[killermosquito]

Please forgive this question but it is one I've pondered often:

"If we pump out all the oil isn't there a huge empty space underground where the oil was and why doesn't the ground that was over where the oil was cave in? "

[AM2000]

ping me when you get an answer to that. I'd like to hear.

[TaMoDee]

Oil is contained in the rock like water is contained in a sponge. The interconnected pores allow the oil to flow through the rock to the well bore which was drilled into oil reservoir. There is no lake of oil as if there is an
open cavity.

Yes, the ground in some case depresses because oil in the pores is removed. The oil helped to hold up the 1000's of feet on overburden over the reservoir. The Long Beach,CA
beach receded many feet downward until water was pumped back into the reservoir to replace the removed oil.

Next question.

HIGH pressures down there.

[blam]

"If we pump out all the oil isn't there a huge empty space underground where the oil was and why doesn't the ground that was over where the oil was cave in? "

In some cases, the ground does subside. I've seen before and after pictures that are amazing.