水平井钻柱横向振动有限元分析

Finite Element Analysis on the Lateral Vibration of the Drilling String of the Horizontal Well

钻柱横向振动是引发钻井事故的主要原因之一,水平井由于井眼弯曲严重,钻柱偏心,容易发生钻柱横向振动。以水平井钻柱单元为研究对象,应用有限元法建立了考虑钻井液影响的钻柱横向振动方程,得出了钻柱横向振动频率数学模型,分析了钻井液和钻井液密度对钻柱横向振动频率的影响规律。编制频率计算程序,结果比较符合现场实际,为计算钻柱共振转速提供依据,减少钻柱剧烈横向振动发生。

Drilling string lateral vibration is one of the main factors on drilling accidents. Borehole curvature of the horizontal well is big and the bias of drilling string is severe, the lateral vibration of drilling string is easily caused. Taking drilling string unit of the horizontal well as study object, by adopting finite element method, a equa- tion of drilling string lateral vibration with the consideration of drilling fluid is built up, and a mathematical model of drilling string lateral vibration frequency is obtained. The influence of drilling fluid and drilling fluid density on lateral vibration frequency is analyzed. By the calculation data of compiled frequency model procedure, it can be seen that this model is in agreement with the field condition, which supplies some evidence for calculating rotation speed of rotary table and reducing the times of drilling string lateral vibration.