US Patent 7661480 Method for hydraulic rupturing of downhole glass disc

A method for rupturing a glass disc in a well completion tool located downhole in a section of production tubing includes providing a wellhead isolation tool, or tree saver, to isolate the wellhead Christmas tree, adding a pressurized fluid to the tubing/casing annulus and pumping a disc rupturing fluid into the production tubing via the tree saver until the disc is ruptured. Following rupture, the pump can be rapidly stopped, or slowed, and started to create a water hammer effect that removes any glass shards remaining in the disc holder.