Experimental and analytical study of the side cutting ability of drill bits

Drilling highly deviated wells such as extended reach and horizontal wells is frequently encountered in drilling operations. Drilling a highly deviated wellbore is more expensive compared to conventional vertical well and a substantial portion of drilling operation costs comes from the use of PDC drill bits. Therefore, improving the efficiency of the drill bits would result in a significant reduction of the costs and non-productive time (NPT) of drilling operation. This in turns requires a comprehensive knowledge of bit and rock interaction. Even though several studies have been conducted in this area, they were mainly focused on face-cutting efficiency without much emphasis on the side-cutting ability. The side-cutting ability is an important characteristic of drilling bits, particularly for PDC drill bits. Side-cutting ability directly impacts deviation control, wellbore stability and borehole quality, drilling performance parameters, tripping operations, cuttings transport performance, casing running assurance, real-time data acquisition, drag and torque, etc. Therefore, conducting research on side cutting ability of PDC bits would eliminate/reduce many problems originated by bit-formation interaction.