顺层瓦斯抽采长钻孔气举排渣模拟试验研究

    Numerical simulation and experimental study on gas lift slag removal in long borehole for bedding gas drainage

    • 摘要: 气举排渣困难及其导致的卡钻、抱钻甚至喷孔事故一直是困扰顺层长钻孔瓦斯抽采技术的重要因素;利用数值仿真与现场试验相结合的方法,对顺层瓦斯抽采长钻孔气举排渣进行了系统研究。研究发现:煤屑粒径较小时,风量和产屑量是煤屑沉积的最主要因素,而对于当煤屑粒径较大时,煤屑沉积受到风量、钻杆转、产屑量3个方面的影响;当风量为500 m3/h时,钻杆转速需要超过80 r/min才能保证有效排渣,而当风量分别为400、300 m3/h时,钻杆的转速需要超过120、200 r/min才能保证有效排渣;为了有效排渣,钻杆的转速应保持在80~120 r/min,且风量应在400 m3/h以上。

       

      Abstract: The difficulties of gas lift slag removal and the accidents caused by sticking drill, holding drill and even jet hole are always the important factors that baffle gas extraction technology of long boreholes along the bedding. In this paper, the numerical simulation and field test are used to study the numerical simulation test of gas lift slag removal in long borehole of bedding gas drainage. It is found that when the particle size of coal cuttings is small, the air volume and chip production are the main factors of coal cuttings deposition, while when the particle size of coal cuttings is large, the coal cuttings deposition is affected by air volume, drill pipe speed and chip production; when the air volume is 500 m3/h, the rotating speed of the drill pipe needs to exceed 80 r/min to ensure effective slag removal, while when the air volume is 400 m3/h and 300 m3/h respectively, the rotating speed of the drill pipe needs to exceed 120 r/min and 200 r/min to ensure effective slag removal; in order to effectively discharge slag, the rotating speed of drill pipe should be kept at 80-120 r/min and the air volume should be more than 400 m3/h.

       

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