The Y-block used when selective testing or production is needed in the presence of two producing zones . The Y-block is run on the long string side below the packer and no flow back is possible thru it.
Underbalance perforation is achieved thru artificial lift on the short string in association with the usage of our Pyro-electrical Time Delay preset at the desired timing between 7 minutes and 8 hours.

It is an economical way of perforating two zones far apart separetly in one trip.