Ground stereoscopic discharge and mining method of coal bed methane

Abstract

The invention relates to a ground stereoscopic discharge and mining method of coal bed methane. The ground stereoscopic discharge and mining method adopts a main shaft to discharge and mine the coal bed methane and is mainly characterized by damaging a natural coal reservoir system, breaking the balance state of the system, leading the system to be homogenized relatively and creating a new coal reservoir system which is beneficial to discharging and mining. In the coal bed around the main shaft, a cavity is built by a directional inclined shaft so as to form a region of stress concentration of the coal bed, the stress of the coal bed around the cavity is released in the process of stress homogenization of the coal bed, and the coal bed is led to generate extension and shear damage, thus forming a new crack, forming interference among the cavities, causing communication of coal bed cracks which are in closed or semi-closed state and further forming a large area of air permeable flow channel. The method has the characteristics of low engineering risk, wide application range and the like, can realize high-efficiency methane discharge and improve the productivity of the coal bed gas shaft.

Description

technical field [0001] The invention belongs to coal bed methane (gas) mining technology, and is a ground drainage method for improving the production capacity of coal bed methane wells. Background technique [0002] Coalbed methane is a kind of resource. my country's coal reservoirs have low gas saturation, low permeability, low reservoir pressure (reservoir energy), low resource abundance, high geostress, strong heterogeneity (including reservoir sex and permeability) and other characteristics. Compared with the Black Warrior and the San Juan Basin, where coalbed methane has been successfully developed in the United States, the main problem in the development of coalbed methane in my country is low permeability, which is 2 to 3 orders of magnitude lower than that in the United States; compared with conventional oil and gas reservoirs, there are also many The big difference: the Young's modulus of coal seams is lower than that of ordinary sandstone or limestone reservoirs, g...

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Problems solved by technology

In addition to the objective factors such as complex geological conditions and low reservoir permeability, the reasons for the low average gas production of single wells and poor overall benefits in the development of coalbed methane fields in my country at present are that the existing coalbed methane drainage technologies and methods affect the productivity of coalbed methane wells. a decisive factor

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