Coal bed methane recovery method

Abstract

The invention discloses a coal bed methane recovery method. A multi-branch U-shaped well is used in cooperation with a coal bed methane heating injection shaft for recovering coal bed methane. By the adoption of the coal bed methane recovery method, the recovery efficiency can be improved, cost is reduced, safety and high efficiency are achieved, and operation is easy.

Description

technical field [0001] The invention relates to the technical field of coal bed gas exploitation, in particular to a coal bed gas recovery method. Background technique [0002] my country is rich in coalbed methane resources, the amount of resources is equivalent to the total amount of conventional natural gas in my country, and has broad development prospects. The development of coalbed methane can not only achieve resource utilization and alleviate energy crisis, but also improve the safety of coal mining, which is of great significance to reduce or even eliminate coal mine gas explosion accidents. [0003] The main area of ​​CBM development in my country is located in Qinshui Basin, Shanxi. Among them, there are mainly two mineable coal seams, which are 3# upper coal seam and 15# lower coal seam. 15# coal seam is 85m-96m away from 3# coal seam. At present, the 3# coal seam is mainly mined, but the mining effect is not ideal. There are few studies and technologies on d...

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Problems solved by technology

[0007] This method requires the injection of large amounts of CO 2 , while producing CO on-site 2 The difficulty and cost are high, the input and output of industrial production do not match, and the mixed gas produced needs to be further separated, which again increases the economic burden. The original coalbed methane mining system was abandoned, and a lot of time and financial resources were spent

Since my country is currently exploiting shallow coalbed methane, coal must be mined after the methane is exhausted, and after the implementation of this method, a large amount of CO will remain in the coal seam. 2 , CO during mining 2 It will escape, which will easily lead to CO of coal miners 2 Poisoning, life-threatening, and a large amount of CO in the coal seam 2 Exhaust to the atmosphere, causing environmental pollution

[0008] A new technology for mining coalbed methane (application number: 200710145879.9, published on January 30, 2008), which injects high-pressure air or high-pressure oxygen into the gas inlet well, and burns the coal seam in the gas outlet well to generate heat and CO 2 However, this method does not fully consider the property of coal as a combustible substance. The process of burning coalbed methane in the coal seam may also ignite the coal, resulting in the danger of gas well scrapping and stratum collapse, and the emitted gas Requires further purification, causing economic loss

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