RE: Going down below 1p again.17 Jul 2023 20:38
A-D,
All wells are connected through infield flow lines to the in field production processing facility, everything has to pass through it, the 3 wells are surface pressure harmonised, meaning they are choked near the well to a "current" flowing pressure of 33 barg.
All flow basically will pass through a large separator to allow any liquids to drop out, the liquids are then diverted to their related in field storage tanks for off take via tanker.
The gas combined dry gas carries on through various processes within the plant, this is to condition it prior to entering the compressor/s.
The compressor/s main objective is to take the produced gas that is entering the compressor/s at around 33 barg, and compress it to a higher pressure which is designated by Shell in this case, the compressor/s have to increase the pressure of the gas entering the pipeline to the national grid, that is likely to be around double the 33 barg flowing pressure from the wells.
In SLBY case, each compressor can likely compress around 7, possibly 8 mmscf/d if the all the wells are producing more than say 7mmscf/d then you need to run a 2nd compressor to accommodate the additional flow, so if slby is producing 10 mmscf/d then you would have to run two compressors, likely fairly evenly split between the two.
If angus were to find more gas within the field and want to produce it and the total flow was greater than say 14 mmscf/d then they would need to add another compressor to accommodate that amount of in flow.
There will be production issues to deal with in due course, as the flowing pressure/reservoir pressure continues to deplete, the in flow/ flowing surface pressure of the gas has to be over a certain threshold for the compressors to work effectively. once the surface pressure drops below this Angus will need to add a "booster compressor" in to the system, the Booster compressor will be before the main compressor/s, and is designed to take all the low pressure gas, boost it to above the main compressor/s threshold and gas production can resume to the grid.
The CPR for the remaining recoverable gas was done based on what the two original wells could recover and the additional new side track could drain.
One factor that "may" affect this is that the side track only managed half the total designed horizontal leg, so it "may" compromise that CPR quoted recovery as the wells stand today.
That said, the field has decent permeability, and gas has a much better mobility than oil at reservoir, BUT the added compromise may also be the Condensate that is banking/building and will only increase as the field depletes, lower pressures and more liquids are not inducive to optimum gas recovery from the field.