双扶正器钟摆钻具组合的优化设计

为了提高钟摆钻具的防斜侧向力,本文应用纵横弯曲连续梁理论,研究在井斜角很小的垂直井中,对双扶正器的钟摆钻具组合如何使用优化方法合理选择钻具参数。采用“对分法”和“伸缩保差法”作为搜索方法,得出防斜侧向力最大的并随着钻压增加而增大的“双扶正器柔性钻具组合”(即两扶正器之间为柔性钻杆)。又对“双扶正器刚性钻具组合”(即两扶正器之间用刚度较大的钻铤)进行优化设计,从而取得了对不同造斜地层打钻时进行参数优选的规律性。优化设计后具有双扶正器的柔性和刚性钟摆钻具可较光钻铤钻具的防斜侧向力有显著的提高(可提高40～60%)。

OPTIMUM DESIGN OF PENDULUM BOTTOMHOLE ASSEMBLY WITH DOUBLE STABILIZERS

The choice of optimal parameters for design of pendulum bottomhole assembly with double stabilizers used in vertical hole with very small deflection angle is discussed, based on the continuous beam theory. A design of flexible assembly with double stabilizers(i. e., with a flexible drilling stem between the two stabilizers) is achieved which has the greatest side force that increases with drilling load for deflection prevention. Another design of rigid assembly with double stabilizers(i. e., with a rigid drilling stem between the two stabilizers) is also sought. The new design gives a side force 40～60% higher that of the conventional.