CAJ | 학술논문

建立直井钻井时复合钻柱局部理论模型，根据截面法推导出复合钻柱任意截面的有效轴向力计算方法。建立直井钻井复合钻柱整体模型，结合局部理论模型结论推导出实际钻井工况下复合钻柱有效轴向力计算公式和考虑液体摩阻力下及射流冲击力下钻压增量计算公式，给出了新的中性点计算方法。经实例比较分析，推导出的中性点计算公式的精度高，但计算复杂，建议在深井和超深井的钻井设计中选用。
건립직정찬정시복합찬주국부이론모형，근거절면법추도출복합찬주임의절면적유효축향력계산방법。건립직정찬정복합찬주정체모형，결합국부이론모형결론추도출실제찬정공황하복합찬주유효축향력계산공식화고필액체마조력하급사류충격력하찬압증량계산공식，급출료신적중성점계산방법。경실례비교분석，추도출적중성점계산공식적정도고，단계산복잡，건의재심정화초심정적찬정설계중선용。
Absttact:Composite drill string partial theory model is established when drilling straight wells to deduce calculation formula of effective axial force on composite drill string’s arbitrary cross sec-tion according to the method of cross section method.Composite drill string whole theory model is established when drilling straight wells to deduce calculation formula of effective axial force on the arbitrary cross section of composite drill string in the actual drilling condition and calculation formula of bit pressure increment considering liquid friction force and jet impact force,calculation method of new neutral point is given.Through a comparative analysis of examples,calculation for-mula of the neutral point of the paper is of high accuracy,but considering its computational com-plexity,drilling design in the deep and ultra deep well is recommended.