After passing through the Christmas Tree, SSV, flowline, choke manifold and other upstream equipment, the wellstream eventually reaches one of the most important pieces of equipment in Surface Well Testing:
The Test Separator.
So, what actually happens inside it?
The separator receives the multiphase wellstream and provides the conditions needed to separate the produced fluids into their major phases:
🛢️ Oil
💧 Water
🔥 Gas
The basic principle is straightforward:
Inlet wellstream → velocity reduction & residence time → phase separation → individual outlet streams.
But for a well tester, the separator is much more than a large vessel.
We monitor and control parameters such as:
▪️ Separator Pressure
▪️ Temperature
▪️ Liquid Level
▪️ Oil Rate
▪️ Water Rate
▪️ Gas Rate
▪️ BS&W
▪️ DP / flow measurements
The objective is to maintain stable operating conditions so that the separated streams can be measured and representative test data can be collected.
The separator also demonstrates an important principle in well testing:
A pressure fluctuation, unstable level or poor instrumentation can influence the quality of the data being recorded.
So while the separator is separating oil, water and gas, the well tester is also turning the well’s production behaviour into meaningful, validated data.