关键词: 钻具组合, 扶正器, 有限元法, 变形, 应力, 计算模型

Abstract: The stress concentration is a key factor causing fatigue failures.It is very important to make a quantitative research on the stress level and distribution characteristics of BHA.The finite element mechanics models for BHA with stabilizers in vertical well or in slant hole were established.The models were solved by the software,and deformation field and the stress field were computed.For BHA,the results show the highest deflection is located in the long span between the stabilizers.The most dangerous position is in the location of deformed drillstem with the biggest corner.The biggest corner is located near the stabilizers,so there is the highest bend moment.The stress level in the position of stabilizer is the highest,and the stress of other places is much lower.Because the threaded connections are just located in these highest stress areas of the drill tool,the fatigue failure of the threaded connections may easily happen.The fatigue failure of the stabilizers almost occur in the positions of threaded connections.

Key words: BHA, stabilizer, deformation, stress, FEA, research