When oil is removed from the oil fields, what fills the voids left?

I was wondering if the removal of the oil, which I guess might be absorbing heat from the earths core?, would result in more heat rising to the earths surface, and contributing to global warming. I am curious to know what fills the spaces that were previously filled with the oils.When oil is removed from the oil fields, what fills the voids left?
With all due respect to RedShift, when it's extracted oil does not leave ';voids'; because oil is not found in large underground caverns of vast open space, rather it is found in the inter-granular spaces in sedimentary rocks (that means it exists in-between the grains making up the rock). These spaces are quite small individually (just like sand on a beach) but taken as a whole they can hold vast quantities of liquid (water aquifers work the same way). When oil is extracted, the space can be left empty or more frequently is filled by water pressing in behind the oil. Also, because these recoverable deposits are relatively close to the surface they are not ';hot'; (maybe slightly warm). But they are far too close to the surface to be affected the the heat of the earth's core. I will leave out the exception of deposits which might occur near Geologic ';hot spots';, since almost none of these exist.When oil is removed from the oil fields, what fills the voids left?
This is a novel idea, one worth praise for. However, Oil fields do not cover enough of the earths surface to absorb such a level of heat that it would cause a global temperature change. While they are located underground, they are not close enough to the core to block heat.





Another key point is that, over time, the oil would heat up, and its temperature would remain constant of that in which the earth's core is giving off.





Now, to solve the question of what is left in the voids... several things can be done/have happened. In some places, they are just left as they are. Sometimes they will cave in on them selves, or they will stand tall.





Other things that have happened is filling them with waste, sea water (to keep the cavern filled), Nuclear waste (Very few), and only in recent years, pipes.





To explain why they would put pipes in the caverns, it is all about geothermal energy. Some wells are close enough to the core that water can heat up and turn into steam, which is then used to turn turbines and generate electricity (Exactly like Nuclear energy, however the steam is not created by the crashing of neutrons.). It is an extremely green source of energy, as the earth its self is very hot at its core, efficient and a renewable source of energy. So, even though the Oil is gone from the well, it still produces even more energy.





Hope this helps explain things a little and put it into perspective.





Cheers,


-RS





[If any flaws are found with my information, please inform me ASAP so I can correct it.]