激光扫描作用花岗岩表面玻璃化特性研究

Study on Vitrification of Granite Surface by Laser Scanning

随着人类能源需求的增长,油气钻井活动日益频繁。激光钻井在能源领域具有极大的应用价值,有望实现井下原位玻璃套管的制造,以替代传统金属套管,为油气钻井工程节省大量时间和资金。激光辐照岩石玻璃化的稳定形成是实现玻璃套管的关键因素。基于激光扫描花岗岩实验并结合物相检测和数值模拟方法,对激光烧蚀花岗岩玻璃化的影响因素和机理进行了研究。结果表明,受激光扫描后,花岗岩各组成矿物按熔化的难易程度分别发生熔化和碎裂现象,部分表面转化为深色玻璃;高速气流可有效清除岩石碎屑和粉尘,且能够提高激光作用效率和增加岩石玻璃的附着力;花岗岩易受温度作用而发生破裂,其较低的扫描速度和气流辅助条件有利于玻璃化的形成。在实际工程应用中,采用控制扫描速度和辅助高速气流的方法控制岩石的温度作用,形成稳定岩石玻璃和制造稳固覆盖于硬岩表面的原位玻璃化井壁。本研究探究了激光扫描作用岩石的玻璃化机理,为拓展激光钻井的工程应用提供了重要参考。

With rising energy demand,oil and gas drilling activities are increasing.Laser drilling has great application value in the energy field and is expected to realize the manufacture of downhole in-situ glass casing to replace traditional metal casing,resulting in time and money savings for oil and gas drilling projects.The stable formation of laser irradiation rock vitrification is a key factor in achieving glass casing.In this study,the influencing factors and mechanisms of laser ablation granite vitrification are investigated based on laser scanning granite experiments,combined with phase detection and numerical simulation.The results show that after laser scanning,the constituent minerals of granite melt and fragment according to the ease of melting,and part of the surface is transformed into dark glass.The high-speed airflow can effectively remove rock debris and dust,improve the laser efficiency,and increase the adhesion of rock glass.Granite is susceptible to temperature fracture,and its low scanning speed and airflow auxiliary conditions favor the formation of vitrification.In practical engineering applications,the temperature action of the rock can be controlled via the scanning speed and auxiliary high-speed airflow to form stable rock glass,and create an in-situ vitrification well wall that firmly covers the hard rock surface.This study focuses on the vitrification mechanism of laser-acting rocks,and provides an important reference for expanding the engineering application of laser drilling.