Ann: Q320 Quarterly Activities Report & 5B, page-13

I said this many years ago....

1) shake a beer bottle that hasn't been opened.
2) pop a single whole on the middle of the cap, then quickly....
3) turn it upside down
4) watch and observe

The drains are at the bedrock underneath the coals, gas even in those amazing physical conditions will still tend to go up with liquids down, so water drains with some gas, while the gas accumulates up top.

If they sandwhiched the coals with drains above and below, then it would have been more efficient with more gas less liquid at top, and more liquids less gas at bottom. Let it all mix in on the trunk well-pipe and sort out the splitting up top.

Thats my armchair/sofa view....