I found the solution meanwhile.
You'r right: the pressure is determined by the resistance due to friction losses downstream (a Pressure-Flow problem is close to a Capacitor-Resistance problem for an electric network...)
Just one thing: since the flow from the well is critical (i.e. choked) it...
I'm running a dynamic model in HYSYS for the following upstrem gas system:
wellhead - Choke - Export pipeline - 100mm Hole(leakage)
The boundary specifications are set as
P=fixed for the wellhead
Pressure drop=fixed for the choke valve
Press @ pipe outlet=fixed...
As far as I know, DBB isolations schemes and guidelines are extensively discussed in the following fundamental
"The safe isolation of plant and equipment"
Oil Industry Advisory Committee, HSE Books 1997
For PSV, if there are 2 PSV's and one is 100% spare, the spare one shall be locked closed...
