钻头切削齿破碎岩石的温度变化试验及机理分析  

Temperature variation tests and mechanism analysis of rock breaking by bit cutters

作　　者：周琴[1,2] 张在兴 张凯 郑国敬 何录忠 ZHOU Qin;ZHANG Zaixing;ZHANG Kai;ZHENG Guojing;HE Luzhong(School of Engineering and Technology,China University of Geosciences,Beijing 100083,China;MLR Key Laboratory on Deep Geological Drilling Technology,Beijing 100083,China)

机构地区：[1]中国地质大学(北京)工程技术学院 [2]国土资源部深部地质钻探技术重点实验室

出　　处：《天然气工业》2020年第10期102-110,共9页Natural Gas Industry

基　　金：国家自然科学基金项目“真空无水低功耗条件下碎岩机理研究”(编号:41672365)、国家重点研究计划项目“小口径高效系列钻具研究”(编号:2018YFC0603404)。

摘　　要：钻头切削齿是破碎岩石的核心部分,在破岩过程中做的绝大部分功会转换成切削热,导致切削齿温度升高,目前对切削齿温度的影响研究成果主要集中在切削深度、切削速度及切削齿结构方面,但对于岩石特性对切削温度影响程度和机理的认识尚不明晰。为此,在自制的MDES 2000微钻平台上,开展了砂岩、大理岩、花岗岩以及玄武岩等4种典型岩石的钻进试验,基于岩石破碎力学模型和数值分析结果,探讨了岩石特性对切削温度的影响程度并进行机理分析。研究结果表明:①在相同的钻进参数下,岩石强度直接影响不同岩石钻进深度,导致岩石破碎模式(塑性、脆性)的转变,从而造成不同岩石切削温度的波动差异,砂岩、大理岩发生塑性破碎,温度波动范围约为±0.5℃,而花岗岩、玄武岩则发生脆性破碎,切削齿温度波动范围约为±1.5℃;②岩石强度是影响切削温度温升速率变化的重要因素,强度越大所需切削力越大,产生切削热增加,导致4种不同岩石钻进时温升速率随岩石强度的增加而逐次递增;③岩石破碎力学模型和前、后刀面温度分析结果表明,切削齿前刀面起主要的切削作用,是造成不同岩石的切削温度波动程度的主要因素。结论认为,钻进试验与数值模拟所得到的温度变化趋势基本吻合,该成果可以为钻头切削齿工作寿命研究提供借鉴和参考。A bit cutter is the core component to break rocks.Most of the work done in the process of rock breaking is converted into cutting heat,which increases the temperature of the cutter.The current research results on the influential factors of cutter temperature mainly focus on cutting depth,cutting speed and cutter structure,etc.,while the influence degree and mechanism of rock characteristics on the cutter temperature have not been clarified yet.For this reason,this paper carried out a drilling test of four typical types of rocks,including sandstone,marble,granite and basalt,on the independently made MDES 2000 micro-drilling platform.Then,based on rock breaking mechanics model and numerical analysis results,the influence degree of rock characteristics on the cutter temperature was discussed and the influence mechanism was analyzed.And the following research results were obtained.First,with the same drilling parameters,the rock strength directly influences the drilling depth of different rocks,which leads to the transformation of the rock breaking mode(plasticity and brittleness),resulting in different cutter temperature fluctuations in different rocks.When plastic crushing occurs in sandstones and marbles,the temperature fluctuation range of the cutter is about±0.5℃;When brittle crushing occurs in granites and basalts,the temperature fluctuation range is about±1.5℃.Second,rock strength is an important factor influencing the rise rate of cutter temperature.Higher rock strength requires stronger cutting force,causing the increase of cutter temperature,so the temperature rise rate is increased gradually with the increase of rock strength in the process of drilling the four types of rocks.Third,the rock breaking mechanics model and the analysis results on the temperature of rake face and flank face show that the rake face of cutter plays an important role in cutting and it is the main factor leading to different fluctuation degrees of cutter temperature in different rocks.In conclusion,the temperature change tren

关 键 词：岩石特性 钻进试验 破岩机理 温升速率 温度波动 力学模型 破碎模式 数值分析 

分 类 号：TE921.1[石油与天然气工程—石油机械设备]