#1 - Kashagan - $116 billion
Location: Kazakhstan
Companies: KazMunayGas, Eni, Shell, Exxon, Total, ConocoPhillips, INPEX

Kashagan is one of the largest oil discoveries of the last 40 years, and one of the largest industrial operations currently under development worldwide.

The Soviets had been working in the region, but it was the fall of communism that turned this once-backwater into the world's most expensive energy project.

The field lies in a remote corner of Central Asia, in the northern part of the Caspian Sea, making logistics a challenge. The oil will need to be moved out by a series of interconnecting rail lines, pipelines and ships.

Harsh weather is also a problem. The northern Caspian is frozen for nearly half the year. To successfully tap oil and gas in the ice-choked region, the companies involved are constructing a series of artificial islands from which to work.

Here, housing for workers is being built on one of the islands.

Source: Wood Mackenzie, North Caspian Operating Company
Cost estimates for oil and gas projects are from the energy consultants Wood Mackenzie. They include possible future costs and other data which may not correspond to company esitmates.
- Last updated August 27 2012 02:47 PM ET