摘要
软煤层钻进过程中孔壁失稳破坏形成钻穴是致使钻进困难的主要原因。建立常态钻孔、开放型钻穴和填充型钻穴排渣模型,对孔内钻屑运移进行气固耦合动力学分析。研究结果表明,开放型钻穴对钻屑运移的影响较小,仅带来一定的压力损耗;填充型钻穴在钻孔底部的钻屑质量分数成倍增长,钻屑颗粒运动轨迹曲折,排出需要更长时间;填充型钻穴区出现瞬间动压波峰,压差损耗是常态钻孔、开放型钻穴的数倍。基于钻穴区钻屑运移特征,提出降低钻杆排渣阻力、增大排渣空间的钻具设计方法,研制了刻槽螺旋钻杆、低螺旋钻杆、等离子熔涂螺旋钻杆等系列钻杆,通过工程应用,软煤层钻进深度和钻进效率得到了有效改善。
The drilling cave is the main cause of drilling difficulty, which is formed by borehole wall instability and failure in soft coal seam drilling. Normal borehole, opened-type drilling cave, filled-type drilling cave slagging model were established, and the gas-solid coupling interaction in borehole was further analyzed. The result has shown that the impact of opened-type drilling cave on drilling cuttings movement is relatively small, and cause only certain pressure loss;drilling cuttings mass fraction in the bottom of the borehole have multiplied in filled-type drilling cave, drilling cuttings particle trajectories have more twists and turns, and more time is needed for the drilling cuttings to be discharged outside the borehole; momentary peak dynamic pressure appeared at the filled-type drilling cave,and the pressure loss was several times larger than that in normal borehole and opened-type drilling cave. Based on the characteristic of drilling cuttings movement in drilling cave, the drilling rod design methods of reducing slagging resistance and increasing slagging space were proposed, and grooved spiral drilling rod, lowspiral drilling rod, and plasma cladding spiral drilling rod were developed. The application of these methods and rods in engineering practice effectively increases depth and efficiency of drilling.
出处
《采矿与安全工程学报》
EI
CSCD
北大核心
2016年第6期1138-1144,共7页
Journal of Mining & Safety Engineering
基金
国家自然科学基金项目(51574110)
河南省高等学校重点科研项目(15A440002)
河南省高校基本科研业务费专项资金项目(NSFRF140135)
关键词
松软煤层
瓦斯抽采
钻孔堵塞
钻屑运移
soft coal seam
gas drainage
drilling clogging
drilling cuttings movement
