An ECP valve was derated by its manufacturer to 6,000 psi after the packer was set in a horizontal well scheduled for plug-and-perf operations. However, the formation required a frac pressure of 6,800 psi.
It was determined that the best solution was to keep the ECP in place and cover the valve with a casing patch to shield it from the frac pressure. The challenge was ensuring sufficient ID to allow passage of frac plugs and subsequent cleanout operations.
A caliper log determined that the minimum casing ID was 4.744 in; a conventional 5.5-in, 20-lbm/ft casing patch would not provide sufficient ID.
SLB proposed its 5.5-in prefracturing expandable steel patch to resolve the issue. The patch was set in 3 hours and fully drifted to 4.35 in. Subsequently, the well was pressure tested to 9,800 psi.
The operator decided to run 4.3-in frac plugs for the stimulation operations, and the.perforation guns and plugs passed through the patch without issue. All 13 stages were fractured using pressures up to 7,000 psi, with 4.5 million lbm of sand and 67,000 bbl of fluid pumped through the patch.
Retrieving the patch from the well by fishing or milling was not necessary. The frac plugs were milled out with a 4.25-in bit, drilling out one plug at a time. The crew cleaned the wellbore by circulating sweeps and making short trips to minimize any tagging or dragging issues. The operator went on to use the same solution for other wells on the pad that had similar valve issues.
