高强内支撑护孔管提高瓦斯抽采钻孔稳定性技术应用研究

我国松软高瓦斯煤层分布较广，井下钻孔抽采瓦斯是目前预防瓦斯灾害的主要措施，由于松软煤层煤体硬度低，抽采钻孔在成孔与抽采期间容易坍塌、变形，瓦斯流动通道被阻塞，使瓦斯抽采效率降低。通过理论分析、实验室测定和工程试验的方法，利用高强内支撑护孔管对提高瓦斯抽采钻孔稳定性进行研究。从护孔筛管的选型入手，分析了护孔筛管在钻孔内受力特性，对比了护孔筛管材料的基本力学性能:PPR管抗压缩变形能力更强，但抗拉伸与扭转剪切能力较差；PE管在基本力学实验中表现适中，PVC管则相对较差；新型内支撑管径向抗压能力比普通管提升了3倍多。通过不同支护方式及不同类型筛管支护现场工程试验表明:护孔筛管的筛孔直径8 mm、密度6个/m或8个/m较好；内支撑筛管支护、普通筛管支护瓦斯抽采纯量与裸孔对比分别提高1.05倍、0.58倍，且内支撑筛管支护抽采达标时间大幅度下降。

Study and application on improving stability of gas drainage drilling by high strength inner supporting pipe

Soft and high-gas coal is widely distributed in China.Drilling is the main measure to prevent gas disaster.Due to the low hardness of soft coal，the drilling is easy to deform，collapse and block the gas flow channel.It is great impact on the gas extraction efficiency.Based on the theoretical analysis，basic mechanics test and field engineering test，this paper takes the high-strength inner support pipe to improve the stability of the gas drainage technology.In this paper，the mechanical properties of the hole in the borehole are analyzed，and the basic mechanical properties of the material are as follows:PPR pipe is more resistant to compression and deformation，but the tensile strength torsional shear capacity is poor；PE pipe in the basic mechanics experiment performance is moderate；PVC pipe is relatively poor.The radial support capacity of the new inner support pipe is more than 3 times higher than that of the conventional pipe.Through the different supporting methods and types of screen support site engineering test，that:hole mesh screen diameter eight millimeter，density 6 per meter or 8 per meter.b.Within the support of the screen support and ordinary screen support，gas pumping pure and bare hole contrast were improved 1.05 times，0.58 times，and the support of the screen support pumping time marked a significant decline.