基于ANSYS的钻柱振动规律分析

Analysis of Drilling String Vibration Law Based on ANSYS

根据牙轮钻头与井底岩石互相作用的特点,将钻柱视为一连续的管梁结构,采用ANSYS工程软件,对钻柱纵向振动规律进行了分析。结果表明:钻柱系统各阶振动固有频率相差约1Hz左右,容易出现共振。高频振动时,钻柱出现"分段振动"的特点,下部钻铤动态力显著增加;转盘转速对钻柱振动的影响较大,当接近共振点时,下部钻铤螺纹联接处动态力呈数量级增加;钻压对钻柱振型、轴向动态力的影响不大。

According to the characteristics of interaction of roller bit with rock in well bottom, with drill string thought as continuous beam structure, by use of ANSYS engineering software, longitudinal vibration law of the drill string is analyzed. Results show that the order difference of the intrinsic frequency of the drilling string system is about 1 Hz, prone to resonance. Under high frequency vibration, drilling string appears the characteristics of segmental vibration, dynamic force in lower drilling collar increases remarkably. Rotation speed of rotary table has great effect on drilling string vibration. When the rotating speed is close to the resonance point, the dynamic force in thread joints in lower drilling collar increases by an order of magnitude. Weight on bit（WOB） has little effect on vibration mode and axial dynamic force in drilling string.