The era of easy oil is long past.
The world may not yet be at a peak in overall production, that may be a decade away, but the potential of the vast fields of the Middle East to increase supplies is clearly limited and the oil companies will have to continue pushing the limits of technology to extract oil from increasingly difficult fields.
As you push the limits of technology you run risks. You run risks about cost and you run risks with the environment. BP has been at the frontier of technology and has been drilling deeper below the oceans than any other company, and maybe taking greater risks.
All oil companies seeking unconventional oil, be it below the ocean floor, locked in shale rock, or produced by some untried process, will have to play safe. They will be required to by the authorities and their shareholders. This will not stop the quest for "difficult" oil but it will make all oil more expensive.
For if this disaster has one overriding consequence, it is to bring home to us that this is a finite resource; a vital one, sure, but one that needs to be used – and extracted – with care. And if that happens, there is indeed a silver lining.