Subsea Valves Not Moving

[daviwy]

Gents,

We have subsea valves that have not been functioned for a while.

As Left: Filled with MEG at ambient
Flowing pressure: 120 barg
Max DP: 120 barg
Content found initially: Hydrate
Valve condition: clear evidence of the valve passing.

The line now is clean and clear of hydrates, however we still can't function the valves even going up to damage torque. Anyone got suggestions that could help?

Thanks

Mechanical Operations Engineer
Oil, Gas & Power

 

[hydromarine]

What size of valve, what type gate ,ball? do you have equal pressure each side of the valve, when where they last operated?

 

[daviwy]

hydromarine,

Morning, they are ball valves, operated over 5 years ago, equalized pressures, had differential pressures across them, cycled the pressure, pumped in methanol, MEG, venting, heating wraps etc and they still said no :-(

Mechanical Operations Engineer
Oil, Gas & Power

 

[hydromarine]

You may what to try removing the mechanical stops on the valve and then try again just to crack them in the opposite direction
what size valves are they?

 

[hydromarine]

Also are you able to slightly slaken off the bolts holding the body of the valve together ...just some ideas,be safe