Where does it go?

[CliveB]

What happens to the gap left in the earth when the oil is removed?

[Clanad]

At least in the western US (my oldest son, being a petroleum engineer explained to me patiently) there is no gap as such remianing when the oil or gas is depleted.  There is no cavern remaining, only a sandstone or sand shale rock formation that is now void of it's previous contents.  Often, this void refills with undergound water.  This water is usually extremely salty and corrosive, being the remnants of an ancient sea that covered 2/3's of the western US during the formation of the rock strata.  The engineers are now experimenting with injecting carbon dioxide gas in liquid form into depleted oil fields.  This would accomplish stabilizing the depleted field as well as storing greehouse gases for thousands of years... (Obviously, I nodded knowingly, as one does when their child explains something)...

[ian.miller]

I believe that there is "cavenous" oil reserves as well as those that are held within porous rock. And for those they inject water to replace the oil they take out, which also means that over time the water/oil mix means falls in favour of oil so therefore they might pump 1million barrels, but that wont all be of oil all the time.

Although this is trying to remember an article in Geographical recently.

[slimfandango]

To answer the question you need to understand the processes by which the oil is removed and the state of the reservoir.

1) Processes.

1.1.

[slimfandango]

To answer the question you need to understand the processes by which the oil is removed and the state of the reservoir.

1) Processes.

1.1.

Gas

[slimfandango]

To answer the question you need to understand the processes by which the oil is removed and the state of the reservoir.

1) Processes.

1.1.

Gas lift.

[Phantaxus]

The oil rigs in the north sea have to have their legs extended to stop them sinking below the waves