【摘要】 根据地层对钻头的反抗扭矩模型和地层各向异性造斜理论,综合考虑钻柱、钻头、地层及钻井参数对斜直井内下部钻柱空间弯曲变形的影响。借助于Laplace变换,获得钻柱空间变形的弹性曲线及地层各向异性指数h=2Q₂（0）/P₀sin2（β-α）sinγ提出了在空间变形状态下打直井的条件,并对定长钟摆钻具及垂直井内下部钻柱的空间变形问题进行了讨论。通过算例分析说明了钻井参数、井斜角（α）、地层倾斜角（β）及地层旋转角（γ）对光钻铤钟摆钻具及定长钟摆钻具的影响。更多还原

【Abstract】 Based on the formation-on-bit drag torque model and the theory of anisotropic deflecting by formation,this paper deals with the influence of the bit,drill string,formation and drilling parameters an threedimensional buckling of lower drill string in a deviatied-straight borehole.By laplace transformation,we obtain the elastic curve of three-dimensional deformation of the drill string W=（[y（x）]² +[z（x）]²）^1/2,tgξ=y（x）/z（x） and anisotropic parameters h = 2Q_z（o） /P_osin2（β-α） sinγand give the condition of drilling a straight borehole F = F_p + F_f^* = 0 and discuss the three-dimensional deformation of fixed length pendulum drill tool and the lower drill string in a straight borehole.The effects of drilling parameters,borehole inclination anglea,formation inclinationβand rotary angleγon collar pendulum drill tool and fixed length pendulum drill tool are illustrated through the calculation.更多还原