Earlier this year, Shell revised its proven oil and gas reserve levels downward by 20 percent, or about 3.9 billion barrels.

Two months ago, the company lowered its estimates of proven oil and gas reserves by about 20 percent, or 3.9 billion barrels.

Shell announced on Jan. 9 that it had overstated its proven oil and gas reserves by 20 percent, or 3.9 billion barrels.

In January, however, the company shocked investors by cutting its estimates for proven oil and gas reserves by 20 percent.

American military occupiers would effectively control the world's second largest proven oil reserves.

The oilfields, which cover a thinly populated area the size of Connecticut, hold 2.1 billion barrels in proven oil and gas reserves.

It has accumulated proven oil of reserves of 4.63 billion tons.

But exploitation of the region's proven oil and gas reserves is not economic at current prices.

The block looks very promising, because it is near a proven oil and gas field.

Another recent success, he said, was an 11 percent increase in Lukoil's proven oil and gas reserves in the last year.