Analysis and 3D Modeling of the Friction Torque for Large Deviated Wells and Horizontal Wells

Extreme drill string torque and friction bring great difficulties and challenges to drilling operation in oriental drilling especially in complex wells,large deviated wells and horizontal wells.To monitor the similar problems occurred in the process of drilling,the friction torque model as a forecasting and monitoring method can forecast and analyze such problems in the process of designing and drilling.The currently widely used friction torque model in drilling industry is mostly based on the equations introduced 20 years ago,which have not changed much.The basic principle of friction torque,factors of large torque friction,well track and drill string buckling and cuttings migration issues are formulated and analyzed in this paper.The standard torque friction model is briefly introduced.Some latest 3Dfriction torque models are introduced at the same time.The paper presents torque friction models of different intervals.Finally,according to the torque and friction characteristics of large deviate wells and horizontal wells,the drill string design criterion of friction torque reduction is given,which goal is to transfer downhole drilling pressure effectively and reduce the drill string buckling to improve the quality of well bore and drilling efficiency.