I have emphasised before that the effects of increased fuel prices will eventually come to reduce fuel demands and create incentives for new sources of supply - these reflect supply elasticity effects and cross price elasticity effects. In the US - which purchases one third of the world's petroleum - this seems to have already occurred with the first annual reduction in gasoline demand since 1991. Part of the decrease might be recession-related and part to changing demographics but most of it seems to be a direct effect of higher prices on demand.
Moreover, with higher food prices now a global reality one would expect these price effects to be relatively most intense in developing countries such as China and India which provide the bulk of the extra demands putting pressure on oil prices globally.
I'll stick my neck out with a bold forecast. Fuel prices will decline considerably over the next 12-18 months. Crude prices at present are having problems breeching the $120US per barrel level so how far do I think they will fall. Medium term prices of around $75US per barrel make investment in the provision of additional oil supplies attractive. That's where I expect them to settle. They might go lower than this - break even prices for tar sands are around $33 per barrel while oil from the Gulf states has a break even price of around $38.
The laws of gravity will eventually apply to oil markets - all cartels fail eventually but they die quicker when demands are falling and competitive fuel products look like they will gain significant market share.