Coal seam gas fracturing and mash gas driving method

A gas driving and gas fracturing technology, applied in the field of gas fracturing, can solve the problems of blocking gas migration channels and unfavorable gas drainage, and achieve the effects of reducing gas gushing, improving gas permeability, and avoiding gas exceeding the limit.

Inactive Publication Date: 2015-11-18
CHINA UNIV OF MINING & TECH
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Problems solved by technology

At present, the methods commonly used to improve the air permeability of a single coal seam are: hydraulic fracturing and hydraulic slotting. Although both methods have the effect of increasing the permeability of the coal seam, they both inevitably ha

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  • Coal seam gas fracturing and mash gas driving method

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Embodiment 1

[0020] Embodiment 1: The method for coal seam gas fracturing and gas driving of the present invention includes two stages of sealing and fracturing and gas driving. For example, the average thickness of a coal seam in a certain mine is about 2.51m, and the buried depth is about 800m. The coal seam is stable. The structure is simple, and the inclination angle of the coal seam is about 0°~6°, with an average of 4°. It occurs in the middle and lower part of the Shanxi Formation, about 50m away from the limestone at the top of the Carboniferous Taiyuan Formation, 36.6m away from the sandstone at the bottom of the coal seam, and about 50m away from the K 4 The aluminum mudstone is 51.51m, the roof is sandy mudstone or sandstone, the floor is sandy mudstone and siltstone, and the coal seam is relatively stable. The gas content is about 11.15m 3 / t, gas drainage radius is 5m, coal seam permeability coefficient is 0.0861m 3 / (MPa 2 .d). The damage type of the coal seam belongs to ...

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Abstract

The invention relates to a coal seam gas fracturing and mash gas driving method, which comprises two stages including a hole sealing fracturing stage and a mash gas driving stage. According to the method, firstly, hole drilling construction is performed in a coal seam; then, a high-pressure rubber pipe is embedded in a drilling hole, and hole sealing is performed; any one drilling hole is selected as a fracturing drilling hole; high-pressure gas is injected into the fracturing drilling hole; the coal seam is fractured through gas pressure energy; the gas permeability of the coal seam is improved; and other drilling holes around the fracturing drilling hole are subjected to mash gas extraction when the high-pressure gas is injected into the fracturing drilling hole. Under the condition of non-ideal gas fracturing effects caused by high coal hardness or great ground stress and the like, high-pressure water can be firstly used for fracturing, and then, high-pressure gas is introduced into the hole; and meanwhile, the drilling holes around the fracturing drilling hole are subjected to mash gas extraction. The method has the advantages that the adsorption performance differences of coal bodies on the mash gas and the fracturing gas are considered; the gas fracturing effect is combined with the mash gas driving effect; the mash gas extraction efficiency can be effectively improved; the number of mash gas extraction holes is reduced; and the inhibiting effect of water on mash gas deabsorption is reduced. The method is simple; safety and reliability are realized; and the effect is good.

Description

technical field [0001] The invention relates to a gas fracturing method, in particular to a method for coal seam gas fracturing and gas driving, which is applicable to coal seam gas fracturing and gas extraction rate improvement. Background technique [0002] Compared with hydraulic fracturing, gas fracturing has less influence on the gas permeability of coal seam, and has less influence on the gas adsorption and desorption effect of coal seam. Research on coal seam gas fracturing technology provides a new way of thinking for increasing the gas permeability of coal seams and improving the gas extraction efficiency of coal seams. In a single outburst coal seam, improving the gas permeability of the coal seam and improving the efficiency of gas extraction are the key to the mining of a single outburst coal seam. At present, the methods commonly used to improve the air permeability of a single coal seam are: hydraulic fracturing and hydraulic slotting. Although both methods ha...

Claims

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Application Information

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IPC IPC(8): E21B43/26E21F7/00
Inventor 黄炳香陈树亮赵兴龙
Owner CHINA UNIV OF MINING & TECH
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