CALCULATION OF FRICTION FORCE OF DRILLING STRINGS IN HORIZONTAL WELL

This paper introdues a calculation method of friction force acted on drill stem at different conditions in horizontal well. Calculation results show that greater friction force exist between drill stem and wall of bore in tripping out and drilling using PDM (positive displacement motor) working conditions. The effect measurement to reduce friction force is arranging build section with greater build up rate to lower bottom section of well and using oil base mud and flexible drill stem.