本文已被:浏览次 下载次 |
码上扫一扫! |
|
|
A novel model of calculating formation force |
PAN Qi-feng, GAO De-li
|
(Faculty of Petroleum Engineering in China University of Petroleum, Beijing 102249, China)
|
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 |
|
|