Running force measurement in high curvature wellbores

This paper presents a new experimental technique to measure running forces of steel rods running through curved and horizontal hole sections with various radii of curvatures and hole sizes. Dimensional analysis has been used to build laboratory models that represent field conditions. The analysis takes into account the radius of curvature, hole clearance, casing stiffness and casing weight per unit length. In general, it was observed that the variation of the running force as rods advance further along curved and horizontal sections depends heavily on the radius of curvature, hole clearance and the interaction between the steel rods and the bore hole walls as seen by visualisation.