CT Extended Reach: Can We Reach Farther?

Abstract

Abstract The ability to perform extended reach operations with coiled tubing (CT) has become increasingly important in recent years as a result of the increased length of horizontal wellbores. Fracturing horizontal wells in stages often requires the use of drillable bridge plugs or sliding sleeves, which are drilled out or slid with CT. As the length of the horizontal section of a wellbore continues to be extended (known as extended reach), the reach of CT also needs to be extended. Drillpipe is able to reach farther than CT due to its ability to rotate (which mitigates sliding friction). The inability of CT to rotate makes extending the reach more challenging. This paper presents the theory and modeling which helps determine the maximum reach in a horizontal well before helical lockup occurs. It presents a parametric study for an L shaped well which shows the significance of each parameter in extending the reach. A new tapered CT string concept referred to as "Extended Taper™", is presented.