installing ESDV at the departing pipeline of well pad area (one well only)

[eng.amrasran]

Dear sirs,

i have been recently incorporated at a new project for oil production through an onshore well , we haven't any engineering party with us as we had just short period to oil producing as soon as possible , so we had to make a miniumum house design facilities for the well oil production instrumentation facilities like WHCP, chemical injection systems,... so on.

My question is about: do we have to install ESDV (emergency shutdown valve) directly after the well flow line (i.e. after the pig launcher) , at the beginning of the departing pipeline which will be routed to another production well pad area (5 Km away).

or we can depend solely on the christmas tree valves from sssv, ssv, wing valves... (through the well head control panel) for any control/emergency action without installing ESDV.

taking into consideration that we installed ESDV on the recieving end of the interconnecting pipeline at the other well pad area.

Thanks
waiting your kind reply
Amr

[FATHI]

..I always though .. a choke valve is first !! but I will try to gather some information if I can

[karthiknew2008]

Dear ,

Please note that Always ScSSV - SSV - Wing vave - Choke valve - is the general sequence of protection. SCSSV , SSV & Wing are all UZ functions, i.e ESD or IPF valves. Installation of Another ESD valve on the D/s of Choke valve could be dangerous as usually Pipe ASME rating goes down after Choke valve. Also note that Slug accumulation and Valve failure would result in serious damage to well head. SHELL prefers Relief Valve is better than the ESD valve in such cases. Secondly ESD valve is easy to install , Do you have a Separate ESD system to control it.

[Florentina]

Dear AMR,
My opinion is that you need the ESD valve after the wellhead. I have the same situation with a gas well (oil is not too much CGR=300m3/1.000.000Sm3/day). SO, in my case, after the christmas tree, we have an ESD valve which is related to pressure and level sensors. The ESD valve choice is also a Hazop decision.
But usually, yes...it's a suplementary measure and it's good to have it especially when you didn't make the right design for your system.