碎软突出煤层空气动力造穴工程主控因素

Main controlling factors of air-cavitation engineering in broken soft outburst-prone coal seams

为揭示空气动力造穴技术在碎软突出煤层中造穴效果的主要工程影响因素及其机制,加大该技术在碎软突出煤层瓦斯治理中的应用力度,通过空气动力造穴机理分析认为,影响造穴效果的工程主控因素为注气压力和返排气体排量;同时采用数值模拟、现场实验和公式推算相结合的方法,对注气压力与返排气体排量的影响机制进行了研究。结果认为:距离井壁越近,储层内的气体压力越大、煤储层结构越容易被空气压力"激动"作用破坏,注气压力在安徽淮南谢一矿实验点的碎软煤层中的有效传导半径为7 m,煤层洞穴半径单次扩大量为0.1 m左右,掏出煤体体积在一定范围内与注气压力、返排气体排量呈正相关关系。

In order to research the master engineering affecting factors and affecting mechanism of air-cavitation technology, increase its application in gas governance of the broken soft outburst-prone coal seams, this paper analyzed the mechanism of air-cavitation and believed that the master affecting factors were gas injection pressure and gas injection displacement. This paper adopted numerical simulation, field experiments and formula derivation so as to research the affecting mechanism of gas injection pressure and gas injection displacement. Results suggested that the closer to the well wall, the larger the gas pressure in the coal seam, the more easily the body structure of the coal was destroyed. The effective conduction radius of gas injection pressure was 7 meters in the broken soft coal seam in this experimental area. The cave radius of one-time expansion in coal seam was about 0.1 meter. The taken out volume of coal body was positively correlated with the gas injection pressure in certain range and well positively correlated with the gas injection displacement.