Raw oil is created in the earth....at what rate?

Question

If the earth took it's million of years to make what we take out to turn into gas, oil etc. won't it eveantually run out? If we take say 1 gallon out of the earth, how long does it take for the earth to reproduce it? Also, when we take oil out...we are leaving an empty space, how come the earth does nt collapse over the empty space? It scares me to think that we have only been taking it for 100 plus years and that it took a long time for the earth to create it. Are we not going to end up taking it faster than it is made?

Answer 1

Oil forms due to burial and heating of organic sediment, eg coal.  The organic sediment breaks down, initially to oil.  The 'oil window' refers to the temperature and pressure conditions at which oil forms.  While geothermal gradients vary, the typical depth of the oil window is 4-6 kms.  If heated to temperatures above the oil window the chemical reaction continues, forming natural gas and so on until there is nothing useful left.

Oil and natural gas, once formed, are more bouyant than the encompassing host rock and will rise due to buoyancy.  Therefore, to 'trap' oil there must be a suitable structure above the buried sediment such as an anticline with a suitable reservoir rock such as a sandstone, and suitable capping rock such as a shale.  Sandstone is generally porous and therefore oil can accumulate within this rock, while shale is considered an aquiclude; a rock type which prevents fluid from passing through it.

Therefore, from the discussion above, it can be seen that the process of oil formation requires the accumulation of large amounts of organic sediment, there burial to depths greater than 4 km BUT not greater than 6, and further requires suitable structures to trap the oil.  If these structures are not in place the oil will simply escape to the surface and evaporate over geologically short timescales.  

To allow significant accumulations of organic material subsidence is generally required, this continuously lowers base level allowing sediment to continue to accumulate.  Furthermore a low energy environment is needed as foreign sediments, eg silicates, will contaminate the organic sediment.  Subsequent burial to the depths occurs over the timescale of 10's of millions of years, and deformation of overlying rocks to form suitable trapping structures generally requires orogenic (mountain building) events, which also occur over a similar time scale.

In conclusion, both the timescale, and the specific events required, make oil formation, and equally important; oil accumulation, very rare events.  Currently there are locations in the world which are accumulating significant organic sediments, eg Bangladesh, however it will only be a matter of luck if they are exposed to the conditions suitable for oil formation in the future.  And of course this won't be for millions of years.

Answer 2

a loooong time or gas prices wouldnt e so high right now.

i dont think oil is just in a hole under the sea. thats probably why nothing has collapsed.

and yes. we ARE taking gas faster than it is made. that is why scientists are trying to find an alternative gas to power cars.

Answer 3

No more oil is being created.  It was produced from the remains of living creatures from millions of years ago.

Once it's gone, it's gone.  This is why petroleum is a non-renewable resource.

Answer 4

That is what we have been saying, it is a non renewable resource because it takes millions of years to replace.  I can't seem to find it now, but I believe the predicted oil resource exhaustion date was about 2030.  When it's gone, we had better have replacement renewable energy systems in place.

As to leaving empty holes:

In the context of oil wells, pumping is a routine operation involving injecting fluids into the well.

Answer 5

we will run out and yes removing the oil does cause the ground to settle, it's called subsidence. New Orleans and it's surrounding areas are sinking at an increasing rate in some areas as much as an inch a year. this is why much of the city including ward 9 will never be rebuilt also FEMA and the army corp of engineers will no longer certify the levees. It's being blamed on both removing the oil and tectonic activity.

It just means we will have to find a new vehicle energy source most likely electric