I’ve also got a question about lift gas splits…. Total gas, produced + lift, should be split at the inlet separators and sent to the gas compressors. However if I look at the forecasts for the liquid separators there is lift gas forecast in each node downstream of the inlet separator.


I just want to check that the ‘total gas’ in the model allows for the produced + lift gas and that the ‘lift gas’ is reported separately in addition to this. If we are not allowing for lift gas in the gas compression node we will be grossly underestimating the forecast gas compression requirements.


The lift-gas data is the amount of lift-gas supplied with the assumption that it comes from the parent node and upwards (I realise this is usually not the case, but you could consider the calculation as half-way between engineering and book-keeping). So the lift-gas rates are not affected by splits.

The total gas is indeed total gas (including lift gas produced). The produced gas is that part of the total gas that originated in the reservoir. The amount of lift-gas in the production stream at any node can be calculated, if you need it, as being the difference between total gas and produced gas.