Bitumen

Bitumen is the heaviest, thickest form of Petroleum. The 2 largest-known sources of bitumen (in Alberta and Venezuela) each contain more petroleum than the entire proven conventional oil reserves of the Persian Gulf. Synthetic crude oil produced from bitumen accounts for about 28% of Canada's total oil production. Compared to conventional oil (obtained from traditional, easily accessible sources), however, synthetic crude from bitumen is expensive and complicated to produce.

The 2 largest-known sources of bitumen (in Alberta and Venezuela) each contain more petroleum than the entire proven conventional oil reserves of the Persian Gulf