Improved Channel Repairs With Small-Phased Circumferential Perforating Guns

Abstract

Behind-pipe communication (channeling) may lead to environmental concerns, lost hydrocarbon reserves, and additional workover costs to detect and attempt channel repairs.This case study of channel' repairs compared (a) perforation phasing and placement, (b) cement i ng procedures, and (c) production data in 37 wells over the past eleven years in the Texas Gulf Coast and East Texas areas.An improved repair technique, which focuses on the phasing and placement of perforations and cementing procedures was implemented, resulting in an increase in the success rate of channel repairs from 37 to 89 percent.Channeling was repaired in wells with undesired gas or water flow past shale intervals from 2 to 29 feet thick. The improved repair success rate was obtained by adding and then squeezing perforat ions wi th IS-degree phas i ng and at 1east 24 shots across an impermeable zone, where possible. The channel repair success rate of the other wells which typically had 90-or 120-degree phased perforations was only 37 percent. This significant change in success rates was largely due to the increased percentage of the cement's circumference that was perforated.Further improvement is anticipated due to a newly developed perforator with 100 percent circumferential coverage over a 6-inch length which has been tested in two wells.