With the goal of providing predictable and repeatable performance in extended laterals exceeding 15,000-ft, customized coiled tubing (CT) solutions that minimize risk and improve overall field economics are driving the industry in unconventional shale resources.
This paper documents the multidisciplinary approach taken to improve operational key performance indicators (KPIs) in extended reach operations, which contributed to the engineering of the largest CT ever manufactured to service super laterals well in North America.
The newest well trajectories involve extensive planning for post-frac plug mill-out and clean-out operations which demand bigger CT sizes and greater pumping pressures to efficiently accomplish the work. Ahead of these interventions, careful job planning involves thorough tubing forces, hydraulics analysis, exact location and number of plugs, fluid selection, and scheduling, in addition to an optimized CT string profile and grade. Upon execution of the operations, results of the post-job analysis of metrics and tubing forces collected from multiple wells were used to feed the analysis of subsequent operations to further improve performance and resolve any previous issues.
Field collected data along with surveys for projected well drillouts fed into the iterative string design methodology that produced a record-breaking string profile of 2.625-in outer diameter with over 30,000-ft in length, using custom-fit wall thickness configurations that featured up to 0.276-in thickness and quench-and-temper 130,000-psi grade materials. This CT engineered solution surpassed 187,000-lbs of combined weight, becoming an important milestone for domestic CT interventions logistics.
Analyses have also shown the need for vibration tools and chemical additives to further extend lateral reach. Operational changes to accommodate this record-setting CT string included the use of the largest capacity CT units in the market and high-powered injector equipment. Additionally, tailored operating techniques helped reduce the average rate of penetration through plugs and stall times, consequently, reducing overall job completion times.
As this paper documents the speed at which the demand for larger and longer CT is growing, continuous innovation is needed in the CT industry. Capabilities of surface equipment, downhole tools, CT materials, and highly engineered string configurations, must be pushed ahead of their current specifications to set CT accessibility records in super lateral wells (Galvan, et.al., 2017).