Multi-component Friction Testing Of Full-scaleDrill Pipe Specimen

The paper presents the results of testing conducted to determine hoop and axial friction components for drill pipe specimens subjected to complex rotation inside a piece of casing. This experiment was performed in water using the SPbSPU’s wear bench which was modified specifically to permit independent rotation of drill pipe section and casing, as well as drill pipe axial sliding. Hoop and axial friction force components were determined during these tests as a function of relative velocity of contact point in complex rotation. The test results were used to establish empirical dependence of these friction force components on axial and relative hoop velocities at transition from sliding to rolling friction. The obtained results have allowed formulations of more precise friction model, which is crucial for the torque and drag analysis of a drillstring inside the wellbore.