| 摘要: |
| 定量计算钻头与地层之间的作用力对井眼轨迹控制具有重要意义。由三维钻速方程出发,根据钻头合位移方 向即为其运动方向的思想,推导出了计算地层力的新模型。该模型综合考虑了地层和钻头的各向异性以及钻头转 角的影响,它不受稳斜稳方位条件的限制,是现有地层力模型的补充和扩展。研究结果表明,钻头各向异性和钻头 转角对地层力均有影响,把钻头当作各向同性处理时,计算出的地层力比实际钻头条件下要小;在井眼方位和地层 下倾方位之间夹角不同条件下,不考虑钻头转角的影响,地层力会略髙或略低于考虑转角的情况。由于钻头转角对 地层力的影响很小,计算地层力时可以忽略。 |
| 关键词: 地层力 计算模型 钻头 地层 各向异性 |
| DOI： |
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| A novel model of calculating formation force |
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PAN Qi-feng, GAO De-li
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(Faculty of Petroleum Engineering in China University of Petroleum, Beijing 102249, China)
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| Abstract: |
| The quantitative calculation of the forces between drill bit and formation is vital for drilling trajectory control. According to the idea that the sense of displacement is the sense of motion for drill bit, a new model of calculating formation force was derived from 3-D rock-bit interaction model. The effects of formation anisotropy, bit anisotropy and bit tilt angle on drilling trajectory change were taken into account in this model. The new model aren't be limited by conditions of angle and azimuth holding, and it supplements or extends the old models. The effects of bit anisotropy and bit tilt angle on formation forces were discussed in detail. The results show that both bit anisotropy and bit tilt angle have effect on formation forces. The formation force obtained considering bit anisotrc^y is higher than that neglecting it. When the bit tilt angle is disregarded, the formation force is little higher or lower than that calculated considering the bit tilt angle in different angles between the drilling azimuth and formation down dip azimuth. Since the bit tilt angle has little effect on the formation force, it can be neglected when the formation force is calculated. |
| Key words: formation force calculating model drill bit formation anisotropy |
