降斜防斜控制技术

防斜打直的传统作业方法是采用慢速的轻压吊打法。随着水平井钻井技术的发展，导向钻井控制井斜及连续控制工艺已应用在定向井和直井中，但增加了钻井成本。要实现降斜打快、防斜打直的目标，必须突破“轻压吊打”的传统观念束缚，采用新的降斜防斜技术。文中从分析井斜原因入手，提出采用钟摆钻具大钻压降斜和光钻铤大钻压防斜的技术手段，以及公转法防斜的基本技术特征，通过几十口定向井实钻证明这些方法是可行的。该技术成倍提高机械钻速，具有推广实用价值。

Controlling drop-off angle and deviation prevention

With the development of horizontal-well drilling technology,deviation control by steering drilling and continuous control techniques have been applied in directional wells and straight wells.But drilling cost is increased.In order to achieve the goal of fast drilling with dropping-off angle,deviation-controlled straight drilling,new drop angle and deviation prevention techniques must be adopted.Starting from analysing deviation causes,this paper proposes technique of dropping -off angle using pendulum assembly,preventing deviation with high WOB and slick drill collars,and revolution method preventing deviation.Through actual drilling of directional wells,the results show these methods are practical,can increase ROP several fold and are worth popularizing.