转速对轴流式PDC钻头井底流场影响  

Effect of Different Rotational Speed on Bottom Hole of Axial Flow PDC Bits

作　　者：曹扬[1] CAO Yang(College of Safety and Marine Engineering,China University of Petroleum(Beijing),Beijing 102249,China)

机构地区：[1]中国石油大学(北京)安全与海洋工程学院,北京102249

出　　处：《石油矿场机械》2023年第5期1-11,共11页Oil Field Equipment

基　　金：中国石油天然气集团有限公司科学研究与技术开发项目“自动化与高效钻完井新装备新工具研制”(2019B-4009)。

摘　　要：PDC钻头在钻进深井过程中,由于钻井液上返速度慢及井底压力大,使得井底岩屑难以上返,从而堆积在井底形成泥包,对钻进效率产生极大影响。为了提升钻进效率,基于轴流泵原理,在PDC钻头保径向上10 mm处设计了轴流泵叶片。该叶片随钻头旋转,给予井底流体向上升力,增加井底钻井液上返速度,降低井底压力。使用Fluent DPM模型对轴流式PDC钻头的井底流场进行数值模拟分析,结果为:随着钻头转速增加,①井底射流区、漫流区和上返区钻井液流速增加,出口区域流速也增加;②井底压力逐渐减小,刀翼切削处压力逐渐增大,钻头在井底的切向力变化较弱;③井底颗粒质量浓度、保径区域颗粒质量浓度和上返区域颗粒质量浓度逐渐降低。During the drilling process of PDC bits in deep wells,the slow upward flow rate of drilling fluid and the high pressure at the bottom of the well,make it difficult for rock chips to return to the bottom of the well,thus forming a mud pocket at the bottom of the well,which has a significant impact on drilling efficiency.In order to improve drilling efficiency,based on the principle of axial flow pump,axial flow pump blades were designed at a radius of 10mm above the PDC drill bit.The blade rotates with the drill bit,providing upward lift to the wellbore fluid,increasing the upward velocity of the wellbore drilling fluid,and reducing the wellbore pressure.Using the Fluent DPM model,a numerical simulation analysis was conducted on the bottom hole flow field of an axial flow PDC drill bit.The results are as follows:as the bit speed increases,(i)the flow rate of drilling fluid increases in the bottom hole jet,diffuse flow,and upstream zone,and the flow rate in the exit zone also increases;(ii)the pressure at the bottom hole gradually decreases,the pressure at the cutter wing cutting gradually increases,and the tangential force of the bit at the bottom hole is weak;(iii)the particle concentration at the bottom hole,the particle concentration in the conformal zone and the particle concentration in the upstream zone gradually decreases.

关 键 词：轴流式PDC钻头 转速 井底压力 流速 

分 类 号：TE921.102[石油与天然气工程—石油机械设备]