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在钻井防斜打直理论中,广泛采用霍奇公式计算满眼钻具两个扶正器的最佳安装位置。本文对霍奇公式提出了—些看法所讨论的钻井防斜钻具的力学模型是纵横弯曲杆的非线性力学体系,在推导横向力公式时,不能象原公式那样用线性叠加原理处理;原公式在计算下扶正器横向位移时,忽略了一些不应忽略的因素,对计算上扶正器的最小安装高度带来了可观的误差;第三,原公式在计算上扶正器最大安装高度时应用了欧拉公式,忽略了下扶正器的存在,实际上,不应以钻柱失稳与否为临界条件,而应以保证下扶正器恒与上井壁接触来进行计算。本文采用了纵横弯曲杆的挠度近似公式,最后求得双扶正器防斜钻具的横向力近似表达式,并对该式进行了简单的分析,求出了为极大值的h_优,计算较为简便。
In drilling anti-inclined straight theory, the Hodge formula is widely used to calculate the optimal installation position of two centralizers for full-eye drilling tools. In this paper, the Hodge formula is put forward. Some opinions about the mechanics model of drilling anti-skew drilling rig are nonlinear mechanical system of longitudinal and transverse bending rod. When formula of lateral force is deduced, it can not be treated by linear superposition as the original formula. The formula neglects some factors that should not be ignored when calculating the lateral displacements of the centralizer, which brings considerable errors to the minimum installation height of the centralizer. Thirdly, the original formula is applied when calculating the maximum installation height of centralizer The Euler formula, ignoring the presence of the lower centralizer, in fact, should not be drill pipe instability or not as a critical condition, but should ensure that centralizer constant contact with the shaft wall to calculate. In this paper, the approximation formula of deflection of vertical and horizontal bending rod is adopted. Finally, the approximate expression of lateral force of double stabilizer is obtained. Based on the simple analysis of the formula, the h_ excellent, Calculation is more convenient.