Definition - What does Casing Patch mean?
A casing patch is a downhole tool system that is used to repair collars, casing damage, leaks and also as a cement backup solution. A casing patch is used as a temporary remedial measure until a workover operation can be scheduled. When a depleted well approaches the end of viable production, a casing patch can be an economical means to return the well to production.
A casing patch doesn't restrict wellbore access because the diameter isn't significantly reduced after the patch is applied.
Trenchlesspedia explains Casing Patch
A casing patch is a great solution for restoring wells integrity, quickly and effectively. Completion issues due to casing damage and leaks need solutions that can resist harsh environments while helping the well to return to satisfactory production levels. Instead of plugging and abandoning a well, a casing patch can be used to remedy and stimulate the well to production.
The casing patch minimally effects internal well diameter after installation thus providing full access downhole.