Safe displacement and drainage method of coal seam gas based on carbon dioxide phase change fracturing device
A carbon dioxide and coal seam gas technology, which is applied in gas discharge, safety devices, mining fluids, etc., can solve problems such as hidden dangers of coal seam safety and limited gas drainage, and achieve convenient operation, high safety, and high gas drainage efficiency. Effect
Active Publication Date: 2020-05-08
CHONGQING UNIV +1
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Problems solved by technology
[0006] In view of the fact that the existing carbon dioxide cracker cracks through the chemical method of combustion, there are still certain safety hazards for coal seam mining, and the carbon dioxide cracker comes with a small amount of liquid carbon dioxide, which is only enough for coal seam cracking, and at the same time, the gas in the coal seam To solve the problem of limited extraction volume, the present invention intends to provide a safe displacement extraction method for coal seam gas based on a carbon dioxide phase change fracturing device
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[0020] Below by embodiment and in conjunction with accompanying drawing, the present invention will be further described:
[0021] combine figure 1 — image 3 As shown, a method for safe displacement and drainage of coal seam gas based on a carbon dioxide phase change fracturing device includes the following steps:
[0022] Step 1. Inject carbon dioxide liquid into the carbon dioxide cracker 4 located outside the borehole through the gas source system. The carbon dioxide cracker 4 is equipped with a constant pressure rupture disc and a release pipe, and the inner cavity does not contain a combustion rod, an ignition head and a carbon dioxide liquid. , the pressure after the pre-filling of the carbon dioxide cracker 4 is lower than the set rupture pressure of the constant pressure rupture disc, and after the pre-filling is completed, disconnect the connection between the gas source system and the carbon dioxide cracker 4 .
[0023] Preferably, the gas source system includes a...
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The invention discloses a coal-bed gas safe displacement extraction method based on a carbon dioxide phase-change fracturing device. The coal-bed gas safe displacement extraction method totally comprises the six steps that through a gas source system, carbon dioxide liquid is injected into a carbon dioxide fracturing device located outside a drilled hole; a high-pressure pressurizing injection mechanism and a large-flow medium-low-pressure injection mechanism are in series connection through a high-pressure hose and then connected with an injection hole of the carbon dioxide fracturing device,and the high-pressure pressurizing injection mechanism and the large-flow medium-low-pressure injection mechanism are connected with the gas source system; the carbon dioxide fracturing device and abag-type hole packer are pushed into the drilled hole by a hydraulic pushing machine, and the drilled hole is sealed; carbon dioxide liquid with the pressure being 60 MPa or above is injected into thecarbon dioxide fracturing device through the high-pressure pressurizing injection mechanism; and carbon dioxide gas or liquid with the pressure being the normal pressure of 10 MPa is injected into the carbon dioxide fracturing device through the gas source system and the large-flow medium-low-pressure injection mechanism. Safety is high, operation is convenient, and the gas extraction efficiencyis high.
Description
technical field [0001] The invention belongs to the technical field of coal seam gas drainage, and in particular relates to a safe displacement and drainage method of coal seam gas based on a carbon dioxide phase change fracturing device. Background technique [0002] The carbon dioxide cracker uses liquid carbon dioxide to heat and gasify and expand, and quickly releases high-pressure gas to break the coal seam. It solves the defects of high destructiveness and high risk in the pre-cracking of explosive blasting mining in the past, and improves coal mining and mining to a certain extent. The safety of pre-splitting, so it is widely used in coal mine operations. [0003] The principle of carbon dioxide cracking is: carbon dioxide exists in a liquid state when it is lower than 31°C, and starts to gasify when it exceeds 31°C, and the pressure is constantly changing as the temperature changes. Taking advantage of the characteristic of carbon dioxide, a certain amount of liquid...
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IPC IPC(8): E21B43/26E21B43/16E21B47/06E21F7/00
CPCE21B43/164E21B43/26E21B47/06E21F7/00
Inventor 张东明何庆兵姬有仓宋润权刘汉波王浩尹思禹余北辰
Owner CHONGQING UNIV