A central processing facility (CPF), sometimes called a central processing platform, is the hub that several satellite facilities tie back to. It can sit offshore or onshore. Offshore it is a large manned platform, or a floating facility doing the same job. Onshore it is the central plant that a field of gathering lines feeds. The word doing the work is central, not the location. It receives commingled production from a handful of satellites, separates it into oil, gas, and water, treats each stream to export specification, and sends them on. It usually carries the power generation, the utilities, the control room, and the people for the entire field.
That concentration is what makes it a different problem from the satellites feeding it. A CPF holds the largest hydrocarbon inventory in the field, the most rotating equipment, and the only permanently manned quarters, so it carries the fire and gas coverage, the blowdown philosophy, and the escalation controls that a wellhead platform does not need. It is also where an incoming shutdown signal from any satellite has to be interpreted and acted on.
Functional safety relevance: Yes, and typically the most of any facility in a development. A CPF holds the largest inventory and the most complex process in the field, so it carries the highest count of safety instrumented functions.
Key Points
- Receives production from several wellhead platforms and performs the separation, treatment, compression, and export for the whole field.
- Carries the field utilities, power generation, control room, and accommodation, which is why escalation control and fire and gas coverage matter more here than on the satellites.
- Its shutdown hierarchy reaches outward, shutting in remote wellhead platforms as well as its own trains.
Example
Four unmanned wellhead platforms flow to one CPF over 10 to 40 km of subsea flowline. A high-high level in the CPF first-stage separator does not simply trip that separator. It cascades outward and shuts in the satellites feeding it, because there is nowhere else for their production to go.
See Also: WHP, FPU, subsea tieback
Cited Sources
- API RP 14C, Analysis, Design, Installation, and Testing of Safety Systems for Offshore Production Facilities