煤层粒子冲击钻井技术的适用性分析及参数优化

Suitability analysis and parameter optimization on particle impact drilling technology of seam

为了更高效地开采煤层气，应用粒子冲击钻井技术提高煤层钻井的钻速，在分析了粒子冲击钻井技术在煤层钻井的适用性基础上，依据煤岩特性对粒子冲击钻井技术参数进行了优化，同时利用耦合光滑粒子流体动力学法（SPH）及有限元法（FEM）模拟研究了粒子冲击破碎煤岩的三维非线性冲击动力学问题，得出了粒子冲击参数随破岩深度的变化规律。结果表明：在考虑有利于粒子的返出情况下，优化了粒子钻进冲击参数，得出煤层钻井时粒子入射速度80～100m／s、粒子直径1．0～1．5mm和入射角度6°～12°为最佳取值，粒子冲击钻井技术在煤层气开采中具有高效实用性。

In order to more high efficiently mine the coal bed methane, the particle impact drilling technology was applied to improve the drilling speed of the seam drilling. Based on the analysis on the suitability of the particle impact drilling technology applied to the seam drilling, the coupling smooth particle hydrodynamics （SPH） and the finite element method （FEM） were applied to simulate and study the three dimensional nonlinear dynamics of the particle impact breaking in the seam and rock. Meanwhile, according to the coal and rock fea- tures, an optimization was conducted on the particle impact drilling parameters. The variation law of the particle impact parameters with the depth the coal and rock breaking depth were obtained. The results showed that in consideration on the particle favorable returning condi- tion, when the drilling was conducted in seam, the optimum value selection scope of the particle impact parameters was optimized, thus the particle shooting velocity was 80- 100 m/s, the particle diameter was 1.0- 1.5 mm and the shooting angle was 6°- 12°. The particle impact drilling technology could have a high efficient and practice in the mining of the coal bed methane.