As the "relatively easy to get" petroleum reserves get used up, the price per barrel or per unit energy will go up until alternative sources become economically feasible. When that happens in 40, 80, 200 years (the variables are too complex to give an undisputed realistic estimate) we may stop extracting the more expensive oil fields entirely because the cost gets too high, so perhaps the real answer is: never. Oil will continue to be the fuel of choice until it becomes too expensive or until a more affordable alternative becomes available. We can already make oil-like fuels, lubricants, etc. from corn, grain, coal and garbage but they are too expensive, so as soon as the price of oil get higher than the cost of processing these resources, companies will stop drilling for and pumping the stuff.

IntellectualCritic's, answer is a good one as far as it goes, but I would just like to add something more. When people try to estimate how much oil we have left (i.e., when it will run out), they are making these estimates based on known reserves (that is, oil that we know is present in the ground). Those that say that we are running out have to ignore the fact that we keep finding more. There were many 20-30 years ago that predicted that we would have run out of oil by now. Obviously we haven't. There are still many places where we can look for more oil (the coastal regions of California, the Gulf of Mexico, and the Caribbean, and the Arctic National Wildlife Reserve in Alaska just to name a few). Nobody really knows how much oil is in any of these regions because environmentalists are doing their best to keep anyone from even looking for the stuff, let alone drill. So, how long until Earth runs out of oil? No one really knows.

According to Islam and holy book of muslims Quran ALLAH the creater of the universe have placed resources (food, oil and all other necesseties ) for whole mankind till the day of judgement.

"According to the World Resources Institute, world proven oil reserves were estimated at 1000 billion barrels in 1995. Since proven reserves are usually less than half the ultimately recoverable reserves, we will assume that about 2000 billion barrels of oil will be able to be recovered and used." If you divide 2000 billion by the consumption rate of 25.3 billion barrels per year, this gives us about 79 more years of oil or until the year 2076 (this was calculated with a starting point of 1997, using statistics from 1995. This number might be slightly different now with the SUV craze that has swept the US since then). Read more about this at: http://www.wou.edu/las/physci/ch371/lecture/oil_reserves/oil1.htm The key is to find RENEWABLE sources of energy. It's really important that we, as a global community, push to develop technology that will reduce and eventually end our need for oil. How we do this without collapsing the global economy is, I think, the major obstacle toward this goal.

Oh - so many ways to answer! A trivial answer is: the Earth will never run out of oil for three reasons. First, even the best Enhanced Oil Recovery techniques (flushing a reservoir with water, carbon dioxide, and/or detergents) don't get it all - perhaps 20% will never be extracted. Second, at some point the price of oil will get so high that we won't be able to afford to burn it! It will be replaced by other technologies (to whatever extent possible) and the remainder will never be extracted. And third, across geological timescales, more is s-l-o-w-l-y being generated. Much of the debate about this comes from misunderstandings about the terminology of resources; specifically "resources" and "reserves", [See http://www.eia.doe.gov/cneaf/coal/reserves/fig2.gif for a visual example, from coal, not oil. I couldn't find a similar diagram for petroleum, but http://www.eia.doe.gov/pub/oil_gas/natural_gas/data_publications/crude_oil_natural_gas_reserves/current/pdf/appg.pdf has ugly tables!] "Resources" are all there is - we generally don't know that number although we can estimate it to one significant figure, and it is a huge number. "Reserves" are the amount that we KNOW to exist ("proven reserves") from drilling, etc. AND that can be extracted, at present, at a profit - a much smaller number. Reserves change as exploration identifies new fields, as consumption drains them, and as the economy and technological advances make them more or less affordable.

It is a good question, better than "Could earth run out of oil". Personally, when I can,t afford oil, that is when I it ran out in my world. All containers are that are drained will one day be empty.

A lot sooner than if we would have paid heed since 1973. It is already getting harder to get the stuff out of the ground. Eventually, all the usable oil will be gone--unless we get to work developing alternate sources of energy. Here are a few suggestions: Get rid of that SUV that gets 18 gallons to the mile and get a bicycle. These use 1/100 the energy to make, and NO fossil fuels to run. And you get fit at the same time. Nuclear energy. We need to develop the technology to use up the radiation of the waste for as long as it is dangerous. Safer plants can always be improved. And, what ever happened to nuclear FUSION? The regulators need to get off the backs of the companies that are trying to work on fusion, NOW. Oil companies that are against innovation need to either shape up or go out of business. Weather power. More wind farms are needed. This would usurp the force of strong winds to supply energy instead of damaging property. Rain, hydroelectric, lightning, and tidal forces can be harnessed as well. If we would develop the technology to usurp a tornado to generate electricity, we save oil as well as reduce the damage from the storm. And there is nothing wrong with solar power. Developing new theories. Using gravity coding or some weird forces from physics may be impractical now, but so was electricity before someone developed the theory and harnessed it. Without all the regulations designed to protect oil companies, I estimate that these would be a good target to develop by the 22nd century. Nuclear (fission and fusion) and weather/geophysical sources will get us there.

The common human is being scammed!! There is enough oil in the Earth to last 1000 years. The limitation and demand is only created by our limited technology in getting the stuff out. Do you really think the Middle East is where the largest oil deposits are? No, it's simply the easiest place to get oil out (under a pile of sand). When technology and machinery catches up, as it has started to do already, we will keep finding and drilling new deposits of oil. Oil companies know this, as does OPEC, but they would never publicly say it. However, if you ask any oil engineer in the Middle East, they will laugh and tell you the truth.