0m, and an azimuth angle of 1°.

[0049] Acid fracturing specifically includes the following steps:

[0050] Step 1: If image 3 , 4 As shown, a group of parallel boreholes 7 are constructed on the vertical roof near the coal wall side between the 6 frames of the coal mining face, which are used for acid fracturing to cut off the coal wall support and reduce the caving step distance of the limestone suspended roof. A group of parallel boreholes 7 is construct...

Embodiment 2

[0061] Acidify the limestone roof 2 above the pre-splitting coal seam to weaken its strength, prompting it to collapse in time with the mining of the coal seam 1, avoiding the formation of a large-scale overhang in the goaf after the erection, and fundamentally eliminating the overhang of the goaf Disaster hazard.

[0062] The average thickness of coal seam 1 in the construction coal mine is 5m, and the roof of coal seam 1 is limestone with an average thickness of 12m. The design length of 6 cutting holes in the coal mining face is 200m, the net width is 7.6m, and the net height is 3.2m. Combined support method.

[0063] Acid fracturing specifically includes the following steps:

[0064] Step 1: If Figure 5 , 6 As shown, a group of parallel boreholes 7 are constructed on the vertical roof near the gob side between the 6 racks of the coal mining face, which are used for acid fracturing to cut off the coal wall support and reduce the caving step distance of the limestone su...

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Abstract

The invention discloses equipment and method for controlling an industrial and mining limestone roof of a well through acid fracturing, and relates to the technical field of mining. The method comprises the following steps of constructing a group of parallel drill holes between working face frames close to a coal wall side and a goaf side; sealing the drill holes, starting a high-pressure pump to inject acid liquor into the drill holes, stopping injecting when the pressure of the pipeline reaches 10 MPa, and maintaining the pressure for 5-10 min; after pressure maintaining is finished, starting the high-pressure pump again to conduct limestone roof acid fracturing for 30 min; after fracturing is finished, turning off the high-pressure pump, and carrying out pressure maintaining for 5-10 min; after pressure maintaining is finished, relieving the pipeline pressure, and taking a hole packer; and repeating the steps until fracturing of all the drilled holes is completed. According to the method, the acid fracturing mode is adopted for treating the industrial and mining hard limestone roof of the well, through dissolution of acid liquor to limestone, on one hand, the construction pressure in the fracturing process can be reduced, on the other hand, the opening degree of a fracturing crack can be increased, the meshing effect of rock blocks on the two sides of the fractured crack is reduced, and sufficient caving of the limestone roof is facilitated.

Description

technical field [0001] The invention relates to the technical field of mining, in particular to equipment and a method for acidizing and fracturing the limestone roof of an underground mine. Background technique [0002] When there is a hard rock formation directly above the coal seam or directly above the thinner roof, with the mining of the coal seam, the hard roof is difficult to collapse in time, and a large area of ​​suspended roof is formed in the gob. Sudden collapse of a large-scale suspended roof is likely to cause impact loads, large-area roof pressure, storms, etc., and even induce ground pressure bursts. There are also a large number of disasters caused by hard suspended roofs in goafs that need to be treated in non-coal mines. [0003] The traditional method to deal with the suspended roof of the goaf is forced roof caving by artificial explosive blasting. However, this method has a large amount of engineering and explosives, high cost, poor controllability, e...

Claims

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Application Information

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IPC IPC(8): E21C41/18
CPCE21C41/18
Inventor 赵兴龙黄炳香陈树亮蔡青旺
Owner CHINA UNIV OF MINING & TECH
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