ABSTRACT
In primary methods of oil recovery, natural expulsive forces drive the oil out of the formation. Recently, new methods of oil recovery have been added to primary and secondary methods, which are called tertiary, improved, or enhanced oil recovery techniques. Although most genetically engineered micro-organisms are being designed for contained facilities like fermenters, some are being examined for their usefulness in the open environment for such purposes as mineral leaching and recovery, oil recovery, and pollution control. Introducing large numbers of genetically engineered micro-organisms into the environment raises questions of possible ecological disruption, and liability if damage occurs to the environment or human health. Neither natural nor genetically engineered micro-organisms are considered useful in this process. In most cases, not enough is known about a well's characteristics to predict the nature of the chemical/crude oil interaction and to forecast the efficiency of oil recovery.
