PDC钻头定向喷嘴井底流场数值模拟  

Numerical Simulation of Bottomhole Flow Field of PDC Bit with Orientation Nozzle

作　　者：黄英勇 李根生[1] 宋先知[1] 付加胜[1] 

机构地区：[1]油气资源与探测国家重点实验室(中国石油大学),北京昌平102249

出　　处：《石油钻探技术》2011年第6期99-103,共5页Petroleum Drilling Techniques

基　　金：国家重点基础研究发展计划("973"计划)项目"深井复杂地层安全高效钻井基础研究"(编号:2010CB226700)部分研究内容

摘　　要：为提高定向喷嘴PDC钻头清洗井底的效果,最大限度地减少钻头泥包的形成。利用计算流体力学理论和数值模拟方法,建立了定向喷嘴PDC钻头的物理模型,并确定了定向喷嘴PDC钻头的物理模型参数,对定向喷嘴和定向喷嘴PDC钻头的井底流场特性进行了分析。结果表明:在定向喷嘴的结构参数中,双流道的直径组合与侧向流道的倾角是影响流量分配的主要因素,侧孔倾角为45°时,既能满足流量分配的要求,又便于加工;定向喷嘴侧向射流将回流限制在新冲击区的上方,减小了井底漩涡区域,与漫流层的叠加补偿了其能量损失,刀翼切削面处的低速区也变小,对井底清岩起到较好的作用,有利于抑制泥包的形成。定向喷嘴与常规水力结构设计相结合可以在预防和清除PDC钻头泥包方面发挥自身的优势,达到提高机械钻速的目的。In order to improve bottom hole cleaning efficiency of PDC bit with orientation nozzle and to prevent bit balling farthest,a physical model of PDC bit with orientation nozzle was established,and the parameters of physical model were confirmed.The characteristics of bottom flow field of PDC bit and its orientation nozzle were analyzed using computational hydromechanics theory and numerical simulation.The results indicate that the diameter combination of two fluid-channels and the obliquity of the lateral channel are main factors for flow rate distribution in the structural parameters of orientation nozzle.When the inclination angle of lateral nozzle is 45°,the requirement of flow distribution of bit nozzle is satisfied and bit nozzle is easy to manufacture.The jet flow of lateral nozzle restricts the backflow in the upper impact zone and reduces the area of bottom vortex.Combined cross flow layer with impact zone can compensate the loss of energy.The low velocity zone at blade wing was reduced,which can give positive effects for cleaning bottomhole and restrain bit balling.Orientation nozzles coupled with conventional hydraulic structure can prevent or eliminate PDC bit balling and increase the penetration rate.

关 键 词：PDC钻头 定向喷嘴 井底流场 数值模拟 钻头泥包 

分 类 号：TE921.1[石油与天然气工程—石油机械设备]