解决钟摆钻具在大钻压下增斜问题的新思路

A NEW METHOD OF SOLVING BUILD-UP HOLE ANGLE PROBLEM ON PENDULUM ASSEMBLY WHILE WOB IS INCREASING

通过对钻头处受力情况的深入分析 ,否定了以前在分析底部钻具组合时 ,将钻头处的边界条件看作铰支 (即弯矩为零 )的一惯做法 ,提出了应先将这里看作是固支 (即转角为零 ) ,只有当弯矩达到一定的值时 ,才能出现转角的新观点 ,并给出了计算弯矩最大值的计算公式。同时利用文中的结论 ,对在倾斜井眼中钟摆钻具在加大钻压时会出现增斜现象给出了合理的解释 ,并针对其产生的原因提出相应的对策。

Through analysing the force on the bit,the author brought out a new idea about the boundary condition in the bit end of the bottom-hole assembly,that unless the moment reaching the maximum moment value available the angle is zero there,instead of the traditional one that the moment is zero there.The calculation formula of maximum moment value was deduced.Based on this new idea,the author explained the reason why the deviation angle will increase while the WOB is increasing,and brought out a new method to resolve this problem.