ABSTRACT
The structure of petroleum has been a topic of some interest for at least five decades when the first theory of petroleum structure was published (Pfeiffer and Saal, 1940). And, the structure of petroleum has become a much more important issue with the increased use of the heavier crude oils. Studies of petroleum structure present indications of the interactions and interrelationships of the constituents. In fact, the implications of petroleum structure as it relates to recovery operations as well to refinery operations have become of significant importance.
