基于CFD-DEM耦合的导向钻头井底岩屑运移特性分析  

CFD-DEM coupling-based analysis of rock chip transport characteristics at bottom of rotary-guided drill bit

作　　者：胡金帅 张光伟[1] 陈雨 李俊岭 闫丰平 HU Jinshuai;ZHANG Guangwei;CHEN Yu;LI Junling;YAN Fengping(College of Mechanical Engineering,Xi’an Shiyou University,Xi’an 710065,China)

机构地区：[1]西安石油大学机械工程院,陕西西安710065

出　　处：《中国粉体技术》2022年第6期37-48,共12页China Powder Science and Technology

基　　金：国家自然科学基金项目,编号:51174164;陕西省自然科学基金项目,编号:2018JM5015。

摘　　要：为了探究旋转导向钻具在导向钻进过程中井底岩屑运移规律,采用计算流体动力学和离散单元法耦合算法(CFD-DEM)建立描述井底钻井液与岩屑颗粒复杂两相流动的模型,运用有限元软件与离散元软件分析旋转导向钻具井底岩屑颗粒的运动学特性;探讨旋转导向钻头偏置角度、钻井液流速、钻头转速、岩屑颗粒粒径对井底岩屑颗粒运移特性的影响规律。结果表明:提高转速与钻井液流速,岩屑颗粒的运移速度随之增大,对于井底岩屑颗粒的运移起到正反馈的作用,可提高井底清洁度;岩屑颗粒粒径的增大会减小岩屑颗粒的运移速度,当岩屑颗粒的直径大于3 mm时,岩屑运移速度减小更加明显;旋转导向钻具钻头偏置会导致井底空间结构的变化,岩屑颗粒动能和钻井液水力能量也会削弱,最终会加剧钻头磨损,产生泥包等。In order to investigate the kinematic characteristics of the rock chip particles in the bottom of the well during the guided drilling process of rotary-guided drilling tools,a complex two-phase flow model describing the drilling fluid and rock chip particles in the bottom of the well was developed by using a coupled algorithm of computational fluid dynamics and discrete element method,and the kinematic characteristics of rock chip particles in the bottom of the well of rotary-guided drilling tools were analyzed by using software of FLUENT and EDEM.The effects of offset angle of rotary-guided drill bit,drilling fluid flow rate,drill bit speed and particle size on the kinematic characteristics of rock chip particles in the wellbore were investigated.The results show that increasing the rotational speed and drilling fluid flow rate increase the transport speed of rock chip particles,which has a positive feedback effect on the transport of rock chip particles and improve the cleanliness of the well bottom.Increasing the particle size of rock chip particles reduces the transport speed of rock chip particles,and when the diameter of rock chip particles is larger than 3 mm,the reduction of rock chip transport speed is more obvious.The offset of the drill bit of the rotary-guided drilling tool causes the change of the spatial structure of the well bottom and the change of rock chip particles.The change of spatial structure,the collision between rock chip particles lead to kinetic energy loss,and the hydraulic energy is also weakened by the change of spatial structure,which makes the rock chip particle transportation efficiency decrease,and eventually will aggravate the bit wear and produce the mud packing.

关 键 词：计算流体动力学 离散单元 耦合算法 井底流场 旋转导向钻具 岩屑运移 

分 类 号：TE928[石油与天然气工程—石油机械设备]