Effects of tribological properties of water-based drilling fluids on buckling and lock-up length of coiled tubing in drilling operations

• We evaluated the impact of lubricants on improving lubricity of drilling fluids.
• We developed an experimental setup that imitates the drilling operation.
• We investigated the effects of friction on buckling of coiled tubing.
• We studied the effects of friction on lock-up length of coiled tubing.
• We studied the impact of lubricants on drilling fluids rheological properties.

This study evaluates the performance of three lubricants on reducing friction between wellbore and coiled tubing (CT) and hence improving axial force transfer, reducing buckling, and enhances the limited reach of CT. The lubricants were evaluated using water-based drilling fluids composed of lubricants of different concentrations. Experiments were conducted in a lubricity tester and by using an in-house experimental setup that imitates the wellbore being drilled in the presence of drilling fluids. Results showed that reducing COF does not change CT buckling shape or mode, but it alters the initiation and transition between buckling modes and increases lock-up length. Effects of increasing lubricants percentages on mud properties were also examined. They showed positive impact compared to tests conducted without lubricants.