An ultimate peak in oil production is an inevitable consequence of a finite resource, and the gap will be sharply enlarged when it transpires.

FORBES: Dr Richard Pike (1950-2011) and Peak Oil

With oil becoming a scarcer resource every day, and no chance of plugging that gap through unconventional plays, Hummel thinks investors should move into energy service companies as well.

FORBES: Move up http://i.forbesimg.com t Move down