Oil PPM in GOSP

[gasoperations]

Is there any guideline or general observation by experience Operation Guys about what is the expected oil ppm in the water drain from 3-phase separators.

It is well understood that the oil ppm in water will depend on operation pressure of the separator & temp & chemical dozing etc.

For 3 stage separators operating at 80 psig & 30 psig, 500 ppm & 300 ppm respectively of oil in the drain water from these two separation stage is with in normal range? ( Process Design Data for these vessels is not traceable now after 40 years of installation)

Any comments will be appriciated

 

[georgeverghese]

A lot depends on emulsion forming tendency of the light phase, which in turn is influenced by the presence of corrosion inhibitors and other chemicals, temperature and some other factors. The values you quote are typical of well behaved 3 phase seps in gas-condensate service. In crude oil service, it could go up to 1000ppmv and more.

 

[LittleInch]

The other factor is that a separator is designed for some level of three phase mix and flow which rarely is then experienced in the field. So its preformance varies as it gets more or less water as a percent or more water than it was designed for.

Some separators have movable weirs to allow for this, but most are fixed in place.

But agree with George, that's not bad for a first stage separator. This sounds like a wet gas system?

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[gasoperations]

@LittleInch & @ George
Thanks for reply and yes it is first stage separator handling fluid (oil, water & gas ) from wellhead.