低透气性煤层群井下增透技术

Permeability improved technology of low permeability seams group in underground mine

针对松藻矿区可采煤层透气性差、难于抽采问题,根据矿区煤层赋存特点,试验研究了水力压裂增透技术,形成了保护层开采卸压增透技术和高压水力压裂增透技术相结合的有效增透技术方法。矿区采取保护层开采卸压增透后,使被保护层渗透率增长倍数最高达2.03×10^4倍。采用高压水力压裂增透技术提高保护层透气性后,水力压裂增透半径可达70 m;增透后平均单孔抽采量提高3-5倍,抽采瓦斯体积分数提高3%-20%。松藻矿区采用这2项增透技术后,实现了低透气性煤层群瓦斯的顺利抽采,同时保证了矿井煤炭资源的安全开采。

According to a poor permeability and hard gas drainage problems of the seam in Songzao Mining Area,based on the seam deposition features of the mining area,the hydraulic fracturing and permeability improved technology was tested and studied and an effective permeability improved technical method combined with the pressure releasing and permeability improved technology of the protective seam mining and the high pressure hydraulic fracturing and permeability improved technology was formed.After the pressure released and permeability improved conducted for the protective seam mining,the permeability rate of the protective seam was increased and up to 2.03× 10^4 times.After the high pressure hydraulic fracturing and permeability improved technology applied to improve the permeability of the protective seam,the hydraulic fracturing and improved permeability radius could be 70 m.After the permeability improved,the gas drainage volume of a single borehole was increased by 3 - 5 times in average and the gas drainage volume fraction was improved by 3% - 20 %. After the two permeability improved technologies applied to Songzao Mining Area,the successful gas drainage from the low permeability seams group was realized and the safety mining of the coal resources in the mine was ensured.