纵横弯曲法对钻具组合的二维分析

一个多扶正器钻具组合可看成是一个受有纵横弯曲的多支点连续梁柱。把它在各扶正器处分开,使其分成几个简支梁柱。然后,即可建立一组“三弯矩方程”组,以解出各扶正器处的内弯矩、钻头上受到的侧向力、以及加于各扶正器上的约束反力等。此时,井身轴线则被假设为一条位于某垂直平面上的圆弧曲线。这样得到的一些数字计算结果与Millheim应用有限元素法求出的结果进行了对比分析。

TWO-DIMENSIONAL ANALYSIS OF BOTTOM HOLE ASSEMBLY BY BEAM-COLUMN THEORY

A multi-stabilized bottom hole assembly in borehole is considered as a continuous beam-column with many supports.It can be divided into several simply-supported beam-columns by separating the sections at each stabilizers.A system of "Equations of three moments" is derived to compute the internal bending moments at stabilizers,the side force on bit and the reactive forces at stabilizers.The borehole axis is taken as a circular arc in a vertical plane.Some numerical results are compared with those qiven by Millheim,based on finite element method.