摘要
准确预测PDC钻头的各向异性指数能够提高定向钻井井眼轨迹的控制能力。在分析PDC钻头在井底的运动状态并给出其切削面积的计算方法之后,采用直线-双圆弧型钻头剖面设计,建立切削面积与钻速的函数关系式,进而建立了钻头受力与钻速的关系模型。验证试验结果表明各向异性指数的计算值与试验值相符合。分析了钻头结构对各向异性指数的影响规律,指出当钻头剖面形状是浅内锥短外锥时,各向异性指数最大;钻头的保径长度越长,各向异性指数越小。
The accurate prediction of PDC bit anisotropy index can improve the control over borehole trajecto- ry during directional drilling. The motion state of PDC bit at the bottom of borehole is analyzed and the calculation method of cutting area is given. A more realistic straight-biarc profile of PDC bit is adopted. The functional rela- tionship of cutting area and rate of penetration is established. Thus, the relation model of forces of PDC bit and ROP has been established. Verification tests show that the calculated anisotropy index is consistent with the experimental value. The influence of the bit structure on anisotropy index is analyzed. Results indicate that the maximum anisotropy index is reached when the bit has a profile shape of shallow inner cone and short outer cone. The longer the bit gauge is, the smaller the anisotropy index will be.
出处
《石油机械》
北大核心
2014年第9期27-30,共4页
China Petroleum Machinery
基金
"十二五"国家科技重大专项之子课题"薄互层水平井导向PDC钻头优化设计及导向特性研究"(05Z12020300)
