A major operator often perforates North Slope wells with 30-ft [9.1-m] BHAs run on coiled tubing. The BHA length is limited by height restrictions of the CT mast units, which are preferred because of their efficiency compared with conventional CT units. However, each well can have as much as 150 ft [45.7 m] of pay to be perforated. This consistently necessitates additional CT runs, increasing the amount of time on location and fluids pumped in the job.
Schlumberger recommended the new pressure deployment CT system to enable perforating in longer segments. In its first operation, the system was used to perforate segments totaling 70 ft [21.3 m] in just one run with 35 bbl [5.6 m3] of fluid compared with three runs and 100 bbl [15.9 m3] of fluid for a conventional operation limited to 30-ft BHAs. The use of time-delay fuses enabled perforating two separate zones without blank guns.