New downhole tool extends coiled-tubing reach

Extending reach is one of the main challenges for coiled-tubing (CT) operators, as illustrated by the development of downhole traction devices for CT. A tool called the CT friction/drag reducer (FDR) is based on a unique patented concept and uses fluid flow to generate axial oscillations in the CT and bottom-hole assembly (BHA) to reduce time-averaged frictional forces significantly. Calculations based on a simple physics-based model predict that reach can be extended by more than 3000 m in a horizontal well,vith a measured-depth (MD) -to-true-vertical-depth (TVD) ratio (MD/TVD) greater than 2.0. Model results march full-scale tests well. The FDR tool was developed and tested as part of a joint industry project (JIP), Full-scale tests with a 7-in.-internal diameter horizontal surface loop have proved the friction-reducing efficiency of the concept. In several tests with 600 m of 13/4-in. CT and a BHA weighing 600 kg, the frictional force during run-in and pullout was reduced by as much as 90%.