As horizontal completions are set at increasing depths, an efficient and economical composite plug coiled tubing (CT) drillout (CTDO) process becomes increasingly important. Therefore, it becomes a significant challenge when multiple composite plugs must be drilled out within a single well. By evaluating and making enhancements to each part of the process, thus reducing and possibly eliminating wiper trips, CT can provide an economic solution for these extended reach composite plug drillouts. The net benefits of this include less pipe fatigue, less fluid and chemicals pumped, and an overall more efficient and economic drillout. Extended reach plug drilling operations require particular attention to detail, combining technical, equipment, and operational improvements to reliably reach total depth (TD) in an efficient and safe manner.
This paper discusses the importance of the following six areas suggested for a successful plug drillout process:
CT string design related to wellbore tubulars and deviation.
Bottomhole assembly (BHA).
Monitoring and control during the job of the associated drillout parameters.
This paper additionally focuses on two case histories where wiper trips were successfully minimized/eliminated using the discussed method and process enhancements. The first of these is in the Williston basin, where a well (10,135 ft vertical and 9,868 ft lateral) with 24 composite plugs was successfully drilled out using 22,230 ft of 2 3/8-in. CT. In the Denver-Julesburg (DJ) basin, a well (6,780 ft vertical and 7,815 ft lateral) with 39 composite plugs was successfully drilled out using 17,990 ft of 2-in. CT.
The synergy of the six areas followed during the CTDO operations has proven to be a cost effective and reliable process, saving the operator well intervention time. Results and recommendations are presented including the lessons learned from the implementation of the process enhancements within these two case histories.