机械式自动垂直钻具上盘阀开口角度的优化分析

动态机械式自动垂直钻具广泛应用于直井作业中，改善其纠斜性能是优化钻具的关键目标。钻具稳定平台中上盘阀的开口角度对其纠斜性能影响很大。以扩径力冲量、导向力冲量、导向力突变幅度和波动幅值作为钻具井眼螺旋程度、有效推靠力作用和导向力稳定性的评价指标，来评价不同上盘阀开口角度下钻具的纠斜性能。通过分析钻具在纠斜过程中的状态，得到巴掌推靠合力的变化规律，并与试验测试值进行对比，最终得到在不同上盘阀开口角度下3种评价指标的变化规律。研究结果表明：推靠合力的理论值与测试值接近；在上盘阀开口角度为180°时，纠斜过程平稳，纠斜效率高，且能最大程度地降低井眼的螺旋程度。3种钻具纠斜性能评价指标的提出及研究结果为后续垂直钻具的整体优化设计提供了新思路。

Optimization analysis of opening angle of upper disc valve of mechanical automatic vertical drilling tool

Dynamic mechanical automatic vertical drilling tool is widely used in vertical well operations.Improving its restoring performance is the key goal of optimizing drilling tool.The opening angle of upper disc valve in the stable platform has a great influence on the restoring performance.In view of this,three indexes of expansion force impulse,guiding force impulse,abrupt transition amplitude and fluctuation amplitude of guiding force were set up to evaluate the degree of borehole helix,effective push force and stability of guiding force,and to evaluate the restoring performance of drilling tool at different opening angles of upper disc valve.By analyzing the state of the drilling tool in the restoring process,the changing rule of the resultant force of outstretched hands was obtained,and compared with the test value.Finally,the changing rule of the three indexes at different opening angles of upper disc valve was obtained.The results showed that the theoretical value of the resultant push force was close to the test value.When the opening angle of upper disc valve was 180°,the restoring process was stable and efficient,and the degree of borehole helix could be reduced to the maximum extent.Three proposed evaluation indexes and the research results provide a new idea for the following overall optimization design of the vertical drilling tool.