| 井下碎软煤层双管双动空气定向钻进工艺研究 |
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| 引用本文： | 王力.井下碎软煤层双管双动空气定向钻进工艺研究[J].煤田地质与勘探,2022,50(7):166-172. |
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| 作者姓名： | 王力 |
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| 作者单位： | 1.煤炭科学研究总院 北京 100013 |
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| 基金项目： | 国家科技重大专项任务(2016ZX05045-003-002)； |
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| 摘 要： | 碎软煤层钻进过程中易发生喷孔、塌孔，造成钻孔深度浅、成孔率低，严重制约碎软煤层瓦斯高效治理。随着“以孔代巷”、递进式抽采等瓦斯治理模式的兴起，煤矿对碎软煤层瓦斯抽采钻孔成孔提出了更高的要求，为了进一步提高碎软煤层钻孔深度、钻孔精度和成孔率，以满足煤矿安全、高效、精准瓦斯治理的需要，提出煤矿井下碎软煤层双管双动空气定向钻进工艺方法。针对该钻进方法涉及的关键钻具和钻进工艺，根据煤矿井下空气螺杆钻具规格和通过性试验，分析确定外管套管、内管螺杆钻具、领眼钻头以及扩眼器等钻具级配；通过理论分析螺旋钻进煤粉颗粒运动速度，优化套管螺旋叶片螺距、头数等参数；根据钻进排粉需求、空气螺杆钻具用风要求，计算双管钻进用风量、风压；采用数值模拟方法，研究排粉规律和最佳钻进工艺参数，最后通过现场钻进试验，验证双管双动钻具级配和钻进工艺的合理性。结果表明:增加风量比增加转速提高排粉效果更明显；钻进时套管转速40 r/min时，对应风量应最小达到500 m3/h，内管钻具滑动定向造斜完成后，应尽快复合钻进排粉，当风量低于400 m3/h时，应当充分回转扫孔排渣；采用?90 mm领眼钻头+?120 mm扩眼器+?73 mm空气螺杆钻具+?73/35 mm宽叶片螺旋钻杆的内管钻具+?140 mm套管钻头+?120/96 mm反螺旋套管的外管钻具组合，采用风量1 000 m3/h、风压1.25 MPa以上的风源、转速40~120 r/min的工艺参数，钻孔深度达到350 m以上、套管护孔深度168 m以上，钻孔轨迹可控制在煤层内，有效提高了钻孔深度和精度，为碎软煤层随钻护孔精确钻进提供新工艺方法。
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| 关 键 词： | 双管双动钻进 空气定向钻进 以孔代巷 碎软煤层 煤矿井下 |
| 收稿时间： | 2022-02-13 |
Techniques of double-pipe and double-acting directional drilling with air in broken and soft coal seams in underground coal mines |
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| Institution: | 1.China Coal Research Institute, Beijing 100013, China2.Xi’an Research Institute Co. Ltd., China Coal Technology and Engineering Group Corp., Xi’an 710077, China |
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| Abstract: | In the broken and soft coal seam drilling, the outburst and collapse of the hole occur easily, resulting in shallow drilling depth and low rate of hole forming, which seriously restrict the efficient gas control in the broken and soft coal seam. With the rise of gas control models, such as replacing roadway with holes and progressive drainage of the broken and soft coal seam, higher requests have been put forward to the gas drainage hole. The further improvement of the drilling depth, drilling accuracy and hole forming rate of the broken and soft coal seam can meet the needs of coal mine safety, high efficiency and precise gas control. On this basis, the double-pipe and double-acting air directional drilling technology for the broken and soft coal seam is proposed. In view of the key drilling tools and drilling techniques involved in this drilling method, the grading of drilling tools such as outer casing, inner drilling tools, collar bits and reamers is analyzed and determined according to the specification and the passability test of underground air motor drilling tools. The parameters such as pitch and head number of casing blade are optimized by analyzing the motion speed of coal particles in auger drilling. According to the demand of cuttings discharge and the air motor drilling tool, the air volume and pressure are calculated. By using the numerical simulation method, the law of cuttings discharge and the optimal drilling parameters are studied. Through the field drilling test, the rationality of the method and the drilling tool grading are verified. The results show that increasing the air volume is more effective than increasing the rotation speed in cuttings discharge. When the casing speed is 40 r/min, the corresponding air volume should reach at least 500 m3/h. After the sliding directional drilling, drilling and cuttings discharge should be done as soon as possible. When the air volume is lower than 400 m3/h, cuttings should be discharged by sweeping the hole. The inner pipe drilling tool with ?90 mm collar bit, ?120 mm reamer, ?73 mm air motor, ?73/35 mm wide blade drilling pipe and the outer pipe drilling tool with ?140 mm casing bit, ?120/96 mm anti-spiral casing are combined with air flow of 1 000 m3/h and air pressure of 1.25 MPa, and the rotating speed between 40 r/min and 120 r/min. The hole trajectory can be controlled within the coal seam, when the drilling depth reaches 350 m and the casing depth reaches 168 m, which effectively improves the borehole depth and precision, and provides a new technological method for precise drilling in the broken and soft coal seams. |
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