Horizontal-drilling staged-fracturing pressure relief method for underground coal bed

A horizontal drilling and staged fracturing technology, which is applied in earthwork drilling, wellbore/well components, gas discharge, etc., can solve the problems of high gas outburst, rock burst, etc., and reduce the gas content and risk , Improve the effect of permeability

Inactive Publication Date: 2013-08-07
珲春市耀天新能源开发利用有限责任公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] The purpose of the present invention is to provide a solution to the occurrence of high gas outburst and rock burst in the existing coal mining process, which can reduce the gas content in the coal seam and the risk of coal seam rock burst, and can provide technical support for the safe production of coal mines. Pressure relief method for staged fracturing of underground coal seam horizontal drilling

Method used

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  • Horizontal-drilling staged-fracturing pressure relief method for underground coal bed
  • Horizontal-drilling staged-fracturing pressure relief method for underground coal bed

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Effect test

Embodiment 1

[0022] According to the characteristics of the coal seam structure of the coal seam face, when the coal seam has good pore geological conditions and good permeability, follow the figure 1 For implementation, the specific method is to drill a main horizontal hole 5 with a length of 500m----1000m with a Φ215.9mm drill bit in the coal seam face 7 of the underground, and then run a steel-grade N80 oil casing pipe with a diameter of Φ139.7mm and a wall thickness of 7.72mm. 4. Cement the well with G-grade cement, wait for setting and then enter Φ118mm*2 after 48 hours 。 The single-bent screw is drilled into the main horizontal hole 5. 8-10 branch holes of 100-200m are drilled. After the drilling is thoroughly cleaned, the pressure-resistant 70MPa high pressure seal is installed at the main horizontal hole 5 through the high-pressure pipeline Hole device 3, and connect the pump injection equipment 2 with a working pressure of 70MPa, and pour 1500m into the hole 3 Or more volume of 0.5% ...

Embodiment 2

[0024] According to the characteristics of the coal seam structure of the coal seam face, in the case of poor pore-forming geological conditions and poor permeability, follow the figure 2 To implement, the specific method is to drill a main horizontal hole 5 with a length of 500m----1000m with a Φ215.9mm drill bit in the coal seam face 7 of the underground, and then run a steel-grade N80 oil casing pipe with a diameter of Φ139.7mm and a wall thickness of 7.72mm. 4. Cement the well with G-grade cement, wait for setting and then 48 hours later, run a Φ118mm screw, and then drill a 500-1000m horizontal borehole on the main horizontal hole 5. After thoroughly cleaning the borehole, enter the main horizontal hole 5. Install the pressure-resistant 70MPa high-pressure sealing device 3 through the high-pressure pipeline to connect the high-pressure pump injection equipment 2 with a working pressure of 70MPa, and then inject the polymer gel liquid with natural quartz sand proppant into ...

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Abstract

The invention discloses a horizontal-drilling staged-fracturing pressure relief method for an underground coal bed. The method mainly comprises the steps of drilling a main horizontal hole which is 500m-1000m in length through a drill on a working face of the underground coal bed; placing an oil casing pipe into the main horizontal hole, cementing a well by G-level cement, placing a single-bending screw after cement curing, and drilling 8-10 branch drill holes which are 100-200m in length on the main horizontal hole; cleaning the drill holes thoroughly, installing a high-pressure hole sealing device at the opening of the main horizontal hole, connecting a high-pressure pump injection device through a high-pressure line, feeding a polymer gel liquid containing a natural quartz sand proppant into the hole, pumping the high pressure to open the coal bed in which a seepage channel with a flowing capacity is formed; and installing a water ring vacuum pump at the opening of the main horizontal hole, and pumping out gas in the main horizontal hole and branch drill holes. According to the method, a crack with the maximum volume can be formed in the working face of the coal bed, the permeability of the coal bed can be improved to the greatest extent, so that partings of the coal bed can be communicated so as to form a crack loose belt at a certain scale, the stress focused in the coal bed can be released, risks of rock burst of the coal bed and the content of gas in the coal bed are reduced, and safety production is guaranteed.

Description

Technical field [0001] The invention relates to a staged fracturing and pressure relief method for horizontal drilling in a coal seam underground. technical background [0002] At present, gas explosion accidents account for about 80% of coal mine accidents in our country, and gas outburst and rock burst have become the number one killer of major coal mine accidents in our country. The occurrence of rock bursts in gas-bearing coal seams is a process of dynamic instability caused by disturbances under the background of certain gas storage conditions and geological factors. When a rock burst occurs in a high gas coal seam, free gas is thrown out along with the coal body. Due to the formation of a new free surface, the free gas in the surrounding coal body will gush out in large quantities, and at the same time reduce the gas content in the surrounding coal. , Accelerates the far-field free gas seepage in the direction of the impact point, so the gas will continue to gush out after...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): E21F7/00E21B43/267
Inventor 张岗许卫
Owner 珲春市耀天新能源开发利用有限责任公司
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