煤矿下斜钻孔用水力冲孔器流体力学分析与结构优化

随钻型水力冲孔器的研制，解决了煤矿井下水力冲孔施工中需要成孔后再下入冲孔器的问题，在上仰穿层钻孔中取得了良好的使用效果。但是在近水平或下斜钻孔中，由于冲孔钻渣重力作用难以随钻井液排出孔口，易造成塌孔、抱钻等孔内事故。文章通过对水力冲孔施工过程及水力冲孔器进行流体力学分析，计算水力冲孔钻具内沿程损失、冲孔器水力换向阀水力压力、排出钻渣需要的冲洗液上返流速等，并通过增加底喷水眼的方法，增大冲孔流量，提高钻井液上返流速，从而解决排渣困难的问题，并根据改进后的水力参数对冲孔器的复位弹簧进行了重新设计。采用改进型水力冲孔器进行了现场试验，试验表明在近水平下斜钻孔中，改进型水力冲孔器换向阀工作稳定，钻渣能够排出孔内，满足了矿方煤层下斜钻孔水力冲孔施工要求。

Hydromechanical Analysis and Structural Optimization of Hydraulic Punch Used in Inclined Boreholes of Coal Mines

Development of hydraulic punch while drilling, solves the problem that the hydraulic punch is required to insert after the drilling hole is finished in hydraulic punching construction in underground coal mine .Good results have been obtained in the drilling of the upward penetration layer hole. But in a near horizontal or lower oblique hole, Drilling slag is difficult to drain from hole with drilling fluid due to the gravity effect of drilling slag, which cause hole collapse accidents. In this paper, hydromechanical analysis is carried out on hydraulic punching construction process, and the loss the hole, the pressure of puncher hydraulic reversing valve and the flow rate of driling fluid needed was calculated. By adding water jets at the bottom, Increase the flow quantity of punching and the upstream flow rate of drilling fluid, So as to solve the problem of slag discharge difficulty. According to the improved hydraulic parameters, the reset spring of the punch was redesigned. The filed test was carried out which the improved hydraulic punch was used, tests show that the direction-change valve of the improved hydraulic punch works stably.Drilling slag can be discharged out of the hole in the near horizontal oblique borehole,which meets the requirement of hydraulic punching construction in under inclined borehole in coal seam.