Hello all,

I am developing a tool to stop backflow of wellbore fluid into reservoir. For that, I am planning to use mechanism of simple sleeve valve. The working of it is like a sliding sleeve but to make it simple I want it to work on pressure differential. For that, I am using slotted liner as a tubing and a cylindrical piston. So, when reservoir pressure will be greater piston moves down and open the slots for flow and when wellbore pressure increase beyond reservoir pressure it moves piston up and closes the flow path by covering those slots.

I have already achieved this but the problem now is in closed position also the fluid is flowing from the clearance between outer body and piston and between inner body and piston. I have tried so much things but nothing is working out. On putting rubber seals, we can stop leakage effectively but it creates problem in piston movement.

I am a recent graduate and want to create something new. So, please anybody can help me? I can share design with you. And, also if you an think of any other effective mechanism please tell me.