Method for effectively improving drainage efficiency of ground coal bed methane by utilizing external sound field

Abstract

The invention discloses a method for effectively improving the drainage efficiency of ground coal bed methane by utilizing an external sound field. In the method, special weights are thrown to the bottom of a ground coal bed methane vertical drainage well from the head of the ground coal bed methane vertical drainage well, when a vibration sound wave produced in a process that the weights impact the bottom of the ground coal bed methane vertical drainage well propagates in a coal bed, a new fracture can be produced on the coal bed, and the original fracture can be expanded, thus permeability of the coal bed is improved; and an ultrasonic wave component in the sound field also can promote desorption of methane adsorbed by a coal mass and the methane adsorbed on the surface of the coal mass. The method is realized by the following two stages: firstly, when the well drilling depth reaches a position 1-5m away from the top of the coal bed in the vertical distance, well drilling is stopped, a plurality of weights are thrown into the well, and the produced downward sound longitudinal wave and transverse wave can increase the fracture quantity when passing through the coal bed; and secondly, when the bottom of the well extends to a position about 1.0m below the top surface of the coal bed, the well drilling is stopped, the weights are thrown into the well, and a sound wave field propagating along the coal bed further improves the permeability of the coal bed. In the method, gravitational potential energy is fully utilized while no additional energy consumption is required.

Description

technical field [0001] The invention relates to a method for effectively increasing the surface recovery rate of coal-bed methane by using an external vibrating sound field, in particular to a non-invasive and low-cost technology for increasing the recovery rate of coal-bed methane. Background technique [0002] Coalbed methane is a new type of clean energy, and its main component is methane (CH 4 ). For coal mining, it is the main threat and burden of safe production; and when it is discharged into the atmosphere with mine ventilation, it is the greenhouse effect ratio of CO 2 About 21 times more greenhouse gases. Therefore, pre-exploitation of coalbed methane is not only an objective requirement for coal mine safety and environmental protection, but also provides clean and efficient energy. Compared with the situation in the United States and other countries, my country's coalbed methane storage conditions are basically characterized by "three lows" (low pressure, low p...

AI Technical Summary

Problems solved by technology

Gas injection mining is coalbed methane, which injects nitrogen, carbon dioxide, or flue gas into the coal seam, and achieves the effect of improving the recovery rate of coalbed methane through adsorption replacement. There are also limitations such as high cost.

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