空气钻井钻具冲蚀磨损机理的分析

空气钻井技术受到越来越多的重视，针对空气钻井中钻具冲蚀磨损严重的现象，首先从阐释冲蚀本质入手，随后对现有的有影响力的冲蚀磨损理论对比分析，得出适合于空气钻井的3套冲蚀磨损理论，并分别进行详细阐述。这3种理论将从不同角度来解释空气钻井钻具的冲蚀磨损机理。微切削理论适用于解释钻屑粒子低入射角的切削情况；变形磨损理论从变形历程及能量变化角度解释了冲蚀现象；二次冲蚀理论从颗粒破碎后对钻具的二次冲蚀角度，更合理地阐述了冲蚀机理。最后就影响钻具冲蚀磨损的主要外部因素——钻屑粒径、几何形状、冲击速度、冲击角度、井内温度进行了定性分析。

MECHANISM ANALYSIS OF BHA EROSION WEAR IN AIR DRILLING

Air drilling technology is being concerned more and more，aiming at the phenomenon of serious erosion-wear of drilling tool（BHA erosion） in air drilling，in this article，explaineding the essence of erosion is firstly done， subsequently，comparative analysis among the influential theory models of erosion-wear carried out，then，three erosion theories for BHA erosion in air drilling educed，with explaining these theories detailedly.These three pieces of theories from different aspects are used to interpret the mechanism of BHA erosion during air drilling.Micro-cutting theory is suitable for explaining cutting condition of low impacting-angle bitcuttings.Deformation wear theory，from the angle of changing energy and deforming process，is used to discusses the mechanism of erosion.The secondary erosion theory interprets the erosion mechanism more overall because it considers the influence of bitcuttings′ breakage to erosion on the surface of drilling tool.At last，a qualitative analysis of main external factors，such as bitcuttings diameter，bitcuttings shape，impacting velocity，impacting angle，downhole temperature，which have great effection on BHA erosion is conducted.