140GHz毫米波岩石钻探技术研究

Study on Rock Drilling Technology of 140 GHz Millimeter-Wave

利用高功率微波加热熔化岩石实现地下快速破岩是全新的钻探技术,具有潜在技术优势。基于140 GHz高功率毫米波系统开展了高功率毫米波能量加热穿透岩石的快速钻井技术研究,测量并分析岩石在微波电磁场下的介电损耗特性,采用多物理场耦合法定量模拟不同波束尺寸和入射功率下的岩石温度分布及烧蚀情况,发现峰值功率密度在1~2 kW/cm^(2)情况下毫米波已经可以在很短的时间内将岩石加热至3000℃以上发生相变直至蒸发。分析表明高功率短时间的微波加热方式可以有更高的效率,为下一步依托140 GHz高功率毫米波实验平台开展的相关钻岩实验提供指导。对井下毫米波长距离功率传输损耗等相关应用问题进行了探讨,探索未来高功率毫米波钻井应用可能性。

Using high-power microwave to heat and melt the rock for rapid underground rock breaking is a brand-new drilling technology with potential technical advantages. Based on the 140 GHz high-power millimeter-wave system, the research on the rapid drilling technology of high-power millimeter-wave energy heating and penetrating rock is carried out. The dielectric loss characteristics of rock under microwave electromagnetic field is measured and analyzed. Using the multiphysics coupling method, the temperature distribution and ablation of rock under different beam sizes and incident powers are quantitatively simulated. It is found that the rock can be heated to more than 3000 ℃ immediately and undergo a phase change until evaporation when the peak power density reaches 1-2 kW/cm^(2). Furthermore, the analysis results indicate that the high-power and short-time microwave heating method is more efficient. This study will provide guidance for the exploration experiments on the 140 GHz high-power millimeter-wave experimental platform. The related application issues such as power loss of downhole long-distance millimeter-wave transmission are also discussed. And the possibilities of future high-power millimeter-wave drilling applications are explored.