煤层密闭取心用超前隔水式PDC钻头设计与优化  

Design and optimization of advanced water proof PDC bit used in sealed coring of coal seam

作　　者：高晓亮 张朋 龙威成 GAO Xiao-liang;ZHANG Peng;LONG Wei-cheng(Xi'an Research Institute of China Coal Technology and Engineering Group,Xi'an 710077,China)

机构地区：[1]中煤科工集团西安研究院有限公司,陕西西安710077

出　　处：《煤炭工程》2021年第7期178-182,共5页Coal Engineering

摘　　要：为提高煤层瓦斯测定精度,一般采用密闭取心的方式进行煤层取样,配套煤层密闭取心用三筒单动取心器,设计了一种密闭取心用超前隔水式PDC钻头。通过对普通底喷式钻头、锥面煤心导进式钻头以及超前隔水式钻头三种结构形式进行对比优化,选用超前隔水式钻头为密闭取心用钻头,该钻头采用超前式小钻头压入煤层,小钻头采用合金切削齿进行干钻,有效隔绝钻井液进入煤心。根据流体力学连续性方程优选水眼数量与尺寸,降低水眼钻井液对煤层冲刷,并采用斜水眼、反向斜面水道等结构进一步防止钻井液进入煤心。根据全覆盖井底的原则进行PDC切削齿排布,优化钻头钻进效率。采用设计的钻头在淮北芦岭煤矿地面采动卸压瓦斯抽采井中进行现场试验,试验证明煤心采取率满足密闭取心施工要求。In order to improve the measurement accuracy of coal seam gas,commonly,sealed coring is used in coal seam sampling.In this article,a kind of advance water-proof PDC drill bit for sealed coring is designed,which is equipped with a three-barrel single-acting coring device for sealed seam coring.By comparing and optimizing the three structure types of common bottom-spray bit,cone-faced coal core guide bit and advanced water-proof bit,the advanced water-proof bit is selected as the core bit for sealed coring,in the drill bit,an advanced small drill bit is pressed into the coal seam,which uses cemented carbide cutting teeth for dry drilling,and isolates the drilling fluid from entering the coal core.According to the continuity equation of hydrodynamics,the number and size of water eyes are optimized,which reduces the erosion of coal seam by waterhole drilling fluid,and inclined water eye,reverse inclined water channel are used to prevent drilling fluid from entering the coal core.The PDC cutting teeth is arranged according to the principle of fully covering the bottom of the well to improve drilling efficiency.The designed drill bit was used in ground mining and pressure relief gas extraction well of Luling Coal Mine in Huaibei,the test proved that the coal coring adoption rate can satisfy the requirements of the sealed coring construction.

关 键 词：密闭取心 隔水式钻头 PDC钻头 钻头设计 

分 类 号：TD402[矿业工程—矿山机电]