ABSTRACT
Heavy oil and bitumen (the primary component of tar sand) are often defined (loosely and
incorrectly) in terms of API gravity. A more appropriate definition of bitumen, which sets it
apart from heavy oil and conventional petroleum, is based on the definition offered by the
U.S. government as the extremely viscous hydrocarbon which is not recoverable in its natural
state by conventional oil well production methods including currently used enhanced recov-
ery techniques (Chapter 1).
