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Large-temperature-difference freeze-thaw cycle method for production increase of surface borehole

A surface drilling and freeze-thaw cycle technology, which is applied in earthwork drilling, wellbore/well components, gas discharge, etc., can solve problems such as unsatisfactory application effect, restricted gas drainage effect, and difficulty in forming long fractures. Achieve the effect of increasing cracking effect, improving cracking effect, and good cracking effect

Inactive Publication Date: 2019-05-21
XUZHOU UNIV OF TECH
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  • Claims
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Problems solved by technology

In order to improve the permeability of coal seams, hydraulic fracturing technology is generally used for coal seam anti-permeability treatment, but related research results show that: the cracks produced by hydraulic fracturing mainly expand along the direction perpendicular to the minimum principal stress, and the number of cracks produced is small, making it difficult to form relatively large fractures. Long fractures, failed to produce bulk fracture effect on coal seam storage, and also have the disadvantage of high fracturing fluid pressure
At present, the application effect of this technology in most mining areas in my country is not ideal, and the relevant technical process needs to be further studied
In addition, the application number is 201410507011.9, and the Chinese invention patent titled "A Cooling and Heating Alternating System for Increasing Coal Seam Gas Drainage" proposes a system for increasing gas drainage drilling output by alternately injecting cold and hot, but the system can realize The lowest temperature is only -50°C, and the highest temperature is 200°C, but in this temperature range, the expansion range of cracks is limited, and the gas drainage effect is restricted

Method used

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  • Large-temperature-difference freeze-thaw cycle method for production increase of surface borehole

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Embodiment Construction

[0022] The present invention will be further described below.

[0023] Concrete steps of the present invention are:

[0024] A. When the gas flow in the gas drainage pipe is greatly reduced to 8m 3 , open the first valve 9 and the second valve 13, start the magnetized water generator 14 and the pulsation pump 11, the magnetized water is pulsated by the pulsation pump 11 to obtain pulsating magnetized water, and the pulsating magnetized water passes through the third pipeline 12, the second pipeline The pipeline 10 and the first pipeline 4 enter the gas drainage pipe 3, and the gas drainage pipe 3 is cleaned and impacted on the coal seam 1, so that the cracks in the coal body develop and expand, and the pulsation frequency of the pulsating magnetized water is controlled to be 0.05 Hz to 0.3 Hz. The pulsation pressure is 12MPa~18MPa, and the pulsation time is 30min~45min;

[0025] B. After the injection of the pulsating magnetized water is completed, close the magnetized water...

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Abstract

The invention discloses a large-temperature-difference freeze-thaw cycle method for production increase of a surface borehole. Firstly, magnetized water is injected into a gas extraction pipe of the surface borehole in a pulsating manner; high-pressure nitrogen drives the magnetized water to enter the coal body; liquid nitrogen freezing is carried out on the magnetized water for many times and themagnetized water and high-temperature nitrogen are melted; the freezing expansion force of the magnetized water and the direct large-temperature-difference effect of the liquid nitrogen and the high-temperature nitrogen are utilized to jointly crack the coal body; by means of interaction of high-temperature and high-pressure nitrogen, liquid nitrogen and magnetized water, an ultra-large temperature difference effect is formed, the coal cracking effect is achieved, finally, the coal cracking effect and the crack expansion range can be effectively improved, the coal permeability is increased, and therefore large-flow, high-concentration and long-time gas extraction through ground drilling is achieved.

Description

technical field [0001] The invention relates to a method for surface drilling to increase production, in particular to a large temperature difference freeze-thaw cycle method for surface drilling to increase production. Background technique [0002] The generally low permeability of coal seams in my country is the main reason for limiting the effectiveness of ground drilling for gas extraction. In order to improve the permeability of coal seams, hydraulic fracturing technology is generally used for coal seam anti-permeability treatment, but related research results show that: the cracks produced by hydraulic fracturing mainly expand along the direction perpendicular to the minimum principal stress, and the number of cracks produced is small, making it difficult to form relatively large fractures. Long fractures fail to produce bulk fracture effects on coal seam storage, and there are also disadvantages of high fracturing fluid pressure. At present, the application effect of...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): E21B43/24E21B43/26E21B43/00E21F7/00
Inventor 王圣程姜慧朱炯殷惠光禄利刚马晴晴朱信鸽张洁赵众庞叶青张朕宋雷
Owner XUZHOU UNIV OF TECH
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