ChevronTexaco on Tuesday raised its long-term assumption for oil prices to $20-$30 a barrel, citing a “structural” change in the global energy market.

The second largest US energy group by revenues is the first of the “super-majors” to explicitly raise its planning price. However, there is widespread recognition in the industry that the oil price used by the companies for internal decision-making has moved away from the long-run average of $20 a barrel.