BallShift Sleeves for Extended Lateral Completions
In a growing number of unconventional wells, total vertical depth often exceeds 20,000 ft, with 10,000-ft or longer laterals. Although coiled tubing sometimes cannot reach the toe of these wells, operators can still get the proven benefits of Multistage Unlimited cemented, single-point stimulation. NCS Multistage now offers BallShift™ sleeves, which are cemented along with the liner, just like NCS GripShift™ casing sleeves. But, where GripShift sleeves are located and shifted using coiled tubing, BallShift sleeves are shifted using progressively larger balls and seats. They are run below the GripShift sleeves in a hybrid completion system that adds up to 14 stages beyond coiled tubing limits.
The BallShift sleeves are made up into the toe end of the liner, followed by the GripShift sleeves. The BallShift section is stimulated by bullheading frac fluids down the liner, dropping balls to open successive sleeves in a continuous operation. When the last BallShift stage is completed, coiled tubing is rigged up, and the Multistage Unlimited frac-isolation assembly is run in to locate the bottom GripShift sleeve. The frac-isolation bridge plug is set inside the sleeve to seal off the wellbore below, and the frac is pumped down the coiled tubing/liner annulus. When the frac is away, a pull on the coiled tubing unsets the bridge plug, and the tool assembly is moved up to the next GripShift sleeve. This sequence is repeated until all stages have been stimulated.