A hole sealing method for gas drainage drilling

Abstract

The invention discloses a method for sealing gas extraction drill holes, which is especially suitable for sealing water-bearing gas extraction drill holes of underground coal mines. A plurality of annular pervious water paper bags with water absorbing material loaded are fixed in a grouting hole sealing section, so that water in cement mortar penetrates through the paper bags to contact with the water absorbing material, and the material is expanded after absorbing water and breaks the paper bags. After the cement mortar is solidified, the expanded water absorbing material can properly fill crescent gaps which are formed above the gas extraction drill holes because of the contractility of cement. After holes are sealed, water is regularly injected into the holes through a water injection pipe, so as to ensure that the water absorbing material keeps in a water-rich saturation state, and the sufficient water in the drill holes can properly seal peripheral cracks and improve the gas extraction concentration according to the principle of sealing liquid with solid and sealing gas with liquid. The method is simple and convenient to operate, the water absorbing material can repeatedly absorb water and the performance of the water absorbing material is not affected, the hole sealing effect is improved, and the method has wide practicability.

Description

technical field [0001] The invention relates to a hole sealing method, which is especially suitable for the hole sealing method of underground water-containing gas drainage boreholes in coal mines. Background technique [0002] my country's coal and gas outburst disasters are serious, which poses a threat to the safe production of coal mines. The implementation of drilling is one of the basic technical means of coal mine gas control. Drilling is widely used in various aspects such as gas drainage, parameter testing, coal seam water injection, and coal seam permeability enhancement. The quality of hole sealing directly affects the performance of various drilling functions. About 2 / 3 of the mine gas drainage drilling holes in my country have short sealing length and poor sealing quality, and about 65% of the mining face pre-extraction gas concentration is lower than 30%, which fails to meet the requirements of the "Regulations on the Prevention and Control of Coal and Gas Out...

AI Technical Summary

Problems solved by technology

About 2 / 3 of the mine gas drainage drilling holes in my country have short sealing length and poor sealing quality, and about 65% of the mining face pre-extraction gas concentration is lower than 30%, which fails to meet the requirements of the "Regulations on the Prevention and Control of Coal and Gas Outbursts" , which fully reflects the current situation of poor sealing quality of gas drainage drilling

Water-containing drilling is one of the most difficult types of drilling. When cementing mortar is used to seal this type of drilling, since the inside of the drilling has a lot of water and the cement has self-shrinkage, the cement cannot fill the entire surface after solidification. In the drilling space, a "crescent" gap is often formed in the upper part of the drilling hole, which makes it difficult to effectively seal the crack area, serious air leakage in the drilling hole, and poor sealing quality

Images