空气锤钻井机械比能计算方法

A method for calculating the mechanical specific energy of air hammer drilling

空气锤钻井是目前硬质岩层钻井提速提效的重要工艺,为了实时评价空气锤钻头的工作效率,提高钻井施工可控性,对空气锤钻井机械比能计算方法进行了研究。基于前人提出的机械比能相关理论,分析了空气锤钻头机械结构和钻进机理,引入冲击效率和冲击速度等参数修正完善机械比能计算模型,并提出能量传递效率ηtr,辅助分析空气锤钻井效率。根据以上理论模型,研制了空气锤钻井机械比能计算软件,可综合利用钻井参数、岩石力学参数、机械比能、能量传递效率等多种连续曲线剖面科学评估空气锤钻头的钻井效率,并采用元坝区域的钻井数据进行验证。结果表明,该计算方法得到的空气锤机械比能和能量传递效率对钻井效率的评价基本与现场实际情况相符,本文所研究的方法对评价空气锤钻井效率、优化钻井参数和钻后分析具有重要意义。

Air hammer drilling is currently an important technology for improving the drilling speed and efficiency in hard rocks.In order to evaluate the operating efficiency of air hammer drilling bit in real time and improve the controllability of drilling operation,this paper studied the method for calculating the mechanical specific energy of air hammer drilling.Based on previous theories related to mechanical specific energy,the mechanical structure and drilling mechanism of air hammer drilling bit were analyzed,and some parameters(e.g.impact efficiency and impact velocity)were introduced to correct and improve the mechanical specific energy calculating model.Then,the energy transfer efficiency(ηtr)was put forward to assist analyzing air hammer drilling efficiency.Finally,on the basis of foresaid theoretical model the software for calculating the mechanical specific energy of air hammer drilling was developed,which can scientifically evaluate the drilling efficiency of air hammer drilling bit by making comprehensive use of various continuous curve sections,such as drilling parameters,rock mechanical parameters,mechanical specific energy and energy transfer efficiency.In addition,it was verified based on the drilling data of Yuanba Block.It is indicated that the evaluation on the drilling efficiency from the aspects of air hammer’s mechanical specific energy and energy transfer efficiency which are obtained by means of the proposed calculation method is basically accordant with the actual situations on site.In addition,the method studied in this paper is of great significance to evaluate air hammer drilling efficiency,optimize drilling parameters and perform post-drilling analysis.