Impact of Well Features on CT Reach

摘要

Coiled tubing (CT) is frequently used in horizontal wells to mill out hydraulic fracturing plugs before bringing new completions online. However, the maximum depth CT may reach while milling plugs can be a major limiting factor for final completion depths. CT reach limits are normally attributed to friction lockup during these milling operations and can reduce effective pay zone penetration if not considered during the well design. In these cases, several common well features typically contribute to the majority of the low force transfer factors leading to insufficient set-down force and helical lockup. This paper will discuss key parameter variations found from a case study of several horizontal well designs, and analyze their impacts on typical coiled tubing reach capabilities using a tubing forces model. Features analyzed include: kick-off build rate, vertical sections and simple deviations down to the heel, trajectory changes in the horizontal section, well completion geometry, and required weight on bit (WOB).