PVT Analysis

[r2s7c8]

I am working on a concept study for an oil & gas onshore field and have got PVT analysis for a number of wells. I would like to know the following:
- which composition should I consider since there are different composition presented in the report (bottomhole sample, recombination etc.)
- what is the design GOR(start of life) to be considered ( the report has a few different GOR's for ex. separator tests , recombination etc.)
- How to fix the GOR for end of life operations.
- significance of separator pressures considered during separator tests : can I consider similar pressures for my separators?
I would be happy if somebody can explain how to interpret the PVT analysis and also the significance of the various points in a PVT analysis from a process engineer viewpoint.

Thanks.

 

[MortenA]

I will recomend that you take a basic course in this subject since your two questions are very fundamental.

Best regards

Morten

 

[r2s7c8]

MortenA :
Thank you. Can you suggest any articles or any internet reference than can throw light on the above subject.

Thanks
Subodh

 

[MortenA]

not really - sorry.

Best regards

Morten

 

[Fluidman]

r2s7c8,

All of the compositions should be the same, it is part of the QA for a fluid study. The BHS is the most likely to be correct, depending on the validity of the sampling, as this is obtained from separating the fluid into 2 phases and measuring the compositions. The separator recombination samples relies on accurate field GOR measurements for mathematically adding the separator gas and liquids. Compositions from the Differential and sep test are summationd over multiple stages so errors can be incurred although a good report will show little difference.

Flash GORs can vary considerably depending on the conditions at which the fluids are collected/speed of flash etc. the sep test GOR is supposed to mimic field/process conditions and the Diff GOR the change in ratio as the fluid depletes.

The sep test has probably been designed to show what happens when the fluid is passed through existing process conditions.

Hope this helps.
May I ask who has produced the pVT reports and for which client?