Evaluating stabilizing initiatives to extend coiled tubing reach

New numerical strategies that reconsider tubing force analysis (TFA) in connection with buckling induced lockup are presented and applied. The strategies introduce new visualizations of downhole instabilities in coiled tubings (CT) for the entire run-in-hole (RIH) process. Most extended reach interventions seek to reduce compressive forces experienced by the CT through usage of lubrication, vibrations or tractors, but little attention has been given to stabilizing initiatives that prevent buckling. A stabilizing initiative is anything that increases the critical helical buckling load of the CT, for example a reduction of radial clearance between CT and wellbore. The strategies presented allow us to (1) evaluate the gain in CT reach from stabilizing initiatives, and (2) automatically determine the minimum requirement for a stabilizing initiative that will bring the CT to the desired operational depth, when it is applied optimally along the length of a CT/wellbore. Thus, the strategies promote investigations of novel stabilizing solutions that can complement existing extended reach technologies. The developed TFA algorithm is validated against field data and the strategies are utilized on a wellbore in the Danish North Sea. The investigation showed that a stabilizing initiative that increases the critical helical buckling load by 31% when introduced into 35.57% of the wellbore length will extend CT reach from 69.72% to 100% into the payzone. With these strategies in place we present a new approach to optimize well utilization.

Automated summary

This study introduces new numerical strategies that focus on tubing force analysis (TFA) and buckling induced lockup, aiming to increase the critical helical buckling load of coiled tubings (CT) and optimize well utilization by identifying stabilizing initiatives. By evaluating the gain in CT reach from stabilizing initiatives and determining the minimum requirement for optimal application, the strategies presented in this research offer a novel approach to complement existing extended reach technologies and enhance operational efficiency in oil wells.