松软煤层双管钻进工艺若干动力学问题研究

This project aims to reduce gas explosion, coal and gas outburst ,water flooding and other disasters, and researches the basic theory of double directional drilling in soft coal seam corresponding some accidents happened in drilling process as hole collapse, block drilling, drillpipe sticking and others. The project reveals the mechanism of drilling-rock breaking and pore-forming in soft coal seam with complex geological structure, and improves drilling efficiency by this way. We also study on the mechanism of substantial hole forced slag discharge to guarantee the drilling length. Moreover we research the mechanism of the whole machine vibration and stick slip vibration to improve the reliability of drilling rig by establishing vibration model and suppressing vibration. Based on these processes, we intend to achieve the goal of improving the drilling rate, drilling length, and the ability of gas emission effectively and get a substantial reduction in coal mine safety accidents .

本项目以减少瓦斯爆炸、煤与瓦斯突出和透水等灾害事故为目标，针对松软煤层钻孔时易出现塌孔、堵钻、卡钻等孔内事故，研究松软煤层双管深孔定向钻进的关键动力学问题：揭示含复杂地质构造的松软煤层钻进破岩与成孔机理，提升钻进效果；对超长孔内强制排渣机理进行研究，保证钻进长度；研究整机振动机理及粘滑振动机理，建立振动模型，抑制振动，提高钻机工作可靠性。最终达到提高成孔率和钻孔长度，有效提高瓦斯排放水平，大幅减少煤矿安全事故的目的。

本项目以减少瓦斯爆炸、煤与瓦斯突出和透水等灾害事故为目标，针对松软煤层钻孔时易出现塌孔、堵钻、卡钻等孔内事故，对松软煤层双管深孔定向钻进的关键动力学问题进行了研究。将钻进系统考虑为质量、刚度和阻尼的综合体，并且考虑了钻井泥浆的作用，建立了轴向-扭转-横向耦合的钻进系统动力学方程。研究了含复杂地质构造的松软煤层钻进破岩与成孔机理，并对切削力进行了精确的建模。钻进系统的轴向、扭转和横向振动是相互耦合的，主要表现为切削力的耦合，这种耦合的模型称为状态依赖模型。研究表明，状态依赖模型模型比以往的常延迟模型更能表现钻柱系统的非线性。粘滑振动是钻进过程中危害最严重的，降低轴向进给速度或者提高顶驱的转速都能有效避免粘滑振动。状态依赖模型的稳定性比常延迟模型要高。岩石的固有比能越高，系统的稳定性越低。适当提高顶驱的转速可以使得系统趋于稳定钻进。钻井泥浆的黏度越大，流速越大，钻进系统的稳定性越高。以上结论为钻机抑制振动，提高工作可靠性，提高瓦斯排放水平，大幅减少煤矿安全事故提供了理论依据。