The objective of this project is to demonstrate that waterflood sweep efficiency can be improved by restricting high permeability zones through growth of indigenous bacteria so that water is diverted to low permeability zones which have been inefficiently waterflooded. The successful development and nationwide application of the microbial enhanced oil recovery (MEOR) technology could result in recovery of billions of barrels of bypassed oil which are now either unrecoverable or only recoverable at much higher cost.