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Method for extracting coal bed gas from circulating pulse type low temperature freeze-thawed anti-reflection coal

A technology of cycle pulse and coalbed gas, which is applied in the direction of mining fluid, mining equipment, earth drilling and mining, etc., can solve the problems of object structure damage and achieve the effect of improving the efficiency of anti-reflection

Active Publication Date: 2017-01-18
CHINA UNIV OF MINING & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Repeated freeze-thaw cycles, causing severe damage to the structure of the object

Method used

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  • Method for extracting coal bed gas from circulating pulse type low temperature freeze-thawed anti-reflection coal
  • Method for extracting coal bed gas from circulating pulse type low temperature freeze-thawed anti-reflection coal
  • Method for extracting coal bed gas from circulating pulse type low temperature freeze-thawed anti-reflection coal

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Experimental program
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Effect test

Embodiment 1

[0032] Embodiment one, such as figure 1 , figure 2 , image 3 and Figure 4 As shown, in the coal seam 12, the water jet slotting equipment 8 is used to construct the drill holes 9-2 and multiple rows of guide slots 11 in the coal seam. There are two guide slots 11 in every row of guide slots, and one end of the guide slots communicates with the borehole. The two guide slots respectively extend to the left and right sides of the borehole in the coal seam along the vertical direction to the borehole. A coalbed methane extraction borehole 13 is provided at the outer end of the guide slot. A coalbed methane extraction borehole 13 is respectively set up on the left and right sides of the borehole 9-2.

[0033] Then the main pipe 9 is arranged in the borehole 9-2, and the conventional method is used for high-pressure sealing, and the length of the grouting sealing section 10 is 5-20 m. Then the coal seam 12 is subjected to freeze-thaw fracturing and permeability enhancement ...

Embodiment 2

[0037] Such as Figure 4 , Figure 5As shown, the low-level roadway 15-1 penetrates the upward drilling and pulsatingly circulates the liquid low-temperature medium to freeze-thaw and enhance the drainage to extract pressure-relieving gas, which is basically the same as the first embodiment. The different parts are mainly for injecting pulsating liquid low-temperature medium from the lower roadway 15-1 to the freeze-thaw anti-reflection area in the upper coal seam 12. The depth of the main pipe 9 should penetrate the rock formation into the coal seam 12. The coal seam is 10m~100m. The remaining parts are all the same as in Embodiment 1, and the same parts are omitted.

Embodiment 3

[0039] Such as Figure 4 , Figure 6 As shown, the high-level roadway 15-2 is drilled down through layers and circulated to inject liquid low-temperature medium to freeze-thaw, increase permeability, extract pressure-relieving gas, and it is basically the same as the first embodiment. The different parts are mainly to inject liquid low-temperature medium into the freeze-thaw anti-permeability area in the lower coal seam 12 from the high-level roadway 15-2 through the layer. The depth of the main pipe 9 should penetrate the rock layer into the coal seam 12. According to the thickness of the coal seam, the main pipe 9 should drive into the coal seam 10m~100m. The remaining parts are all the same as in Embodiment 1, and the same parts are omitted.

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Abstract

The invention discloses a method for extracting coal bed gas from circulating pulse type low temperature freeze-thawed anti-reflection coal. Firstly, a borehole and multiple rows of guiding slots are constructed in a coal bed, the guiding slots are communicated with the borehole and extend to two sides of the borehole in the direction perpendicular to the borehole in the coal bed, and coal bed gas extraction boreholes are formed at the outer ends of the guiding slots. A liquid low-temperature medium is injected into the borehole and the guiding slots in a high-pressure pulse mode, the coal bed is freeze-thawed by adopting a pulse circulating low temperature freeze-thawing method to fracture for increasing reflection, and a coal bed gas extraction fracture network is thus formed. Coal bed gas is extracted via the coal bed gas extraction boreholes. By combining freeze-thawing erosion with coal bed gas extraction and combining pulse circulating injection of the liquid low-temperature medium with freeze-thawing phase change fracture, the method significantly improves the anti-reflection efficiency of coal. The method is simple, feasible and low in construction cost, can effectively improve the single-pore extraction quantity and extraction concentration of coal bed gas and prolong the attenuation time of gas concentration, and is particularly suitable for coal bed gas extraction in low-osmosis and high-gas bearing coal beds.

Description

technical field [0001] The invention relates to a method for extracting coal-bed methane, in particular to a method for extracting coal-bed methane in a cycle pulse type low-temperature freeze-thaw anti-permeability coal body. [0002] technical background [0003] As an unconventional energy source, coalbed methane is used as an alternative energy source in many countries. The total amount of coalbed methane in China is large, which is equivalent to the total amount of natural gas resources. With the increase of mining depth, the content and pressure of coalbed methane in coal seams are gradually increasing. The coal seam permeability gradually decreases, and the gas disasters such as coal bed methane explosion and coal and gas outburst are becoming more and more serious. Due to the low permeability of coal reservoirs in my country, overcoming the problems of low concentration and small drainage volume of coalbed methane has always been the top priority in the control of gas...

Claims

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Application Information

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IPC IPC(8): E21B43/00E21B43/16E21F7/00
CPCE21B43/006E21B43/16E21B43/164E21B43/168E21F7/00
Inventor 翟成秦雷徐吉钊于国卿孙勇董若蔚武尚俭
Owner CHINA UNIV OF MINING & TECH
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