The problems of utilizing heavy crude oil and natural bitumens centre on their high viscosity which makes them difficult to produce, store, transport, and refine. These factors are reflected in costs. World reserves are substantial, however, perhaps as much as 7 trillion† barrels estimated to represent 0·9 trillion barrels of recoverable oil.
Nearly 2·1 trillion barrels of heavy crude oil, more than 50% of the world's total reserve, are located in Venezuela largely in the Orinoco Oil Belt. About 75% of the natural bitumen, 2·6 trillion barrels, is located in Canada in the Athabasca, Cold Lake, and Peace River areas of Alberta. Most of the estimated undiscovered heavy crude oil in the world, approximately 630 billion barrels, is outside the US and Canada.
Data required to determine the cost of finding natural bitumen and heavy oil are roughly the same as for other mineral commodities. Similarly for recovery costs. The variables are so extensive that dollar amounts have little meaning without qualification.
Recovery depends on depth below surface. Near-surface deposits are recovered by mechanical mining. Deeper deposits must be won by thermal means. Transportation by pipeline is feasible only if the viscosity is lowered by partial upgrading, heating, or by the use of diluents. Part of the high cost of refining results from the major investment required for the large installations that are needed for economic rates of production.