鱼骨型分支井开窗下部钻具力学性能分析

鱼骨型分支井开窗时下部钻具组合在井底的受力及变形特征直接影响分支井眼的轨道形状，分支井眼轨迹控制不当将难以保证轨迹在储层中有效穿过，从而直接影响鱼骨型分支井的产量，同时分支井眼的窗口质量好坏也将影响主井眼完井管柱的安全下入。采用有限元法建立了鱼骨型分支井开窗时下部钻具组合力学性能分析的有限元模型，分析了开窗时下部钻具的受力及变形特性，计算了开窗时下部钻具组合的造斜能力，分析了下部钻具组合结构及工具面角对造斜能力的影响。新疆油田的应用实践表明:理论计算鱼骨型分支井开窗时的造斜率符合实钻结果，误差在13%以内，在工程应用中是可靠的。该分析方法可以为鱼骨型分支井开窗时井眼轨道的有效控制提供依据，具有重要的现场应用价值。

Analysis of BHA mechanical behavior of window cutting of herringbone multilateral wells

In the process of herringbone multilateral window cutting, BHA mechanical behavior in the bottom hole exerts direct effect on the trajectory shape of the branch hole. Improper control of the branch hole trajectory will be difficult to ensure the trajectory to go through the reservoir effectively, thereby will decrease the output of herringbone multilateral wells, the quality of the branch hole window will affect the safety of original hole completion string’s trip in the original hole. This paper establishes the finite element model of BHA of fishbone multilateral well window cutting, analyses BHA mechanical behavior of window cutting, calculates build-up ability of BHA, analyses the affect of BHA structure and TFO (tool face orientation) on the angle build-up ability. The application in XinJiang Oilfield shows that the calculating rate of build-up of fishbone multilateral well window cutting accords with the result of actual drilling, the error is less than 13%. The research lays sound basis for trajectory control of fish bone multilateral well window cutting.