随钻水力冲孔技术在松软低透气煤层瓦斯增透中的应用

Application of Borehole Hydraulic Flushing while Drilling in Low-permeability Coal Seam Gas Antireflective

松软低透气性煤层,由于煤层松软、透气性低,瓦斯抽放浓度低、持续时间短、抽放量小,使煤层瓦斯区域预抽效果不理想。作为改善瓦斯抽采效果的有效方法之一,水力冲孔法以其原理简单、易于实现的优点广泛应用于各大煤矿,但是需要预先施工先导孔,辅助作业时间长。为解决这一问题,研究了随钻水力冲孔技术,该技术采用钻进-冲孔一体式钻具,将钻孔施工与冲孔施工一次完成,不需重复起下钻,提高了工作效率。采用随钻冲孔技术在赵庄煤矿进行了现场试验,试验证明,随钻水力冲孔技术能够满足矿方施工要求,且通过计算对冲孔直径进行了评价,瓦斯抽采钻孔通过水力冲孔可将原常规施工钻孔直径扩大12.2倍。

In soft and low permeability coal seam,due to soft coal and low permeability,gas drainage concentration is low,short duration,drainage volume is smaU,pre-pumping effect of coal seam gas is not ideal.As one of the effective methods to improve the gas drainage effect,hydraulic punching method with its advantages of simple principle,easy to implement was widely used in major coal mines. However,pre-construction pilot holes need to be aided,which used a long time.To solve this problem, studies the hydraulic punching while drilling technology,which used drilling-punching integrated drilling tools,Drilling construction and punching construction completed in one time,which improve work efficiency.Hydraulic punching while drilling technology was used in Zhaozhuang coal mine,and the test proved that hydraulic punching while drilling technology meet the construction requirements of the mine.Through the calculation,the punching diameter was evaluated ,hydraulic punching can enlarge the diameter of drilling hole to 12.2 times.