矩形喷嘴PDC钻头水力性能研究新方法  

New Method for Hydraulic Performance Study on PDC Drill Bit with Rectangular Nozzle

作　　者：郝金克 

机构地区：[1]中石化胜利油田石油工程技术研究院

出　　处：《石油机械》2015年第12期33-36,共4页China Petroleum Machinery

基　　金：国家科技重大专项"胜利油田薄互层低渗透油田开发示范工程"(2011ZX05051)

摘　　要：为了量化研究矩形喷嘴PDc钻头的水力性能,以5刀翼、布置6个矩形喷嘴的PDC钻头为基础模型,建立了流域模型,将岩屑建模为从切削齿表面射人流场的固相颗粒,采用计算颗粒追踪法对固相颗粒进行了追踪,同时使用岩屑运移速度比C_t作为钻头性能评价的参数。分析结果表明,井底岩屑运移是三维不规则运动,沿程存在碰撞与反弹,在岩屑从井底向环空出口运动的过程中,速度逐渐减小;相同条件下,矩形喷嘴钻头的C_t大于圆形喷嘴钻头的C_t值,且随长宽比的增大而增大,与圆形喷嘴钻头相比,矩形喷嘴钻头的水力性能更好;对于同一钻头,1.0mm岩屑的C_t值最大,当粒径小于1.0 mm时,C_t随岩屑尺寸的增大而增大,当粒径大于1.0 mm时,C_t随岩屑尺寸的增大而减小。To quantitatively study the hydraulic performance of PDC bits with rectangular nozzles, a three-di-mensional flow volume model was established for a PDC bit with five blades and six rectangular nozzles. Cuttings were modeled as spherical particles injected into the flow field from cutters surfaces. The computational particle tracking method was used to track the cuttings. Cutting transport velocity ratio Ct was taken as the evaluation param-eter of the hydraulic performance of bit. Results show that downhole cuttings transport is a chaotic three-dimensional motion along with collision and rebound. Cutting velocity decreases gradually from bottomhole to annular out-let. Given the same conditions, Ct of bit with rectangular nozzles is bigger than that with circular nozzles. As the length-width ratio increases, the hydraulic performance of rectangular nozzle bit is better than that of circular nozzle bit. For the same bit, the maximum Ct value is observed on 1. 0 mm particle. For the particle size less than 1. 0 mm, the Ct value increases with the increase of particle size. For the particle size bigger than 1. 0 mm, the Ct val-ue decreases with the increase of particle size.

关 键 词：矩形喷嘴 PDC钻头 水力性能 颗粒追踪 岩屑运移速度比 井底流场 

分 类 号：TE921[石油与天然气工程—石油机械设备]