FRICTIONAL ANALYSIS BASED ON ANALYSIS OF THE FORCE AND DEFORMATION OF THE DRILLSTRING

In the directional wells and horizontal wells,frictional analysis is an issue that can not be ignored.In this paper,the whole drillstring is regarded as an elastic beam,previous"soft models" are not adopted and frictional load is computed according to contact conditions beween the drillstring and bore wall.Considering the stiffness of drillstrings,the gap between drillstring and well wall,the placement of BHA stabilizers and so on,the model is close to the field operation conditions of drillstrings and enhance the accuracy of friction prediction.During pick-up and slack-off of a drillstring in the build section of a horizontal well,frictional loads are computed.The force and deformation are obtained.A new method is developed for frictional analysis of the drillstrings.