"The easy oil has already been found and developed", according to one recent analyst. There are reportedly 1,200 billion barrels of proven reserves left, which might be interpreted as being sufficient to last for another 40 years (working on the basis that 1 trillion barrels is enough for 33 years); and since this is about equal to the amount of oil that has been used since the first "black gold" gusher strikes of the 1860's in the U.S., we can conclude that we are at the point of "peak oil", when half is gone but half is left, as an optimist might view the situation. Even accepting these figures baldly, it is obvious that while it took almost a century and a half to get through the first trillion barrels, at current extraction rates we will get through the rest in about a quarter of that time. However, demand for oil is rising inexorably, especially in the developing world (in China and India particularly), and hence that milestone must be moved back accordingly. In detail, however, rising demand is unsustainable on a number of grounds. Production from all the major wells is actually down, and has been falling for the past few years. There is no reason to think that this trend will desist, and meeting even present demand in terms of volume will prove pressing and shortly impossible. The other major issue concerns the quality of the oil, of which we can expect more to be of the "heavy" rather than the "light" kind, which will require more in terms of processing to provide a suitable form for hydrocarbon fuels. The future extraction of crude oil per se, will be a more intensive, difficult and energy expensive undertaking, as increasingly inhospitable resources must be tapped, e.g in the deep-sea. All in all, there is little comfort to be found in the figures on closer inspection.
I have mused previously, that the immediate signs of peak oil are likely to be economic, i.e. prices of goods going up, and it will be drivers of this kind that begin to apply the brakes to demand for oil. It is a messy thought that the countryside and roadsides will become littered with Hummers and indeed all other vehicles that no one can afford to fuel any more. Localised communities may begin to arise around our feet as we are increasingly less able to move further afield. But as I allude, it is the economic drivers that we should watch out for, to gauge how things are going in terms of global fiscal health. Indeed, the international oil giants are in trouble, as oil reserves shrink, taxes and other costs rise, and producing nations (e.g. in the Middle East, Russia and South America) renege on deals which the west particularly are relying upon, or simply nationalise (hang onto) their assets. One solution to these troubles might be massive mergers between companies (or effectively even between nations).
I note that the main holders of oil reserves are Saudi Aramco, PDVSA (Venezuela), Iraqi Oil Ministry and NIOC (Iran) which account for around 700 billion barrels. Interestingly, the major gas holders (forgive the pun) are Gazprom (Russia), Qatar PET and NIOC (Iran), controlling gas reserves to a total of 500 billion barrels of oil equivalent. There is less gas than there is oil, though the quantities are comparable, but these fuels are used for different purposes. Clearly, Iran is very well endowed in both gas and oil, and it will be instructive to see how the economic chess-pieces are deployed on the atlas-board that will decide the new world order.