1 reply to this topic

[mosayef]

dear all,

 

i need a reference to understand the process control of the wellhead and flowline, i can find it in the Appendix A.1 API RP 14 C but i need more explanation since i am a junior engineer. something related to Choke Valve, PSV, Shut in Tubing Pressure, Surface Safety Valve etc. i need more explanation than available in API RP 14 C to understand  process safety philosophy in the wellhead and flow line. please recommend me a handbook or anything to help me. thanks

[mannycalavera]

Hi. I wouldn't say there is process 'control' as such, in my experience the choke valve is a a manual valve adjusted by operators to achieve the desired flow from the well. This valve will be fully rated (i,e, pipe/valve design pressure is above max process pressure) to the SITHP. Note that choke valves are often used to limit flow, too much flow will erode the pipe bends, especially if sand etc is present.

 

The flowline (pipe downstream of the choke) is normally fully rated, but if not (e.g. if there is an ESP, etc) then downstream pipework/equipment will need to be protected with a PSV (or high integrity pressure protection system).

In either case its common to have a high and low pressure trip on the flowline. This will normally shut in the well wing valve.

 

The subsurface valve and tree master valve (normally hydraulic) will shut in on fire and gas, platform emergency shutdown, etc.

Hope that helps mate.