摘要
针对φ311.15mm(121/4英寸)井眼采用复合钻进时存在的岩屑量大,钻头处存在重复破碎等问题,在前人研究的基础上,对某区块常用的φ311.15mmPDC钻头进行了水力结构分析与优化。通过数值模拟,得到了钻头表面速度矢量图、喷嘴中心剖面速度矢量图及刀翼表面速度矢量图,并在此基础上确定了水力结构优化方案。仿真结果表明,改进后涡心与射流区的距离增加,漩涡边界流体切入到漫流层中并附壁上返,漩涡强度减弱,漫流区厚度与速度增加,携岩能力提高,清洗与冷却能力增强。
In light of the problem that there exist large amounts of cuttings and repeated breaking of the drill bit during compound drilling inφ311.15 mm borehole,the hydraulic structural analysis and optimization of the bit were carried out.Through numerical simulation,the speed vector diagrams for the bit surface,the nozzle center profile and the blade surface were obtained,and the optimization scheme of the hydraulic structure was determined based on these diagrams.The simulation result shows that after the improvement,the distance between the vortex center and the jet zone increases,the boundary fluid of the vortex cuts into the cross-flow stratum and goes back up the wall,the vortex strength decreases,the thickness and speed of the cross-flow zone increase,the cuttings-carrying capacity is improved and the cleaning and cooling capacities are enhanced.
出处
《石油机械》
北大核心
2010年第8期1-4,104,共4页
China Petroleum Machinery
基金
国家自然科学基金资助项目"气体钻井钻具与井壁的碰摩机理及量化评价方法研究"(50804040)
