Making trajectory of borehole as far as possible to achieve ideal condition an preventing the phenomenon of dogleg .
可在钻进过程中起到修整井壁的作用，使井眼轨迹尽量达到理想状态，防止出现狗腿现象。
2
The basic method and features of coal seam permeability by using borehole flow method inversion is studied, the basic condition of coal seam permeability inversion in determined.
研究了钻孔流量法反演煤层透气性的基本方法和特点，确定了煤层透气性反演的基本条件。
3
Based on comparison of acoustic data logged in different conditions of cementation, casing and borehole, the applicable condition and limitation of through-casing acoustic logging are summarized.