关键词: 定向, 井摩擦阻力, 钻柱

Abstract: Based on investigation for the domestic and Foreign information,the frictional drag model for full-stiffness of drillstring in cliretional well is built by analysis on the space forces and moments acting on drillstring according to differential geometry.theory,which synthetically considers the tension,buoyancy,rigidity of all drillstriag,the 6ehw for and geometrical size of the wellbore and hydrodynamic viscous drag of drilling fluids.etc.It is more perfect and conforms to the actual drilling situations.With this model.the actual data from eight directional wells in the middle part of Daqing field are dealt with and analysed.Initial result is that the frictional coefficient of wellbore is generallv 0.15——0.21 and the average value is 0.1769.Through the analysis of the frictional drag,it is known that the sideforce and fzictional force on the drillstring is not linear distribution along all the drillstring and the sideforce in tire,building angle section is tt.u ally larger.It basically coincides with oilfield phenomena.